《讨论〉太阳能聚光光伏发电技术
Solar Energy
Solar energy is the least polluting and most inexhaustible of all known energy sources. We are just beginning to tap its potential.
In a sense, virtually all of the energy we use comes from the sun - even fossil fuels like oil, natural gas and coal, which are the stored, compressed solar energy of plants that lived millions of years ago. While energy radiating directly from the sun has always been available to humankind, we have not been able to use it as effectively as other sources. Creating a system which provides a reliable energy supply from solar energy can be a technical challenge. However, not all solar energy systems are difficult to create or use.
Historic Timeline
The appeal of solar energy is so direct that its history is measured by concrete results and in some cases the products of a run-away imagination. Silicon has the benefit of over thirty years of large scale, reliable use.
Here are a few highlights in the long history of important events related to solar power:
1883 Charles Fritts builds the world’’s first solar-electric module: Selenium coated with gold. Werner von Siemens calls it “scientifically of the most far-reaching importance”. J.C. Maxwell, baffled by effect, creates the field of quantum mechanics at Cambridge University’’s Cavendish Laboratory.
1921 Albert Einstein wins the Nobel Prize in physics. The Nobel committee cites his work on the photo-electric effect, which includes an explanation relevant to solar cell operation, as his most important achievement.
1953 Gerald Pearson shines lamplight on a Silicon transistor developed by colleagues at Bell Labs and discovers lithium doped silicon as a powerful photovoltaic material, superior to selenium in that it offers better contacts, lower series resistance, and higher bandgap energy (more voltage).
1953 Bell Labs’’ Pearson, Fuller, Chapin announce the first solar cell. The New York Times comments that this is “the beginning of an era, leading eventually to the realization of one of mankind’’s most cherished dreams—the harnessing of the almost limitless energy of the sun for the uses of civilization”.
1956 The first earth-orbiting satellite is powered by solar cells. Solar’’s cost/performance is at $500/Watt but solar wins as the best electricity source for this application.
1970 Solar’’s cost/performance is down to $100/Watt for solar cells produced with high-grade silicon feedstock (such as used by the microelectronics industry). All satellites are now powered by solar cells.
1973 Solar’’s cost/performance is down to $50/Watt by virtue of using cheaper reject silicon wafers and maintaining the silicon wafer’’s original.
1978 Solar modules are deployed on large scale terrestrially in Australia to support telecommunication networks.
1985 Solar electricity powers 30,000 emergency call boxes along California’’s highways. Providing electricity for new streetlights and bus shelter illumination is now generally more economical than connecting to the grid.
1995 The cost/performance of solar systems reaches $8.50/Watt (solar cell + installation equipment) but is still an order of magnitude too high to be competitive with grid electricity.
2002 Solar system cost/performance is below $6 per Watt (solar module is ca. $3/Watt). The solar-cell market surpasses $1 billion and is growing at over 40% in key counties including Germany and Japan.
