A sign is seen as Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

Pitlochry Power Station releases excess capacity of water over Pitlochry Dam, part of the Tummel hydro-electric power scheme in Perthshire, Scotland, Britain February 17, 2020. REUTERS/Russell Cheyne 

A truck drives along a bridge across the Yenisei river near the hydro electric power station with the air temperature at about -31 degrees Celsius outside Krasnoyarsk, Russia December 24, 2018. REUTERS/Ilya Naymushin 

A rainbow over the Yenisei river is seen near the hydro electric power station with the air temperature at about -31 degrees Celsius outside Krasnoyarsk, Russia December 24, 2018. REUTERS/Ilya Naymushin 

A man fishes under the bridge across Yenisei river with the air temperature at about -31 degrees Celsius during sunset near the hydro electric power station outside Krasnoyarsk, Russia December 24, 2018. REUTERS/Ilya Naymushin 

A man fishes under the bridge across Yenisei river with the air temperature at about -31 degrees Celsius during sunset near the hydro electric power station outside Krasnoyarsk, Russia December 24, 2018. REUTERS/Ilya Naymushin 

A fisherman is seen on a bank of the Yenisei River at sunset near the Krasnoyarsk hydro electric power station, with the air temperature at about minus 32 degrees Celsius (minus 25.6 degrees Fahrenheit), outside Krasnoyarsk, Russia January 26, 2018. REUTERS/Ilya Naymushin SEARCH "POY GLOBAL" FOR FOR THIS STORY. SEARCH "REUTERS POY" FOR ALL BEST OF 2018 PACKAGES. TPX IMAGES OF THE DAY. 

A fisherman is seen on a bank of the Yenisei River at sunset near the Krasnoyarsk hydro electric power station, with the air temperature at about minus 32 degrees Celsius (minus 25.6 degrees Fahrenheit), outside Krasnoyarsk, Russia January 26, 2018. REUTERS/Ilya Naymushin SEARCH "POY GLOBAL" FOR FOR THIS STORY. SEARCH "REUTERS POY" FOR ALL BEST OF 2018 PACKAGES. TPX IMAGES OF THE DAY. 

A general view shows the building of a machine hall at Krasnoyarsk hydroelectric power station, located on the Yenisei River outside Krasnoyarsk, Russia October 10, 2018. REUTERS/Ilya Naymushin 

An aerial view shows a bridge across the Yenisei River near the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Russia June 8, 2018. REUTERS/Ilya Naymushin 

An aerial view shows a forest fire in the Siberian Taiga area on the bank of the Yenisei River near the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Russia May 3, 2018. REUTERS/Ilya Naymushin 

Workers from China's Sinohydro Corp are seen outside the Kariba South hydro electric power plant in Kariba, Zimbabwe, March 27, 2018. Picture taken March 27, 2018. REUTERS/Philimon Bulawayo 

An aerial view shows the Krasnoyarsk hydro electric power station on the Yenisei River outside Krasnoyarsk, Russia February 24, 2018. REUTERS/Ilya Naymushin 

An aerial view shows the Krasnoyarsk hydro electric power station on the Yenisei River outside Krasnoyarsk, Russia February 24, 2018. REUTERS/Ilya Naymushin 

An aerial view shows the Krasnoyarsk hydro electric power station on the Yenisei River outside Krasnoyarsk, Russia February 24, 2018. REUTERS/Ilya Naymushin 

A contractor walks in a tunnel at the construction site at Karuma 600 megawatts hydroelectric power project under construction on River Nile, Uganda February 20, 2018. Picture taken February 20, 2018. REUTERS/James Akena TPX IMAGES OF THE DAY 

A fisherman is seen on a bank of the Yenisei River at sunset near the Krasnoyarsk hydro electric power station, with the air temperature at about minus 32 degrees Celsius (minus 25.6 degrees Fahrenheit), outside Krasnoyarsk, Russia January 26, 2018. REUTERS/Ilya Naymushin TPX IMAGES OF THE DAY 

A fisherman is seen on a bank of the Yenisei River at sunset near the Krasnoyarsk hydro electric power station, with the air temperature at about minus 32 degrees Celsius (minus 25.6 degrees Fahrenheit), outside Krasnoyarsk, Russia January 26, 2018. REUTERS/Ilya Naymushin 

A fisherman is seen on a bank of the Yenisei River at sunset near the Krasnoyarsk hydro electric power station, with the air temperature at about minus 32 degrees Celsius (minus 25.6 degrees Fahrenheit), outside Krasnoyarsk, Russia January 26, 2018. REUTERS/Ilya Naymushin 

A worker walks past an SSE van outside the Pitlochry Dam hydro electric power station in Pitlochry, Scotland, Britain, November 8, 2017. REUTERS/Russell Cheyne 

People walk past an SSE vehicle parked outside the Pitlochry Dam hydro electric power station in Pitlochry, Scotland, Britain, November 8, 2017. REUTERS/Russell Cheyne 

An SSE company logo is seen on signage outside the Pitlochry Dam hydro electric power station in Pitlochry, Scotland, Britain, November 8, 2017. REUTERS/Russell Cheyne 

An SSE vehicle is parked outside the Pitlochry Dam hydro electric power station in Pitlochry, Scotland, Britain, November 8, 2017. REUTERS/Russell Cheyne 

An SSE vehicle is parked outside the Pitlochry Dam hydro electric power station in Pitlochry, Scotland, Britain, November 8, 2017. REUTERS/Russell Cheyne 

An SSE vehicle is parked outside the Pitlochry Dam hydro electric power station in Pitlochry, Scotland, Britain, November 8, 2017. REUTERS/Russell Cheyne 

