No Silicon Valley venture capitalist has invested in it.
Government subsidies for it are skimpy, at best.
It lacks clout in Washington.
And it's been around forever.
Yet it's by far the most popular form of renewable energy used at home, dwarfing the impact of rooftop solar panels and appealing not just to well-to-do greens but to poor people, African-Americans and, we'd bet, climate change deniers, too.
Yep, I'm talking about -- as Popular Mechanics put it recently -- the "high-tech, cutting-edge, carbon-neutral alternative fuel of the future: wood."
About 80 percent of residential renewable energy is created by wood heat appliances (not including fireplaces), while just 15 percent comes from solar and 5 percent from geothermal, according to Energy Information Administration statistics provided by the Alliance for Green Heat, a small nonprofit created two years ago to promote environmentally-friendly wood heat. Some 15 million American homes use wood as a primary or secondary heat source.
Of course, there's nothing new about wood heat. Wood supplied more energy than fossil fuels in the U.S. until the 1880s, when it was displaced by coal and, more recently, natural gas, oil and electricity.
What's new is the arrival of modern high-efficiency wood stoves, as well as a fast-growing wood pellet industry, that enable either cordwood or wood pellets to be burned more cleanly that before, dramatically reducing emissions of soot. Here's a look at one:
Provided the wood burned in these stoves comes from waste or from well-managed forests, it can then be deemed an environmentally friendly fuel. Wood is already seen that way in much of western Europe, according to this 2009 article in Science [subscription req'd] which argued that "sustainable wood energy offers recurring economic, social, and environmental benefits."
"We're the only modern, industrialized country that hasn't looked at wood as a serious way to reduce fossil fuels," says John Ackerly, who started the Alliance for Green Heat two years ago.