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10ИННОВАЦИОННЫЕ РЕШЕНИЯ В АЛЬТЕРНАТИВНОЙ ЭНЕРГЕТИКЕ И ЭКОЛОГИИ
INNOVATIVE SOLUTIONS IN ALTERNATIVE ENERGY AND ECOLOGY
Статья поступила в редакцию 06.10.2011. Ред. рег. № 1126 The article has entered in publishing office 06.10.11. Ed. reg. No. 1126
УДК 621.311.24
СОВМЕСТНЫЕ НАУЧНЫЕ ИССЛЕДОВАНИЯ РОССИЙСКИХ И ГЕРМАНСКИХ УЧЕНЫХ В ОБЛАСТИ ВОЗОБНОВЛЯЕМЫХ ИСТОЧНИКОВ ЭНЕРГИИ
С. Ветцель, Е. Соломин
Компания ВЕРТИКАЛЬ-ЕВРОПА Ребенвег 16, 76756, Белльхайм, Германия Тел.: 0721 95588-14, факс: 95588-44, e-mail: vertical.europa@googlemail.com
Заключение совета рецензентов: 16.10.11 Заключение совета экспертов: 20.10.11 Принято к публикации: 25.10.11
Статья описывает успехи в области возобновляемых источников энергии в Германии и совместные достижения российских и германских ученых Южно-Уральского государственного университета, ООО «ГРЦ-Вертикаль» и Компании ВЕРТИКАЛЬ-ЕВРОПА в разработке технологии возобновляемых источников энергии.
Ключевые слова: ветроэнергетика, солнечная энергетика, возобновляемые источники.
JOINT SCIENTIFIC RESEARCH OF RUSSIAN AND GERMAN SCIENTISTS
IN RENEWABLE ENERGY
S. Wetzel, E. Solomin
VERTICAL-EUROPA Company Rebenweg 16, 76756, Bellheim, Germany Tel.: 0721 95588-14, fax: 95588-44, e-mail: vertical.europa@googlemail.com
Referred: 16.10.11 Expertise: 20.10.11 Accepted: 25.10.11
The article describes the progress of Renewable Energy in Germany and mutual achievements of Russian and German scientists of South Ural State University, SRC-Vertical, Ltd. and VERTICAL-EUROPA COMPANY in the development of renewable energy technologies.
Keywords: wind power, solar power, renewable energy sources.
The part of electricity produced from renewable energy in Germany has increased from 6.3 percent of the national generating in 2000 to about 17 percent in 2010. In 2010, investments 26 billion euros were made in German renewable energies sector. According to official figures, about 370,000 people in Germany were employed in the renewable energy sector in 2010, especially in small and medium sized companies. This is an increase of about 8 percent compared to 2009 (around 339,500 jobs), and over twice the number of jobs in 2004 (160,500). About two-thirds of these jobs are attributed to the Renewable Energy Sources Act. Germany is the world's first major renewable-energy economy. In 2010 nearly 17% (more than 100 Terra-Watt-hours (TWh)) of Germany's electricity supply (603 TWh) was produced from renewable energy sources, more than the 2010 contribution of gas fired power plants.
Renewable electricity in 2010 was 101.7 TW h including wind power 36.5 TWh, biomass and bio waste 33.5 TWh, hydropower 19.7 TWh and photovoltaic (PV) solar power 12.0 TWh.
Since the passage of the Directive on Electricity Production from Renewable Energy Sources in 1997, Germany and the other states of the European Union have been working towards a target of 12% renewable electricity by 2010. Germany passed this target early in 2007 when the renewable energy share in electricity consumption in Germany reached 14%. In September 2010 the German Government announced the following new aggressive energy targets:
- Renewable electricity - 35% by 2020 and 80% by 2050;
- Renewable energy - 18% by 2020, 30% by 2030, and 60% by 2050;
International Scientific Journal for Alternative Energy and Ecology № 11 (103) 2011
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- Energy efficiency - Cutting the national electrical consumption 50% below 2008 levels by 2050.
Today the German Government reports that in 2010 renewable energy (mainly wind turbines and biomass plants) generated more than 100 TWh (billion kilowatt-hours) of electricity, providing nearly 17% of the 600 TWh of electricity supplied.
The renewable energy sector benefited when the Alliance '90 / The Greens party joined the Federal Government between 1998 and 2005. The renewable energy sector was aided especially by the Renewable Energy Sources Act that promotes renewable energy mainly by stipulating feed-in tariffs that grid operators must pay for renewable energy fed into the power grid. People who produce renewable energy can sell their 'product' at fixed prices for a period of 20 or 15 years. This has created a surge in the production of renewable energy.
