Statistically Speaking: The Evolution of the Silicon Solar Cellby Bill Chameides | October 31st, 2008
posted by Erica Rowell (Editor)
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A modern-day single-crystalline solar cell sitting atop the first solar cell (Bell Labs ~1953-1954). The image shows the historic contrast between the two cells. (Susannah Pedigo/NREL)
How expensive will avoiding dangerous climate change be? The answer is intimately tied to the pace at which renewable energy technologies advance. And speaking of advancements, a major milestone was just passed in silicon solar cells.
Photovoltaic solar cells come in a variety of forms. The one that’s been with us the longest is the silicon solar cell.
Developed at Bell Labs in the early 1950s and originally called a solar “battery,” this first modern cell had a conversion efficiency of 4.8 percent. That means that of all the incoming solar energy just under 5 percent of it is converted to electricity. Within a year its conversion efficiency had jumped to 6 percent.
You can chalk up at least part of that improvement to competition, according to John Perlin, author of From Space to Earth: The Story of Solar Electricity (see article [pdf]).
Around the time Bell was working to increase its solar cell’s efficiency, RCA released a nuclear-powered cell with a PR splash that paid off. Calling RCA’s invention “revolutionary,” the New York Times wrote that the new “atomic cell” might eventually allow a wrist watch “which would run for twenty years.” But the atomic cell’s efficiency clocked in at an unimpressive 0.4 percent.
Bell Labs management took note of their competitor’s tiny inroad and encouraged their solar cell engineers to get moving. On April 26, 1954, the New York Times trumpeted Bell Labs’ superior solar cell, predicting “it may mark the beginning of a new 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.” The paper also noted, “The new Bell solar battery thus delivers 50,000,000 times the power of the RCA atomic battery.”
Now let’s fast-forward to 2008 –- and the latest leap in solar cell efficiency. Last week came the news that Martin Green and his colleagues at the University of New South Wales have designed a silicon solar cell that slips past the 25 percent efficiency threshold. This new benchmark puts PV technology tantalizingly close to its theoretical maximum efficiency of 29 percent.
Here’s a timeline of the solar cell’s steady rise in efficiency.
“A Brief History of the ARC Photovoltaics Centre of Excellence,” University of New South Wales – www.pv.unsw.edu.au/research/achievements.asp
Waldemar Kaempeffert, “First Direct Use of Atomic Energy Sets up Electric Current, Small but Prophetic,” New York Times, January 31, 1954
John Perlin, “The Silicon Solar Cell Turns 50,” National Renewable Energy Laboratory – www.nrel.gov/docs/fy04osti/33947.pdffiled under: climate change, energy efficiency, faculty, global warming, renewable energy, science, Statistically Speaking
and: alternative fuel, renewables, solar, solutions