Solar Power to Meet US Energy Needs Would Cost $45,000 per US citizen

At least, this is the figure that William Trousdale, Emeritus Professor of Physics, Wesleyan University, arrived at while preparing for his talk Monday evening at the Russell Library. This was the third in the series of seminar presentations by Trousdale and moderated by Marvin Farman on "Global Warming and Energy Options".

Imagine a few hundred thousand of these. [photo credit: solarishi]

In a detailed presentation, Trousdale calculated the cost based on the total estimated field of photovoltaic cells required (20,000 square miles, or an area the size of about 3 Connecticuts) to satisfy per capita US energy consumption at 5,000 kilowatt hours per year. (This consumption figure is a conservative projection, and is about half of current consumption rates). The construction cost of the solar field alone would amount to over $29,000 per person. Add another $15,000 or so per person for energy storage (solar and wind both require storage systems, since the power is wasted otherwise) and about $670 per person for transporting the energy on massive high-capacity aluminum lines from the southwest--where the sun shines--so as to minimize loss, and we're at around $45,000 per person. (Actually, the power transmission estimate here is also low, since it does not include the cost of financing.)

Given that the US population stands at around 300 million, Trousdale concluded that the US would need to spend in the neighborhood of about $13.5 trillion to create a solar energy system that could satisfy US energy requirements. This assumes, not unreasonably, that the US population can conserve energy to the point that it ends up using about half what we currently consume. Given that the US has spent the last six or seven decades ginning up a frenzied consumer culture, the casual observer may be forgiven for thinking that such conservation is beyond the realm of the possible. But, as Trousdale noted, the American people have sacrificed for massive projects before. He pointed to the Hoover Dam and World War II in particular.

This array is said to power 10,000 homes in Sevilla, Spain. [photo credit: treehugger.com]

$13.5 trillion is a lot of money, approaching the size of the US annual GDP (about $14.26 trillion in 2009). By contrast, it was estimated that building the equivalent capacity of nuclear power would cost somewhere between a quarter and a half of that amount. According to a Trousdale (in a follow up email exchange), "current Department of Energy estimates are that nuclear power is not much different from solar but it gets close to one half when storage is factored in. ["Storage" here refers to "storage of power", not fuel rods, on which see below. Nuclear, unlike solar, does not require facilities to store power.] Any large scale nuclear endeavor, a thousand or so one thousand megawatt plants, would be done with a standard design, greatly reducing the cost per unit. According to reports China builds nuclear power plants at about one sixth the cost in the USA." Of course, with nuclear you do have greater risk and political opposition associated with storage of spent fuel.

So much depends on whether we think we face a crisis with respect to global warming and whether we can come up with ways of dealing with radioactive waste. As to the former question, a close reading of essay in the New York Review of Books, June 12, 2008, by the eminent physicist Freeman Dyson, entitled "The Question of Global Warming", is in order. Dyson suggests that simply planting lots of trees may be the best thing we can do in the short term to deal with the excess of carbon in our atmosphere.

As to the question of what to do with spent fuel rods, this is harder to resolve. One solution that has been mooted by some governments (e.g., the Indians, Russians), and discussed in a previous session, is to build breeder reactors that consume most of the spent uranium and actually produce, in some cases, more usable fuel than they consume. [photo credit: Defence Forum of India] But this creates other issues, such as the production of weapons-grade plutonium and the potential for extremely high exposure when the plutonium is extracted for reprocessing. Trousdale also mentions (in a follow-up email) subcritical reactors, "which, according to their backers, have the potential of burning not only all of the Uranium but most of the radioactive waste as well." Finally, there is also (for those willing to wait a little longer) fusion technology. Fusion devotees are particularly focused on the LIFE project at Lawrence Livermore Labs in California, an experimental laser-aided system that (according to the folks in California) "has the potential to meet future worldwide energy needs in a safe, sustainable manner without carbon dioxide emissions." According to a current story in The Chronicle of Higher Education (subscription only), the Livermore scientists are reporting a "major breakthrough." But they seem to be in the habit of doing so, as in this story from March. (Then again, were I on the verge of a technological breakthrough that would change life as we know it, I'd probably brag about it too.)

In any case, the talk attracted a large audience, including scholars, energy plant entrepreneurs, and movement environmentalists. A lively discussion followed the presentation, some of which focused on the importance of cleaner fossil fuel solutions in the short term, such as "clean" natural-gas-fed power plants that run at about 55 to 59% efficiency (depending on whom one is talking to, which in any case is substantially higher than conventional steam turbine plants which operate at about 40 to 45% efficiency) that may act as a bridge to future long-term solutions.