USAGE OF WIND DERIVED ENERGY IN ELECTRIC TRANSPORT Текст научной статьи по специальности «Электротехника, электронная техника, информационные технологии»

ВЕТРОЭНЕРГЕТИКА

WIND ENERGY

ИСПОЛЬЗОВАНИЕ ЭНЕРГИИ ВЕТРА. ТЕХНИКА, ЭКОНОМИКА, ЭКОЛОГИЯ

WIND ENERGY APPLICATIONS. ENGINEERING, ECONOMY, ECOLOGY

Статья поступила в редакцию 07.08.12. Ред. рег. № 1396 The article has entered in publishing office 07.08.12. Ed. reg. No. 1396

УДК 620.92; 621.311.24; 621.331

ИСПОЛЬЗОВАНИЕ ЭНЕРГИИ ВЕТРА В ЭЛЕКТРИЧЕСКОМ ТРАНСПОРТЕ

И. Дирба, Я. Клеперис

Институт физики твердого тела при Латвийском университете Латвия, Рига, LV-1063, ул. Кенгарага, д. 8 Тел.: (+371)67187816; (+371)67132778, e-mail: [email protected]

Заключение совета рецензентов: 20.08.12 Заключение совета экспертов: 25.08.12 Принято к публикации: 30.08.12

Создана система для получения электроэнергии из энергии ветра и зарядки аккумуляторов электромобилей. Ветряные двигатели с вертикальной осью мощностью 3 кВт были сконструированы, произведены и прошли испытание в условиях Латвии. Мощности турбины достаточно для того, чтобы в течение ночи зарядить аккумулятор малого автомобиля с электромотором, заряда которого хватает для того, чтобы проехать 100 км. Так как в системе используются инновационные решения для электрической цепи и дизайна мотора/генератора, уменьшены потери при передаче энергии и цена. Данное решение рекомендовано для экологичного решения проблем мобильности в небольших городах и деревнях.

Ключевые слова: электрический автомобиль, ветротурбина, экологический транспорт.

USAGE OF WIND DERIVED ENERGY IN ELECTRIC TRANSPORT

I. Dirba, J. Kleperis

Institute of Solid State Physics, University of Latvia 8 Kengaraga str., Riga, LV-1063, Latvia Tel.: (+371)67187816; (+371)67132778, e-mail: [email protected]

Referred: 20.08.12 Expertise: 25.08.12 Accepted: 30.08.12

The compatible set of technological equipment is created to extract energy from the wind and to charge batteries of electric vehicle. Vertical axis wind turbine with power 3 kW is design, fabricated and tested in Latvia's wind conditions. The capacity of turbine is sufficient to charge the battery of one minicar with electric motor during night and to run distance 100 km in day. Electric vehicle and wind turbine has reduced power transmission losses and costs because previously unknown solutions for electric circuit and motor/generator design are used. It is propose to use such equipment as green mobility solutions in villages and small cities.

Keywords: electric car, wind turbine, ecotransport.

Orgaization(s): PhD student at Faculty of Physics and Mathematics, University of Latvia from 2011; Research Assistant at Institute of Solid State Physics, University of Latvia.

Research is connected with new magnetic materials and their application in magnetic machines. During Master Science studies developed renewable energy technologies, established his own company, applied to projects and receive support from Investment and Development Agency of Latvia and from Ministry of Environment to built up efficient and cheep electric vehicles (rebuilding used cars), vertical axe wind generator with power 3 kW. Received Latvia's patents on original constructions of electric generator and design of vertical axe wind generator. Works with different modeling programs, COMSOL including, to model magnetic machines, wind generators, magnetic nanoparticles.

Introduction

There are two important things to know about electric cars: electric vehicle is as "clean" as the technology used to produce the electricity needed to operate it, and electric motors are much more efficient than the combustion engine. Consequently, a shift from the current petrol and diesel cars to electric cars could save a large amount of fossil fuels for other applications. An important note is that the larger the share of renewable energy in Europe's power mix, the cleaner the electric vehicles of the future will be [1, 2]. Approximately assuming that an average electric vehicle consumes 0.2 kWh per kilometer and has average annual mileage of 10,000 km, an electric car will consume 2,000 kWh per year, and the wind energy produced in Europe in 2010 could power 90.8 million such electric cars [1]. Changing to prices, 1 year driving with such electric car in Latvia will cost 235 € (average electricity price (2011) in private sector was 0.1174 €). The fuel for an internal combusting car with diesel consumption 5 litter/100 km and annual millage 10,000 km would cost 680 € (average fuel price in Latvia 2011 was 1.36 €/1 litter). Therefore the wind energy is delighting with competitive prices, but penetration is limited by fluctuating supply. Variability in wind output implies limited predictability; high natural ramp rates; and, often, limited coincidence with peak demand [1-3]. These factors can restrict the ultimate penetration of wind power into traditional electric power systems. The high reliability required by such systems dictates that ample capacity is always available and that conventional generators are able to follow the variations in loads, forced outages, and variable supplies like wind, and it usually incurs additional costs [3].

