THE RENEWABLE ENERGIES: EXTENT AND TIME OF DEVELOPMENT ESTIMATES OF COST

John O'M.Bockris

ЭНЕРГЕТИКА И ЭКОЛОГИ

г \

ENERGY AND EÜOLOGY

THE RENEWABLE ENERGIES: EXTENT AND TIME OF DEVELOPMENT ESTIMATES OF COST

John O'M. Bockris ^

Member of the International Editorial Board

World Hydrogen Gainesville, FL 32608 Phone: 352-335-3843/352-335-6578, fax: 352-335-6925, e-mail: jbockris@cox.net

Professor, University of Pennsylvania (1953-1972). Distinguished Professor, Texas A&M University (1978-1997).

John O'M. Bockris

Inside a decade, the availability of our conventional fuels will be doubtful. It is already late, then, to consider what sources we should develop. The principal requirement in addition to sufficient availability, at an acceptable cost, is that use of the New Energy no longer involving injection of pollutants, in particular CO2 into the atmosphere. CH4 is a seldom mentioned danger: it comes increasingly with the rising temperature.

WHERE NOT TO LOOK

COAL: Coal is generally rejected as a future energy source mainly because it produces CO2 on being burned. Because many countries, including the USA, Russia, and China have larger amounts of coal, the product from which, electricity, is particularly cheap, the question comes as to whether it would be possible to use coal to take the oxygen off the CO2, venting it, and returning powdered carbon to the mines. Hence, no CO2 into the atmosphere. Alternatively, CO2 from the atmosphere can be reacted with H2 from the solar decomposition of water to form CH3OH. Used as a fuel, it would be CO neutral.

Many processes have been suggested for CO2 sequestration [1]. However, there are daunting difficulties with all published so far [2].

Under consideration for a U. S. patent is the following: A solid electrolyte, e. g., ZrO2Y2O3 or UQOaY,O„ is heated to 1000 °C and the CO2 stream

3 8 2 3 2

brought into contact with it. There should be dissociation at this, — or higher, — temperature. A small pd (4 volts?) applied to the membrane would electro diffuse O- to the atmosphere side of the membrane where the O- would be released as O2. The viability of this subject depends on the cost of the electricity.

Were this acceptable, we would have as much as fifty years worth of coal to use without global warming being affected.

NUCLEAR

The semi knowledgeable citizen usually assumes that "we have plenty of coal" and, — if we have to, — we could go nuclear. Everyone thinks that nuclear wastes are dangerous.

Should we build 1700 more reactors (to supply the whole country with nuclear energy), exhaustion

Статья поступила в редакцию 22.10.2007 г. Ред. per. № 200. The article has entered in publishing office 22.10.2007. Ed. reg. No. 200.

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

of the present known supplies of uranium would come in a generation [3].

The fact that no serious accident has occurred after the one in Chernobyl (Russia) in 1986, supports those who claim that nuclear reactors are safe. However, if we relied on nuclear power as a main source of energy, would imply that, in the USA, on average, several dozen reactors would have to be operating in each state! The problem of the transport and disposition of wastes from so many plants would present a new problem.

A weapon firing at the protective dome over a nuclear reactor would be likely to lead to the spilling of nuclear debris wherever the wind would take it.

The time to build 1800 reactors has been estimated as fifty years (three per month!) [4, 5]. Even the Chinese are building only four per year: we, none.

Cost. The cost of operating an already built nuclear reactor is a few cents per kwh. However, one has to pay heavily to construct the reactor (twelve years), and would also have to pay for its complex, safe, burial after thirty to forty years. When these two costs are taken into account, together with the cost of waste removal, the total costs per kwh of nuclear energy are significantly higher than those for wind or thermal solar (4.5-6 cents kWh-1) [6-9]. The building time (fifty years) is too long if Hub-bert's peak is to be reached before 2037 [10]. Breeder reactors would be more expensive than their fission counter plants. Burying everything to avoid the suspected terrorists would increase costs greatly.

However, published estimates of oil exhaustion refer to extraction of oil found as oil in «pools». There is another source of oil mixed with sand and this is plentiful in Alberta and also in Venezuela. The extraction of oil from «tar sands» is difficult (and has been contemplated for decades). However, some companies in Canada are already producing oil from this source. The eventual problem is having enough (non CO2 producing) fuel to give the heat necessary to distill the oil out of the sand.

For some years, it has been clear that the end of the fossil fuel age would come either because of global warming or fossil fuel exhaustion. Economically, satisfactory extraction of oil from tar sands in America implies that global warming will be the final limit to CO2 and CH4 injection into the atmosphere. (Cf., processes for the use of atmospheric CO2 to make a useable fuel). The concern is that delay in converting our system to renewables will run us into insupportable temperatures and flooding of our coastal areas.

HYDRO RESOURCES

Paid up hydro power (e. g., Niagra Falls), provides the cheapest electricity known.

Hydro power is associated with engineering feats around the world: For example, the Hoover Damn in the USA and the largest hydro plant in the world at Itaipu on the Uruguay-Brazilian border (produces electrical power equivalent to that from 12 nuclear reactors).

However, we will limit description of the development of hydro as a source of power here because the use of US hydro resources is to decrease rather than expand! The reason is environmental.

It might seem that no source of energy could be cleaner than that of natural water falling under gravity. It is not the operation of the plant which leads to environmental restrictions but the disturbance which the construction of a dam, etc., causes.

Thus, the shortened life of fish has been allowed to prevail in the USA over that of humans. Perhaps, the situation may be reconsidered as the cost of energy increases, and its fading even of polluting fossil plants becomes realized.

At present (2007), hydro power provides some 10 % of U.S. energy resources but if the restrictive changes planned are made, it will be only 6 %o.

On the other hand, there are also groups dedicated to the expansion of hydro resources in the USA [11]. Hydro represents, after construction, not only the cheapest but the cleanest. The cost of maintenance and operation is only 0.5 cents/kWh [12, 13].

Opportunities for enterprise here seem great. But it is not only disturbance of the fauna which limits the award of licenses but also competition with other needs for water (irrigation, cooling water for nuclear power plants, etc.).

The average size of a hydro plan in the USA is lamentably small, 30 MW (lifetime fifty to 100 years). However, the trend is to reduce the average size still further and utilize the mini resources (1000 kW and even less) available at more than 5000 sites in the USA. Such small resources have less environmental effect (being natural) than big artificial dams.

Were all the 5000 mini hydro resources each worth 1000 kW, the total contribution of this clean inexhaustible hydro resource would be worth half a dozen nuclear reactors.

Japanese use of hydro power

A far more encouraging attitude toward hydro power exists in Japan than in the USA. The mountainous character of the main Japanese island has for long provided plentiful opportunities for hydro power. 1847 plants are in operation (2006) and 2,732 more unevaluated. Were these latter opportunities developed, Japan would have about one-third of the needed energy from very low cost hydro resources. Development of hydro resources is legally required in Japan. The development includes micro plants of <1000 kW.1

1 Hydro electricity is still cheaper, when paid off, but fraught with legal barriers in the USA, and much more limited in total availability.

Summary

Many more hydro sites could be developed in the USA, particularly small (1000 kW). However, their development is increasingly obstructed by environmental regulations aimed at protecting fish whilst diminishing the cheapest source of energy available.

WIND Introduction

Wind energy development is encouraged because it is the cheapest energy, potentially available on a very large scale. It is not only inexhaustible but, by going seaborne, it can supply large amounts of energy for many countries. Winds at sea move faster than those on shore, — lessened obstruction, — and the energy in wind increases with v3 where v is the average yearly wind velocity. To be sure, seaborne plants are more expensive to construct than those on land because one has to pay for machines to transfer the energy back to shore, but the extra investment in building is compounded by the higher yield per rotor.

There are places in the extreme south (Patagonia, Antarctica)with yearly average wind velocities of 40 mph are known [14]. 120 mph is the speed of gusts accompanying such average wind speeds. But the financial advantage if turbines able to remain secure in such winds should attract research for such generators would produce energy of at least 15 times cheaper than those available in 15 mph average wind speeds, is great.

Futuristic ideas propose mechanisms which would make use of the jet stream and produce energy at less than 1 cent/kWh (competitive with paid off hydro).

Wind turbines

There are two main designs in electricity generation from the wind: horizontal axis and vertical axis (Fig. 1 and 2 [15]). The horizontal axis is more frequently seen (i. e., is cheaper to build) than the vertical.

Does the efficiency of conversion increase with the number of blades? Extra blades in a horizontal axis turbine collect more energy but the expense of

increasing the blade number does not pay for the extra energy.

Seaborne wind generators have to be designed with a low center of gravity to prevent the high gusts blowing them over (Fig. 3 and 4 [16]). A number of smaller rotors are used in the ensemble shown with weighting below.

Fig. 3. Possible design for a large sea-borne generator with individual wind-panels (aluminum frames and sail-cloth) to rotate the central drive-shaft and then rotate themselves to the minimum profile position for rotation direction against the wind [16]. From Environmental Conservation, John O'M. Bockris, No.4, Vol.2, 1975

Fig. 4. Alternative sea-borne generator with a major rotor having a wide radius. A large number of smaller rotors could be used with a motor generator attached to each [16]. From Environmental Conservation, John O'M. Bockris, No. 4, Vol. 2, 1975

International Scientific Journal for Alternative Energy and Ecology № 12(56) 2007

A cone-shaped entry will compress the wind blowing into a turbine mouth, e. g., twice the radius of the opening for the rotors and thus increasing the wind velocity when it reaches the latter. Such a design has not yet been commercialized.

A basic theory of wind power

"Aerogenerators have not hitherto been considered as a massive source of power because: (i) wind is sporadic and unreliable except on a yearly basis; (ii) if strong winds exist, they are in remote areas (e. g., in Alaska), and were therefore formerly of little interest as a power supply; (iii) the equation (Eqn. 1) which connects the dimensions of a rotor to the generation of wind energy is approximate, and examinations of the divergence of actual energy generated versus what the equation predicts have seldom been made.

The "ideal" equation (Eqn. 1) for instantaneous energy (i. e., power) is:

(Equation 1)

per unit area swept by a rotor, where p is the density of the air and v the velocity of the wind. is the kinetic energy of the wind per unit volume and is a hydrodynamic factor for the extraction of energy. However, the equation neglects the effect of rotor-air resistance. The basic empirical equation (Eqn. 2) is:

(Equation 2)

where c is a parameter, generally taken as but falling with an increase in wind velocity. The cube law dependence of power on wind velocity v is noteworthy.

The wind equation requires the mean of the cubes of the instantaneous wind velocities over the year. If the mean of the velocities is cubed, results are 2 to 3 times too small (Bockris, 1975)" [16].

