Wind farm

Wind farm in Lower Saxony

A wind farm (also called a wind farm ) is a spatial collection of wind energy plants (WEA). These can form a unit organizationally (by an investor or operator) and technically (by jointly feeding in electrical power). Wind farms can be divided into the following types:

• "Grown" wind farms have arisen due to the spatial proximity of successively constructed plants.
• Planned wind farms are, on the one hand, collections of systems of a planner, manufacturer or operator that were built or planned in the course of a construction project. This includes later extensions.
• On the other hand, there are officially designated areas for wind turbines. The aim is to concentrate these in certain regions in order to relieve the rest of the landscape. For example, in 2011 wind power was approved on 0.8% of the area of Schleswig-Holstein ; the state government wants to expand it to at least 1.5%.

Wind farms can be built inland ( onshore ), on the coast ( nearshore ) or at a considerable distance from the coast at sea ( offshore ). They can comprise only three, but also well over 100 wind turbines and provide a feed-in power of a few MW to many 100 MW. In some wind parks, only a single type of system is used, but there are also wind parks in which several types of system, also from different manufacturers, are used. By using wind turbines with different hub heights, the mutual spacing of the wind turbines can be increased with the same spatial extent of the wind farm, which reduces the mutual influence.

Wind parks often include wind measurement masts , which are either used temporarily in advance of construction to forecast the yield or which are permanently erected for the purpose of meteorological research. As a rule, the yield is predicted using a wind report based on long-term data over several years or decades.

Onshore wind farms on land

Wind measuring mast at the Gussenstadt wind farm

Wind turbines in Germany 2011

Approval procedure in Germany

The Federal Administrative Court (BVerwG) ruled in June 2004 that a collection of at least three wind turbines is considered to be a wind farm under licensing law in Germany if they are "spatially assigned to each other in such a way that their areas of influence overlap or at least touch" ( Federal Administrative Court :) These must then approved according to the more complex Federal Immission Control Act (BImSchG), while otherwise only a building permit is required . It is irrelevant whether the systems to be considered are assigned to several operators. In addition, individual or "only two" systems must be approved according to the BImSchG if a system reaches a total height of more than 50 meters.

financing

Wind farms were initially financed either by individual major investors or through project financing , for example in the form of the establishment of a closed fund . In a closed-end fund, several investors raise the equity, which is supplemented by a bank loan. Since 2005, other forms such as leasing or the issue of profit participation certificates have also been possible. In addition, community wind farms have increasingly established themselves, for example in the legal form of a cooperative , as an alternative financing option. Here those directly involved have a secure share of the profit and a lower economic risk. For the financing of large offshore wind farms with an investment volume of up to one billion euros, only large banks, international corporations or consortia of such corporations can usually be considered.

planning

From the investors' point of view, it is an advantage that the planning can be done from a single source: A separate approval procedure does not have to be carried out for each plant. On the other hand, a more complex process is required for planning wind farms.

In order to minimize the mutual influence, the rotors must be arranged with a certain minimum distance from one another, which mainly depends on the size of the system and the prevailing wind direction . The rule of thumb for wind farms on the coast has been five times the rotor diameter in the main wind direction and three times the rotor diameter in the secondary wind direction as the minimum distance.

However, in large wind farms, the turbulence behavior of the rotors depends on the position of the individual systems. According to more recent studies, the optimum efficiency is only achieved at about 15 times the rotor spacing. Using simulations, researchers at Johns Hopkins University came to the conclusion that wind turbines placed in a checkerboard pattern in large wind farms are not an advantageous structure. Arranging them staggered in blocks reduces the reduction in wind yield due to turbulence between the wind turbines.

In 2020, a working group at DLR came to the conclusion, using computer simulation, that in wind farms in the northern hemisphere, the wind turbines in at least the second row could generate up to 23 percent more energy if they were designed to rotate counterclockwise instead of clockwise, while clockwise wind turbines in the southern hemisphere were the best Direction of rotation. This effect, which can be traced back to the Coriolis force , mainly arises at night.

Establishment

Construction of wind power plants in the Erkelenzer Börde

With the construction of planned wind farms in one go, the investor has the advantage that the entire infrastructure can be concentrated. Systems, cranes and access roads can be used for several systems at the same time. For example, the large crawler cranes do not have to be dismantled in order to move from one wind turbine to the next. If there are delays in the construction of a system, work can be carried out on another system during this time.