Is it possible to harvest wind energy without integration in grids? Our answer is - yes. This article describes results of project "Usage of wind derived energy in commercial transport" financed by Climate change financial instrument in frame of public tender "Greenhouse gas emission saving technology development" (2010-2011) [4]. Project promoters are to small enterprises "Power Project Ltd" (representative of company, Head of project and author of this article Imants Dirba) and "OSC Ltd" (represented by Andris Dambis et all).

The Climate Change Finance Instrument is Latvian equivalent of GIS (Green Investment Schemes). The money for competition was obtained by selling the assigned amount units (AAU) to Austria, Netherlands, Spain and Japan (2009), and the contracts stated that this financing must be used for fighting climate changes and improving energy efficiency in the state owned education establishments, increasing the energy efficiency in local municipalities buildings, implementing renewable resources technologies and creating new technologies limiting greenhouse gas emissions, development and implementation of policy [5]. Latvia signed the United Nations Framework Convention on Climate Change (UNFCCC; Convention) in Rio de Janeiro in 1992, and Saeima (Parliament) of the Republic of Latvia ratified the

Convention in 1995 [6]. It means that since then Latvia has undertaken to implement series of internationally prescribed commitments to mitigate global climate change. The Kyoto Protocol to the Convention (Protocol) was adopted in Kyoto on 11.12.1997 and Latvia signed the Protocol in 1998 (Saeima ratified it on 30.05.2002). In accordance with the Protocol Latvia, individually or in a joint action with other country, should reach the level when aggregate anthropogenic direct greenhouse gas (GHG: CO2, CH4, N2O, HFC, PFC and SF6) emissions by the years 20082012 are 8% below emission level of 1990. There are three flexible mechanisms for GHG emission reduction prescribed by the Kyoto Protocol: joint implementation (JI) projects, clean development mechanism (CDM) and international emission trade (ET). Latvia chose last one. Total available AAU amount for Latvia is 40 millions. Latvia can sell AAU because according to the Kyoto protocol obligations (to reduce 8% emissions in comparison to 1990) Latvia won't need all AAU which belongs to the state and it is possible to sell surplus units for other countries which need them. It is impossible to use Assigned amount units in other ways or to convert them to emission quotes. Although AAU can't be allocated to businessmen the state can sell these units and invest the money in projects which promote low carbon economics.

Project description and results achieved

The task of this project is to build a wind generator prototype and rebuilt two commercial midget fossil fuel cars to electric cars. Outcomes of project could be used at SME who own a park from small cars with high mileage in the city, installed wind turbines on the roof of office of this SME are charging batteries for electric vehicles to be able to at least 100 km mileage in city traffic daily.

The aim is to create compatible set of technological equipment, which charge electric batteries using energy produced by wind. Project is required due following reasons:

- Increase the prices of fossil fuels and increase the taxes on vehicles using fossil fuels (CO2 - tax);

- Increasing awareness among people about the need to use renewable energy options not only in industry and everyday life, but also in transport;

- Development of new wind turbines to be able to work efficiently in low wind conditions is on their way and would be suitable for installation in Latvia, but is hindered by the lack of corresponding legislation on renewable resources & technologies, and possibility to use existing distributed electricity networks for storage of wind energy; therefore it is necessary to look for another ways how to accumulate rapidly changing and unpredictable electricity generated by wind power, for example in batteries of electric vehicles.

Project activities have two directions:

- Wind energy acquisition and use to charge batteries with a small but effective wind generator;

- Construction of electric car to be charged from small wind generators.

International Scientific Journal for Alternative Energy and Ecology № 09 (113) 2012

© Scientific Technical Centre «TATA», 2012

Project implementation will not give immediately marketable wind turbines and electric cars, but it will allow the creation of a compatible pair of innovative equipment: small vertical axis wind generator and the electric car.

