Renewable energy

Examples of renewable energy options: concentrated solar power with molten salt heat storage in Spain; wind energy in South Africa; the Three Gorges Dam on the Yangtze River in China; biomass energy plant in Scotland.

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Renewable energy (or green energy) is energy from renewable natural resources that are replenished on a human timescale. The most widely used renewable energy types are solar energy, wind power and hydropower. Bioenergy and geothermal power are also significant in some countries. Some also consider nuclear power a renewable power source, although this is controversial. Renewable energy installations can be large or small and are suited for both urban and rural areas. Renewable energy is often deployed together with further electrification. This has several benefits: electricity can move heat and vehicles efficiently, and is clean at the point of consumption.^[1][2] Variable renewable energy sources are those that have a fluctuating nature, such as wind power and solar power. In contrast, controllable renewable energy sources include dammed hydroelectricity, bioenergy, or geothermal power.

Renewable energy systems have rapidly become more efficient and cheaper over the past 30 years.^[3] A large majority of worldwide newly installed electricity capacity is now renewable.^[4] In most countries, photovoltaic solar or onshore wind are the cheapest new-build electricity.^[5] From 2011 to 2021, renewable energy grew from 20% to 28% of global electricity supply. Power from sun and wind accounted for most oft his increase, growing from a combined 2% to 10%. Use of fossil energy shrank from 68% to 62%.^[6] In 2022, renewables accounted for 30% of global electricity generation, and are projected to reach over 42% by 2028.^[7][8] Many countries already have renewables contributing more than 20% of their total energy supply, with some generating over half or even all their electricity from renewable sources.^[9][10]

The main motivation to replace fossil fuels with renewable energy sources is to slow and eventually stop climate change, which is widely agreed to be caused mostly by greenhouse gas emissions. In general, renewable energy sources cause much lower emissions than fossil fuels.^[11] In 2022 the International Energy Agency (IEA) requested all countries to reduce their policy, regulatory, permitting and financing obstacles for renewables.^[12] This would increase the chances of the world reaching net zero carbon emissions by 2050.^[12] According to the IEA, to achieve net zero emissions by 2050, 90% of global electricity generation will need to be produced from renewable sources.

The deployment of renewable energy still faces obstacles, especially fossil fuel subsidies,^[13] lobbying by incumbent power providers,^[14] and local opposition to the use of land for renewables installations.^[15][16] Although most renewable energy sources are sustainable, some are not. For example, some biomass sources are unsustainable at current rates of exploitation.^[17]