In wind farms, the systems must be marked with obstacles. This includes the colored marking of the rotor blade tips and the lighting in poor visibility. In new parks within a wind park, the flashing or flashing of the lamps is synchronized via the DCF77 time signal. In some cases, this is also being retrofitted in older parks.

See also : Identification of obstacles in wind turbines

business

For the electricity network operator (energy supplier), all wind turbines in a wind farm appear like a single power plant; Thus, for example, the feed-in billing for the operator of the wind farm is simplified and cheaper. A wind farm is controlled centrally for the entire wind farm. Each system also has its own control. Since a grown wind park is sometimes made up of different types of wind turbines that place different demands on the wind speed, the wind conditions can lead to individual wind turbines being switched off.

System maintenance can also be carried out in a concentrated manner on several systems. There are no long journeys and times for the technicians. Experience shows that the longer maintenance technicians stay there also increases the likelihood that a technician will be on site (in the wind farm) in the event of a system malfunction. The response times are shortened.

Loss of yield due to shading (WAKE losses)

Wind power plants can influence each other negatively by aerodynamically "shadowing" each other in certain wind directions ( slipstream , WAKE or wake). How high these losses are is controversial. Modern Wind-LiDAR measurement technology can provide a more detailed picture of the lag effects. An attempt is made to keep these losses as low as possible by means of a shadowing analysis. In the case of floating wind turbines, there are plans to avoid or minimize these losses by means of multiple systems or relocation.

Feed-in problems

Since the existing power grid has so far only been partially geared to the strong expansion of wind farms, local energy surpluses can occur during times of high wind power generation, especially in northern and eastern Germany, which can lead to a limitation of the energy fed in by the network operator. As a result, around 407 gigawatt hours (GWh) of wind power were lost in 2011, almost 1% of the electricity actually fed in from wind energy of around 48,900 GWh. Because the operators have so far had to be compensated for such production cuts, the industry estimates that costs of 18 to 35 million euros will arise.

Recently, temperatures and wind speeds have been measured on overhead lines , as both factors influence the capacity of an existing overhead line (lower temperatures and higher wind speeds have a positive effect). The Dena network study also considered the necessary adjustments associated with the wind farms planned in the sea. From the point of view of a power grid operator, large virtual power plants must be connected to the power grid at a great distance from the consumer, which leads to considerable investments.

Experimental wind farms

There are also wind farms that focus on testing and measuring wind turbines. In such wind farms, there is usually only one copy of each type of turbine that belongs to the manufacturer. To measure the wind speed, there is also at least one wind measuring tower in such wind parks. One such test wind farm is the Østerild wind turbine test field .

Lists of wind farms

By far the largest wind farm in the world, the Gansu wind farm with 20 GW installed capacity in the final stage of expansion

The California Alta Wind Energy Center of Oak Creek Road from

The Shepherds Flat Wind Farm in Oregon

Fântânele-Cogealac wind farm in Romania

Whitelee Wind Farm, a Scottish wind farm south of Glasgow

Wind farm in Andalusia, Spain.jpeg

List of the largest wind farms

rank	Wind farm	Nominal power ( MW )	country	Remarks
01	Gansu wind farm	7,965	People's Republic of China
02	Zhang Jiakou	3,000	People's Republic of China
03	Urat Zhongqi, Bayan Nur	2,100	People's Republic of China
04th	Hami Wind Farm	2,000	People's Republic of China
05	Damao Qi, Baotou City	1,600	People's Republic of China
06th	Alta Wind Energy Center	1,547	United States
07th	Walney offshore wind farm	about 1,100	United Kingdom
08th	Jaisalmer wind farm	1,064	India
09	Hongshagang, Town, Minqin County	1,000	People's Republic of China
010	Kailu, Tongliao	1,000	People's Republic of China
11	Chengde	1,000	People's Republic of China
12	Shepherds Flat Wind Farm	845	United States
13	Roscoe	782	United States
14th	Horse Hollow	736	United States
15th	Tehachapi Pass CA	690	United States
16	Capricorn Ridge	663	United States
17th	London Array offshore wind farm	630	United Kingdom
18th	San Gorgonio Pass CA	619	United States
19th	Altamont Pass CA	606	United States
20th	Fowler Ridge	600	United States
21st	Fântânele-Cogealac	600	Romania
22nd	Sweetwater	585	United States
23	Race Bank offshore wind farm	580	United Kingdom
24	Gwynt y Môr offshore wind farm	576	United Kingdom
25th	Zafarana	544	Egypt
26th	Whitelee Wind Farm	539	United Kingdom
27	Buffalo Gap	523	United States
28	Dabancheng	500	People's Republic of China
29	Meadow Lake	500	United States