For 2005-2010 period the Federal Government set aside nearly 800 million euros for scientific research in the country. That research is going to be earmarked for policies of long-lasting development. Additionally, in 2001 a law passed requiring the closing of all nuclear power plants within a period of 32 years. The shut down time was extended to 2040 by a new government in 2010. After the Fukushima incident, the law was reverted and the end of nuclear energy was set to 2022 .
The German energy policy is framed within the European Union, and the March 2007 European Council in Brussels approved a mandatory energy plan that requires a 20% reduction of carbon dioxide emissions before the year 2020 and the consumption of renewable energies to be 20% of total EU consumption (compared to 7% in 2006). The accord indirectly acknowledged the role of nuclear energy - which is not renewable, but emissions-free - in the reduction of the emission of greenhouse gasses, allowing each member state to decide whether or not to use nuclear generated electricity.
Also a compromise was reached to achieve a minimum quota of 10% Biofuels in the total consumption of gasoline and diesel in transport in 2020.
Closely after the USA, Germany is the world's second largest user of wind power with an installed capacity of 23,903 MW by the end of 2008, ahead of Spain which had an installed capacity of 16,740 MW. 20,301 wind turbines are located in the German federal area and the country has plans to build more wind turbines.
In 2009, 6.5% of Germany's total electricity consumption was satisfied by wind power. 867 wind power plants were constructed in 2008, and 952 more in 2009. At the end of 2009, Germany possessed 21,614 wind power plants. Their installed electricity production capacity was 25,777 MW. However this is a theoretical maximum, the actual output is vastly smaller.
Wind power currently produces about 7% of Germany's total power and it is said that no other country has more technological know-how in this area. Wind
power in Germany provides over 70,000 people with jobs and German wind energy systems are also exported. However, the economics of wind power in Germany are under close scrutiny and there are other issues which deserve consideration. These include the effect of wind turbines on the landscape, the effect on the bird population, and the effect on the tourist industry.
Following the 2011 Japanese nuclear accidents, German Federal Government is working on a new plan for increasing energy efficiency and renewable energy commercialization with a particular focus on offshore wind farms. Under this plan the large wind turbines will be erected far away from the coastlines, where the wind blows more consistently than it does on land, and where the enormous turbines won't bother the inhabitants. The plan aims to decrease Germany dependence on energy derived from coal and nuclear power plants.
At the end of 2007 Germany had an installed capacity of 3,830 MW. By the end of 2009, capacity had increased to 9,800 MW. The first 9 months of 2010 added about 5,400 MW in new solar capacity. In 2006, the European Commission anticipated that Germany may have installed about 4,500 MW by 2010. For 2009, the German government calculated that the PV industry provided 64,700 jobs in production, distribution and installation. Over 90% of solar PV installations are in grid-tied applications in Germany.
Completed in 2006, the 12 MW Solarpark Gut Erlasee photovoltaic system, near Arnstein in Bavaria was at the time of construction the world's largest PV system. The Waldpolenz Solar Park, which is the world's largest thin-film photovoltaic (PV) power system, became fully operational by the end of 2008. The power plant is 40 MW solar power system using state-of-the-art thin film technology.
The installed capacity for geothermal energy in Germany was 8.4 MW in 2007.
The total installed capacity of hydroelectricity in Germany at the end of 2006 was 4.7 GW. Hydropower meets 3.5% of the electricity demand. Latest estimates show that in Germany in 2007 approx. 9,400 people were employed in the hydropower sector which generated a total turnover of €1.23 billion.
German renewable energy sector is among the most innovative and successful worldwide. Nordex, Repower, Fuhrländer, Siemens and Enercon are wind power companies based in Germany. SolarWorld, Q-Cells and Conergy are solar power companies based in Germany. These companies dominate the world market. Every third solar panel and every second wind rotor is made in Germany, and German turbines and generators used in hydro energy generation are among the most popular worldwide.
Nearly 800,000 people work in the German environment technology sector; an estimated 214,000 people work with renewables in Germany, up from 157,000 in 2004, an increase of 36 percent.
Рис. 1. Доли производства электроэнергии возобновляемыми источниками в 2009 году Fig. 1. Renewable electric power produced in 2009 by energy source
Germany main competitors in solar electricity are Japan, the US and China. In the wind industry it is Denmark, Spain and the US.
Distribution between energy segments is shown on Fig. 1 below.
