Photovoltaic power inherited the most important benefits of
its older brother, solar
thermal energy: it's a completely clean, inexhaustible source of electricity.
But the low maintenance required by photovoltaic cells extends their merits far
beyond those of traditional flat-plate solar thermal collectors.
This ease of maintenance makes PV perfect for many applications. While one of the most important and obvious benefits of themal solar power has always been that it can provide electricity where the power company cannot or will not, PV carries this much farther. With a documented annual failure rate of under 1 in 10,000, photovoltaic cells are so durable that it's not unreasonable to leave an untended panel in the middle of the desert and expect it to operate for decades (many companies do just that). PV cells can operate long-term with absolutely NO infrastructure -- no roads, no technicians, no tools, and of course no grid.
For this reason, the photovoltaic industry has traditionally been driven by remote applications. The first real use of PV was on satellites, where there simply were no other options for electrical sources once the batteries ran out. The money poured into the technology by NASA and American aerospace giants in the days of Sputnik essentially created an entire industry ex nihilo.
Today, remote applications are still crucial to PV's success. One of the first earth-bound uses of was PV was, ironically, in electricity transmission. Utility companies need to keep diagnostic equipment running at various points along long-distnace transmission lines. Since these lines are very high voltage, tapping into them (without frying the diagnostic equipment) requires stepping down the voltage to usable levels, requiring expensive equipment and often "dirtying" the electricity being transmitted (by introducing unwanted harmonics in the alternating current). Photovoltaic cells, with batteries for night-time use, turned out to be exactly what was needed, and have been supplying diagnostic equipment with electricity for decades now.
Far more exciting, in many ways, is the use of PV cells in rural
electrification efforts across the globe. According to the
Solar
Electric Light Fund (SELF)
two billion people are currently living without access to electricity, most
of whom rely on kerosene to light the night. In addition to the risk of
fire, kerosene is quite toxic: used nightly, its effect on a person's lungs is
roughly equivalent to two packs of cigarettes a day.
Even if it were possible for these people to pay the enormous sums necessary for grid extension, two billion more electricity consumers would have unimaginable effects on global fuel prices, and would exacerbate the environmental crisis disasterously. One simple, sustainable solution is being explored by many organizations all over the world: photovoltaics.
Of course, the systems being installed by organizations like SELF are unassuming to say the least. In general, these systems provide enough power for several florescent bulbs and a black-and-white television, running a few hours a day. Although humble by G7 standards, these systems are transforming the lives of thousands of people in pilot programs in Indonesia, Zimbabwe, Vietnam, Nepal, and dozens of other places.
Introduction to Photovoltaics --
John Fraser