Types of Renewable Energy

From LoveToKnow GreenLiving

Increasing demand for types of renewable energy will help reverse global warming and reduce our reliance on fossil fuels. Renewable, non-polluting energy sources are useful for electricity generation, transportation fuels, and heating and cooling.

Types of Renewable Energy

Types of renewable energy include hydropower, geothermal energy, wind energy, solar energy, biomass, tidal energy, and hydrogen energy.

Hydropower

Hydropower works by converting flowing water into energy. The Energy Information Administration (EIA) states that hydropower accounts for 6 percent of all electricity production in the United States, and nearly 70 percent of electricity generation from renewable energy sources.

Hydropower relies on the planet's water cycle to produce electricity. Energy from the sun causes surface water to evaporate. This water vapor rises, condenses and forms clouds, and then returns to the planet's surface as rain or snow. As this water flows through rivers and streams on its way back to the ocean, it produces energy. Pipes work to channel the water and direct the flow to push against turbine blades, which in turn power generators and produce electricity.

Geothermal Energy

Geothermal energy occurs naturally as heat deep beneath the planet's surface. Trapping and harnessing this heat creates hot water and steam that powers steam turbines to generate electricity. The steam can also heat buildings directly. Because decaying radioactive particles inside the Earth continuously generate heat, geothermal energy is a very reliable form of renewable energy.

In addition to electricity generation and heating, geothermal energy has several industrial applications. Food dehydration, milk pasteurization, and gold mining all benefit from geothermal energy. The U.S. leads the world in geothermal power generation, but geothermal energy accounts for less than 0.05 percent of American electricity production.

Wind Energy

Generating electricity from wind is a simple process. Blades attached to wind turbines collect the kinetic energy of wind, causing the blades to turn. The turning blades connect to a main drive shaft that spins a generator, converting the kinetic energy to electrical energy. The amount of energy produced during the process depends on the size of the wind machine. Homes and farms use smaller turbines, while factories and power stations use larger turbines.

In 2008, wind machines generated approximately 1.3 percent of all electricity in the United States. While this percentage is small, it is nearly double the amount of electricity resulting from wind power in 2006. Wind power is not always a reliable source of energy production, and alternative sources of energy are necessary when the wind is not blowing.

Solar Energy

Solar energy is the most abundant energy source on the Earth, capable of producing enough power to meet the planet's current energy demands many times over. Unfortunately, solar power is intermittent and requires supplementation by other energy sources, such as hydropower or geothermal energy.

Solar cells, or photovoltaic cells, absorb radiation from the sun and create electricity. Other solar systems work by using large mirrors to produce hot water or generate steam and heat. When converted to heat energy, solar power can heat water for buildings and swimming pools and can provide space heating for homes and greenhouses. Solar power converted to electricity can power everything from lights to televisions.

Biomass

Using biomass as a source of energy is environmentally beneficial in more than one way. In addition to being one of the most versatile types of renewable energy, increased use of biomass energy reduces landfill crowding and can significantly slow global warming by replacing coal in factories and power plants and reducing greenhouse gas emissions. According to the EIA, biomass fuels currently provide approximately 4 percent of all energy used in the United States.

Biomass is any organic material produced by animals and plants, such as crops, wood, manure, municipal solid waste, ethanol, methane, and biodiesel. During photosynthesis, plants absorb the sun's energy. Some of this energy is stored and passed on to animals and humans that consume the plants. Burning releases this stored energy as heat. For example, burning wood or garbage releases energy in the form of heat. Harnessing this energy provides a renewable fuel source for electricity and heat production.

It is also possible to convert biomass to other forms of useable energy, such as methane, biodiesel, and ethanol.

Other Sources of Renewable Energy

Two other types of renewable energy are receiving increasing scientific attention: tidal energy and hydrogen fuel cells.

Tidal energy results from the gravitational pull of the moon on the oceans. Tidal power is captured using turbines driven by the rise and fall of the tides or by the movement of tidal flows.

Fuel cells are created by combining hydrogen and oxygen to produce heat, water, and electricity. Fuel cells are similar to batteries and convert chemical energy into usable electricity. As long as a continuous source of hydrogen is available, the fuel cell will continue to produce energy.

Considerations

Converting to renewable energy sources is not as simple and installing solar panels and building wind turbines. Renewable energy is more expensive to produce than fossil fuels, and power from renewable sources is often intermittent. Moreover, renewable resources are not always accessible, with many located in remote areas or only in one area of the country.

Fortunately, research is currently underway to improve current renewable energy technologies and develop new technologies that can make green energy available to the entire population.