Are you curious to know how solar energy compares to other renewables, such as wind, tidal, geothermal, and hydroelectric power? One difference is that solar energy can be isolated to individual homes, whereas energy from others sources is largely drawn from plants. Nevertheless, it’s always a good idea to gauge your alternative power source with the names that often get included in the same sentence. We’ve collected some renewable energy facts, listed below, from the U.S. Department of Energy and the Environmental Literacy Council. After reading this post, you can judge for yourself how solar energy compares.

Wind

• A renewable resource, wind is a form of solar energy generated by unequal heating patterns along the Earth’s surface. As long as the sun shines, there will be wind and the capacity to generate electricity from it.
• Wind is a domestic energy source.
• Energy generated from wind has tripled since 1998.
• The U.S. installed more new wind energy capacity in 2005 than any other country in the world. This capacity was at 9,149 MW in 2005, enough to power 2.3 million households, and jumped to 11,603 MW in 2006.
• Wind energy is one of the lowest-priced renewable energy technologies available, costing between 4 and 6 cents per kilowatt-hour.
• Wind is intermittent, so no energy can be collected when the wind isn’t blowing.
• Windmills have been known to negatively impact wild bird populations.
• Windmills aren’t conducive to the individual residences, unless you live in a rural area with a lot land.

Tidal

• Tidal energy is generated when tidal differences in coastal areas are used to harness electricity. However, the tidal differences must be more than 16 feet, and only 40 sites on Earth have tidal ranges in this magnitude.
• There are currently no tidal power plants in the United States. One of the few commercial tidal power stations in operation is located at the mouth of the La Rance River in France.
• Because seawater has a much higher density than air, ocean currents carry significantly more energy than air currents.
• Negatives of tidal energy collection include the impediment of sea life migration and silt build-up behind tidal power plants.
• Construction costs of tidal power plants are high, and the payback period can be lengthy.

Geothermal

• Geothermal energy is available 24 hours a day, 365 days a year.
• Geothermal power plants have average availabilities of 90% or higher, compared to about 75% for coal plants.
• Geothermal energy is domestically produced and renewable. It is generated from the heat in the earth’s core.
• Geothermal energy can be tapped almost anywhere on Earth with the use of geothermal heat pumps and direct-use applications. Other resources, such as hot dry rock and magma, are yet to be accessed.
• Geothermal plants are known for having low emissions, prolonging the life of reservoirs, and in some plants, producing sludges that can be extracted for sale.
• Geothermal plants impose no visual impacts, with the exception of steam.
• Geothermal power is sold at about $0.05 per kWh.

Hydroelectric

• Hydroelectric power uses water’s energy to create electricity. This is typically done with hydraulic turbines that rotate due to moving water flowing from a higher to lower elevation.
• Twenty percent of the world’s electricity is produced by hydropower plants.
• There are over 2,000 hydropower plants in the United States, providing approximately 10 percent of our total electricity.
• Adjustments can be made to hydroelectric power generation, depending on demand.
• It is a clean, renewable source of energy.
• Hydropower has a low operating cost, once installed, and can be highly automated.
• Reservoirs can also offer a variety of recreational opportunities, including fishing, boating, and swimming.
• Dams can block fish passage to spawning grounds or to the ocean, impact stream flow, or even cause a river channel to dry out, degrading both aquatic and streamside habitats. Hydroelectric plants can also have an impact on water quality by lowering the amount of dissolved oxygen in the water. In the reservoir, sediments and nutrients can be trapped and the lack of water flow can create a situation for undesirable growth and the spread of algae and aquatic weeds.

Links:

U.S. Department of Energy: Wind and Hydropower Technologies Program
Tidal Power Plants
Geothermal FAQs
Environmental Literacy Council: Hydroelectric Power
Advantages and Disadvantages of Wind Energy
Ocean Tidal Power

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Posted on February 11th in Solar News by Renee.