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Renewable energy
Beginner
Energy from sources replenished naturally.
Renewables (solar, wind, hydro, tidal, geothermal) are replenished naturally. Solar panels convert about 20% of sunlight, wind turbines up to 59% (Betz limit) of wind's power.
A 1 m² panel at 1000 W/m² and 20% gives 200 W.
Intermittency needs storage or grids.
In more detail
Renewable energy comes from natural flows that are replenished, such as sunlight, wind, water and geothermal heat. Their output can vary, so they are often combined with storage or other sources.
Real-world uses
- Offshore wind farms supply electricity to coastal cities.
- Rooftop solar panels reduce household electricity bills.
- Wind farms and solar panels supply energy that is replaced naturally, unlike coal or gas which take millions of years to form.
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Frequently asked questions
Is renewable energy always available?
No. Sun and wind vary by time and place, so storage and grid planning are important.
Are renewable sources efficient?
Solar cells and wind turbines convert only part of the available energy, so efficiency matters.
Is renewable energy always available?
No. Solar and wind vary with weather and time of day, so storage or a backup supply is needed.
Related topics in Work, Energy & Power
Mechanical equivalent of heat · Mass–energy equivalence · Sources of energy · Conservation of energy in collisions · Virial theorem · Principle of virtual work