A Solution to the Global Energy Crisis?

A Caltech professor says there's one way out of our energy predicament: the sun.

ByLee Dye

Nov. 14, 2007 — -- There is a potential solution, and possibly only one, to the global energy crisis. It will require a huge investment, several scientific breakthroughs and a little luck. But unless we give it the very highest priority, it will soon be too late.

That's the message that a highly respected professor of chemistry at the California Institute of Technology has been delivering for several years now, but it's not clear whether anyone is listening. Nate Lewis isn't your typical prophet of doom. He has won a list of awards as long as the beard he wore years ago as a young scientist when I first met him. And to hear him tell it, the solution to the energy crisis is as clear as the nose on your face, or at least the shadow it casts.

Lewis quips that he belongs to the "Willie Sutton school of energy management." When asked why he robbed banks, Sutton responded "because that's where the money is."

"I believe in that too," Lewis told an energy symposium at Caltech earlier this year.

In his case, however, Lewis is banking on the sun.

"More solar energy hits the earth in one hour than all the energy the world consumes in a year," he told the symposium. So if you want to solve the energy crisis, he argued, go to the bank where the energy is kept — the sun.

None of the other sources of energy, including fossil fuels that threaten our planet, or nuclear energy that has never lived up to its potential, can do the job, Lewis maintains. He isn't arguing in favor of those huge water bladders we are supposed to have atop our houses to capture heat from the sun. Lewis sees an entirely different solution. He sees cheap ways to convert solar energy directly into electricity, which can be used to convert water into fuel, like hydrogen, that can be turned back into electricity on demand.

What we need, he argues, is something as basic as paint that is engineered to capture electrons from the sun and make the electrons march into our utility lines. Go to your local home center, buy a bucket of paint and brush it on your roof to power all those gadgets and heat your domicile and create the fuel to run your scooter. Sounds pretty far out, but Lewis is dead serious.

There are, he readily admits, a few problems. Current technology can convert sunlight directly into electricity, and generate hydrogen, but it isn't scalable. One such device towers over nearby structures and it works, but it produces only a kilogram of hydrogen in an entire day, the energy equivalent to one gallon of gasoline.

"We need to find a better way to make fuel from sunlight directly so that we can bring energy to whoever wants it whenever they want it — day or night, summer or winter," Lewis told the Caltech symposium. "My lab and other labs at Caltech are working on that, too."

The answers need to come soon, he adds, to avoid disaster by about the year 2050.

But why only solar? Isn't a new generation of nuclear power plants on the horizon? Isn't the oil industry hiding huge reserves that will buy a few hundred years? Surely somebody out there is working on a new widget that will make our cars run on air. Why only solar?

Lewis ticks off the reasons:

  • Nuclear

    To match the growing global demand for energy, "we'd need 10,000 of our current 1-gigawatt reactors, and that means we'd have to build one every other day somewhere in the world for the next 50 straight years. … It isn't going to happen," he said. Besides, there isn't enough uranium to run all those power plants, so they would have to run on plutonium, the stuff that nuclear bombs are made of.

  • Carbon

    We hear a lot about pumping carbon dioxide back into the ground, and "sequestering" it so we can continue to burn fossil fuels. We might be able to do that, but if just one-tenth of 1 percent leaks out of the reservoirs, that would wipe out all the progress on the drawing boards for reducing greenhouse gases.

    "We know that CO2 migrates underground," Lewis said. "It bubbled up in Lake Nyos, Cameron, on Aug. 26, 1986, and killed some 1,700 people. So we're going to have to demonstrate within the next 10 years that it will leak less than 0.1 percent, globally averaged, for the next millennium in thousands of different aquifers around the world."

  • Hydropower

    "It's cheap, it's abundant, and we've pretty much maxed it out."

  • A bunch of other potential sources, such as wind and biomass, are useful on a limited scale, but they are not going to solve global problems. Conservation is important, he adds, but "no amount of saving energy ever turned on a light bulb."
  • OK, so we've got a problem. But what's the rush? Don't we have a few decades to work things out?

    Lewis is part of a growing number of scientists who believe we've overlooked a few things when it comes to estimating just how quickly the globe's climate is likely to change.

    He cites permafrost, the upper latitude soils that are supposed to remain permanently frozen, as one example.

    "As the ice crystals in it melt, it reflects less light and turns darker, absorbing more light, and that melts more permafrost. Helium dating of trapped bubbles in the permafrost shows that we're melting permafrost now that hasn't been melted in 40,000 years. And there's enough CO2 and methane trapped in the permafrost to have the greenhouse gas levels not go up by a factor of two, but by a factor of 10."

    So if we stay on the current course, the problem could be much worse than current projections.

    My guess is nobody has ever accused Lewis of sounding like a preacher. But there is something messianic in his comments these days. He began his talk to the Caltech symposium with these words:

    "Energy is the single most important technological challenge facing humanity today. Nothing else in science or technology comes close in comparison. … "

    "With energy, we are in the middle of doing the biggest experiment that humans will have ever done. And there is no tomorrow, because in 20 years that experiment will be cast in stone. If we don't get this right, we can say as students of physics and chemistry that we know that the world will, on a time scale comparable to modern human history, never be the same."

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