Wind belts

It is important to locate the rotors in areas ("wind belts") in which the average wind speed is maximal. Due to the rotation of the earth, gravity forces air raised by heat over the equator to drop, colder air on various parts of the earth (Fig. 5) [17].

Two main systems are shown in Fig. 5. The southern pink winds, "trade winds," were vital to sailing ships en route from England to Australia. The ships traveled south of the Cape of Good Hope to reach the West to East wind which blew them eastward to Western Australia and onwards, at about 14 knots.

Clearly, the lower the velocity at which winds could be useful, the better. Experience, however, shows that wind speeds below 12 mph are no longer economically attractive. As to the higher speed limit and its practicality, that is not sharply defined. Great advantage is offered by higher winds. However, there are higher winds available, and were they

Fig. 5. World map showing two mid latitude westerly wind belts (shown in dark arrows). The northern belt blows from west to east across North America, the North Atlantic Ocean, Europe, and Asia. The southern belt blows from west to east across the South Pacific Ocean, Chile, Argentina, the South Atlantic Ocean, South Africa, the South Indian Ocean, Southern Australia, and New Zealand. The light arrows in the picture also show two tropical easterly wind belts blowing from east to west on either side of the equator. The northern tropical easterly belt blows across the Pacific Ocean, Southeast Asia, India, the North Indian Ocean, the Arabian Peninsula, Saharan Africa, the Atlantic Ocean, the Caribbean Sea, Southern Mexico, and Central America. The southern belt blows from east to west across Northern Australia, the Indian Ocean, Southern Africa, the South Atlantic Ocean, the middle of South America, and the South Pacific Ocean [17]

usable they would make electricity at attractively low costs. Although at first 40 mph does not seem so much (it is 2.6 times) more than 15 mph, the difficulty is that high average speeds bring with them gusts of much (e. g. five times) higher velocity and it is difficult to build generators to withstand, e. g., 120 mph gusts.

Very high average wind speeds are available in parts of Antarctica and Patagonia. If we achieved engineering rotors to withstand the gusts (120 mph) associated with these winds we would have cheap electrical energy, so cheap that (so long as the cost of constructing the rotors had been paid for) the electricity costs should be less than 2 c/kwh. Were electricity at such low cost available on site, liquefaction of H2 obtainable electrolytically (Cl2 evolution neglected in the barren environment) would be economically possible. After that, tankers to northern countries, bearing the liquid fuel, would open up an interesting major source of energy. These suggestions of a major long-term energy source represent possibilities, and are more than speculations.

The distribution of winds

A picture of the wind belts of the world has been given (Fig. 5). However, it is of interest to identify places where the big winds blow. Both the Department of Energy and the Wind Energy Association publish maps of yearly average wind speeds in most parts of the world and particularly those in North America. The following quotations are from documents published by these organizations [18]. The terminology is explained in Table 1.

Table 1

Wind classes and wind speed

Class 3 (Marginal) 12 mph year average

Class 4 (Satisfactory) 13_mph year average

Class 5 (Good) 14 mph year average

Class 6 (Excellent) 15 and above mph year average

Class 7 (Outstanding) 16 and above mph year average*

* The v3 law makes the difference in wind energy of the outstanding winds as giving more than an 85 %% increase in energy from "outstanding" sources 916 mph) compared with those term satisfactory 913 mph) [18, 18a]

"Alaska is Class 7.

Great Plains (North Dakota) area is Class 5.

Montana hilltops and uplands are Class 4.

Hawaii area has areas of Class 6 but includes Oahu with Class 7 winds."

"Areas that are potentially suitable for wind energy applications (wind power class 3 and above) are dispersed throughout much of the United States. Areas which have useful wind energy resources include: the Great Plains from northwestern Texas and eastern New Mexico northward to Montana, North Dakota, and western Minnesota; the Atlantic coast from North Carolina to Maine; the Pacific coast from Point Conception, California, to Washington; the Texas Gulf coast; the Great Lakes; portions of Alaska, Hawaii, Puerto Rico, the Virgin Islands, and the Pacific Islands; exposed idge crests and mountain summits throughout the Appalachians and the western United States; and specific wind corridors throughout the mountainous western states."

"Exposed coastal areas in the Northeast from Maine to New Jersey and in the Northwest southward to northern California indicate class 4 or higher wind resource. Class 4 or higher wind resources also occur over much of the Great Lakes and coastal areas where prevailing winds (from the strong southwest to northwest sector) have a long, open-water stretch. The Texas coast and Cape Cod in Massachusetts are the seats of coastal wind resources which extend inland a considerable distance [18]."

"Offshore data from Middleton Island indicate class 7 wind power. Shore data such as Cape Spencer, Cape Decision, Cape Hinchinbrook, and North Dutch Islands reflect class 5 or higher power." "Most of the coastlines associated with these areas are heavily wooded, so wind power estimates are very site-specific."

"Interactions between prevailing trade winds and island topography determine the distribution of wind power. On all major islands, trades accelerate over coastal regions, especially at the corners. The best examples are regions of class 6 or higher wind

power on Oahu, Kauai, Molokai, and Hawaii. The rampart-like mountain crests of Oahu enhance prevailing winds to class 6. On other islands, circular mountain shapes and extreme elevations prevent the type of wind acceleration observed, e. g., on the Oahu ranges."

"On Oahu (Honolulu County), the long Koolau mountain rampart and shorter Waianae Range enhance trades to class 6, although the rugged topography, watershed value, and turbulent air flows over these ranges make practical application more difficult. The northeastern (Kahuku) and southeastern (Koko-head) tips of Oahu have areas of class 7 and broad areas of class 3 or higher. A class 3 and 4 area exists at Kaena Point on the island's northwestern tip, and class 3 areas exist along the southern coast west of Honolulu and southeastern coast north of Makapuu Point [18]."

Winds in Antarctica

Winds in Antarctica are caused by heavy cold air located over the Antarctic plateau falling under gravity toward the sea. As the air falls it gathers speed and reaches speeds of more than 300 knots (375 mph) at the coast. Sir Douglas Mawson's journal of his Antarctic expedition contains a graphic description of these terrible storms. At the Pole the air moves quite slowly with top speeds of just 30 knots [19]."

Mawson Station (Australia) [20]

Average wind speed 67 km/h 44 mph

Highest wind speed 320 km/h 198.8 mph

iНе можете найти то, что вам нужно? Попробуйте сервис подбора литературы.

Average wind speeds in most locations in Northern Patagonia are 7.2 to 7.8m/s (0 17mph). In Southern Patagonia (Santa Cruz, Chubut), it is 9 to 11.2 m/s (□ 23mph) [21]." Such winds can be transduced to electricity by modern wind turbines.

Several nations have research stations on Antarctica and the most available energy source is the wind. Winds in Antarctica are particularly dependent on location. Installations for producing electricity from wind energy have been built on Black Island and at the Greenspeace Base, World Park, Antarctica since 1991, although electricity from local winds in parts of Antarctica has been used from earlier times [21].

Storage of wind energy

For individual situations, farms, etc., batteries can be used. Electronic circuitry smooths the varying voltage arising from charges in the wind speed.

However, the present article looks to a time in which winds are used as a major resource to give up to half the clean energy needs of the USA to replace the exhausting fossil fuels. Storage in batteries will

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

hardly do. Even the new electrochemical capacitors which may reach 1 kWh/kg would not have sufficient storage power, e. g., for the storage of wind power to supply electricity to big cities, including energy for transportation.

A possibility is storage of large amounts of electricity in compressed hydrogen (100 ats). The scheme needs development work. Water electrolysis to create hydrogen and oxygen can be carried out at high pressure (no mechanical compressors). However, electrolyzers which actually do this and are able, structurally, to withstand 100 ats pressure, have not yet been constructed.

Were the electrolyzers satisfactorily coupled with effective production from the wind turbines, and storage at ~100 ats achieved, an energy source of great potential would become practical. (The 100 ats, after being used for compression would be used to drive a turbine at the receiver end so that the energy needed for compression would be largely recovered.)

Engineering development work is needed, and government funding is needed for that. What is needed is a building plan and great speed. If built and the gas stored, the hydrogen, — clean, — could be piped to users.

The peak in the world oil production (apart from tar sands) is likely to come 2010-2020. Unfortunately, any new method of obtaining energy, — and wind is the cheapest and the simplest to build, — is going to take more than ten years to build throughout the country, — and suggested resources after the peak are the tar sands, coal, or the use of solar energy to grow plants (1 % efficiency and using more energy to make the alcohol than can be got from it).

There is a new and attractive method for storing electrolytic hydrogen: combine it with atmosphere origined CO2 to form CH3OH, a liquid. If the CO2 is extracted from the atmosphere, then, when burned, it simply replaces the CO2, — it would be a CO2 neutral process. The combination of H2 and CO2 needs a special catalyst but there is much evidence that it does occur.

The handling, storage, and transportation of methanol will be similar to that of gasoline.

The uS position in the development of wind technology

Since the middle 80's the US began to lag behind European Nations (particularly Denmark, Holland and Germany) in the development of wind power (Fig. 6) [23]. However, in 2005, the USA installed more new energy capacity than that of any other country (2,431 MW). The total cultivated wind energy in this country (2006) is equivalent to only about ten nuclear plants [22].

In cases in which yearly average winds above 15 mph are available, the upper limit of wind velocity

1990 1995 2000

GWEC, WorldWatch Fig. 6. From Wind Energy Fact Sheet, American Wind Energy Association, 2001 [23]

which can be used in practice depends on engineering resources. Disasters which have befallen wind generators in the past have been brought about by storm-borne gusts of an intensity unallowed for in the design.

Reports of an extension of the capacity of modern wind generators so that they can operate in winds of 50 mph [24].

Effect of height

Wind increases with height and there has to be a trade off between extra costs of building above the ground and the gain in average wind speed 30 feet above the ground is used in measuring average yearly speeds. The use of mountain regions looks attractive but wind farms are difficult to build there.

Sometimes natural geographic arrangements give helpful situations such as that in which an approaching wind is increased in velocity by being compressed in a geographically natural funnel.

Future of wind energy

At present (2007), European building of wind generators is ahead of that in the USA, though DOE is said to be attempting to have funds for wind included in its budget. It only needs Congress to fund them.

However, if our Congress continues to protect the remaining (polluting) fossil fuels by giving no funds for a massive development of wind energy, one can hope that some of our larger corporations (particularly GE) jump in to put their financial sources into massive and profitable construction in our wind belts.

In 2006, the total installed wind energy is equivalent to about 50 nuclear power plants. That's good in some ways, i. e., some countries, particularly Germany, are getting on with it, but of course, very little in respect to the fact that wind energy so far is only a few percent of the total, although it is the cheapest and most available energy the world over.

