The low-down on Renewable Energy

Have you heard people discussing our need to cut down on using oil? Even though the earth continues to produce fossil fuel, technology and power use has increased so much that people are using fossil fuels at a higher rate than the Earth can produce. Because most of the energy the U.S. uses comes from fossil fuel, and because fossil fuel will eventually run out, scientists and researchers are looking into alternative energy sources.

Alternative energy sources can be either non-renewable (once it’s used it doesn’t come back) or renewable (it can never be exhausted). Non-renewable sources are like the fossil fuels we currently use: coal, natural gas, crude oil, etc. Renewable sources can be used over and over again, and can often harness enough power to meet a significant amount of power need in the country. Currently, renewable energy accounts for 25% of the human energy use around the world.

There are many types of renewable energy, harnessing power from things like the sun, water, wind and biomass.

HYDROPOWER:

We can use the water that naturally flows in rivers and streams to make power. In order to do this, rivers are dammed to make a big reservoir of water. The water from the reservoir is released, and as it flows it spins turbines that run electric generators. Hydropower is the most intensely used renewable energy source. It made up 6.9% of the U.S. energy usage in 2004.

While hydropower does not produce any air pollution, damming rivers means changing the natural habitats of the region in a big way. Fish and plants that usually live in or along the river could die because of changes in water temperature or water level.

WIND POWER:

Wind power is harnessed through wind turbines that turn as the wind blows. The wind turbines are connected to generators that then produce electricity. This electricity then goes into power lines that bring it right into people’s homes.

However, in order to gather the most electricity, the wind has to be constantly blowing. This doesn’t happen very often, so wind power does not always generate that much electricity. An upside is that wind, unlike the sun, is available day and night.

BIOMASS ENERGY:

Biomass can be trees, plants, corn, plant waste—basically plant matter. This biomass can be burned for heat/electricity or changed into fuel. The fuel can be liquid (ethanol/methanol) or gaseous,

Fuel made from biomass has great potential for being the next big source of energy for transportation. Biodiesel can replace typical diesel fuel to run cars!

Biomass is renewable, but only if we don’t use it faster than it is naturally produced. Also, when creating any fuel, there will be pollutants released when biomass is burned.

SOLAR POWER:

The sunshine that warms you on a chilly day also contains energy that can be gathered into electricity to keep our lights running and our kitchen appliances humming. Many homes are now being designed to better harness the energy from the sun. You can also use solar heat to heat up water in your house.

While the energy from the sun is useful just for its warmth, we can also use it to produce electricity. This is done in two main ways: the photovoltaic process and solar thermal electric process. The photovoltaic process uses special cells that take sun’s rays and make them into electricity. It’s useful for places that can’t otherwise get near an electric grid. Solar thermal electricity uses the sun’s heat to boil water. The boiling water makes steam and the steam moves a turbine that causes a generator to make electricity.

Solar power has some issues though—the sun isn’t always up so its heat isn’t available 24/7. But, solar power is a renewable, environment-friendly source.

GEOTHERMAL ENERGY:

Geothermal energy is energy gathered from heat inside the earth. In order to get it, deep wells are drilled into the surface of the earth to get hot water that has been heated by magma and use it as a source of energy. This heated water, like in solar thermal electricity, can then move a turbine that runs an electricity generator. Geysers are usually the best places to get this kind of energy.

However, geothermal energy might not be a renewable energy source if we use it faster than it can be remade by the earth.

TRASH:

Trash can be used for power! Solid waste can be burned in plants to produce electricity and a gas called methane can be harvested from landfills as solid waste decays.

A Renewable Future?

The United States and other countries around the world are investing in research around renewable energy. How can these sources be used more effectively? What technology needs to be implemented to get the most energy out of things like the wind? Scientists and researchers are working towards answers to these questions. Maybe one day the world will run on renewable sources!

Sources:

U.S. Department of Energy: Energy Efficiency and Renewable Energy

Wikipedia--Renewable Energy