Wind turbines generate power at the Loraine Windpark Project in Loraine, Texas U.S. August 24, 2018. Picture taken August 24, 2018. REUTERS/Nick Oxford

A wind turbine generates power at the Loraine Windpark Project in Loraine, Texas U.S. August 24, 2018. Picture taken August 24, 2018. REUTERS/Nick Oxford

Wind turbines generate power at the Loraine Windpark Project in Loraine, Texas U.S. August 24, 2018. Picture taken August 24, 2018. REUTERS/Nick Oxford

Wind turbines generate power at the Loraine Windpark Project in Loraine, Texas U.S. August 24, 2018. Picture taken August 24, 2018. REUTERS/Nick Oxford

Wind turbines generate power at the Loraine Windpark Project in Loraine, Texas U.S. August 24, 2018. Picture taken August 24, 2018. REUTERS/Nick Oxford

Power-generating windmill turbines are pictured at the 'Amrum Bank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrum Bank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrum Bank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrum Bank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

A special construction vessel is pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrum Bank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

A special construction vessel is pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

A special construction vessel is pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrum Bank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

A special construction vessel is pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

A special construction vessel is pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

A special construction vessel is pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen

Power-generating windmill turbines are pictured at the 'Amrumbank West' offshore windpark in the northern sea near the island of Amrum, Germany September 4, 2015. REUTERS/Morris Mac Matzen TPX IMAGES OF THE DAY

Wind turbines are pictured in RWE Offshore-Windpark Nordsee Ost in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Wind turbines are pictured in RWE Offshore-Windpark Nordsee Ost in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

A symbolic plug is pictured before the inauguration of RWE Offshore-Windpark Nordsee Ost and TenneT converter platform HelWin alpha as part of G7 energy ministers meeting, on HelWin alpha converter platform in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Wind turbines and the converter platforms HelWin alpha and HelWin beta are pictured in RWE Offshore-Windpark Nordsee Ost in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Wind turbines are pictured in RWE Offshore-Windpark Nordsee Ost in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Wind turbines are pictured in RWE Offshore-Windpark Nordsee Ost in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Wind turbines are pictured in RWE Offshore-Windpark Nordsee Ost in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

German Economy Minister Sigmar Gabriel (C) and other officials arrive for the inauguration of RWE Offshore-Windpark Nordsee Ost and TenneT converter platform HelWin alpha as part of G7 energy ministers meeting, on HelWin alpha converter platform in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Japan's parliamentary Vice-Minister of Economy, Trade and Industry Shigeki Iwai, Director-General of International Renewable Energy Agency Adnan Z. Amin, Chief Executive Officer of TenneT Holding B.V Mel Kroon, EU Commissioner for Climate Action and Energy Miguel Arias Canete, Prime Minister of the German State Schleswig-Holstein Torsten Albig, Hamburg's first mayor Olaf Scholz, German Economy Minister Sigmar Gabriel and Peter Terium, CEO of German power supplier RWE (L-R) hold a symbolic plug during the inauguration of RWE Offshore-Windpark Nordsee Ost and TenneT converter platform HelWin alpha as part of G7 energy ministers meeting, on HelWin alpha converter platform in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

Japan's parliamentary Vice-Minister of Economy, Trade and Industry Shigeki Iwai, Director-General of International Renewable Energy Agency Adnan Z. Amin, Chief Executive Officer of TenneT Holding B.V Mel Kroon, EU Commissioner for Climate Action and Energy Miguel Arias Canete, Prime Minister of the German State Schleswig-Holstein Torsten Albig, Hamburg's first mayor Olaf Scholz, German Economy Minister Sigmar Gabriel and Peter Terium, CEO of German power supplier RWE (L-R) hold a symbolic plug during the inauguration of RWE Offshore-Windpark Nordsee Ost and TenneT converter platform HelWin alpha as part of G7 energy ministers meeting, on HelWin alpha converter platform in the North sea, 30 km from Helgoland, Germany, May 11, 2015. REUTERS/Christian Charisius/Pool

People look at the off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday German Chancellor Angela Merkel attended an opening ceremony for the 21 wind turbines EnBW Baltic 1. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT CITYSCAPE)

CEO of energy company EnBW Hans-Peter Villis (L-R), German Chancellor Angela Merkel and state premier of Mecklenburg-Vorpommern Erwin Sellering attend the opening ceremony of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

German Chancellor Angela Merkel (R) and CEO of energy company EnBW Hans-Peter Villis attend an opening ceremony of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

German Chancellor Angela Merkel delivers a speech on the opening ceremony of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

German Chancellor Angela Merkel arrives for the opening ceremony of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

German Chancellor Angela Merkel attends the opening ceremony of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

German Chancellor Angela Merkel and CEO of energy company EnBW Hans-Peter Villis arrive to pose next to a miniature of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

CEO of energy company EnBW Hans-Peter Villis (L-R), German Chancellor Angela Merkel and state premier of Mecklenburg-Vorpommern Erwin Sellering pose next to a miniature of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

CEO of energy company EnBW Hans-Peter Villis (L-R), German Chancellor Angela Merkel and state premier of Mecklenburg-Vorpommern Erwin Sellering pose next to a miniature of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

CEO of energy company EnBW Hans-Peter Villis (L-R), German Chancellor Angela Merkel and state premier of Mecklenburg-Vorpommern Erwin Sellering pose next to a miniature of an off-shore windpark at the Baltic Sea in Zingst, May 2, 2011. On Monday Merkel attended an opening ceremony for the 21 wind turbines. REUTERS/Tobias Schwarz (GERMANY - Tags: ENERGY ENVIRONMENT POLITICS)

Wind turbines are seen in a windpark 23 km (14 miles) off the coast of Ijmuiden September 3, 2007. REUTERS/ Michael Kooren (NETHERLANDS)