Now, some good news is that progress is being made in turbine design. The new turbines are getting 3 to 4 MW's each, older ones, 1 MW or less. This is certainly good news, and the range of convertible wind energy, — until about 2000, 20 mph, is now ranging up toward 50 mph [24a].

This would mean that there is every hope from these new turbines may be able to deal with the 40 mph average winds available in some parts of the Antarctic, and in Patagonia (although there is no news yet as to the sustainability of these turbines in the great gusts of wind, which accompany average wind energies of 40-50 mph.

As far as cost are concerned, we have quoted above the costs issued by the Department of Energy in 2006, but lower costs of wind energy are already in practice in some parts of the United States. For example, in Lake Bentwood, MN, established prices are 3.2 cents/kWh using turbines of only 1 MW have been available for some years.

Of course the idea of wind generators in the jet stream is as yet on paper only, but nevertheless with the pressure that would come upon wind energy directly the realization of the exhaustion of fossil fuels comes to the public, it may well be that such wind generators can be a reality within the next ten years.

With all these things, the major requirement is SPEED. In the present Administration there is not a glimmer of the knowledge of the catastrophe of fuel exhaustion before substitutes have been built2.

Finally we must deal with the storage of the wind energy and German organizations, which are the dominant ones in the world at the moment (2007) for wind energy, claim [24b] that at least 50 %o of the total capacity of the wind generator must be in storage to be able to give a level supply.

Here, as in so many cases with the new energies, is the chance for new engineering, and again, the problem is that there may no longer be enough time left before fossil fuel exhaustion.

Cost of wind energy

Discussions of wind energy in the 2006 literature are usually aimed at small scale wind farms or even individual users. The problem with them is that they mix up the (large) amortization costs of construction with the (small) costs of operating and servicing the equipment. The amortization costs are usually spread out over the expected life of the plant (twenty to thirty years) so that the very low costs of wind energy, free of repayment for the costs of construction, are seldom brought out. (Though 2006 forecasts of wind energy even by 2010 are quoted

2 There is a frightening analogue of this on Easter Island. According to the history made out, the inhabitants waited until the population was too much for the resources whereupon they make new canoes from the available wood and took off to explore for new islands. But there came a time when there was no more wood...

at 3.5 cents/kWh, — well below the 2007 prices of gasoline in the USA.)

Range of practical wind energies now

With wind turbine technology, commercially available in the USA, the acceptable wind velocities range from 12-15mph, ^ 2, is therefore a measure of the practical range of wind energy for use under 2003 conditions and acceptable to the US Department of Energy in 2007.

This small range of practical wind speeds3 explains why wind costs of wind energy are often stated without defining the wind speed. In 2006, the range of total costs (construction and operating) quoted by DOE, are 4-6 cents/kWh but the national agency associated with wind energy predicts 3 and even 2 cents/kWh within a decade. No other source, except paid up hydro, could compete with these costs, half the costs of polluting fossil fuel-based electricity.

Among published costs of recent times are those of some wind farms of 0.51 MW. The dependence of cost on wind speed, experimentally established as follows [23]:

— 16 mph = 4.8 cents/kWh;

— 18 mph = 3-6 cents/kWh;

— 21 mph = 2-6 cents/kWh.

and thus do show a sizable effect of wind velocity in present practice. Reports from non-governmental sources in the USA extend acceptable wind speeds to much higher values and lower costs.

One tends to look back to Churchill's description of the defeat of the Nazi Air Force by the Royal Air Force, in the Battle of Britain in World War II (1941), "Never has so much been owed by so many to so few." Applied to the present situation of the lack of the massive government financed development of the available, clean wind energy in the USA, one might write. "Never has so much been left unused by so few, when needed by so many."

SOLAR

There are three methods of conversion from the sun to electricity.

Photovoltaics

This is the most well known of the three methods that to which the major government funding has been given. The photovoltaic cell consists of two pieces of silicon (or other semi conductor). One of these is a so-called p type semi conductor plenty of holes and the other an n type. When light falls upon this "couple," electrons are stimulated from the valency band and those which absorb enough energy to overcome the energy gap, enter

3 The lowest mph, 12, is only marginally worth while economically. 15 mph is a much less definite limit and is exceeded by some available generators. But, remember, 15 mph average winds may contain gusts of much higher speeds.

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

the conduction band. In the ideal case, having traveled over the energy gap (a forbidden range of energy for electrons), the electrons travel to the interface of the semi conductor with a metal contact and proceed to meet a "load" in an outer circuit. A potential drop is thus created (its ideal maximum is the value of the energy gap), and is in practice quite small, for example, 0.6 V for Si at open circuit. The available potential decreases on passage of current. Photovoltaic cells in series can be made to give practical total voltages. The volts can also be transformed to higher values electronically. Absorption is related sharply to the light energy (Fig. 7) [25].

There are many photovoltaic materials apart from silicon (Fig. 7). However, the advantage of silicon is the combination of a reasonably suitable energy gap4 with fairly good economics in constructing silicon from easily available silica, - basically common sand.

The optimal value in respect to energy gaps is 1.7 eV (Fig. 8) [27]. Silicon has an energy gap of 1.1 eV so its energy gap is lower than the ideal value (increasing deactivation of phot-stimulated electrons). However, the easy availability of SiO2 and the corresponding relatively low cost of the pure semi conductor grade silicon combines with a fairly good energy gap to give the most used photovoltaic material.

The attraction of low cost has been taken a further step in Swiss work (M. Grgtzel) by utilizing TiO2 as the semiconductor, not Si. This material can be made into a semi conductor grade more cheaply than silicon but its energy gaps is higher (Eg = 3.0 eV) [27] and hence the number of solar electrons available for electricity production upon exposing it to solar light is less than that using Si. To counter this disadvantage, Grgtzel and his collaborators (1999) have tried to absorb a greater amount of light than would be calculated from the large energy gap of TiO2. One method relies on using serrated surfaces. Light, when striking a semi conductor surface is both absorbed and reflected. In a serrated surface, some of the initially reflected light has a chance to strike the surface again, a calculable fraction being absorbed. This may be made to occur several times leading to a significantly enhanced absorption of light.

One of the questions in the development of photovoltaics is the question as to whether to use expensive single crystal silicon or cheaper poly-crystals. Single crystals give a higher efficiency of absorption of light. The photovoltaic efficiency of

4 If the energy gap is too large, only a small fraction of solar photons will have the energy to climb over it. But if the energy gaps is too small, a depressing fraction of the electrons stimulated from the valence band into the conduction band will fall back into the valance band, whilst on the way to the metal contact and thus become inactive.

Fig. 7. Optical absorption constant a as a function of photo energy hv (eV). John OM. Bockris, Energy: The Solar-Hydrogen Alternative, John Wiley and Co., New York, 1975, P. 98 [25]

\ 20

¡i , „ Си. InP 2о

Gi эА Сс S JTe Al Sb s е G íaP С< dS

G е

) < > с

) с

i i > ( X 1 1 i > с i с i

Eg, eV

Fig. 8. Conversion efficiency and energy gap. J. O'M.Bockris, A. K. Reddy, Modern Electrochemistry, Vol IIB, Plenum, New York, 2000 [27]

polycrystalline silicon has been improved in recent years. At present it is ~15 % (commercially available), 18 %% soon available.

Small samples of silicon in the laboratory have given up to 30 % efficiency of conversion of light to electricity, but the same material, on being built up into a big practical cell gives only half that efficiency. This is a difficulty which will be improved upon in the next few years: it needs highly trained workers and great cleanliness which can be more easily realized in small university laboratories, than in large spaces need in factory production.

We will not describe obtaining energy on a big scale from practical modern photovoltaics further in

this paper because the cost of 18 %o efficient photovoltaic cells is at present several times in excess of the costs of the two alternative methods of converting solar light to electricity available in 2007 and reviewed below. However, there is little doubt that solar farms consisting of banks of photovoltaic cells will be part of the practical picture, e. g., before, say, 2050. Like much else, it depends on the degree of federal research grants.

Solar thermal

Conceptually, the Solar Thermal method of collecting solar energy and converting it to electricity is the easiest pathway to solar-originated electricity. In one version, mirrors (as many as 1000) are focused to reflect solar light upon a relatively small central object (e. g., a boiler), raised on a tower, containing water, which the solar light converts to steam, used to drive generators under the tower.

Renewable energy technologies, with the exception of hydro generators, are being improved and this means that the cost of solar electricity per kwh. To state the cost of building such systems now (9-13 cents/kWh) is misleading. The massive building phase of solar energy which must surely come is not yet government backed. A practical use of such systems might be expected from around 2040 but again all advances causing cost reductions depends on research and this has to be paid for. Solar energy organizations are small. They look for research money to the government. But the funding agencies sometimes receive advice as to where to put the money and on what from the politically influenced White House.

In the meantime, individual companies will be researching to lower cost per kwh. In early 2007, some of the predictions from DOE are:

1) "To build solar thermal now would give electricity at 9-13 cents/kWh" during the pay back phase [28].

2) "A twenty-year projection gives us (in 2006), 4-6 cents/kWh" for solar thermal [29].

In 2006, the building cost would be around $3900/kW [30].

Other figures for the cost of solar thermal electricity are quoted in the 2006 literature. Smaller plants (30 MW) give predicted costs of, e. g., 12 cents/kWh whilst the plant is being paid for over twenty years [31].

On the whole the quoted figures for solar thermal are higher than one would expect from the simplicity of the plant. The difficulty with these figures is that there is a lowering of future cost predicted on improved engineering and an increase in apparent cost due to inflation. The latter change can be taken out if one knows the inflation rate and this has been done here: All costs stated are for 2006.

Knowing more about solar thermal

The solar-thermal technology is at present the most used way of converting solar energy to electricity (steam turbines). About half of the users of solar energy in 2006 use this method [32].

Were we to use a patch of the Southern USA 100 miles by 100 miles and fill it with solar thermal apparatus, we could have not only all the electricity but also all the other energy needs, now supplied by burning polluting oil.

The cost of solar thermal varies significantly with its location. In Southern Europe and North Africa, solar radiation is intense enough to make export of solar electricity (at about 10 cents/kWh) economically attractive.

A comparison of a future photovoltaic and solar thermal show the latter to be cheaper in latitudes' 30-50. At present, solar thermal plants are commercially available up to 200 MW. They could begin to supplant dirty fossil fuel plants immediately.

The rising cost of fossil fuels in their exhaustion phase will increase the competitive advantage of solar thermal and by 2020, a reasonable prediction is 5 cents/kWh during the pay back period and 1-2 cents/kWh (2006) for operation and insurance after the plant has been paid for by income from the plant5.

There are two ways of arranging solar thermal conversion. The more obvious is the power tower (Fig. 9a, b), but the parabolic trough technology (Fig. 10a, b) is an alternative. Of course, it has to be paid for but the operating costs with the trough have dropped (2006) to ~2 cents/kWh.

