Energiaallikate

Energiaallikate (Estonian for energy sources) are resources or natural phenomena from which energy can be obtained to power devices, generate electricity, heat buildings, or move vehicles. They can be broadly categorized by origin as primary energy sources and by the energy form after conversion as secondary energy sources.

Primary energy sources include fossil fuels (coal, oil, natural gas), nuclear energy, and renewable resources found in nature such as sunlight, wind, flowing water, biomass, geothermal heat, and tides. Secondary energy sources refer to energy that has been transformed for convenient use, most commonly electricity and refined fuels.

A common distinction is renewable versus non-renewable: renewable sources replenish naturally on human timescales (solar, wind, hydro, biomass, geothermal, and marine energy), while non-renewable sources rely on finite stocks (fossil fuels and uranium).

The choice of energy sources is influenced by availability, geography, technology, cost, and environmental considerations, notably greenhouse gas emissions and local air quality. Some sources, like wind and solar, are intermittent and require storage or backup capacity; others, like baseload hydropower or nuclear, provide steadier output.

Global energy systems are in transition toward low-carbon mixes, driven by policy, technology, and market dynamics. The mix of energy sources varies by country and region and is subject to ongoing transitions in the coming decades.