Renewable Energy

Renewable energy comes from natural processes that are replenished constantly. It is central to efforts to cut greenhouse gas emissions.

Sources

Solar

Photovoltaic panels turn sunlight directly into electricity, and costs have fallen sharply since 2010.

Wind

Turbines on land and at sea convert moving air into power.

Hydropower

Dams and river systems remain the largest source of renewable electricity in the world.

Challenges

Wind and sunlight vary through the day and the year, so grids need flexibility, transmission lines and storage.

Energy storage

Batteries and pumped hydro store surplus power, which helps grids rely on variable sources such as wind and sunlight.