Vertical axes wind turbine

Vertical ax wind turbine was designed and built as real prototype in dimensions - diameter 4 m, height - 3 m (Fig. 1). The testing of wind turbine without generator was carried out on the flat site in windless weather conditions using the truck with an open trailer. The torque and output power of wind turbine was measured synchronously in real time using computer and torque measuring equipment - torque to the rotational axis controlled with the optical revolution counter - rotation speed per minute.

Рис. 1. Ветротурбина на месте эксперимента Fig. 1. Wind turbine standing on test place

Wind speed was changed using different driving conditions and measured with an anemometer and a computer. From calculated data the mechanical power on an ax of wind turbine was evaluated at certain wind speeds (Fig. 2). Self-built generator with Nd permanent magnets with rated power 3 kW was attached to the turbine and first real field tests done in Ventspils during January-February 2012. Ventspils in January this year was very stormy, and the turbine was tested in the work to the maximum endurance.

Average wind speed in Ventspils at height 10 m is only 3-4 m/s (data collected for period 2007-2012 [7]) therefore it is need to think improvements in wind turbine design. Other constructions with different blade number, angle of attack, airfoil/dragfoil profiles and with/without specific wind deflector were compared using CFD software package OpenFOAM in 2D and tested in Wind Tunnel (Riga Technical University).

Power, W

2500 2000

1500 -

1000 500

о —

0 3 6 9 12 15

Wind speed, m/s

Рис. 2. Зависимость механической мощности на осях турбины от скорости ветра Fig. 2. Mechanical power to the turbine axis in dependence on wind speed

Conversion of standard internal combustion engines to electric cars

Two standard street cars MINI Cooper (year of release 2004) and KIA Picanto (year of release 2006) were chosen to be converted from internal combustion engine to electric driving technology (Fig. 3). The conversion of both internal combustion engine vehicles to electric cars for city mileage needs was successful - transport units are created fully consistent with set objectives - reduced emissions (CO2 including), and reduced running costs.

Рис. 3. Обычные уличные машины MINI Cooper (a) и KIA Picanto (b), переделанные под электрический двигатель с коробкой передач Fig. 3. Standard street car MINI Cooper (a) and KIA Picanto (b) converted to electric drive car with a one gear transmission

An internal combustion engine is removed from the engine room electric motor with a single gear transmission placed instead (Fig. 4, a). The battery pack is placed instead of passenger seats in rear row, with extension to luggage compartment (Fig. 4, b).

b

Рис. 4. Моторный отсек переделанных машин (а) и блок батареи вместо задних сидений (b) Fig. 4. Engine room of converted car (a) and battery pack instead of rear passenger seats (b)

Technical parameters of both converted cars are next: MINI Cooper: Electric Motor: AC, three phase, induction, 4 poles; Power: 15 kW (nominal), 20 kW (max) Torque: 140 Nm (max); Milleage: 70-90 km; Battery Pack: Winston Battery; Energy Capacity: 14.4 kWh; Voltage: 144 V;

In Pack 45 batteries, each 100 Ah, 3.2 V; Average price - 4500 €;

Battery charging: 8 hours with 3 kW charger from 220 V; 14 hours with 2 kW charger from 220 V using an active battery management system;

Capacity: Two people and two hand luggage suitcases;

Maximal speed: 100 km/h;

Nominal speed: 60 km/h;

Weight change after conversion: 1030 kg (reduced by 20 kg).

KIA Picanto: Rated output - 15 kW;

Maximum power - 25 kW;

The peak torque - 100 Nm;

Nominal torque - 48 Nm;

Rated voltage - 144 V;

Rated engine speed - 3000 r/min;

Maximum engine speed - 6000 r/min;

The range of engine speed - 0-6000 RPM/min;

Cooling - typical coolant liquid;

Mileage per charge - up to 100 km (when air temperature above 0 °C; in winter mileage drops to about 65 km);

Charging time - 8 hours;

Battery Type - LiFePO4 (lithium iron phosphate) with cell voltage - 3.2 V;

The number of cells set - 45 units (in series);

The total battery voltage - 144 V;

Brake system booster - an electric vacuum pump;

Cabin heater - liquid cooling of the engine and controller;

Power of car electric system (alarm, central locking, lights, etc.) - DC-DC converter (144 V to 12 V).

Principal electric circuit of rebuilt KIA Picanto is shown in Fig. 5, but electric torque and power curves in dependence engine speed - Fig. 6.

