As David Lammers' interview with Richard E. Smalley makes clear (see Dec. 6, 2004, page 1), when it comes to solar energy, Professor Smalley gets some things right and some things wrong.
It is true that sometime after my lifetime (I'm 56), we will run out of oil, in the sense that the oil available will be lower in supply and much higher in price. At that time, we will either have to consume less energy or turn to alternative sources, such as solar power. It is also true that solar energy is a pure, "green" source of energy, which produces no greenhouse gases, unlike other alternative-energy sources, even those in the highly hyped "hydrogen economy." That's why Cypress Semiconductor acquired SunPower Corp. in 2002 and recently pumped $200 million into building a high-efficiency solar-cell factory. We put our money where our mouth is.
Smalley's solution to the energy problem is for the government preferably under a "visionary" leader such as Jimmy Carter to spend huge sums to focus carbon-based nanotechnology, buckyballs and nanotubes on solar-energy applications. He wants the taxpayer to fund his vision. Smalley puts your money where his mouth is.
Those of you who believe that big-government funding is the way to solve engineering problems won't be convinced to the contrary by this letter, so I won't try. For me, big government has always been an obstacle to commercializing technologies not a solution.
Smalley believes that we need to make solar cells with "a factor-of-five or -10 higher efficiency" that are "as cheap as paint." A man who wants so much funding should be closer to the numbers of the industry he intends to serve. SunPower currently makes silicon solar cells with 21 percent efficiency; that is, 21 percent of the approximately 1,000 watts per square meter of sunlight that illuminates the earth are converted into electrical energy by our cells. It's going to be problematic to increase that 21 percent figure by a factor of five or 10.
Right now, SunPower sells a 32 x 64-inch, 72-cell solar panel that produces 200 watts for $700. That's $50 per square foot, comparable to the price of a layer of paint if the paint is applied by a man wearing a beret and using small brushes. However, the cost of solar energy has been dropping for decades and has now become competitive with grid energy in areas where power is unreasonably expensive: California, Japan and Germany. SunPower sells solar panels in all of those places. As the price of oil increases over the years and the price of solar energy declines, solar energy will proliferate.
Smalley is right in that the entire annual output of the solar industry, approximately 1 gigawatt, is equivalent only to the output of one large coal-fired power plant (or to one-half of the two-dome Diablo Canyon nuclear plant). However, since our industry is growing at 40 percent per year, in 10 years the solar industry's annual output will take the place of 14 of those coal-fired plants. That's a big deal that will improve everyone's life without taxpayer funding (except for the subsidies that are currently almost phased out in Japan and declining in the United States).
No one other than Smalley foresees the need for buckyball "quantum conducting" wires to distribute that energy. Solar panels will reside on the roofs of homes and factories worldwide, connected by short copper wires. And the storage problem Smalley foresees at least for the next few decades will be solved by the fossil-fuel infrastructure that already exists: As solar cells collect the sun's energy to supply our peak energy needs during the day, we will need to draw less oil out of the ground and build fewer power plants to support peak capacity, [thus conserving] precious petroleum resources.
It is true that nanotechnology might be used to dramatically increase the efficiency of solar cells. Currently our 21 percent of the cells (the best available in production) are getting close to the projected 29 percent efficiency limit of silicon. The fundamental efficiency limit in silicon solar cells comes from the bandgap nature of the element. Infrared light, with photon energies lower than the 1.1-electron volt (eV) bandgap of silicon, passes right through the solar cell, which is transparent in the infrared. Blue and violet light with photon energies well in excess of 1.1 eV produce only 1.1 eV of electrical energy; the rest is wasted as heat. If we could tune nanomaterials to absorb a broader fraction of the solar spectrum, they might prove much more efficient than silicon.
Professor Smalley should stop talking about megagrants and megaprojects until he can articulate a clear-cut path as to how nanotechnology can contribute to the improvement of the solar industry in a vision at least as specific as the one above.
T.J. Rodgers President and CEO Cypress Semiconductor Corp. San Jose, Calif.