Ocean thermal energy conversion (OTEC) is a type of renewable energy that uses the temperature difference between warm ocean surface water and cold deep water to operate a machine that produces electricity. It is a special way of creating clean energy that can provide a reliable and ongoing power source. Even though there are challenges to solve, OTEC can still offer a steady and long-lasting form of clean energy, especially in tropical areas where deep ocean water is available.
Wave power is the process of capturing energy from wind-driven ocean waves to perform tasks such as generating electricity, removing salt from seawater, or moving water. A device used to harness this energy is called a wave energy converter (WEC). Ocean waves are created mainly by wind blowing across the surface of the sea, as well as by forces such as the gravitational pull of the moon and sun, changes in water temperature, and other natural factors.
Tidal power, or tidal energy, is captured by changing the energy from tides into electricity and other useful forms of power. Although not widely used today, tidal energy has the potential to generate electricity in the future. Tides are more predictable than wind or sunlight.
Hydroelectric power is a type of electricity made from water energy. In 2023, hydropower provided 15% of the world’s electricity, about 4,210 terawatt-hours, which is more than all other renewable energy sources combined and also more than nuclear power. Hydropower can supply large amounts of electricity with low carbon emissions, helping to create reliable and clean energy systems.
A vertical-axis wind turbine (VAWT) is a type of wind turbine where the main rotor shaft is positioned perpendicular to the wind direction, and the main parts are placed at the base of the turbine. This setup places the generator and gearbox near the ground, making it easier to service and repair them. VAWTs do not need to face the wind directly, which eliminates the need for systems that sense wind direction or adjust the turbine’s position.
China has the largest total power generation ability from wind energy among all countries and continues to add new wind power facilities quickly. Because of its large size and long coastline, China has excellent wind power resources. In 2021, wind power was the third-largest source of electricity in China, making up 7.5% of all electricity produced.
Wind power is part of the energy industry and has grown quickly in the United States in recent years. In 2025, wind power produced 464.4 terawatt-hours of electricity, which is 10.48% of the total electricity in the United States. On average, a wind turbine can generate enough electricity in 46 minutes to power the average American home for one month.
Wind power is a major source of electricity in Germany. The country’s energy plan, called the Energiewende, has stopped using nuclear power by 2023. About 60% of Germany’s electricity comes from renewable sources, with half of that from wind power.
Denmark was an early leader in creating commercial wind power during the 1970s. Today, many wind turbines worldwide are made by Danish companies like Vestas, which is the largest wind-turbine maker, along with other suppliers of parts. As of 2022, Denmark has the second-highest amount of wind power generation capacity per person in the world, behind only Sweden.
The total power that wind can produce worldwide has grown quickly since the year 2000. By the end of 2023, this power was over 1,000 gigawatts. Since 2010, more than half of all new wind power added globally was built outside Europe and North America, mostly because of growth in China and India.