Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Aerial view of Baihetan hydropower station, China

The Baihetan hydropower station in Liangshan, China. Scientists have found that sunlight absorbed by hydropower reservoirs can offset the environmental advantages of this power source. Credit: TPG/Getty

Climate change

Darkened reservoirs can blot out hydropower’s climate gains

At some stations, stored water absorbs enough sunlight to offset the station’s carbon savings.

A hydropower station’s dark reservoir can soak up enough solar energy to cancel its climate benefit.

More than 3,700 major hydropower stations are planned or are under construction, and could bolster the world’s supply of low-carbon electricity. But hydropower requires storing large volumes of water, and a hydropower reservoir often absorbs more incoming solar energy than the terrain it replaced.

Georg Wohlfahrt at the University of Innsbruck, Austria, and his colleagues analysed satellite data at 724 hydropower stations around the world and found that the reservoirs were darker than the surrounding landscape and thus absorbed more solar energy. The team then calculated the extra warming from each reservoir as well as the warming that would be avoided at each by generating electricity from hydropower rather than fossil fuels.

The team found that nearly half of the stations produced net climate benefits within four years. But 19% needed more than 40 years to produce such a benefit, and 12% of stations failed to do so within their estimated 80-year lifetime. The authors suggest that reservoir design should account for reflectance changes.

More Research Highlights...

Ember and thick smoke from bushfires reach Braemar Bay in New South Wales

Vast bush fires that swept across Australia at the end of 2019 and the start of 2020 filled the skies with enough smoke to warm a portion of the atmosphere. Credit: Saeed Khan/AFP/Getty

Atmospheric science

Smoke from Australian fires turned up the heat in the southern sky

The catastrophic wildfires of late 2019 and early 2020 triggered a lingering temperature rise in a section of Earth’s lower atmosphere.
Visible and infrared images of the device in fully discharged and charged states

A display screen in its uncharged (top left) and charged (top right) state in visible light. The screen reflects one range of infrared wavelengths when uncharged (bottom left) and another range when charged (bottom right). Credit: M. S. Ergoktas et al./Nature Photon.

Optics and photonics

One screen, three images — some invisible in ordinary light

A graphene-based device can display several images simultaneously using a range of wavelengths.
Woman harvesting teff, Ethiopia

A farmer in Ethiopia harvests teff, a cereal. Small farms tend to have more-diverse landscapes than do sprawling industrial operations. Credit: Andia/Universal Images Group/Getty

Environmental sciences

Small farms outdo big ones on biodiversity — and crop yields

Large-scale farms account for most of the global food supply, but smallholdings protect species and are just as profitable.
Diagram of the nuclear composition and electron configuration of an atom of xenon-132.

A xenon atom’s electrons (grey circles; illustration) have been observed and even manipulated as they shifted their position. Credit: Carlos Clarivan/Science Photo Library

Atomic and molecular physics

An atom shuffles its electrons at ultrahigh speed — and is caught in the act

Scientists capture the movement of electrons in a xenon atom, a phenomenon that lasts for a fraction of one-billionth of a second.
Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing


Quick links