Renewable energy is a source of energy that can never be exhausted.
We can obtain renewable energy from the sun (solar energy), from the water (hydropower), from the wind (windmills), from hot dry rocks, magma, hot water springs (geothermal) and even from firewood, animal manure, crop residues and waste (Biomass).
Friday, October 10, 2008
Why have over 1.5 million Americans invested in solar?Surveys taken over the last ten years confirm that the vast majority of owners (94% or more) consider that investment a wise decision. Consumer investment and satisfaction have spawned a small but growing solar hot water (SHW) industry here in the U. S. that is providing even broader benefits to our nation and has the potential to contribute much more.
Clean and SafeSolar hot water systems in use today produce approximately 1000 megawatts of energy annually. That is the equivalent of two medium-sized coal plants. The life-cycle costs of SHW systems are about the same as gas and far better than electric water heating systems.
Solar energy is pollution-free, an important benefit when the cost of removing pollutants from the environment is considered. For example, a typical SWH system will, over its lifetime, displace 10.5tons of CO2if replacing a natural gas system, or 71.5 tons if replacing an electric system.
Readily Available ResourceThe U. S. Department of Energy estimates that Americans consume approximately 2.5 quads of end-use energy annually to produce hot water at a cost of over $20 billion dollars. Solar energy currently provides only a tiny fraction of that demand, but huge portions of our country possess sufficient insolation to produce much greater quantities of energy.
Enough sunlight reaches the earth’s surface each yearto produce approximately 1000 times the same amount of energy produced by burning all fossil fuels mined and extracted during the same period. Sunlight does not have to be explored, mined, extracted, transported, combusted, transmitted — or imported.
Quality, Reliability, Durability
Solar water heating technology, pioneered in the U. S., is the oldest and most developed of all renewable energy systems. Modern solar water heating systems can provide a large portion (40 - 80%) of household hot water demand depending on local climate conditions and the size and type of system. Most systems pay for themselves in four to sevenyears and continue to provide hot water for many years thereafter.
Much of the United States receives abundant sunshine, making solar hot watersystems a very economical investment. This map shows the average daily solar radiation available on a south-facing surface measured in megajoules per square meter each day.
Solar pool heating often provides an even better investment. Payback can be as low as two years and the solar system can extend the swimming season by several weeks without additional cost. Many homeowners have regretted the purchase of a conventional pool heating system after receiving their first utility bill.
Another cost-efficient application for solar energy is preheating ventilation air for commercial and industrial facilities.
The vast majority of U. S. manufacturers of solar equip ment voluntarily comply with national consensus standards devel oped by the Solar Rating and Certification Corporation (SRCC). The SRCC tests and certifies collectors as well as complete systems for performance, reliability and durability. In addition, manufacturers and installers comply with the SRCC’s strict requirements for proper installation, labeling and homeowner information regarding operation and maintenance. Assurances of performance and quality are backed by warranties that in many cases exceed the guarantees of other household appliances.