Photovoltaics (PV)
The term photovoltaics (PV) derives from two roots, photo or photons, particles of light, and voltage, a measure of electricity.
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The discovery of photovoltaic properties of some substances rivals the discovery of fire by an ancestor of man when he rubbed two sticks or stones together one day and created a spark. Back in 1839, Edmund Necquerel, a French physicist from a family of scientists, (his son won a Noble Prize in physics), saw electricity sparks fly, so to speak, in his laboratory while conducting an experiment.
Modern day photovoltaic science traces back to 1950s with the discovery of the process for producing relatively pure silicon crystals, the material most commonly used to produce solar cells. In 1954, the Bell Telephone Laboratories produced the first silicon based photovoltaic cell, and since that time, the technology has advanced in leaps and bounds. Three different technological approaches drive current research and development practices today characterized primarily by the type of crystal used as solar cell's core electricity generating medium:
- single crystal
- multicrystal
- thin film technology (aka amorphous crystals
Efficiency (the amount of sunlight received that can be converted to electricity) is the sine qua non of solar cell research and development and over the course of the past decade, efficiency improvements have been close to stunning. Whereas in 1997 solar cell efficiency levels of 17% or so were record setting, today's solar cell efficiency levels are reaching 32% in the laboratory, with whispers of the possibility of surpassing the 40% mark in the near future.
Because solar cell efficiency levels have traditionally been relatively low, meaning the cost of producing solar energy has been comparatively high, widespread adoption of solar cells has been limited to their use as power devices for watches, calculators and other small electronic devices.
Solar panels (collections of solar cells tied together) are gaining increasing acceptance as residential electricity generation tools, especially in areas remote from established electric power grids. The most recent projections from the Energy Information Agency (EIA) suggest continued growth in small scale solar projects through the year 2020, but little growth in large scale adoption of the technology.
Forecasting, of course, is always a risky business. EIA forecasts for stable oil and natural gas prices through 2000-2001, for example, needed to be adjusted in light of actual events. Continued improvements in solar cell research offers the hope that large scale solar energy projects will move to the mainstream sooner rather than later.
© 2001. Patricia A. Michaels.