Travis BradfordOn Nov. 30, we published an interview with Travis Bradford, author of Solar Revolution: The Economic Transformation of the Global Energy Industry and founder of the Prometheus Institute for Sustainable Development.

The interview was reprinted on Alternet, where it kicked up a vigorous, extended discussion. I asked Travis if he’d like to respond to some of the themes and comments there. His thoughts follow.

I was delighted to see so much serious discussion of solar and other renewable energy sources follow my interview with David Roberts. Many of the questions and ideas readers raised are addressed in much greater detail in my book. But I’d like to take a few moments to address some specific issues.

First, should the solar revolution — which has already happened in Japan and Germany, and is well underway in other European countries and in California — be centralized or localized?

Precisely because, as one Alternet reader wrote, “the sun doesn’t always shine [and] the wind doesn’t always blow,” in industrialized countries my bet is on grid-connected applications. With sensible incentives, feed-in tariffs, and interconnection standards, the grid essentially serves as a storage mechanism for solar-generated electricity.

Plus, having solar in a lot of small locations creates a more robust system than a smaller number of centralized plants. To minimize the upfront system costs until cheaper fuel-cell or battery technology advances solve the problem of solar intermittency, we will also need some means to “store” solar power. Right now net metering and feed-in tariffs offer our best options without the need for expensive additional equipment.

Another Alternet reader bemoaned the fact that like gas, oil, and coal, solar photovoltaic (PV) cells, modules, and systems will still be produced by centralized corporations. But it is simply naive to expect that any energy resource be at once clean, renewable, affordable, and do-it-yourself. We can have the first three, but demanding the fourth is asking the impossible.

Energy is the linchpin of all economic endeavor. Unless we are willing to undergo a severe decline in the lifestyle enjoyed by citizens of industrialized nations — and write off the chances of developing countries to achieve reasonable levels of economic well-being — we will have to accept that the modern corporation is the most efficient way to mass-produce the energy we need at prices we can afford. Once the PV is manufactured, it is distributed to users who need little in the way of an ongoing relationship with the manufacturing company. Nokia, Motorola, and Sony are large corporations providing wireless handsets, but few people bemoan their involvement in telecommunications. If you don’t like one company’s product, you can easily switch to another next time.

One reader took issue with my doubts about the long-term viability of biofuels. “For regions that produce agricultural waste, biofuels are a great idea — just look at what Germany and Brazil have done with cellulose and sugarcane crops …”

Sugarcane is not an agricultural waste product. The price of sugar on the world market has doubled in the past 18 months, and world corn and wheat prices are up 25% so far in 2006. The fact that these crops can be used for fuel doesn’t mean they ought to be; raising prices on food staples amounts to a regressive tax on the world’s poorest people. By competing for scarce resources, biofuels insidiously export a portion of our energy costs through the grocery store where we don’t see them.

And if you think the price of oil and gasoline are volatile over time, ask a farmer about his ability to predict future changes in the price of the agricultural products he sells.

All other things being equal, technologies move toward the most abundant, least restricted resources. No matter who makes solar cells and modules, the sun is the ultimate public good and as such cannot be trademarked or privatized. Silicon is the second-most abundant element in the earth’s crust and is already being recycled for the production of PV cells. No single solution will solve our energy problems, but based on standard economic models of learning and scale, solar electricity will dominate the world’s energy mix by 2040 — far sooner if we can muster the political will for sensible, phased PV incentives in the U.S.