The United States is encouraging the development of solar energy at least in three ways: contract with big solar energy generating companies, install solar panels on roofs of big companies and other public buildings, and encourage residents to install solar panels on their home roofs.

Rudy Perez, manager of solar energy at Southern California Edison, told Xinhua in a recent interview that Southern California Edison is the largest power supply company in the country and also the biggest supplier of solar energy, which provides 65 percent of the total solar electricity in the United States.

The dry weather condition, coupled with long days of sunshine, has made Southern California an ideal place to develop solar energy. The Solar Energy Generating Systems in California is the largest solar energy system in the world with nine solar generating facilities in the Mojave Desert boasting a total capacity of 354 megawatts.

Under construction is the Ivanpah Solar Power Facility, a 392 megawatts solar thermal power facility in south-eastern California. There are plans to build many other large solar plants in the United States and the largest of these is the proposed 968- megawatt Blythe Solar Power Project to be located in Riverside County, Southern California.

Earlier this month, Southern California Edison signed a power purchase agreement with First Solar for 250 megawatts AC of electricity to be generated with solar photovoltaic panels. This emission-free power source is the equivalent, in greenhouse gas terms, of removing 30,000 cars from the road annually.

The solar panels will be ground-mounted on about 2,500 acres of public land in Nevada. First Solar is developing the project, which is expected to begin producing electricity as early as 2014 and be fully operational by May 2017.

Perez said right now Edison depends mainly on those contracted solar power plants for solar electricity. However, it has also invested in projects to install solar panels on the roof tops of large commercial and office buildings to generate solar electricity. Businesses, offices and schools that cooperate with Edison will get some subsidies.

To encourage private home owners to install solar panels on the roof tops of their houses is another way to develop solar energy, according to Perez. Former California governor Arnold Schwarzenegger had signed legislation designed to have one million solar roofs built in California by 2018.

This is viewed as a huge step in the right direction for the state of California. The plan, when implemented, will provide 3, 000 megawatts of solar energy and will make the air in California much cleaner. Three thousand megawatts is the equivalent of about 5 electric power plants, and will provide California with clean and much needed energy.

Perez estimated that the one million solar roofs plan could be completed by 2016. Nationwide, there is a plan to have two million solar roofs by 2015.

Customers who participate in this program will be able to sell back excess solar power to the power companies for credit on their bills.

Perez said rooftop solar energy is important because it will provide additional electricity during peak hours. In California, summer is the peak season and the electricity generated by solar panels on roofs will relieve the power shortage.

Both the federal and local governments provide incentives for rooftop solar panels. U.S. President Barack Obama signed the American Recovery and Reinvestment Act into law on Feb. 17, 2009, which provides tax credits and grants for installing solar.

The bill extends the 30-percent Residential Solar Investment Tax Credit for residential solar installations for eight years through Dec. 31, 2016. It also removes the cap on qualified solar electric installation expenditures from 2,000 dollars, effective for systems placed in service after Dec. 31, 2008.

The California Solar Initiative (CSI) is the solar rebate program for Californians who are residential or business customers of Pacific Gas and Electric (PG&E), Southern California Edison ( SCE) and San Diego Gas & Electric (SDG&E). Together with the rebate programs offered through dozens of publicly-owned utilities in the state, the CSI program is a key component of driving adoption for solar energy in the state of California.

The total budget for the CSI program is 2.167 billion dollars for 2007-2016 and has a goal of installing 1,940 MW of new solar power generation capacity. The CSI-Thermal program -- for the installation of solar domestic hot water systems -- has a total budget of 250 million dollars for 2010-2017, and a goal to install 200,000 new solar hot water systems.

According to Perez, renewable energy in the United States consists of 17 percent of the total energy at present, while some 6 percent of the renewable energy comes from solar energy. He noted solar energy only consists of 1 percent of the total power in the United States, and the goal of the country is to have one third of the total energy from renewable energy by 2020.

Monique Hanis, Director of Communications & Spokesperson for the U.S. Solar Energy Industries Association, told Xinhua that there have been many technologies on solar energy. While new technologies will constantly make solar energy more efficient and cost effective, the present technology has already greatly cut down the costs and made solar electricity more acceptable.

Hanis said there are mainly two ways to generate solar energy, the photovoltaic program and the thermal program. Both programs have their own advantages and disadvantages, and in the United States, both have been developed based on different usages and weather conditions.