List of the largest wind farms (under construction)

rank	Wind farm	Nominal power (MW)	country	Remarks
1	Gansu wind farm , Jiuquan	20,000	People's Republic of China
2	Markbygden	approx. 4,000	Sweden
3	Fosen Vind	k. A. (278 turbines)	Norway

List of the largest wind farms (in planning)

rank	Wind farm	Nominal power (MW)	country	Remarks
1	Dogger Bank offshore wind farm	up to 9,000	United Kingdom
2	East Anglia offshore wind farm	up to 7,200	United Kingdom
3	Hornsea offshore wind farm	up to 6,000	United Kingdom
5	Ulanqab Wind Power Base	6,000	People's Republic of China	Subsidy-free, completion planned for 2023
5	titanium	5,050	United States
6th	Norfolk offshore wind farm	up to 3,600	United Kingdom
7th	Seagreen offshore wind farm	more than 2,300	United Kingdom
8th	Zofia wind farm	750	Ukraine

Offshore wind farms

→ Main articles : Offshore wind farm  and List of offshore wind farms

The Belgian offshore wind farm Thornton Bank

The term offshore wind farm is used for wind farms whose foundations are in the sea. There, the continuously occurring wind should be used. So far, however, wind farms have not been built on the “high seas”, but exclusively on the continental shelf .

In 2002, Horns Rev, the largest offshore wind farm in the world at the time, went online in Denmark : There are 80 wind turbines in the North Sea. They generate 600 GWh of energy annually, enough for 150,000 Danish households.

The largest offshore wind farm in the world is currently the London Array with 175 turbines and a total output of 630 MW (as of May 2013).

The largest offshore wind farms

Surname	( MW )	country	Turbines and model	Start of operations	source
London Array	630	UK	175 × Siemens SWT-3.6	2012
Gwynt y Môr	576	UK	160 × Siemens SWT-3.6	2015
Greater Gabbard	540	UK	140 × Siemens SWT-3.6	2012
Global Tech I.	400	Germany	80 × AREVA Wind M5000	2015
Anholt	400	Denmark	111 × Siemens SWT-3.6-120	2013
BARD Offshore 1	400	Germany	80 × BARD 5.0	2013
West of Duddon Sands	389	UK	108 × Siemens SWT-3.6-120	2014
Horns Rev	369	Denmark	80 × Vestas V80-2MW 91 × ​​Siemens 2.3-93	2009
Walney	367	UK	102 × Siemens SWT-3.6	2012
Thornton bench	325	Belgium	54 × Repower 6 MW	2013
Sheringham Shoal	317	UK	88 × Siemens 3.6	2013
Thanet	300	UK	100 × Vestas	2010
North Sea East	295	Germany	48 × Senvion 6.2M126	2015
Amrumbank West	288	Germany	80 × Siemens SWT-3.6-120	2015
Butendiek	288	Germany	80 × Siemens SWT-3.6-120	2015
DanTysk	288	Germany	80 × Siemens SWT-3.6-120	2015
EnBW Baltic 2	288	Germany	80 × Siemens SWT-3.6-120	2015
Sea wind south / east	288	Germany	80 × Siemens SWT-3.6-120	2014
Lincs	270	UK	75 × Siemens 3.6	2013

Environmental impact

→ Main article : Wind turbine # Impact on the environment  and wind energy

Like all types of energy generation , wind farms also have an impact on the environment. The effects are shown in the articles wind turbine and wind energy .

