Energy obtained from naturally replenished flows or stocks on a human timescale. Replenishment does not by itself prove low life-cycle emissions or negligible environmental impact. Variability, geographic availability and conversion equipment matter when a source is integrated into an energy system.
Useful power extracted from surface-water waves. Resource variability, extreme-storm survivability, offshore access, moorings and electrical connections affect practical performance. Its potential and costs are distinct from those of tidal power, even when both use marine locations.
Power extracted from tidal water-level differences or tidal currents. Astronomical timing is predictable, but output is not constant. Basin geometry, flow changes caused by extraction, environmental effects and connection infrastructure constrain practical resources; a local undisturbed-flow power density is not a whole-channel extractable-energy estimate.
Conversion of sunlight into useful power through photovoltaic or solar-thermal systems. A first areal estimate is annual mean irradiance times conversion efficiency and system-performance factors. Storage, transmission, land use, night-time operation and seasonal balance require separate accounting.
Conversion of atmospheric kinetic energy into useful power, commonly by turbines driving generators. Annual energy equals nameplate capacity times capacity factor times elapsed time, while the contribution to reliable peak supply is a separate system property. Weather correlation, transmission, flexibility and curtailment affect large-scale integration.
Energy recovered from biologically produced material, for example by combustion or conversion into fuels. Sustainable regrowth can recycle biogenic carbon, but land-use change, cultivation, processing, transport and regrowth time belong in its life-cycle assessment. Harvested energy is incident solar energy times area, elapsed time and annual conversion efficiency; dry and wet mass yields require different heating-value conventions.
Articles by others on the same topic
There are currently no matching articles.