Technology planning for the future outlines the research and development challenge to full competitiveness of concentrating solar power (CSP) with conventional power generation technologies within a decade. The potential of solar power in the Southwest United States is comparable in scale to the hydropower resource of the Northwest. Specifically, a desert area 10 miles by 15 miles could provide 20,000 megawatts of power, while the electricity needs of the entire United States could theoretically be met by a photovoltaic array within an area 100 miles square. Concentrating solar power, or solar thermal electricity, should harness the sun's heat energy to provide large-scale, domestically secure, and environmentally safe electricity.
The price of photovoltaic power should also be competitive with traditional sources of electricity as the technology improves, and solar electricity is additionally used to electrolyze water, producing hydrogen for fuel cells for transportation and buildings. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, accounts for most of the available renewable energy on earth. Only a fraction of the available solar energy is being harvested to fulfill planetary energy requirements.
Solar powered electrical generation relies on heat engines and photovoltaic collectors. Solar energy's uses are limited only by human ingenuity. Solar energy applications include: space heating and cooling through solar architecture, potable water via distillation and disinfection, day lighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes. To harvest the solar energy, the most common methods are active and passive solar panel collectors. Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of solar thermal collectors (image 01) and photovoltaic panels (image 02) to generate or collect energy as heat or electricity, respectively whereas passive solar techniques include orienting a building to the Sun, selecting materials with high thermal mass or light dispersing properties, and designing spaces that naturally circulate air.
Image 01: Solar Thermal Collectors
Image 02: Photovoltaic Panels