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. Resources such as solar radiation, tides, and winds are perpetual resources that are in no danger of being used in excess of their long-term availability.

Natural resources such as fresh water, timber, and biomass might be considered as renewable, depending on usage and location. They can become non-renewable resources if used at a rate greater than the environment's capacity to replenish them. For example, groundwater may be removed from an aquifer at a rate greater than the sustainable recharge. Removal of water from the pore spaces may cause permanent compaction (subsidence) that cannot be reversed. A life cycle assessment provides a systematic means of evaluating renewability.

Renewable resources may also include commodities such as wood, paper, and leather. Furthermore, alcohol derived from corn, sugar cane, switchgrass, etc. is also a renewable source of energy. Similarly, oils from plants and seeds can used as even as a substitute for non-renewable diesel. Methane is also considered as a renewable source of energy.

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
Solar power is the energy derived from the Sun. It is the most abundant source of energy on Earth.

Wind power
Wind power is the conversion of wind energy into more useful forms, usually electricity using wind turbines. In 2005, worldwide capacity of wind-powered generators was 58,982 megawatts; although it currently produces less than 1% of world-wide electricity use, it accounts for approximately 23% of electricity use in Denmark, 9% in Spain, and 6% in Germany. Globally, wind power generation more than quadrupled between 1999 and 2005.

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. Wind power is used in large scale wind farms for national electrical grids as well as in small individual turbines for providing electricity to rural residences or grid-isolated locations. Wind energy is ample, renewable, widely distributed, clean, and mitigates the greenhouse effect if used to replace fossil-fuel-derived lightning. To make the power, the windmill captures the wind and spins a generator. The generator then gives off gas which then forms into electricity. The siting of turbines has become a controversial issue amongst those concerned about the value of natural landscapes, particularly since the best sites for wind generation tend to be in scenic mountain and oceanside areas.

Hydropower
Hydropower is the capture of the energy of moving water for some useful purpose. Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, milling of grain, textile manufacture, and the operation of sawmills.

The energy of moving water has been exploited for centuries; in Imperial Rome, water powered mills produced flour from grain, and in China and the rest of the Far East, hydraulically operated "pot wheel" pumps raised water into irrigation canals. In the 1830s, at the peak of the canal-building era, hydropower was used to transport barge traffic up and down steep hills using inclined plane railroads.

Direct mechanical power transmission required that industries using hydropower had to be situated near the waterfall. For example, during the last half of the 19th century, many grist mills were built at Saint Anthony Falls, utilizing the 50 foot (15 meter) drop in the Mississippi River. The mills contributed to the growth of Minneapolis. Today the largest use of hydropower is for electric power generation, which allows low cost energy to be used at long distances from the watercourse.

Renewable materials

Sustainable agriculture
Techniques in agriculture allow for minimal or controlled environmental damage and qualify as sustainable agriculture.

Water
Water can qualify as a renewable material when carfully controlled usage, treatment, and release are followed. If not it would then qualify as a non-renewable resource.

Some contents courtesy of Wikipedia