Examples of special wind farms

Tauernwindpark

• The world's most powerful wind farm in October 2016 is the Gansu wind farm in the People's Republic of China with an installed capacity of 20 GW.
• The largest wind farm with the most individual plants in the world is the Roscoe Wind Farm near the town of the same name in Nolan County in Texas (USA). It consists of 627 wind turbines with a total output of 781.5 MW and at the time of its completion in 2009 was also the most powerful wind farm in the world.
• The largest and most powerful offshore wind farm in the world is the London Array in January 2013 in the North Sea off the Thames estuary with an installed capacity of 630 MW and 175 turbines.
• The largest planned offshore wind farm is the Dogger Bank offshore wind farm with 1,500 wind turbines with a total nominal output of around 9,000 MW. This corresponds to the nominal output of around seven nuclear power plants. The annual energy yield corresponds to about four to five nuclear power plants with an assumed 4000–4500 full load hours for the wind turbines and 7500–8000 full load hours for the nuclear power stations.
• The first wind farm in Europe was commissioned in 1982 on the Cycladic island of Kythnos , consisting of five wind turbines with a total output of 100 kW. The system replaced the supply with a diesel power plant. In 1983, a solar system was included in the “Kythnos Island Model” supply concept.
• The largest (under construction) onshore wind farm in Europe is the Sinus Holding Wind Farm near Vaslui in Romania , which consists of a cluster of five neighboring wind farms and with a total of 350 individual plants is to achieve a total nominal output of 700 MW.
• The highest wind farm in Europe is the Gries wind farm in Switzerland at around 2500 m above sea level. M. It comprises four plants with a total of 9.3 MW.
• The first wind farm in Germany, wind energy park west coast in the Kaiser-Wilhelm-Koog at the Schleswig-Holstein North Sea coast, was put into operation on 24 August 1987th
• The first German wind park in the low mountain range was the Vogelsberg wind energy park near Hartmannshain in Hesse , which went into operation in November 1990.
• The first German offshore wind farm was alpha ventus in the North Sea northwest of Borkum , which has been fully operational since the end of 2009.
• The highest wind farm in Germany was built in 2016 on the 1173 meter high Rohrenkopf in the southern Black Forest.
• In the Holtriem wind farm in East Friesland and in the Euro Wind Park Vetschau near Aachen , a wind turbine is equipped with a viewing platform at a height of 60 m.
• The Estinnes wind farm in Belgium comprises eleven Enercon E-126 turbines, which at the time (June 2012) was the most powerful wind turbine in the world with up to 7.5 MW .
• At the time of commissioning in December 2014, the Tarfaya wind farm in Morocco is the most powerful wind farm in Africa with 301 MW. With the wind farm Lake Turkana in Kenya, an even more powerful wind farm is planned with 310 MW. Extremely high average wind speeds of 11.1 m / s prevail on site, construction will start in June 2014.
• The Pampa wind farm in Uruguay achieves an unusually high standard energy capacity of approx. 640 million kWh for onshore wind farms thanks to the use of low wind systems with a total output of approx. 142 MW . This corresponds to a capacity factor of approx. 51% or 4500  full load hours ; Values ​​that are usually only achieved by offshore wind farms.
• The Dutch wind farm Eemmeerdijk , built in 1998, is exclusively equipped with two- blade rotors, while almost all other wind turbines use three-blade rotors.
• The Steinriegel 1 + 2 wind farm (from 2005 and 2014) in Ratten (Styria) is the largest in a high alpine location (in the Alps) with 21 wind turbines and 79 GWh / a generation.
• Hywind Scotland, the first commercial floating wind farm, was completed off the coast of Scotland in 2017 . The park consists of five floating wind turbines and has a total output of 30 MW.

See also

• Repowering - replacing older systems with modern ones
• List of wind turbine manufacturers
• List of European wind turbine types
• National Master Plan for Maritime Technologies

literature

• DEWI: Annual wind energy balance 2010. In: Hansa , Heft 5/2011, p. 22, Schiffahrts-Verlag Hansa, Hamburg 2011, ISSN  0017-7504
• Numbers and facts about wind power. In: Hansa , Heft 5/2011, p. 23, Schiffahrts-Verlag Hansa, Hamburg 2011, ISSN  0017-7504
• Sören Schöbel: Wind energy and landscape aesthetics - For the landscape-appropriate arrangement of wind farms. JOVIS-Verlag, Berlin 2012, ISBN 978-3-86859-150-7 .