High-voltage lines from the Russia's largest hydropower station, Sayano-Shushenskaya, are seen outside the Siberian town of Sayanogorsk, in the Republic of Khakassia, Russia September 27, 2017. Picture taken September 27, 2017. REUTERS/Ilya Naymushin 

High-voltage lines from Russia's largest hydropower station, Sayano-Shushenskaya, are seen outside the Siberian town of Sayanogorsk, in the Republic of Khakassia, Russia September 27, 2017. Picture taken September 27, 2017. REUTERS/Ilya Naymushin 

The Salime dam and hydroelectric power station is seen near Grandas de Salime, Spain August 11, 2017. Picture taken August 11, 2017. REUTERS/Paul Hanna 

A car drives under a bridge with a shiplift, which is used to allow passage of ships past the dam situated on the Yenisei River, on it at the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Siberia, Russia, July 5, 2017. REUTERS/Ilya Naymushin 

A boat is transported in a shiplift, which is used to allow passage of ships past the dam situated on the Yenisei River, at the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Siberia, Russia, July 5, 2017. REUTERS/Ilya Naymushin 

A boat is transported in a shiplift, which is used to allow passage of ships past the dam situated on the Yenisei River, at the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Siberia, Russia, July 5, 2017. REUTERS/Ilya Naymushin 

An aerial view shows a dam of the Krasnoyarsk hydro electric power station, located on the Yenisei River, outside Krasnoyarsk, Russia, May 29, 2017. REUTERS/Ilya Naymushin 

An aerial view shows the Krasnoyarsk hydroelectric power station and a bridge across the Yenisei River outside Krasnoyarsk, Russia, May 14, 2017. REUTERS/Ilya Naymushin 

A general view shows the Krasnoyarsk hydroelectric power station, located on the Yenisei River outside Krasnoyarsk, Russia, March 2, 2017. REUTERS/Ilya Naymushin 

A general view shows the Krasnoyarsk hydroelectric power station, located on the Yenisei River outside Krasnoyarsk, Russia, March 2, 2017. REUTERS/Ilya Naymushin 

A general view shows the Krasnoyarsk hydroelectric power station, located on the Yenisei River outside Krasnoyarsk, Russia, March 2, 2017. REUTERS/Ilya Naymushin 

A general view shows a mosaic panel with a portrait of the Soviet state founder Vladimir Lenin at the Krasnoyarsk hydro electric power station, located on the Yenisei River outside Krasnoyarsk, Russia, February 21, 2017. REUTERS/Ilya Naymushin 

Employees walk in front of the dam of the Krasnoyarsk hydro electric power station, located on the Yenisei River outside Krasnoyarsk, Russia, February 21, 2017. REUTERS/Ilya Naymushin 

A truck drives along a bridge across the Yenisei river near the Krasnoyarsk hydro electric power station, with the air temperature at minus 25 degrees Celsius (minus 13 degrees Fahrenheit), outside Krasnoyarsk, Siberia, Russia, January 28, 2017. REUTERS/Ilya Naymushin 

A security guard walks along a bridge across the Yenisei river near the Krasnoyarsk hydro electric power station, with the air temperature at minus 25 degrees Celsius (minus 13 degrees Fahrenheit), outside Krasnoyarsk, Siberia, Russia, January 28, 2017. REUTERS/Ilya Naymushin 

A view of Macagua dam and the Antonio Jose de Sucre Hydroelectric Power Station, in Puerto Ordaz at the southern state of Bolivar, Venezuela January 27, 2017. REUTERS/Marco Bello 

A view of Macagua dam and the Antonio Jose de Sucre Hydroelectric Power Station, in Puerto Ordaz at the southern state of Bolivar, Venezuela January 27, 2017. REUTERS/Marco Bello 

A general view of the Krasnoyarsk hydroelectric power station, illuminated on the occasion of the New Year and the upcoming Christmas, on the Yenisei River outside Krasnoyarsk, Russia January 1, 2017. REUTERS/Ilya Naymushin 

An employee walks past a shiplift, which is used to allow passage of ships past the dam situated on the Yenisei River, at the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Siberia, Russia, October 3, 2016. REUTERS/Ilya Naymushin 

A shiplift, which is used to allow passage of ships past the dam situated on the Yenisei River, is seen at the Krasnoyarsk hydro electric power station outside Krasnoyarsk, Siberia, Russia, October 3, 2016. REUTERS/Ilya Naymushin 

Venezuela's President Nicolas Maduro (R) gestures while he speaks next to Colombia's President Juan Manuel Santos during their meeting at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (C) walks next to Colombia's President Juan Manuel Santos during their meeting at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela, August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (2nd R) speaks next to (L-R) Colombia's Foreign Minister Maria Angela Holguin, Colombia's President Juan Manuel Santos and Venezuela's Foreign Minister Delcy Rodriguez during their meeting at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (R) speaks in front of a painting of South American independence leader Simon Bolivar, during his meeting with Colombia's President Juan Manuel Santos at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela, August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (R) speaks in front of a painting of South American independence leader Simon Bolivar, during his meeting with Colombia's President Juan Manuel Santos at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela, August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (R) and Colombia's President Juan Manuel Santos shake hands in front of a painting of South American independence leader Simon Bolivar, during their meeting at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro waits the arrival of Colombia's President Juan Manuel Santos at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela, August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (L) talks to his wife Cilia Flores while they wait the arrival of Colombia's President Juan Manuel Santos at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela, August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro (L) talks to his wife Cilia Flores while they wait the arrival of Colombia's President Juan Manuel Santos at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela August 11, 2016. REUTERS/Carlos Garcia Rawlins 

Venezuela's President Nicolas Maduro waves while he waits the arrival of Colombia's President Juan Manuel Santos at Macagua Hydroelectric compound in Puerto Ordaz, Venezuela, August 11, 2016. REUTERS/Carlos Garcia Rawlins