Waste heat from solar thermal is being used for solar desalination in North Africa and the Middle East. In the USA, California possesses some plants which are using molten salts for energy storage with solar thermal.

High voltage transmission lines have made it economic to transfer power in the form of electric currents up to 1500 miles. 1000 mile lines are needed in India and China. Larger distances may justify the energy losses by electrolysis of water to hydrogen and the reconversion to electricity at the end, e. g., a 2000 mile transfer in hydrogen at 100 ats, the work of pressurizing being recaptured at the receiver and when the pressure is made to work a turbine, then produces electricity.

Costs of wind energy in California for solar thermal electricity during the period in which the apparatus is being paid for, in 2006, run at

5 These costs involve the amortization of the plant over a time of as little as five years followed by (small) operation costs. In a 10 cent/kWh plant, the fraction used for operating the plant might be 2 cents/kwh and that is what the cost will be (constant 2006) for, say, the thirty years after the plant has been paid off. Of course, such costs are far less than the 2007 price of gasoline in the USA.

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

Table 2

specific examples of low pay back time

Hydro power Twelve months

iНе можете найти то, что вам нужно? Попробуйте сервис подбора литературы.

Wind power Six months

Solar Thermal in Morocco Five months

Polycrystalline photovoltaic Four years

OTEC (Estimated) Five years

Fig. 9a. Schematic of a power tower. Image adapted from Energy Efficiency Renewable Energy Network [33]

Fig. 9b. Solar Two, power tower. Image courtesy of NREL's Photographic Information Exchange [34]

Its basis is the (~20 °C) temperature difference between the solar heated tropical sea surface and the cold water found 1000 m below the sea surface.

Obtaining electricity from temperature gradients of the type mentioned is based on the following process. On a platform floating on a tropical ocean there is placed a container of, e. g., liquid ammonia, a low boiling point liquid, which can be maintained liquid at room temperature by means of pressure.

Concentrator

Fig. 10a. Schematic of a parabolic trough concentrator. Image adapted from Energy Efficiency Renewable Energy Network [35]

Fig. 10b. Trough concentrator system at the Australian National University, which is designed to incorporate photovoltaic power generation or water heating and steam production. (Image courtesy of the Centre for Sustainable Energy Systems, Australian National University [36]

10-12 cents/kWh 4-6 cents are predicted by 2016. Operating costs (i. e., after only five years in which income from the plant would be used to pay the construction costs) are in the region of 3 cents/kWh. Production costs should drop to 6 cents/kWh by 2020 (2006). The short pay back time makes the operating costs (for fifty years at 3 cents/kWh, 2006) more important than the production costs (Ungeheuer, loc.cit) [37].

The short pay back time (Table 2 [38]) is one of the attractions for solar thermal compared the much longer period with photovoltaics. In some sunny regions of the world solar thermal may even be economically preferable to wind.

OCEAN THERMAL ENERGY CONVERSION (OTEC)

This third method for converting solar energy to electricity was first suggested "in 1881... by a French physicist, Arsene d'Arsonval" [39].

The warm sea on the surface is then used to boil the liquid ammonia and the (relatively) hot vapor drives a turbogenerator. If electricity is what is required, it is transferred to shore by cable, but in a mobile OTEC plant the electricity can be made to create electricity and make NH3 which can be collected by a depot ship, transferred to shore and the ammonia converted to hydrogen.

Now, to complete the circuit, the hot vapor, after passage thru and driving the turbine comes into a container containing tubes through which circulates the cold water, pumped up from low level through the 1000 m pipe. When the warm vapor of the NH3 contacts the cold pipes, it condenses once more and can be pumped back into the hot zone whereupon it evaporates and completes the cycle by driving the turbine, once more.

The thermal efficiency of the OTEC process is low, around 4 %. However, there is much cost-free surface warm sea and much cold seas underneath it

and the process will run itself, with pumps needed only to take the cold water from the depth and pump it as described [39].

The OTEC process is more complex than either photovoltaics or solar thermal. However, it gives two substantial advantages. It is independent of the usual night and bad weather losses which assail the two other solar methods (effectively a four times advantage). In addition it produces a large supply of fresh water from saline which may be used as drinking water and for some forms of marine culture. (It is bacteria free.)

Cost of OTEC

Small OTEC plants (e. g., 1 MW) are being built around the world right now (2007). Thirty year life times are assumed in calculation of cost.

OTEC electricity at 2006 from a big plant during the payoff stage would cost 7-9 cents/kWh. Building an OTEC plant would cost $3000-6000/kW.

Two methods of building OTEC plants

OTEC can also be run without the working fluid liquid ammonia. One uses the evaporation of water at low pressure to create the pressure to drive the turbine. Done in this way, OTEC can also be a major source of converting sea water to (much needed) fresh water, as well as a different kind6 of method of converting solar energy to electricity.

vapor condenses on contact with the cold pipes and can be pumped back into the warm zone at 22 °C, whereupon the liquid evaporates and its vapor drives the turbine.

But, let us look at another way of operating an OTEC plant (open cycle, Fig. 12) [41]. Instead of ammonia, warm surface water itself is the working fluid. It can be vaporized by inducing low pressure in a compartment and the vapor from the boiling water is used to drive the turbine. (This gives the substantial advantage that the process produces desalinated sea water as a cost-valuable byproduct on a very big scale, a major contribution to sea water desalination.)

NonWarm condensable seawAler En pscs

I 1

desalinated Oesallnatetí

wáler water

vapor vapor

(unaaluratcd) (SJluratad)

Cold sea water discharge lo sea

□eaeration • j Vacuum __

(optional) ; 1 chamber

1 : Hash

: evaporator

í ; Non- 1 Warm

condensable seawaler

gases discharge

ta sea

J.

Tu "tjD ^^^ gentrato'

Dcsallnalcd Condenser—-*- wiaier (optional)

Cold «imM In

Fig. 12. Schematic of Open-Cycle OTEC System. Open cycle OTEC Schematic- Ocean Thermal Energy Conversion: Possible Applications in Circum Pacific Island Nations, Alicia Altagracia Aponte, http://www.poweringtherim.org/ casestudies/alicia.html [41]

Warm Discharge

water in water to sea

»Ming Working t

fluid fluid I

vapor vapor

Evaporator i lurpt>'. —..» Condenser generator

Discharge water to sea

Working fluid pressurizer (boiler feed pump)

Cold water In

Working fluid

Working fluid condensate

Fig. 11. Schematic of closed-cycle OTEC system. Closed cycle OTEC schematic-ocean thermal energy conversion: Possible applications in circum pacific island nations, Alicia Altagracia Aponte, http://www.poweringtherim.org/casestudies/alicia. html [40]

In the method (Fig. 11, closed cycle) [40], the working fluid is liquid ammonia. Brought under pressure into contact with 20-22 °C available on the surface, the ammonia boils and drives a turbine. After passing through the turbine in the entry state at about 22 °C, the ammonia is brought back to the liquid state by introducing the gaseous (post turbine) ammonia into a chamber containing pipes through which passes cold water (4-6 °C) pumped up through the 1000 m long pipe from the depth through the long tube. The ammonia

6 The 4 %o efficiency looks different when one recalls that the plant operates four times longer per 24 hours than other solar conversion plants.

Calculation shows that OTEC becomes economically attractive when the price of oil rises above $40 per barrel. In October 2007, it is $67 per barrel, heading upwards.

In considering the net economics of OTEC, the process may also be used to support low temperature aquatic agriculture. The cold water is free of pathogens, thereby making it a product (along with byproduct fresh water) to be valued in estimating the overall economics of an OTEC plant.

Locations for OTEC

There are several possible locations for an OTEC plant. The traditional one is that of a floating platform carrying the turbine and electrolysis apparatus, with pumps needed to move the warm and cold water. A mobile platform enables the plant to graze around until it finds the warmest patch of surface water. A design life of only twenty years is usually assumed in discussion of design.

There are many situations which could profit from the presence of an OTEC plant now. It is suitable for islands needing energy and drinking water. Hydrogen as a clean fuel (and significantly valuable fresh water) can be off loaded from an OTEC plant ship. The economics of OTEC must be regarded in terms of the length of the pay back time: only five years. After the plant has been paid for by sale of its product, the running costs are quite low: 6-8 cents and this would be lowered by

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

the sale of desalinated water, including the amortization. Operating costs (the only costs after five years) will be less than half this figure. The capital cost is high at $9000/kW but this has to be seen in terms of income not only from the sale of electricity but also of fresh water, a surprisingly short pay back time.

Limitations of OTEC plants

The main limitation in a full-sized OTEC plant is the amount of water used to operate it. It is comparable to the flow of a medium size river!

The pay back time is important for all renewa-bles. According to Schott, (Udo Ungeheuer, Chairman of Schott, Inc., December 19, 2006) [41, 42].

TIDAL ENERGY

Readers should note that it is just important to assume the differences between hydro and tidal. Hydro power arises from differences in gravity and the flow of liquids through waterfalls, some of which are very considerable and correspond to several nuclear power stations. Tidal energy is really one of the unreasearched aspects of energy conversion and if it were exploited, it would be a very great help.

Some use of tides to obtain energy was made before 1000AD. The essential characteristic is a sufficiently big difference between high and low tides. The difference varies greatly from place to place. Tidal differences as low as 4 m (12 feet) can be used economically for energy production. Among the best locations is in Western Australia, e. g., near Broome (13 m) [43].

Outstanding locations seen as favorable for the development are exemplified in table 3 [44].

On the other hand, some of these locations, (those in table 3 would be equivalent to more than a

Table 3

some larger tidal power schemes under consideration around the world

Country Location Tidal height (m) Power (thousands of MW'S)

Argentina San Jose 5.9 6.8

Australia Cobequin 12.4 5.3

Canada Cumberland 10.9 1.4

Shepody 10.0 1.8

India Cambey 6.8 7.0

UK Severn 15.0 8.6

US Knich Arm 7.5 2.9

Turnequin Mezen 7.5 9.1 6.5 15

Russia Tuger Penzhmskaya Bay — 7.0 50.0

dozen nuclear plants) have not yet been developed, partly because the (large) expense of building a tidal station repels private investors and partly because some of the best locations for big tidal energies are far from populations which need their energy. For organizations which borrow capital needed to pay the building costs, a paid off tidal plant will yield electricity at low costs for fifty- one hundred years. A collection of locations at present seen as fruitful are listed in Table 3 and this is a minimum list because, in selecting them, a factor has been taken into account which may be dropped in future planning. I refer to the distance between the location of the tidal plant and the population center which needs the energy. In the past the IR drop in the electricity transmitting cables has made distances of more than 500 miles between the tidal station and its receiver cities, too far. However, the increased potential (e. g., 100 kV) which are being used for transmission has reduced the I in the IR drop so that longer distances for transmission lines have becomes a lesser burden. Conversion of the electricity generated at the tidal source to hydrogen, low-cost transmission of the hydrogen through pipes at high pressure, and reconversion to electricity by means of fuel cells, may diminish the penalty of long distance ( sending hydrogen through pipes in low cost), although one has to allow for energy losses suffered in electrolysis and fuel cell reconversion to electricity. Recovery of the compression work by allowing the gas at high pressure to drive turbines at the receiver end helps the net cost.