Web links

Commons : Wind farms  - album with pictures, videos and audio files

Wiktionary: Windpark  - explanations of meanings, word origins, synonyms, translations

• WindPower Television
• List of wind farms
• Online application for the design and recalculation (map) of wind turbines, export of the 3D rotor blade geometry in CAD format
• List of the largest planned and existing wind farms

Individual evidence

1. ^ Dieter Hanisch: Renewable energies: A real fight against windmills. ZEIT ONLINE, November 30, 2011, accessed January 22, 2013 . 
2. ↑ Stefan Paetow , Günter Halama , Stephan Gatz , Alexander Jannasch : BVerwG 4 C 9.03. June 30, 2004, accessed January 22, 2013 . 
3. ↑ As a rule, the bank requires an equity ratio of 40%, a general contractor for the construction of the park, insurance cover during operation, a maintenance contract during operation and compliance with the Renewable Energy Sources Act in Germany or comparable laws in other countries.
4. ↑ Martin Greiner: Wind energy and physics: from turbulence to wind parks to complex networks. (PDF; 91 kB) University of Regensburg, Faculty of Physics, November 24, 2008, accessed on January 22, 2013 . 
5. ↑ Phil Sneiderman: New study yields better turbine spacing for large wind farms. Research seeks cleaner, more cost-efficient energy. In: The Gazette. The Johns Hopkins University, January 18, 2011, accessed January 22, 2013 . 
6. ↑ PHYSICS - Building wind farms is not optimal. , Deutschlandfunk - “ Forschung aktuell ” from April 2, 2014 (source: Journal of Renewable and Sustainable Energy / doi: 10.1063 / 1.4869568 ).
7. ↑ Otto Wöhrbach: 90 percent of wind turbines turn the wrong way round. In: Der Tagesspiegel. June 11, 2020, accessed June 12, 2020 . 
8. ↑ Description of the WAKE effect (PDF; 748 kB) ( Memento from November 12, 2013 in the Internet Archive )
9. ↑ WAKE effect - visible consequences in an offshore wind farm
10. ↑ MUFOW reduce the WAKE loss
11. ↑ Concept to reduce the WAKE loss ( Memento from March 28, 2012 in the Internet Archive )
12. ↑ Frequent forced shutdowns of wind farms . In: Handelsblatt , November 28, 2012, accessed on March 2, 2013
13. ↑ More wind power in the north German power grid. Network capacity in Schleswig-Holstein expanded / Eons first step. (No longer available online.) Bundesverband WindEnergie eV, September 18, 2006, archived from the original on September 24, 2006 ; Retrieved January 22, 2013 . 
14. ↑ ^{a b} Xinhua: Jiuquan Wind Power Base Completes First Stage , Xinhua News Agency , November 4, 2010, accessed on ChinaDaily.com.cn website January 3, 2013.
15. ↑ ^{a b c d e f g h} 2014 China Wind Power Review and Outlook . GWEC. Retrieved November 12, 2015.
16. ↑ United Nations Framework Convention on Climate Change: CDM: Gansu Guazhou 300 MW Wind Power Project . Retrieved May 28, 2015.
17. ↑ Jiuquan wind power base completes first stage . In: China Daily . Retrieved March 2, 2014.
18. ^ Winds of change blow through China as spending on renewable energy soars . In: The Guardian . Guardian News and Media Limited. Archived from the original on September 1, 2013. Retrieved March 2, 2014.
19. ^ Alta Wind Energy Center. Retrieved May 7, 2014 . 
20. ↑ BS Reporter: Suzlon creates country's largest wind park . May 11, 2012. Retrieved May 28, 2015.
21. ↑ E.ON Delivers 335-MW of Wind in Texas. RenewableEnergyWorld.com, September 23, 2008, accessed January 22, 2013 . 
22. ↑ ^{a b c d e f g h} Drilling Down: What Projects Made 2008 Such a Banner Year for Wind Power?
23. ↑ ^{a b c} AWEA: US Wind Energy Projects - Texas ( Memento from September 18, 2010 in the Internet Archive )
24. ↑ Fantanele-Cogealac Wind Farm, Romania . Power Technology, accessed July 26, 2014.
25. ↑ China - Dabancheng Wind Farm now has a combined generating capacity of 500 MW
26. ↑ Energy Information Administration of the USA - October 2010 edition of the Electric Power Monthly
