Renewable energy comes from natural sources or processes that are constantly replenished. Offerings would encompass sunlight, wind, rain, tides, waves and geothermal heat. The renewable resources harnessing these flows of energy are constantly renewed in a short timeframe. They are virtually inexhaustible, unlike rapidly depleting non-renewable sources like coal, natural gas and oil.

Harnessing renewables to produce energy also creates virtually zero global warming emissions and air pollutants. It helps mitigate climate change and improves public health compared to fossil fuel energy plants. As clean alternatives, they help countries achieve energy security, resilience and independence goals as well reduce reliance on imported fuels. For these environmental, economic and social benefits, governments aim to maximize their renewable portfolios.

The main types of renewable energy are solar, wind, hydropower, biomass and geothermal. Solar panels convert sunlight into electricity. Arrays of wind turbines in wind farms harness the kinetic energy of wind to spin large blades connected to power generators. Hydropower utilizes water flows to spin turbines, often behind dams. Biomass includes harvested wood, municipal waste, landfill gases and plant materials to produce electricity or transportation fuels. Geothermal taps heat from under the earth’s surface to generate steam to drive turbines. Ocean renewable technologies also harness thermal, wave or tidal energy.

Besides the obvious renewables like wind mills and solar panels, renewables also include “green” hydrogen produced from water by electrolysis and then used for fuel or energy storage. Batteries, synthetic gas and biomass converted to fuels are also classed as renewables since they utilize sustainable inputs.

Most renewables generate power very differently from traditional, centralized electricity plants relying on steam turbines. They utilize modular technologies that pair well with decentralized grids and intermittent energy flows. Combined with efficiency gains, technological improvements and various storage methods to compensate for variability, very high renewable penetration on decarbonized grids is possible today.

Rapid growth, falling technology costs, increased private and public investment, and a supportive regulatory environment have positioned renewables as central to the global transition toward sustainable energy. Continued expansion of renewables promises to provide inexpensive, reliable and clean energy across the world.