Although tides are regular and predictable, generation of electricity is greater during outflow condition than during in flow. There may be conditions whereby storage of tidal energy and use of the stored energy to smooth out the difference in inflow and outflow rates can be useful.

These introductory words lead to an energy source which, — if greater distance between the source and user site can be accepted, — could lead to the development of as yet undeveloped and undeveloped tidal power sites in Africa, Russia, and South America. This could make unnecessary many hundreds of expensive nuclear plants. Creation of artificial "basins" to store the inflowing tide would be low cost.

Origin of tidal power

This is the gravitational tug between the moon and the earth. The high tides occur when the location on earth falls underneath the moon. The moon's tug pulls the water underneath it "up" several tens of feet7.

7 The Gulf Stream is related to such an interaction of the earth with the moon when the latter is over the equator. The sea is drawn up and falls down when the moon has passed by. Some of the fallen water constitutes the Gulf Stream.

Although the range of tidal differences regarded as useful lies between 12 and 45 feet, the Bay of Fundy in Nova Scotia has a tidal differences up to 60 ft.

How tides can give massive amounts of energy

The first method, and the most developed, requires a location where the tidal difference is at least 4 m, preferably much more. At a high tide, the available water is trapped in a basin. The gravitational energy thus trapped is made to drive turbines on outflow. Inflow is also of use, though it is slower.

Another method involves the generation of electricity from tidal currents. Turbines are put in the path of a natural neck between the sea and the basin. Such a method involves lower building costs than that involving basins.

Suitable tides are found in most countries although astonishingly, few have been developed. The countries in which the best undeveloped sites exist are in Russia, followed by Australia and the UK (Table 3) [43].

iНе можете найти то, что вам нужно? Попробуйте сервис подбора литературы.

Ebb generation

At high tides, the gates are closed and stay that way until the receding tide has dropped to a level which, when water is allowed to flow out of the basin, passes through turbines at a desired rate.

Flood generation

When the basin nears empty, the turbines can be run in the reverse direction and produce electricity during the filling of the basin. This is called "Flood generation".

Flood generation of electricity is less effective than Ebb generation. Thus, the volume of water flowing in and filling the basin is less in volume per unit time than that reached during ebb flow.

The low rate during flood flow can be increased by driving the turbines so that they help the rate of inflow of water. The energy lost by this speedier method is then recovered when the extra water flowed in, flows out.

Intermittency

The difference of the rate of ebb and flood has been explained. In practice, not only is there a greater production of electricity during ebb condition but other delays mean that in practice only six to twelve hours are production times in a day. Thus, although tidal energies are praised for their regularity, they do not produce steadily in the 24 hours of the day, (Cf., OTEC 24 hours' production), although this could be contrived by storing excess energy during the ebb condition, and using it to smooth out flood flow.

Tidal plants at present in operation

In France, a tidal plant at La Rance on the Normandy Coast has been in operation steadily

since 1968. In Canada, Annapolis Royal in Nova Scotia there is a plant operating at 20 MW. In China, a "large plant" is under construction (2007) at Jiangyin. The UK government is committed to replace a large coal burning, polluting plant by a clean tidal plant.

However, much of the development in the future are proposed in countries where plants can be built in areas far from population and therefore probably free from legal obstructions.

Tidal mapping from space [45]

Blue areas are where the water is at a lower level than the average. Seas are lifted up to 45 feet by the moon's tug. Red areas are high. The white areas separate higher and lower seas for a given area at a defined local time.

A lost opportunity

Tides at Broome in Western Australia are the highest in Australia. The tidal power potentially available in NW Australia could supply the entire energy needs of the Australia Continent. (Just as the development of the solar resources of Australia converted, e. g., to methanol could supply that country's energy needs and indeed, by export, many of the needs of China and Japan8,9.) Here is an excellent opportunity to consider the economics of pipeline transport of energy (NW TO SE) in hydrogen versus conversion of the hydrogen with atmosphere-derived CO2 and methanol.

Cost

Cost of building tidal stations must vary greatly with the location. To speak of the cost of tidal electricity without description of the location (and tidal height) cannot be done. Tidal power shares with other renewable energies, the characteristic of greatly falling prices after the newly operating plant has paid off its building costs from its operating income. The cost of tidal energy thereafter is small, far less than he cost of electricity from fossil fuels.

Tidal plants last more than fifty years so that the plant may be paid off (five to ten years) long before the end of its life. This is the origin of the stunning difference between the cost (1-2 cents/kWh) of electricity from the paid off hydro plants in Canada compared with the energy from, e. g., oil and natural gas (5-10 cents/ kWh).

Thus, to answer the question "what is the cost of tidal power" must be done plant by plant. What plant in which country and when? Cost of money? Time to pay off? Cost of fuel before and after the plant is paid off?

8 Transport of the potential excess Australian solar energy to Asia could be done by conversion to megacycle frequency a. c. and beaming it to a power relay satellite, stationary over the equator, which would then beam the energy down to countries requiring it.

9 "Seldom has so little been built for so many by so few."

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

Cost will be around 10-12 cents/kWh until the loan is paid off. After that the plant will continue to produce electricity at low cost, say, 1-2 cent/kWh (2006) for a further, say, a hundred years.

BIOFUELS

"Biofuels" are bio-materials which are now contemplated as grown specifically for the purpose of providing useful heat upon combustion. Hawaii and Maine are where agriculture is being used to produce fuels instead of food. This activity is being embraced both because new fuels from plants are seen as necessary in view of the approach of Hub-bert's Peak, but also because many local farmers need paying jobs.

This early group of fuel-growing farmers has generally cared mainly for the combustibility of what they grow. They do not seem to pay attention to the reduction of Greenhouse gases, one of the objectives of some researches.

Alcohol from solar-grown plants

Some companies are applying with the concept of producing a convenient final fuel product (ethanol is the general goal) and they all have as their model the scheme which has for long been in use in Brazil to drive a fraction of the Brazilian car population by a process which produces no net CO210.

I went to observe this operation in Rio de Janeiro in 1981. By 1986 about three-fourth of all new cars in Brazil were built to be fueled by solar-produced alcohol. [46] There was no doubt which cars used ethanol because one could smell the fuel as the car drove by11.

The Brazilian scheme originates from the well known photochemical growth of sugar cane and then the secondary spontaneous fermentation of the sugar cane to form ethanol.

The photochemical growth equation for plants, grass, trees, etc., is:

(Equation 3)

The CH2O is the hypothetical monomer of the polymer representing various kinds of green plants.

Seeing the reaction of (3), brazilian chemists assumed that it represents, in a simplified form, the photochemical formation of sugar. Upon the

10 They also have the backing of the U.S. President who appears to have enthusiasm sufficient to override the analyses made by Pimentel and Farrel. The great oil companies are setting up institutes to study how to make CO2 - neutral alcohol. The attraction is that were a CO2 neutral process found with light absorption of

10 %, (at present it is 1 %) the oil companies could continue to fuel the country without having to build a new infrastructure.

11 Although the percent of ethanol driven cars in Brazil in 1986

was already 76 %, the fact that it is now only about 1 % greater and that none of the other countries (even the next door Argentina) have joined the thirty-year old Brazilian scheme, asks why that is.

resulting alcohol being used as a fuel, CO2 would be produced. However, the Brazilians assumed the photochemical formation reaction (would use up that CO2 from the atmosphere) and the final burning would replace the CO2 removed from the atmosphere on the way (see above equation) to form the sugar. They assumed the net reactions after burning of alcohol would thus be CO2 neutral. This use of solar energy involved, at first, a higher cost than imported gasoline, though the Brazilian solar method can be made to pay if the residual material is burned as a fuel.

One advantage of the Brazilian development is that it leads toward familiar features for the motorist: gasoline a liquid, — alcohol a liquid, — the public might hardly notice the difference (except for the odor). At first (in the USA) the gasoline would be mixed with the alcohol, with development eventually toward a possible pure alcohol.

Unfortunately, the Brazilian scheme cannot be applied directly in the USA for more than one-third of our need because the amount of highly insolated land free for agriculture (needed for the growth of the plants) is much less per unit of population than that available in Brazil. Direct conversion of solar energy is electricity and can be made (up to 30 % efficiency) on any open space, e. g., deserts, relatively cheaply so that the need for the 1 % method is not clear.

This realization came in 2005 and to substitute for it, — on the way to the convenient alcohol (little new infrastructure needed), — alcohol from corn is being made12.

Solar growth of corn as a substitute for sugar

The alcohol from corn scheme has been faced with criticism by chemistry faculty in US universities, though greeted enthusiastically by directors of a number of small corn growing companies. For example, the well-known Chemist David Pimentel of Cornel University [47, 48] has concluded that processes needed to bring the corn finally to alcohol would lead to the co-production of more Greenhouse gases than the corresponding burning of gasoline! Pimentel's publications show that taking corn to alcohol would cost more energy than could be got back by using it as a fuel Alex Farrell, of the University of California at Berkeley, argues that if the wastes created in synthesizing ethanol via corn were used to feed cattle, corn as a path to ethanol would save a mere 13 % of the Greenhouse materials [49]. But the complete elimination of CO2 injection into the atmosphere (i. e., 100 %o) is needed.

Other points against the use of solar derived corn to make alcohol have been made, — the removal of agriculturally useful land would endanger the

12 However, methanol irom atmosphere derived CO2-solar derived

H2 could be CO2 neutral.

U.S. food supply. Pesticides and fertilizer would be needed and both would add to cost (and to air pollution when burned).

Other attempts to create CO2 neutral ethanol (2006)

Significantly, the Chinese have decided on the growth of cassava [50] as a route to ethanol. I have not been able to find the chemical pathways for the reactions in taking the solar derived cassava to alcohol, so that the degree to which it might give rise to an automotive fuel without CO2 cannot yet be stated. (For example, does the synthesis of cassava obey the photochemical law entirely? Do any fossil fuels have to be burned to complete the alcohol formation?)

Two U.S. companies are aiming at the large scale production of ethanol and one, methanol. However, they use enzymes. This would add to the complaints about and cost of, the processes which will have to face the low cost of wind —based electricity/hydrogen (costs significantly less than 2006 gasoline in the USA).