27. ↑ Appeal court approves 1.8GW Swedish project . In: Windpower Monthly , June 20, 2018, accessed June 21, 2018.
28. ↑ Swiss investment displaces indigenous people . In: srf.ch , December 11, 2018, accessed December 25, 2018.
29. ↑ BKW is investing in Europe's largest wind farm . In: srf.ch , February 23, 2016, accessed on December 25, 2018.
30. ↑ The world's largest wind farm is being built in the Irish Sea , Tagesschau. June 4, 2010. Archived from the original on August 16, 2010. Retrieved on August 16, 2010. 
31. ↑ Domestic firms win all 6GW of China's first subsudy-free site . In: Windpower Monthly , April 3, 2019, accessed April 7, 2019.
32. ^ BP Ramps Up to Full Construction of First Phase of Wind Farm in South Dakota August 5, 2009
33. ↑ Klaus Bonanomi: Wind farm in Ukraine - China is investing heavily in European project. In: srf.ch . Retrieved October 28, 2019 . 
34. ↑ London Array's own website announcement of commencement of offshore works (PDF) Retrieved July 6, 2013.
35. ^ Wittrup, Sanne. First foundation Ing.dk , March 8, 2011, accessed March 8, 2011
36. ^ London Array Project home page . Londonarray.com. February 22, 1999. Retrieved July 6, 2013.
37. ^ Rupert Denholm-Hall: World's second largest offshore wind farm opens off coast of Wales . walesonline.co.uk. Retrieved June 30, 2015.
38. ^ Greater Gabbard: SSE wind farm project website . Sse.com. Archived from the original on August 14, 2011. Retrieved July 6, 2013.
39. ↑ Global Tech: Windpark - Global Tech 1 . globaltechone.de. Retrieved February 4, 2016.
40. ↑ DONG Energy: Facts on Anholt Offshore Wind Farm . dongenergy.com. Retrieved February 2, 2014.
41. ↑ BARD Offshore: Pioneering wind farm project BARD Offshore 1 successfully completed on the high seas . BARD offshore. August 1, 2013. Archived from the original on August 21, 2014. Retrieved on August 21, 2014.
42. ↑ Horns Rev II turbines . Dongenergy.com. Retrieved July 6, 2013.
43. ↑ Walney . 4COffshore. February 9, 2012. Retrieved February 9, 2012.
44. ↑ World's biggest offshore wind farm opens off Britain as new minister admits high cost . In: The Telegraph , February 9, 2012. 
45. ^ Belgium: Thornton Bank Offshore Wind Farm Officially Inaugurated . offshorewind.biz. September 18, 2013. Retrieved August 21, 2014.
46. ↑ Sheringham Shoal . scira.co.uk. Retrieved August 21, 2014.
47. ^ Thanet . The Engineer Online. July 25, 2008. Archived from the original on April 15, 2012. Retrieved on November 26, 2008.
48. ↑ Thanet offshore wind farm starts electricity production . In: BBC News , September 23, 2010. Retrieved September 14, 2010. 
49. ↑ E.ON's Amrumbank West offshore wind farm is fully connected to the grid . In: offshoreWIND.diz , October 22, 2015, accessed on October 22, 2015
50. ↑ Butendiek offshore wind farm fully operational . In: Focus , August 4, 2015, accessed on August 4, 2015
51. ↑ DanTysk North Sea wind farm officially goes online . In: heise.de , April 29, 2015, accessed April 30, 2015
52. ↑ Running: "Baltic 2" wind farm is on the grid . In: NDR , September 21, 2015, accessed on September 21, 2015
53. ↑ Meerwind Süd / Ost (Germany) offshore wind farm 4C , accessed on December 14, 2014.
54. ↑ Welcome to WindMW - Project MEERWIND South - East . Retrieved May 28, 2015.
55. ↑ Lincs OWF: Centrica express train Gratitude to Local Community (UK) . offshorewind.biz. July 4, 2013. Retrieved August 21, 2014.
56. ↑ (PDF; 482 kB) ( Memento from February 28, 2013 in the Internet Archive )
57. ↑ Wind farm in Kaiser-Wilhelm-Koog has existed since 1987 ( Memento from May 14, 2011 in the Internet Archive )
58. ↑ Africa's largest wind farm is now in operation. In: The business world of the regenerative energy industry. IWR - International Economic Forum for Renewable Energies, December 16, 2014, accessed on December 16, 2014 . 
59. ↑ Intense wind harvest in the pampas . In: Renewable Energies. Das Magazin , March 18, 2015, accessed on March 18, 2015