Increases in installed renewable electric power capacity and generation in recent years is shown in the table below:
Установленная мощность и производство электроэнергии Installed renewable electric power capacity and production
Year Installed capacity [MW] Hydropower [GWh] Wind energy [GWh] Biomass [GWh] Biogenic share of waste [GWh] Photovoltaics [GWh] Geothermal energy [GWh] Total electricity generation [GWh] Share of gross electricity consumption [%]
1990 5,043 15,580 71 221 1,213 1 0 17,086 3.1
1991 5,149 15,402 100 260 1,211 2 0 16,974 3.1
1992 5,270 18,091 275 296 1,262 3 0 19,927 3.7
1993 5,483 18,526 600 433 1,203 6 0 20,768 3.9
1994 5,830 19,501 909 569 1,306 8 0 22,293 4.2
1995 6,415 20,747 1,500 665 1,348 11 0 24,271 4.5
1996 6,927 18,340 2,032 759 1,343 16 0 22,490 4.1
1997 7,521 18,453 2,966 880 1,397 26 0 23,722 4.3
1998 8,472 18,452 4,489 1,642 1,618 32 0 26,233 4.7
1999 10,040 20,686 5,528 1,849 1,740 42 0 29,845 5.4
2000 11,937 24,867 7,550 2,893 1,844 64 0 37,218 6.4
2001 14,817 23,241 10,509 3,348 1,859 76 0 39,033 6.7
2002 18,333 23,662 15,786 4,089 1,949 162 0 45,648 7.8
2003 21,617 17,722 18,713 6,086 2,161 313 0 44,995 7.5
2004 24,848 19,910 25,509 7,960 2,117 556 0.2 56,052 9.2
2005 28,300 19,576 27,229 10,978 3,047 1,282 0.2 62,112 10.1
2006 32,048 20,042 30,710 14,841 3,675 2,220 0.4 71,488 11.6
2007 35,851 21,249 39,713 19,760 4,130 3,075 0.4 87,927 14.2
2008 40,108 20,446 40,574 22,872 4,659 4,420 17.6 92,988 15.1
2009 46,377 19,059 38,639 25,989 4,352 6,578 18.8 94,636 16.3
2010 55,702 19,694 36,500 28,710 4,750 12,000 27.2 101,681 16.8
2010 Q1 4,370 10,900 6,840 1,160 1,460 24,900 17.1
2011 Q1 5,270 11,560 7,170 1,320 2,780 28,100 19.2
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A 2009 study from RWI Essen of the effects of the Renewable Energy Sources Act concluded that:
- using photovoltaics in emission reduction is 53 times more expensive than the European Union Emission Trading Scheme's market price, while wind power is 4 times more expensive, thereby discouraging other industries from finding more cost-effective methods of reducing emissions;
- although renewable energy subsidies increase retail electricity rates by 3%, they reduce the profits of German electrical utilities by an average of 8%, making them less competitive with other European utilities;
- despite lavish subsidies, German photovoltaic industry is losing its market share to other countries, particularly China and Japan;
- it stifles renewable energy innovation by arbitrarily awarding subsidies to different technologies, instead of according to their cost-effectiveness.
German Federal Ministry for Environment, Nature Conservation and Nuclear Safety responded to the RWI Essen study, describing the criticisms as "well known and refuted a long time ago".
A significant amount of engineering is required to develop a tower that will support a windmill. Since the cost of the tower is directly related to the calculated wind loads placed upon the tower, it is very unlikely that an existing communication tower could be retrofitted with wind turbines of any significant size, without exceeding the wind load specifications for that tower. Therefore the most cost efficient approach is to incorporate wind and solar power into new towers that have been designed to support wind, solar and communications antennas on the same towers.
The second most cost efficient approach is to select a specific version of a tower, where many of the exact same type have been installed, and undertake the engineering task to retrofit wind and solar equipment to these towers. The general idea being to spread the cost of engineering and retrofit kitting across a large number of units, however without study and specific information, it is not possible to determine if this approach will be cost effective.
The third approach is to assume that the wind and solar power will be installed on an independent tower. While this avoids reworking existing towers, the cost of the tower and foundation represents approximately 65% to 80% of the total system cost. While it may be economically feasible to support existing communication towers using this approach, it is far less cost effective than an integrated tower that supports wind, solar and communications on the same tower.
We have made the assumption that potential customer which owns/uses cell towers is unlikely to find a company that has already designed, tested, tooled up and manufactured components that exactly meet his requirements. Therefore, it will be necessary to develop solutions specific to his needs. This includes engineering and development costs, with associated development schedules.
Since we have been working on similar solutions, we have many of the components developed, so we are likely to provide a shorter time line, at a lower cost than other alternatives.