It is too early to extract estimates of costs for synthetic ethanol, CO2 neutral. It seems unlikely that these, — in some cases complex, — chemical syntheses of ethanol are likely to meet price competition from the renewable methods described in t his paper13. Further, CO2 is not associated with electricity production from renewables, — the likely way cars will be driven when consciousness of heat terror becomes more well known.

Thus, the competing process to plant-based ethanol does not have to be a gas, but is likely to be electricity stored in the new electrochemical condensers having storage capacities greater than that of lithium batteries, and rechargeable in seconds. Large scale energy from renewables could be stored in atmosphere derived methanol and transported as with gasoline.

wave energy

Wave energy is the wind-origined kinetic energy of waves.

Salter, of the University of Edinburgh, was the first to publicize a method for transducing wave energy [51]. He devised boats which maximized their pitching motion. These "Salter's Ducks," as they were called, contained mobile weights which moved up and down with the motion of the boat. The weights passed through a magnetic field and produced thereby electric currents. The ducks were placed near to the shore where waves increase as the sea depth is reduced. With fleets

13 All the renewables provide cheap and super cheap electricity after production from the plant has paid for itself. The biofuels become available after growing starting materials, passing it through at least two chemical processes, after which electricity production can begin.

of ducks and a suitable wave producing climate, town-sized amounts of electricity could perhaps be produced.

However, although stormy seas are required for the wave method of obtaining energy, a sea can be too rough. Some earlier methods for transducing wave energy have fallen to stormy seas.

Recently, a "Land-Installed-Marine-Powered Energy Transformer" (LIMPET) has been devised in a joint effort between the University of Belfast and a UK company, "Wavegen" (Langston) [52, 53]. The essence of LIMPET is a water column, built into the rocks. The water column is designed to move up and down in the column with the ebb and flow of the waves, the water columns being confined in a pipe, open at the bottom and closed at the top. Therefore, the air in the top part of the column is compressed as the wave strikes the pipe, fills it, causing air to be compressed, and this in turn works a turbine. It is desirable that the turbine should receive momentum from the pulses both when the waves are incoming and when they are receding. A Wells turbine, can function in both conditions. In moderately good waves, 20 kW/m is produced. A 500 kW unit (25 m) supplies the energy for 250 homes.

Wave generated electricity is being sold in Scotland, in Washington State, and in Oregon. Electricity produced from the Wells turbine is being sold at ~8 cents/kWh and may come down in price as use of the method spreads.

There are other methods for harnessing wave energy, for example, waves are made to exert pressure on piezo-electric systems, thus creating electricity directly [54].

There is no government supported program for wave energy in the USA. In Australia there is a vigorous development involving blades of adjustable pitch. The energy of the waves is focused to a narrow area (Tom Dean, 2001) [55].

Wave energy seems to be a suitable small scale method for islands (e. g., the Orknies) where the wave potential is generally high. Although wave energy is unlikely to grow to be compared with the wind approach, its usefulness in remote areas has already been proven.

GEOTHERMAL

When we stand on the "solid earth," we stand, in fact, upon solid surface layer, about 40 miles thick. Underneath that is 4000 miles to the center of our sphere, and the rest of the way is full of hot and sometimes molten silicate rock under increasing pressure as we move toward the center. The temperature is about 900-1000 °C at the bottom of the thin layer which shields us from the ball of heat below.

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

But the heat below the solid layer on which we live has ways of reaching the surface (volcanos) and then there are geysers underground, rivers, etc. The rivers are hotter than surface rivers, in fact, some of them are boiling, — steam, — and some are under pressure, — giving very hot steam.

These outbreaks of steam are what we mean by geothermal heat. It is a reliable source of energy, not likely to exhaust. At present it is little developed as a practical heat source in the USA because the major part of the cost comes at the building stage, and we have been living very well on cheap oil. Once the initial flow of income has paid of the construction loan, the geothermal site will go on giving its owner income for a very long time. How long? We can refer, e. g., to OLD FAITHFUL, the geyser which perks up and shoots steam and water into the surroundings in Yosemite Park. "As of August 2002, the average interval between spirts was 94 min." It has been observed to provide the behavior described for more than 300 years [56].

Each geothermal station, — because of its varied size and surroundings, — may vary over a large range in building cost. Hence, each site will provide energy at a different initial cost, so that the question, "How much does geothermal energy cost?" can only be answered by a range of prices, giving electricity from (paid for) plants for as low as 0.5 cents/ kWh, — but the construction cost may make it close to 10 cents until the sale of the energy produced has paid for the construction of the plant.

Where, then, are these (geothermal) gifts from Nature in the USA? The ones already put into use are in California. However, there are undeveloped sites in the Dakotas and in Texas. New Zealand is the country in which geothermal energy forms a significant part of the National Energy Supply (about 12 0%).

The fact that many geothermal sites have been recognized for hundreds of years, and that little attempt to develop them has been made, depends on the high construction cost and perhaps on the lack of recognition of the low cost power which results. Of course, as fossil fuels exhaust in the 21st Century, the high price of developing a geothermal plant will be seen as more worthwhile paying to reach the low cost of electricity which such a paid off plant provides.

The geothermal stations so far developed in the USA taken together are worth only about four nuclear power stations. Our present knowledge of them (many more may be potentially available near the surface and need exploration) is insufficient to judge their long-term potential. (But Cf., Hot Rock Geothermal, below).

Economics

Once a geothermal site has been discovered, there is exploration to be done before a reliable

estimate can be made as to what its development will cost.

The figure as quoted in the 2006 literature for "the cost of geothermal energy" expressed varies from 2-7 cents/kWh. This wide range is due to the feature named above. Each site costs a substantially different amount from the others to build.

As to the pay back time, this will also cover a range, though some figures of this from sunny climes, e.g. North Africa, can be astonishingly low (Table 4) [56a].

As to the lifetime of a geothermal plant, this will be "long," minimum of one hundred years. The source will, of course, last longer than one hundred years but one may find a wearing out of parts in some plants; or there may be new technology to exploit, e.g., large scale thermo-electric couples for transfer of the heat to electricity.

Environmental

Geothermal plants are reliably inexhaustible, and negligible in respect to CO2 after the plant has been built. In some sites, 2-3 % SO2 is present in the initial production.

Geothermal sources are cheaper to engineer when compared with large hydro sources needing dams.

Hot rock geothermal

There are numerous ideas for a long term energy supply from the earth, because the maximum supply rate of normal oil from the earth is near to its maximum (Fig. 13) [57].

Some ideas for future energy being discussed are "far out," i. e., they look feasible in a hundred-year future (e.g., building photovoltaic systems orbiting the sun then beaming the electricity to earth). However, some ideas do seem feasible now, as far as paper studies tell us. Why are these not at least tried out on small scale experiments?

This may apply to an idea presented here. It is to all intents and purposes a renewable energy source fo its exhaustion will parallel that of the earth inner heat, though will exhaust. It has been subjected to a US government systems analysis [58, 59, 60].

The idea is called HOT ROCK GEOTHERMAL. The concept is: 40 miles of solid rock exist downwards to the junction of the hot rock of the outer layer and the semi-molten interior at about 950 °C where the solid rock becomes the magma, - semisolid silicates.

The boiling point of water, — at room pressures, — is 100 °C. To find a good steam making temperature we will have to have about 150 °C. Mines in South Africa go down more than 5 miles but after that it would need reliable and expensive cooling equipment to protect life. However, one does not need miners to get steam. Once one has steam, one has to get it to the surface before it condenses, — the rest is classical engineering.

Table 4

2007 estimates for data on renewables (2006)

SOURCE COST: CENTS/KWH IN SITUATION BEFORE CONSTRUCTION PAID FOR COST $/KW TO CONSTRUCT* TIME TO BUILD THIS SOURCE (ESTIMATED) COMMENTS

HYDRO 6 $1,700 to $2,300 (EIA-DOE $1485) NOT APPLICABLE LIMITED INSUFFICIENT SOURCES

WIND 4-6 (FALLING) $790 - $,2600 (EIA-DOE $1194) 25 YEARS (THROUGHOUT COUNTRY) EXCELLENT PROJECTIONS

SOLAR (pv) 15 (FALLING) $7,800 (EIA-DOE $4105) 15 YEARS (FROM 2025) PRESENT COST TOO HIGH

SOLAR (THERMAL) 10 $3,900 (EIA-DOE $2521) 20 YEARS (THROUGHOUT COUNTRY) PRESENT USE PRACTICAL

SOLAR (OTEC)** 12 (INCLUDES DESALINATION, ETC.) $3000 to $12,000 (DEPENDING ON THE SIZE OF THE PLANT BUILT) 10 YEARS PER PLANT EXPENSIVE TO BUILD -ONLY SOLAR PLANTS OPERATING 24 HOURS PER DAY

BIOFUELS 6 (CO2 NEUTRAL) (projected) $1000 (EIA-DOE $1833) 10 YEARS IF SUFFICIENT LAND BUT ONLY USEFUL IF NO NET CO2

iНе можете найти то, что вам нужно? Попробуйте сервис подбора литературы.

GEOTHERMAL 4 VARIABLE NOT APPLICABLE LONG TERM

HOT ROCK GEOTHERMAL (ESTIMATED) 12 $1500-$2500 (EIA-DOE $1615) ESTIMATED FIVE-TEN YEARS EFFECTIVELY INEXHAUSTIBLE ENERGY SOURCE (SYSTEMS ANALYSIS ONLY)

TIDAL 10 $1,000 DEPENDS ON SITE, FIVE -TEN YEARS SOME OUTSTANDING SITES CITED FOR DEVELOPMENT (CF. TABLE 3) WOULD BE EQUIVALENT TO TEN -FIFTY NUCLEAR PLANTS.

WAVE 15 $1000 NOT APPLICABLE TECHNIQUES DEVELOPING

* EIA-DOE figures for the cost $per KW to construct are projected costs for the year 2010 in $2004. ** Includes price built up by co-production of desalinated water and marine culture products. [56a, 57]

Will this be the origin of a source of energy buildible at any sea level location world wide? Could it become a source of energy analogous to that of the sun, from which, — according to present geology, — it appears to have had its origin?

The first difficulty is cooling of the hot rock cavity as a result of repeated contact between it and the injected cold water used in creating a flow of steam. One may bore a cavity less than 10 miles deep and attain 150 °C. One is going to drop cold water into this hole for several years and this is going to take heat out of it in the form of steam.

Calculation suggests the surface temperature of the sides of a cavity bored downwards and inundated repeatedly with cold water can stay above 100o C for around five years, whereafter, injecting cold water will no longer produce steam. If one then stops pouring in the cold water, the sides of the cavity then gradually heats up again, i. e., heat flows from the

surrounding hot rock so in a few years the hole is a usable long-term source of steam again. In the meantime one will have been getting energy from a sister cavity, opened up sufficiently far from the first one to be unaffected by its draining of heat from its surroundings.

