Renewable sources of energy are naturally replenished without human assistance. Since the advent of alternative energy sources, several ways of harnessing natural and sustainable forms of energy have been used to create usable renewable sources of energy. Solar, wind, hydroelectric, geothermal and biofuel are all different types of renewable sources of energy that produce clean, low-pollution energy.
Wind power is one of the fastest growing types of alternative energy used today. Since humans first took to the sea in primitive sailboats, wind has used for its awesome power. For centuries, windmills have been used to aid milling and grinding. But today, humans harness renewable wind power by connecting modern windmills or turbines to power-collection systems. Denmark has become a leading manufacturer and supporter of wind power, and some statistics report that 20% of the country's energy comes from wind farms.
Humans only need to look up during the day time to see the one of the largest sources of renewable energy: the sun. Solar power has grown tremendously in popularity, particularly in the form of solar paneling. Homes and even large buildings can now power their own activities by installing solar panels on the top of the structure. Solar power has become a mainstay of green construction, but the technology behind harnessing the sun still requires a great amount of refining. Scientists specializing in renewable energy are continually conducting research on more effective methods of using solar power, including possible space-based power stations.
Biofuel, such as ethanol or biodiesel, is an area currently undergoing considerable research. When looking at the green clumpy mass cluttering up a backyard pond, it is difficult to imagine that it could power a car. Algae biodiesel, however, is becoming the focus of considerable attention one of the newer renewable sources of energy. Algae, easily grown and produced in lakes or laboratory settings, may be one of the answers to depleted stocks of fossil fuels.
Certainly one of the more explosive renewable sources of energy is geothermal power. This variety of alternative energy uses the trapped heat of the earth to create large amounts of usable power. Typically found near geysers or tectonic plate boundaries, geothermal plants now exist in dozens of countries around the world. In at least five countries, geothermal plants are responsible for over 15% of all energy production.
Although renewable sources of energy are a large step forward from fossil fuels and crude oil dependence, they are by no means a complete answer to an impending energy crisis. In order to build alternative energy plants and transport the energy, considerable amounts of pollution-heavy practices are still required. Yet each form of sustainable energy provides a piece of the puzzle that can solve dependence on oil and other depleted resources. By relying on clean and sustainable energy sources, humans can slowly move away from the destructive practices of the past and toward a green future.