The September 2008 U.S. Department of Energy (DOE) Renewable Energy Data Book explored where solar power is used most, both worldwide and within America.

The U.S. DOE listed Germany as the top producer of solar energy in the world, with 2,670 M kWh generated annually in 2006. Japan and the United States rounded out the top three in worldwide solar energy production, generating 1,787 M kWh and 1,652 M kWh respectively. Solarbuzz listed Spain as the most rapidly growing market for photovoltaic deployment in 2008.

In 2008, states with the most aggressive solar energy incentive programs achieved the highest rate of photovoltaic (PV) deployment and solar power production. California, New Jersey, and New York led in solar energy production using photovoltaic technologies. California and Nevada produced the most solar energy with concentrating solar power facilities.

Solar power generation in the United States increased from 970 million KW in 2000 to 2,143 KW by 2007. This represents a 221 percent increase in production capacity.

Photovoltaic (PV) and concentrating solar power (CSP) plants are the primary types of large-scale solar power generation. PV arrays consist of silicon chips or thin film technologies. CSP plants use mirrors to gather solar energy. Passive heating systems like those used in simple solar-powered hot water heater installations also contribute to solar power use.

The sun provides an endless power supply and the technologies tapping its power are rapidly increasing in efficiency and affordability. Solarbuzz points out that more energy reaches the earth in one hour of sunlight than the whole world uses in a year. As a clean and inexhaustible energy resource, solar power use will grow more rapidly with favorable government incentives.

Solarbuzz claimed in 2009 that almost 2 billion people live without access to electricity. Photovoltaics may provide a cheap energy source as increased demand and production capacities drive down costs. While off-grid residential use of solar power is not practical or cost-effective in all regions or building sites, solar power hot water heaters are feasible in many applications and have an extended record of use throughout the world.