Another difficulty comes with an apparent advantage. When cold water contacts a sufficiently hot surface, there will be cracking of the rock and the cavity will spread. This appears to constitute an advantage for the transfer of an increased amount of the heat in the rock to inflowing water. However, the cracking will produce a rain of stones, and rock fragments which will be thrown up with the rising steam. The turbines receiving the steam must be protected from these fragments. At present there is no method suggested for this but such a difficulty should not part us from a potential energy source of solar magnitude.

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

1900 1950 2000 2050 2100 2150

production year

Fig. 13. Laherrure's Oil Production Forecast. 1930-2150. Reprinted with permission from Correspondence with Bill Horvath, a correspondence specialist of the U.S. Department of Energy on March 29, 2001. It is authored by the Energy Information Administration and entitle "Long-term World Oil Supply" [57]

Hot rock geothermal and what we know of it in 2007, looks good. We need a reworking of the earlier analyses; some exploratory experiments, and a small plant working for ten years [61].

In earlier work done on this method, I estimated how long it would take for the operation of sufficient hot-rock energy stations to give all the energy we need from this source alone to cool the earth's interior 1o C. The answer was about 106 years. This justifies calling hot rock geothermal an inexhaustible energy source.

AUSTRALIAN INITIATIVE

In spite of the availability of solar sources on a grand scale in the deserts of Australia and those of the tides of its N.W., Australia has shown abnormal initiative in seeking new sources of energy (Cf. the solar chimney) [62].

MAJOR DIFFERENCES IN COST ACCOUNTING FOR RENEWABLE AND NON RENEWABLE FORMS OF ENERGY

It has been made clear that the cost of renewables comes mostly in the construction of the plants which thereafter use the "free" energies of nature.

In the non renewables the plants to capture the materials and modify them for fuels (refining oil to gasoline, for example), are simple and use well known technology. The cost of producing the usable fuel from the raw materials takes place as the source is being taken from the ground. Thus, when one says that the pump price of gasoline is $3 per gallon, ($6 to $8 in Europe) the pump price corresponds nearly all to the cost of production from the source at that time, together with whatever tax the government finds its subjects willing to accept. The "construction costs" are small and are paid for

when non-renewable material is burned and the heat energy of the combustion is sold for, e. g., fueling transports.

In the case of renewables, e. g., hydro energy, one builds the plant, creates the dam, one has to have considerable loan power, the product of which buys many decades of energy. The plant pays back what may be between one or ten (etc.) years. After the income from the plant has paid off the construction cost, the plant for renewables goes on producing energy for many decades, sometimes for a century, at very low cost.

This difference in costing makes it easy to start the exploitation of a non-renewable source which will last a few decades but can be exploitable with little entrance fee (e.g., no dams to build, etc.). Renewables are expensive to build and cheap to run.

ENVIRONMENTAL EFFECTS OF RENEWABLES

The renewable resources will not involve hidden land acquisition costs, no air or water contamina-tion14, no killing of animals except for collisions in dams.

The use of renewables also involves a huge (but invisible) cost saving, eventually born by the taxpayers because of the elimination of environmental damage, after the plant has been set up and started to operate. The fossil fuel burning stage has already caused immense damage, ranging from health damage to humans ("smogitis') to damage (e.g. the Parthenon in Athens) to buildings.

LIMITATIONS OF COST ESTIMATES

Inflation: When no 2006 or 2007 costs were available, I have adjusted the value to 2006$ assuming inflation averages 4 %% per year.

There is a general difficulty in making the prices of the various methods comparable. Thus, some (e. g., wind sources) refer to a market of small shareholders and even individuals because that was the market at the time of writing. In these cases the seller stretches mortgage payments over the life of the plant (e. g., thirty-forty years for wind); more generally, the time to pay off the construction costs is simply determined by the financial output of the plant, which is used in the early years to pay off the construction costs. After the plant is paid off, the operating costs of renewable energy plants are small and the electricity from them is much cheaper than the cost of electricity from nonrenewables.

Lastly, there may be only a few plants built and each represents such different costs due to the ef-

14 But there may be damage to air and land in the construction phase. In the Assuan damn in Egypt, for example, villages had to be removed, — the land they had occupied was then flooded, etc.

fect of change of location that the values given for constructing costs of a plant for that method may be of little value in judging the support needed for the next plant of that kind.

The mean value of the price given is 9 cents/ kWh (2006). If wind energy were available at 5 cents/kWh, why develop more expensive sources? The answer here is not so simple. In what part of the world is this cheaper method available? What of its durability in weather extremes? How long do plants last compared with the time for more expensive methods? Are there limitations of materials which would make it of limited use to build, say, two plants of this type?

Extracting energy from nonrenewables depends only on refining, the cost of operation occupied a somewhat higher fraction of the total cost because the material which gives energy was being supplied "as we went along." In renewables, the fuel cost (e. g., of solar) is zero: it is the plant which costs, — there will always be "free" hydro, solar, wind, tides, etc., but how much does it cost to collect it and bring it to a usable form, — either electricity or, where the need to overcome the sporadicity of renewables leads to the need for storage, — in methanol!

renewable sources OF ENERGY: a brief summary

Several times during the writing of this article I have been reminded of Churchill's famous summary of one of the critical turning points of World War II, — the defeat of Gn;ring's Nazi Air Force by the Royal Air Force mainly over London in 1941. "NEVER WAS SO MUCH OWED BY SO MANY TO SO FEW." As the size, low cost, and availability of the renewable energies became clearer, it seemed to me that the present course of our Energy Aims is completely distorted, for we are trying to drag the last dregs of the fossil fuels forth and use them although their production of CO2 is constantly warming our atmosphere.

All that the US voting public knows about is all is that they might have to risk the dangers of Nuclear Energy and retreat to converting dirty coal to oil. They have all heard of "solar energy" and hope it might do something but worry what will happen in the winter (and at night?). The same with wind, — for it does not always blow. The fact that our populations, — it may be a little better in Germany and Northern Europe, — still think of coal and nuclear power and seems not to know any of the renewables is someone's fault, - whose?

So that is the TRUTH about energy sources called "renewables"? Well, there may be many more things to say about them than what is said here. But a very simple version is this: The fuels we now rely upon, — oil and its products, — are in the last

stage of development. It's true that by taking the large resources of oily sands which exist in Canada and Venezuela, we could go on for some decades still but it would be with a very heavy price tag, — which would include temperatures which would drive us out of our homes to live underground and eventually (two generations more) give up the will to live here anymore. Meanwhile, (by the end of the Century?) the water from the ice from Iceland, Greenland, and Antarctica would have invaded our shorelines and made the coastal cities uninhabitable.

And why? The reason is the ignorance of the population that vast, effectively inexhaustible energy sources are available to us AND ENTIRELY CLEAN. Whose fault is it that we have allowed the situation to go on so far whilst we in the USA remain preoccupied by an impossible war, — using the little fossil energy we still have to try to win an incomprehensible attack against a billion Muslims.

Well, I have said enough to lift the curtain a bit, — and show you the dark scene. Now, let the sky brighten. All the energy we shall ever need is all here. All we have to do is to insist that our Congressmen WAKE UP and make sure that the main way our money is being spent is to build our future energy supply, — inexhaustible and clean.

Here, then, is my micro-summary of the re-newables.

1). Firstly, if we take them all together, there is plenty of energy for the present world population. I think it will be best presented in the form of electricity and atmosphere-based methanol.

2). Wind is the cheapest one which we could have in plenty. It could be cheaper than the gas we are using now but in a decade or so according to the American Wind Energy Association the price in 2006 could be halved and MAYBE in a further decade (but this statements is based on a newly minted idea only: 1 cent/kWh).

3). Solar energy will certainly be part of our future but the sort of solar energy collection, — photovoltaic cells, — which people who have read a bit about our new energy sources think, — pho-tovoltaics, — is much more expensive than alternative ways of getting electricity from wind. One is the simplest and the cheapest. It's called solar thermal. The other seems at first more expensive (about twice as expensive as solar thermal) but it works 24 hours/day versus six to seven hours for the solar thermal, so twice as expensive for four times as much may mean it is the cheapest. But proceed with caution here because only little plants have been as yet built and of course we would have to try it out with a couple of major plants and run them for a few years before we would go in for a massive building program.

4). Then, there is the latest idea: BIOFUELS. The Brazilians have been using them for thirty

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

years. In their version you grow sugar cane (it takes much of sun-favored agricultural land). The sugar cane ferments to alcohol, — and that is the fuel. Now, we cannot do it because insolated space we have is being used for food production. Corn can be grown with the aid of solar energy (1 % efficiency only) and after some further chemical processes you get alcohol. When I heard of this I was repelled by the use of a 1 % process when were are solar methods which give you electricity directly at, — say, — 15 %o on up to 30 %o. But other chemists have come forward from Cornell and from the University of California. One has presented energy balance for the corn growing,

- and finds you have to put more energy in than you would get out even using a fuel cell. The other shows you produce a lot of CO2 in producing the alcohol and of course CO2 productions is a main reason for changing from our fossil fuels so using precious solar energy.

5). Next, taking the geothermal energies as an energy source would not make sense, because one is dependent on certain parts of the earth,

— geysers, — where the energy inside the earth bursts forth. I think we should not bother too much about that one because there is not much of it but there is a related source, — not yet tried out in practice, — called hot rock geothermal where you bore cavities in the earth sufficiently deep so that when you put cold water in, - steam comes out. I think much of this one, — it could be comparable with wind and solar in the immensity of what could be available.

6). We must not forget HYDRO. If you have a mountainous country like Japan, — you can use this source, — basically waterfalls, — and even get one-third of your energy from it. This would not do here but up in Canada there are copious hydro plants and many have been going strong for fifty years or more. Paid off they supply the cheapest energy of all, — 1 to 2 cents/kWh. But of course, the supply is limited.

7). Then, there are the tides. Tides of more than 4 m are economically useful. It is a great pity that so few of the attractive sites, — some of them worth a dozen nuclear plants have not yet been developed. Again, once the building costs are paid off, the energy is very cheap.

8). Lastly, waves. I think that the hydro plants are the oldest methods of getting energy in the form of electricity right back. But using waves are the newest. One of the two methods being sold now gives electricity directly. To say the obvious, this method does best in northerly climes and islands without other renewable energy resources. It could give us much energy (Cf., our northwest coast).

So, you see, we have a plentitude of natural inexhaustible energy. But this does not mean we are safe and have no problem with global warming and no running out of oil. There's plenty there but most of that has been known for twenty years. So why is it not being developed?

