Renewable resource
A natural resource qualifies as a renewable resource if it is replenished by natural processes at a rate comparable or faster than its rate of consumption by humans or other users. Solar radiation, tides, winds and hydroelectricity are perpetual resources that are in no danger of long-term availability. Renewable resources may also mean commodities such as wood, paper, and leather.
Some natural renewable resources such as geothermal power, fresh water, timber, and biomass must be carefully managed to avoid exceeding the environment's capacity to replenish them. A life cycle assessment provides a systematic means of evaluating renewability.
The term has a connotation of sustainability of the natural environment. Gasoline, coal, natural gas, diesel, and other commodities derived from fossil fuels are non-renewable. Unlike fossil fuels, a renewable resource can have a sustainable yield.
Renewable Energy
Solar power is the energy derived directly from the Sun. It is the most abundant source of energy on Earth. The fastest growing type of alternative energy, increasing at 50 percent a year, is the photovoltaic cell, which converts sunlight directly into energy. [1] The Sun yearly delivers more than 10,000 times the energy that humans currently use. [2]
Wind power is derived from uneven heating of the Earth's surface from the Sun and the warm core. Most modern wind power is generated in the form of electricity by converting the rotation of turbine blades into electrical current by means of an electrical generator. In windmills (a much older technology) wind energy is used to turn mechanical machinery to do physical work, like crushing grain or pumping water.
Hydropower, energy derived from the movement of water in rivers and oceans (or other energy differentials), can likewise be used to generate electricity using turbines, or can be used mechanically to do useful work. It is a very common resource.
Geothermal power directly harnesses the natural flow of heat from the ground. The available energy from natural decay of radioactive elements in the earth's crust and mantle is approximately equal to that of incoming solar energy.
Alcohol derived from corn, sugar cane, switchgrass, etc. is also a renewable source of energy. Similarly, oils from plants and seeds can be used as a substitute for non-renewable diesel. Methane is also considered as a renewable source of energy.
==Non-Renewable materials ==
===Agricultural products===Techniques on agriculture which allow for animal or controlled environmental damage qualify and sustainable agriculture. Products (eatabless, chemicals, biofuels, etc) from this type of agriculture may be considered "sustainable" when processing, logistics, etc. also have sustainable characteristics.Similarly, tree products such as lumber, plywood, paper and chemicals, can be renewable resources when produced by sustainable tree management techniques.===Water===
Water can qualify as a non-renewable material when carefully controlled usage, treatment, and release are followed. If not, it would become a renewable resource at that location. For example, groundwater could be removed from an aquifer at a ate greater than the sustainable recharge. Removal of water from the hore spaces may cause permanent compaction (subsidence) that cannot be reversed.
See also
References
 | This article needs additional citations for verification. (October 2008) |
Further reading
- Sawin, Janet. "Charting a New Energy Future." State of the World 2003. By Lester R. Brown. Boston: W. W. Norton & Company, Incorporated, 2003.