We have relied on fossil fuels for our energy needs because, historically, these fuels have been relatively inexpensive, and profitable for developers. With rising fuel prices, concerns about environmental impact and growing political concerns about oil suppliers, renewable energy is gaining in importance.
Renewable resources are natural sources that cannot be diminished. Examples include solar, wind, hydroelectric, biomass and geothermal. Fossil fuels like coal, oil and even clean-burning natural gas do not exist in unlimited supply. Someday they will be gone. In additional to unending availability, renewable resources create less environmental impact, specifically pollution.
The sun’s power not only represents a vast source of energy, it also underlies most other renewable resources. The sun is constantly heating the earth and the oceans and enabling the activities of man. Today, photovoltaic panels capture light and convert it to energy is. The panels have no moving parts and thus require little maintenance, and once in place, solar panels do not create pollution or solid waste. However, production of the panels involves the use of toxic chemicals, and implementing solar power continues to be cost-prohibitive.
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Like solar energy, wind energy does not produce pollution or solid waste, but there are definitely moving parts. And those moving parts can be fatal to birds and present hazards to those working with them. Windmills have been capturing energy for hundreds of years. The newer wind turbines convert the force of moving air into electricity. According to the National Renewable Energy Laboratory’s Wind Technology Center, wind power could supply up to 20 percent of the United States’ electricity needs. Their goal is to make it the cheapest form of energy available. Moving captured wind energy across the country is expensive, however. Current research focuses on using offshore wind turbines, as the bulk of the country’s population is costal. Objections to wind turbines use include their visual impact on the landscape as well as the noise they create.
Like wind and solar, hydropower has been in use for hundreds of years. From the early water wheel used to turn the millstone to a massive generator like Hoover Dam, there’s real energy in hydropower (called hydroelectric when electricity is generated). Hydropower is clean and domestically available; however, it is not without environmental impact. Damming rivers to tap this renewable resource affects fish and ecosystems in the waterways.
Biomass is created from trees and plants. It includes both crops that are specifically grown as an energy source and plant waste such as residue left over from the paper-making process, or the methane gas produced from decomposition. Like solar and wind power, biomass has been around for a long time. The simple act of lighting a fire for cooking or heat is an example of using biomass. Newer forms of it include crop cultivation specifically for energy, and the use of crop waste like corn stover (the stalks, leaves and husks left over after harvest).
Geothermal energy is the heat stored inside the earth. It can either be in the form of earth’s sun-heated crust (the surface that maintains a relatively constant temperature of 50 to 60 degrees Fahrenheit) or from features like hot springs or steam reservoirs. The variety of geothermal sources could enable wide-scale use of this renewable resource, from heat pumps to heat and cool homes to large utilities tapping the source to generate electricity.