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Renewables 4 min read
What Are Renewable Energies?
A guide to the main renewable energy sources — solar, wind, geothermal, hydro, ocean and biomass — and how they differ from fossil fuels.
Renewable energy comes from natural sources that replenish faster than they are consumed, such as sunlight and wind. Fossil fuels — coal, oil and natural gas — are non-renewable resources that take hundreds of millions of years to form and release CO2 and other greenhouse gases when burned. Renewable generation produces significantly lower emissions, while also creating jobs in the clean energy industry and strengthening energy security.
Main sources
- Solar: the most abundant source, with photovoltaic panels converting sunlight into electricity even under cloud cover.
- Wind: turbines convert the wind's kinetic energy into electricity through blade movement.
- Geothermal: taps heat from inside the Earth; in Portugal significant electricity output only exists on São Miguel, Azores.
- Hydropower: dams or diversion structures drive turbines with the force of water, also serving irrigation and flood control.
- Ocean: wave, tidal and ocean-thermal energy, still at an early commercialisation stage.
- Biomass: organic material (farm and forest waste, energy crops) burned or converted into fuels.