Energy efficiency: the energy should always work twice.

K ES SL ER /R EU TE RS /C O RB IS The power flows freely at West Virginia Alloys. This factory, tucked into the Kanawha River valley about 50 kilometres upstream from Charleston, West Virginia, is the second largest consumer of electricity in the state. It routinely pulls more than 120 megawatts of power from the grid, directing it into five electric arc furnaces that heat quartz to about 1,500 °C to make highgrade silicon for computer chips, solar cells and other uses. Then the plant takes the furnaces’ 800 °C exhaust, which still contains much of the original energy, and sends it billowing out of the smokestacks. Unfortunately, West Virginia Alloys is not unusual, says Thomas Casten, an industrialist who has been preaching against this kind of energy waste for 30 years. Consumers around the world have embraced personal energy conservation in compact fluorescent light bulbs, home insulation and hybrid vehicles. But the industrial sector — including much of the electric power industry itself — continues to waste energy at a staggering rate. Thanks to generations of cheap energy, industrial process designers have typically had neither the expertise nor the economic incentive to do otherwise. Now, however, West Virginia Alloys is one of a small but increasing number of companies trying to change their throwaway habits. By 2011, equipment being installed by Recycled Energy Development (RED) in Westmont, Illinois, a company that Casten co-founded in 2006, will start converting the plant’s waste heat into electricity at a rate of more than 40 megawatts. That’s enough to reduce the plant’s power consumption by a third. Such opportunities are everywhere, says Casten. There are 300 or so silicon plants in the world; each of them could repeat the West Virginia Alloys’ story. Then there is steel. About half the steel in the United States is made by recycling scrap in arc furnaces; each furnace could recycle perhaps 15 megawatts of electricity. And for the manufacture of tyres, huge amounts of carbon black are used as a toughening agent for rubber. Carbon black is made by the partial combustion of tars, and the heat wasted could generate about 1 gigawatt of electricity. Improving the energy efficiency of traditional fuel use is at least as good a way of protecting the environment as pushing for greater use of renewables, says Ahmed Ghoniem, a mechanical engineer at the Massachusetts Institute for Technology’s Center for 21st Century Energy in Cambridge. Burning fossil fuels accounts for around 85% of the world’s energy use, he says, so that a 20% increase in efficiency, “which is not unachievable”, would reduce pollution and emission of greenhouse gases as much as would doubling the global proportion of ‘green’ energy generation — a goal that’s years if not decades away, he adds. And in the United States alone, Casten says, energy recycling could offset the equivalent of about 200 gigawatts of electricity generation — about one-fifth of the nation’s total capacity. The challenge will be to get there — through a labyrinth of technological issues, costs, national energy policies and the often byzantine regulatory structures that govern electric power generation. “It’s inordinately complicated to put all this together,” says Casten.