Sustainable energy is the provision of energy such that it meets the needs of the present without compromising the ability of future generations to meet their needs. A broader interpretation may allow inclusion of fossil fuels as transitional sources while technology develops, as long as new sources are developed for future generations to use. A narrower interpretation includes only energy sources which are not expected to be depleted in a time frame relevant to the human race, which can potentially also include nuclear power if it is utilized differently from the current manner.
Sustainable energy sources are most often regarded as including all renewable energy sources, such as biofuels, solar power, wind power, wave power, geothermal power and tidal power.
Hydroelectric power may be unsustainable if it involves damming a river and thus disrupting the river's ecosystem, including nutrient flows via silt and fish migration. This impact can be reduced through measures such as fish ladders, but not easily eliminated. Microhydro and any run-of-the-river hydroelectric scheme potentially has a very much smaller environmental impact.
The broader concept "sustainable energy technology" can be used to include improvements to energy efficiency.
Types of energy and energy harvesting methods
Several types of energy can be harvested; these include
- Wind power; can be harvested using Wind energy conversion systems
- Hydropower; can be harvested using Hydro energy conversion systems
- Solar energy; can be harvested using Solar energy conversion systems
- Biomass; can be harvested using ?
- Muscle energy; can be harvested using ?
- Geothermal energy
- Nuclear energy
- Other types of stored energy (ie coal, fossil fuel, biofuel, ...) can be harvested using fossil fuel power plants, steam engines, internal combustion engines, stirling engines, ...