Renewable Energy to Renew the World
Sources of renewable energy include biomass, solar, wind, hydro and geothermal energy. Renewable energy is constant and is self-replenishing. It is also cleaner and more friendly to the environment. Renewable energy sources have made a huge impact in decreasing emission of carbon dioxide (CO2) into the Earth’s atmosphere. It is expected that renewable energy sources, especially wind energy, small hydro electrid power stations, biomass energy and solar energy will become economically competitive to conventional energy sources in the future, however they are not expected to overtake fossil fuels in keeping up with the global energy demand due to the fact that renewables have limitations.
Sun radiation is major contributor to energy sources. Solar technology uses the sun’s energy to provide heat, light, hot water, electricity and also for cooling homes, business and industries. Solar power is expanding as technology advances and cost becomes more competitive. These methods use photovoltaic systems, passive solar heating and solar process heat and space cooling.
Using the wind as a source of energy provides a clean, inexhaustible way to generate enough electricity to power millions of people. Wind power is the world’s fastest growing source of energy after solar. The United States can currently generate more than 10,000 megawatts (MW) of electricity from the wind, which is enough to power 2.5 million average American homes. Industry experts estimate that, with proper refinement and development, wind energy could provide 20% of the U.S. energy needs.
Biomass energy uses plant matter like trees, grasses, agricultural crops or other biological material. This can be used as a solid fuel, or converted into liquid or gaseous forms, for the production of electric power, heat, chemicals, or fuels. By incorporating a diversity of biomass conversion processes, all of these products can be made in one facility, which is called a biorefinery. This technology will provide a cost effective, environmentally friendly way of obtaining energy, and will decrease the dependence on foreign oil, improve air quality and support rural economies.
Geothermal energy, which derives heat from the earth’s inner core, is meeting a vast portion of electrical power demand in several developing countries. Approximately 8,000 megawatts of geothermal electricity is now being produced globally. To use geothermal energy, several new technologies have been developed to produce electricity from hydrothermal (hot water/steam) resources. In the future, it might be possible to use the heat of the deep, hot, dry rock formations of Earth’s crust, and possibly the even the deeper and nearly unlimited energy in the Earth’s magma. There are two basic types of geothermal power plants used today: Steam and binary. The steam plants use very hot (more than 300° F) steam and hot water resources. The steam then turns turbines, which drive generators that generate electricity. The only significant emission from these plants is steam (water vapor). Minute amounts of carbon dioxide, nitric oxide, and sulfur are emitted, but are nearly 50 times less than the traditional fossil-fuel power plants. Energy produced this way currently costs about 4-6 cents per kWh. Binary plants use lower temperature, but much more common, hot water resources (100° F – 300° F). The hot water is passed through a heat exchanger in conjunction with a secondary fluid with a lower boiling point. The secondary fluid vaporizes, which turns the turbines, which drive the generators. The remaining secondary fluid is simply recycled through the heat exchanger. With binary plants nothing is emitted. Energy produced by binary plants currently costs about 5 to 8 cents per kWh.
In the future, the use of renewable energy will significantly increase because the number of non-renewable energy supplies will diminish over time, as well as the desire to provide a less damaging effect on the environment.