Technology approach: The top of a communication tower is reserved for the antenna (Fig. 2).
Рис. 2. Мачта сотового оператора Fig. 2. Communication tower
The typical propeller or Horizontal Axis Wind Turbine (HAWT) arrangement is not satisfactory.
The blades of the windmill should not interfere with the RF patterns, so the HAWT (Fig. 3) cannot be mounted in the same location as the antenna. Also the mechanism to allow the HAWT to rotate into the wind becomes overly complex when it cannot be located at the centerline at the top of the tower.
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Рис. 3. Традиционные ветроэнергетические установки Fig. 3. Traditional wind turbines
The Vertical Axis Wind Turbine (VAWT) has significant advantages in this application. It can be mounted below the antenna, and it does not needed to seek the wind direction (Fig. 4).
Рис. 4. Концепция вертикально-осевой ветроэнергетической установки, расположенной на антенне мачты Fig. 4. Concept of VAWT mounted below the antenna on the tower
In addition to the mounting advantages shown above, the location of the tower is determined by the needs of the tele-communications company, not by the wind resource. As such many of the towers will be located in locations with modest and variable wind resources. The SRC-Vertical (SRCV) Vertical Axis Wind Turbines (VAWT) have been designed with these wind resources in mind (Fig. 5).
To develop the idea of placing the windmill on the cell tower it is required to make some analysis of what is available.
Рис. 5. Базовая конструкции вертикально-осевой ветроэнергоустановки ГРЦ-Вертикаль Fig. 5. Basic design of the Wind-sail VAWT
For now SRCV has the air foils and basic turbine design.
To install the turbine on the tower it is needed to accomplish the following:
- Increase the power level to meet specific requirements;
- Increase the diameter of the assembly to allow the tower structure to pass through;
- Provide cable access for the antennas;
- Design a turbine that can be maintained without disassembly of the tower;
- Develop a manufacturing process to make the units cost effective.
Advantages of the SRCV six blade, VAWT design:
- Omni directional: It doesn't matter compass heading the wind comes from, and it doesn't matter how rapidly it changes direction, turbine still takes power from the wind. Unlike HAWT, there is no requirement for the windmill to "seek" the wind direction, therefore we have eliminated the expensive and unreliable mechanics related to pointing the windmill.
- The VAWT acts as a flywheel, picking up some speed in wind gusts and continuing to rotate in the short periods of low wind, this provides a smooth, steady, quiet motion eliminating noise, and reducing energy losses of starting and stopping. Vibrations in the mounting structure are reduced, while the flywheel effect gives a more constant voltage output to the electronics.
- On cell towers, the ideal location for the antennas is at the top of the structure, the VAWT can be adapted to allow the tower structure to support the middle of the windmill, while allowing necessary power and RF cables to pass thru undisturbed.
- Since a primary cost factor in windmills is the foundation and the tower, new integrated towers get the bonus of low cost renewable energy without having to pay for a second tower.
- The VAWT can be at any height on the tower as long as it is in the wind, various designs are possible to adapt to available tower constructions. It is possible to stack multiple turbines on the same tower to increase power output, if the tower can support the turbines.
- Since cell towers are located basis of radio coverage and real estate availability, wind resources are a lower priority. The SRCV VAWT was designed for use in relatively low wind conditions. In low wind areas, most likely to be found where most cell towers are located, the Omni directional feature of the SRCV VAWT will generate 2-2.5 times more power from the low wind resources available than a HAWT of the same size, however since the blades of the turbine are of constant cross section, it is relatively low cost to increase the turbine size to adapt to lower wind speed conditions, providing more power for at a lower cost.
- Because SRCV VAWT turbine catches wind from any horizontal direction, the turbine captures more power in light and variable winds than HAWT in the same conditions. When wind directions change for a HAWT, the unit must overcome the gyroscopic forces to
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point into the wind. If the propeller is not facing directly into the wind, the efficiency drops of as a function of the cosine of the angle to the wind. At 15 degrees off the wind direction, the propeller efficiency drops by 20%; at 30 degrees the drop is 40% (Fig. 6). The gyroscopic force of the rotating propeller makes it slow to respond
to changes in wind direction; as such the HAWT in light and variable wind conditions is very seldom operating at peak efficiency. Thus the much touted efficiency advantage is not realized in variable wind conditions. Below is a graphic depiction of this wind angle problem for HAWT.
Рис. 6. Зависимость мощности от ометаемой площади горизонтально-осевой ветротурбины Fig. 6. Dependence of power on swept area in HAWT
If we look at the volume of space consumed by a propeller type turbine, it is basically a sphere, where the diameter of the sphere is the diameter of the turbine blade, plus the off set from the centerline of the mast.