Рис. 5. Электрическая схема для переделанной KIA Picanto Fig. 5. Principal electric circuit of rebuilt KIA Picanto

International Scientific Journal for Alternative Energy and Ecology № 09 (113) 2012

© Scientific Technical Centre «TATA», 2012

Рис. 6. Переделанная KIA Picanto: кривые зависимости характеристик электропривода и мощности от скорости Fig. 6. Rebuilt KIA Picanto: electric torque and power curves in dependence engine speed

First tests were done in winter month when outdoor temperature already was around zero degrees and the roads were slippery. The test drive showed that the cars are feeling stable on the road, the driving in city traffic is a safe, and just due to low temperatures the mileage was reduced to 65 km. Full-year tests will be done in future to record actual operating results in different driving conditions.

The energy to charge batteries of both electric vehicles was exclusively derived from wind generator which was design and built in the frame of this Project. CO2 emissions of wind-powered electric vehicles was calculated accordingly European Commission Joint Research Centre guidelines of Co2 emissions from wind-powered electric vehicles [8] - 3 grams CO2/km. Assuming that mileage of car during the year is 37,500 km, calculated CO2 emissions in one year is no more than 113 kg. The diesel version of MINI Cooper 1.6D emits just 104 g/km CO2 [9], what equals 3900 kg annual for the same mileage. As it is seen, CO2 emissions are significantly lower for electric MINI Cooper version, charged from wind generated power.

Conclusions

It is concluded that conversion of internal combustion engine vehicles (MINI Cooper, KIA Picanto) to electric cars for city mileage needs was successful - transport units are created fully consistent with set objectives - reduced emissions (CO2 including), and reduced running costs.

First tests showed that the cars are feeling stable on the road; the driving in city traffic is a safe. Full-year test must be done in future to record actual operating results in different driving conditions.

It is proved that the energy to charge batteries of both electric vehicles can be exclusively derived from wind generator. Built wind turbine prototype allows charging the batteries of both vehicles during night time.

Calculated CO2 emissions. CO2 emissions of wind-powered electric vehicles was calculated accordingly European Commission Joint Research Centre guidelines

of CO2 emissions from wind-powered electric vehicles [5] - 3 grams CO2/km. Assuming that mileage of car during the year is 37,500 km, calculated CO2 emissions in one year is no more than 113 kg. The diesel version of MINI Cooper 1.6D emits just 104 g/km CO2 [6], what equals 3900 kg annual for the same mileage. As it is seen, CO2 emissions are significantly lower for electric MINI Cooper version, charged from wind generated power.

Acknowledgments

ID together with Power Projects Ltd and OSC Ltd acknowledge Ministry of Environmental Protection and Regional Development of Latvia, and Climate Change Financial Instrument for financial support to project No. KPFI - 2/23 "Usage of wind derived energy in commercial transport"

References

1. Catching the wind with electric cars: SmartPlanet News September 23, 2011. Available from: http://www.smartplanet.com/blog/intelligent-energy/ catching-the-wind-with-electric-cars/9118.

2. Electric vehicles could help store NW wind power: KPIU885 News 01.09.2011. Available from: http://www.kplu.org/post/electric-vehicles-could-help-store-nw-wind-power.

3. Denholm P. Improving the Technical, Environmental, and Social Performance of Wind Energy Systems Using Biomass-Based Energy Storage // Renewable Energy. 2006. Vol. 31. P. 1355-1370.

4. Project "Usage of wind derived energy in commercial transport". Available from: http://osc.lv/blog/1380-no-vejiegutas-elektroenergijas-izmantosana-komerctransporta/.

5. Contract between Latvia and New Energy and Industrial Technology Development Organization (NEDO) on AAU. Public Information Division: Ministry of the Environmental Protection and Regional Development. Available from: http://www.varam.gov.lv/eng /informacija_ presei/preses_relizes/?doc=9695.

6. Ministry of Environmental Protection and Regional Development: Global Climate Change http://www.varam.gov.lv / eng/darbibas_veidi/global_climate_change/.

7. Bezrukovs Vl., Bezrukovs Val. Wind speed and energy at different heights on the latvian coast of the Baltic sea. Report to WREF 2012. Available from: http://ases.conference-services.net/resources/252/2859/pdf/ S0LAR2012_0214_full%20paper.pdf.

8. Energy consumption, CO2 emissions and other considerations related to Battery Electric Vehicles. European Association for Electri Vehicles, 2009. Available from: http://ec.europa.eu/transport/strategies/consultations/ doc/2009_03_27_future_of_transport/20090408_eabev_(sci entific_study).pdf.

9. Mini Cooper Hatchback 1.6D 3dr Review. Available from: http://www.whatcar.com/car-reviews/ mini/cooper-hatchback/1-6d-3dr/summary/61091/.

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