I think Churchill's famous saying when the Germans withdrew and decided not to try to invade England is very much applicable to our energy situation now: NEVER HAS SO MUCH BEEN LEFT UNDEVELOPED ACCORDING TO THE DICTATES OF SO FEW, — WHILST NEEDED BY SO MANY.

References

1. Wikipedia, CO2 Sequestration, October 2007, http://en.wikipedia.org/wiki/Co2_sequestration.

2. John O'M. Bockris. Energy Options, Australian/New Zealand Book Co. Sydney Australia,

1980. PP. 61, 62, 65, 68

3. The Institute of Science in Society, ISIS Press Release 22/06/06, We Need A Change in Energy

Policy As Well As in Government, by Rt. Hon. Michael Meacher MP, http://www.i-sis.org.uk/ energyPol.php.

4. NRC — Regulator of Nuclear Safety (NUREG/ BR-0164, Rev. 4), Last revised Monday, April 04,

2005, http://www.nrc.gov/reading-rm/doc-col-lections/nuregs/brochures/br0164/r4/, Office of Public Affairs, U.S. Nuclear Regulatory Commission, Washington, D.C.

5. "The Hype About Hydrogen" Joseph Romm.

Island Press. 2004.

6. Symposium" section of Insight on the News on 27 August 2001. Hunter and Amory Lovins's

original text.

7. http://archive.greenpeace.org/comms/no.nukes/ nenstcc.html, Nuclear Energy, No Solution to

Climate Change, A background paper.

8. Grubb M., Vigotti R. Renewable Energy Strategies for Europe, Volume II. Royal Inst. of International Affairs, Energy and Environment Program.

Earthscan Publ'ns. 1997. ISBN 1 85383 284 7. 9. Pearce D. W., Bann C., Georgiou E. The Social Cost of Fuel Cycles. Report to the Department of Trade and Industry, HMSO publications. 1992.

ISBN 011-4142-882. 10. http://www.hubbertpeak.com/summary.htm, updated 2003 December 22. 11. Idaho National Laboratory. http://hydropower. inel.gov/

12. Connor A. M., Frentfort J. E., Rhinehart B. E. US Hydro Power Resource Assessment. US Dept of Energy, Contact DE Ac-07-9411)13223. December 1998.

13. Ciocci L. C. Barriers Affecting New Hydro Power. May 10, 2005, Washington D.C. 14. Gustav Grob, Switzerland, 2007.

16. John O'M. Bockris. Environmental Conserva-

tion. 1975. No. 4, Vol. 2.

17. http://meted.ucar.edu/hurrican/strike/text/

htc_desc.htm.

18. Wind Energy Resource Atlas. http://rredc.

nrel.gov/wind/pubs/atlas/chp2.html. 18a. Wind Energy Resource Atlas. http://rredc. nrel.gov/wind/pubs/atlas/chp3.html

19. http://www.ast.leeds.ac.uk/haverah/spase-

man/faq.shtml.

20. http://globe-net.ca/market_reports/index. cfm?ID_Report=762.

21. Wind Power in Antarctica — Case Histories of the North Wind HR3 Wind Turbine, Clint (Jito) Coleman, Cold Regions Engineering Proceedings

of the 6th International Specialty Conference. February 26-28. 1991. P. 768.

22. U.S. Department of Energy. Energy Efficiency and Renewable Energy, Wind and Hydropower Technologies Program. http://www1.eere.energy.gov/

windandhydro.

23. Wind Energy Fact Sheet, American Wind Energy Association, 2001.

24. Heinberg R. The Party's Over. New Society

Publishers. 2005. Gabriola Island. 24a. Heinberg R. The Party's Over. New Society

Publications. 2006. P. 154. 24b. Heinberg R. The Party's Over. New Society

Publications. 2006. P. 156. 25. John O'M. Bockris. Energy: The Solar-Hydrogen Alternative. John Wiley and Co. N. Y. 1975. P. 98.

26. Renewable Energy Access. 02/11/2006. http://www.renewableenergyaccess.com/rea/ news/story?id=43336. 27. J.O'M. Bockris, Reddy A. K. Modern Electrochemistry. Vol IIB. Plenum. N. Y. 2000. 28. Renewable Energy Access. 02/11/2006, http://www.renewableenergyaccess.com/rea/ news/story?id=43336. 29. White S. Paper on solar thermal plant technology. http://www.us.schott.com/ newsfiles/20061110004007_SCHOTT_US_Solar_

Thermal__White_Paper.pdf.

iНе можете найти то, что вам нужно? Попробуйте сервис подбора литературы.

30. Renewable Energy Access. 02/11/2006, http://www.renewableenergyaccess.com/rea/ news/story?id=43336. 31. White S. Paper on solar thermal plant technology. http://www.us.schott.com/ newsfiles/20061110004007_SCHOTT_US_Solar_ Thermal__White_Paper.pdf.

32. Conversations with several DOE experts. 2007.

33. High Temperature Solar Thermal http://www. rise.org.au/info/Tech/hightemp/index.html.

34. High Temperature Solar Thermal http://www. rise.org.au/info/Tech/hightemp/index.html.

35. High Temperature Solar Thermal http://www. rise.org.au/info/Tech/hightemp/index.html.

36. High Temperature Solar Thermal http://www. rise.org.au/info/Tech/hightemp/index.html.

37. White S. Paper on solar thermal plant technology". Page 3. http://www.us.schott.com/ newsfiles/20061110004007_SCHOTT_US_Solar_ _Thermal_White_Paper.pdf. 38. White S. Specific Examples of Pay Back Time. Paper on solar thermal plant technology. http://www.us.schott.com/ newsfiles/20061110004007_SCHOTT_US_Solar_ Thermal_ _White_Paper.pdf.

39. Startt J. M. OTEC - BEORSE April 1980. http://shamcher.wordpress.com/2005/12/28/otec-

beorse-article.

40. Closed cycle OTEC Schematic-Ocean Thermal Energy Conversion: Possible Applications in Circum Pacific Island Nations, Alicia Altagracia Aponte. http://www.poweringtherim.org/cases-

tudies/alicia.html. 41. Open cycle OTEC Schematic- Ocean Thermal

Energy Conversion: Possible Applications in Circum Pacific Island Nations, Alicia Altagracia Aponte. http://www.poweringtherim.org/cases-tudies/alicia.html. 42. White S. Paper on solar thermal plant technology". http://www.us.schott.com/ newsfiles/20061110004007_SCHOTT_US_Solar_ Thermal_ _White_Paper.pdf.

43. Some larger tidal power schemes under consideration around the world. http://en.wikipedia.org/ /

wiki/Tidal_power. October 2007.

44. Electricity for Biomass. State Planning Office, pub. in "An Examination of The Costs of

Maine's Energy Policy" Maine Energy Institute. 1994.

45. NASA's Goddard Space Flight Center. http://

svs.gsfc.nasa.gov/stories/topex.

46. Ogenis Magno Brilhante. Brazil's Alcohol Programme: From an Attempt to Reduce Oil Dependence in the Seventies to the Green Arguments of the Nineties // Journal of Environmental Planning and Management. Routledge. Part of the Taylor & Francis Group. Vol. 40. No. 4. July 1,

1997. P. 435-449. 47. Cornell University. Alternative Fuels. Fuel Cells. Energy Technology. Petroleum. Nuclear Energy. Agriculture and Food. Ethanol And Biodiesel From Crops Not Worth The Energy // Science Daily, Cornell University, ITHACA, N.Y., July 6, 2005.

48. Pimentel D., Tad W. Patzek report // Natural Resources Research Vol. 14:1. P. 65-76. 49. CORN ETHANOL MAY NOT BE THE ANSWER TO OUR ENERGY WOES. The Osgood File. Charles Osgood on the CBS Radio Network.

International Scientific Journal for Alternative Energy and Ecology № 12 (56) 2007

December 28, 2006. 50. http://en.wikipedia.org/wiki/Wave_power. 51. Gordon Feller. WIND, WAVES & TIDES. Economically Viable Energy from the World's Oceans. August 9, 2003. http://ecoworld.com/Home/arti-cles2.cfm?TID=334. 52. #1 Realities of Wave Technology; #2 Islay Limpet Project Monitoring Final Report; #3 Islay Limpet Wave Power Plant; #4 Islay Limpet Wave Power Plant-Research into Further Development; #5 Islay Limpet Wave Power Plant-Research into Further Development (Supplement); #6 Dynamic Response of a Variable Pitch Wells Turbine; #7 EPCC/Wavgen CFX Users Conference CFD Simulation of the Wells Turbine; #8 The Construction, Commissioning & Operation of the LIMPET Wave Energy Collector, Wavegen, 13a Harbour Road, Inverness IV1 1SY, Scotland, http://www.wavegen.co.uk/research_papers.htm.

53. Technology Solutions, Wave Power Goes Commercial. Environmental Science and Technology // American Chemical Society. 2001. Vol. 35, Issue 3.

P. 80A-81A.

54. Piezo Electric Systems. Eneco. Salt Lake City.

Utah. 2007.

55. Wave Power in The USA. Permitting and Ju-risdictional Issues. E21 Global EPRI DOE NREL

008-US. Bonnie Ram (Energetics) 12/21/2004.

56. http://www.yellowstone-natl-park.com/old-

faithful.htm. 56a. Bent Sorensen. Renewable Energy. 3rd Edition. 2004. Elsevier. Amsterdam.

57. Correspondence with Bill Horvath, a correspondence specialist of the U.S. Department of

Energy on March 29, 2001. It is authored by the Energy Information Administration and entitle Long-term World Oil Supply D0E/ID-10743, March, 2000. 58. Center for Energy Efficiency and Renewable Energy (CEERT). Geothermal Power. Accessed August 15, 2005. http://www.ceert.org/ip/geo-thermal.html. 59. National Renewable Energy Laboratory (NREL) for U.S. Department of Energy (DOE) (September 1998). Geothermal Heat Pumps. D0E/G0-10098-652. Accessed August 15, 2005. http://www.eere.energy.gov/consumerinfo/ factsheets/geo_heatpumps.html. 60. U. S. DOE. EERE. Geothermal Technologies Program (August 2004). Direct Use. DOE/GO-102004-1957. Accessed August 31, 2005. http:// www.nrel. gov / docs/fy04osti/36316. pdf. 61. DOE/ID-10743, March 2000. 62. Australian Solar Tower Project. 2006. Annual Report. http://www.enviromission.com.au/ project/project.htm.

THE RENEWABLE ENERGIES: EXTENT AND TIME OF DEVELOPMENT ESTIMATES OF COST Текст научной статьи по специальности «Строительство и архитектура»

Похожие темы научных работ по строительству и архитектуре , автор научной работы — John O'M.Bockris

Текст научной работы на тему «THE RENEWABLE ENERGIES: EXTENT AND TIME OF DEVELOPMENT ESTIMATES OF COST»