From the same viewpoint our VAWT defines a rectangle (Fig. 7, 8). If we were to define our turbine as a square that had the same height and width as the diameter of the sphere consumed by the HAWT, the swept area of our turbine would be 27% greater just due to the shape. However by using a rectangle the swept area can be 2 or 3 times greater using the same amount of roof area. When faced with the problem of a fixed amount of roof area, the HAWT cannot take advantage of height without also consuming width. See the comparison graphic below.
Рис. 8. Ометаемая площадь эквивалентных ветротурбин Fig. 8. Swept areas of equal power turbines
Рис. 7. Модели эквивалентных ветротурбин Fig. 7. Models of equal power turbines
- The SRCV VAWT has few moving parts, so there is less to maintain, less to wear out. Since reliability of communications is more important to the cell company than the cost per watt of power, a more reliable system offers greater value.
- The rotational speed of the air foils is considerably slower with the VAWT than it is with the HAWT. Tip speed ratios are on the order of 2.5-3 times the wind speed, as compared to 5 - 7.5 on the HAWT. As such there is less wear on the blades due to particle abrasion. There is less vibration introduced into the tower structure. The lower speed not only increases blade life, but reduces mechanical stresses on the turbine and tower, increasing the reliability and life of both.
Рис. 9. Измерения шума крупных 1 МВт горизонтально-осевых ветроэнергетических установок в Германии около г. Белльхайм Fig. 9. Measurements of noise of big 1 MW HAWT in Germany near Bellheim
Рис. 10. Белка на мачте установки ГРЦ-Вертикаль (Челябинск, Россия) Fig. 10. Little Squirrel on the SRCV VAWT mast (Chelyabinsk, Russia)
The measurements of big HAWTs were arranged by South Ural State University (Chelyabinsk, Russia) and made on 15-18 June, 2011 near Bellheim (Germany) by Eugene Solomin under supervising of VERTICAL-EUROPA company, to check the noise of HAWT (Fig. 9). It appeared that the level of noise increases 65 dB(A) which is not acceptable for both German and Russian standards if using the windmill near the living house. Instead the SRCV small VAWT had shown the low noise up to 60 dB(A) http://www.eng.src-vertical.
com/nodes/452/ which allows not only placing the windmill near the house but even allows small animals climbing on the mast (Fig. 10). The noise measurements were made by Chelyabinsk Sanitary Commission certified for these purposes, in 2009.
- The lower rotational speed of the turbine greatly reduces bird kill problems. Birds in general are able to comprehend the lower speeds of these turbines, since the top speed is approximately 85 MPH it is easily within the range of speeds birds encounter in a natural environment. The SRCV claim is: Low or no bird kills.
- While it is not apparent the SRCV VAWT is self starting, it only takes a light breeze to begin the turbine rotating, once it is spinning it continues to collect energy from the wind gusts that occur. While the wind doesn't have much power at low speeds, the fact that the turbine is rotating, allows some trickle of power to be going to the batteries which greatly increases the overall reliability of the power system.
- The fact that we have six power pulses per revolution not only reduces power ripple in the electrical power, but it also greatly reduces the amplitude of the mechanical vibrations in the tower structure. This hidden feature significantly reduces the fatigue in the tower structure, preserving its useful life at no significant additional cost as compared to a HAWT in the same situation.
- In addition to the wind turbines designed by a large team of Russian scientists and engineers, a new alternator was developed specifically and adapted to this wind turbine technology. The turbine rotor turns at relatively low RPM (typically 50-200 RPM) a directly driven alternator that does not include any form of mechanical gearing provides greater reliability and higher efficiency. In addition the alternator does not have magnetic cogging, so it allows the turbine to begin rotating in very light wind conditions.
- Controlling a wind turbine, while charging a storage system like batteries is more complex than it appears. The input power from the wind is variable, so the output power to the system must be variable to maximize the total power delivered. At the same time battery charging must be done properly or the battery life will be greatly diminished. In a partnership with another company, we have been developing a control system to accomplish this task.
From the above analysis it is evident that the Russian-made VAWT today are acceptable and required for German renewable sector. The TUV certification should start shortly by VERTICAL-EUROPA after the formal arrangements of companies for International cooperation.
The article was written in accordance the Priority Direction of Development #1 of South Ural State University, Chelyabinsk.
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International Scientific Journal for Alternative Energy and Ecology № 11 (103) 2011
© Scientific Technical Centre «TATA», 2011
