Conventional power plants generate waste as well as electricity, and they need to buy fuel in order to operate. Even today’s emission-free plants, such as nuclear reactors, leave operators with the task of disposing of hazardous spent fuel.
Add to all that the waste of the energy in heat, which is generated by between 40 and 80 percent of the fuel they use.
Now a start-up has developed what it calls the E1, a generator that could harness some of that waste and simultaneously reduce fuel consumption and toxic emissions by up to 3 percent. While that may not seem like a great savings, the Massachusetts Institute of Technology says air travel alone accounts for 2 percent of the world’s carbon dioxide emissions.
At the heart of the new generator, created by Alphabet Energy of Hayward, Calif., is tetrahedrite, an abundant, highly efficient and affordable thermoelectric mineral recently discovered by researchers at the University of Michigan that converts heat into electricity.
Such materials have been available for decades, but in conventional form, they’ve been too costly for most applications and have been limited to special cases such as spacecraft, where fuel storage is at a premium.
Alphabet Energy’s device using the new thermoelectric matter can simply be attached to the exhaust of a 1,000-kilowatt generator and help the plant produce enough electricity to save more than 50,000 liters of diesel fuel in an average year – a saving of 2.5 percent, according to the company’s CEO, Matt Scullin. He says savings would be a bit higher with smaller generators.
So far, Scullin says, he expects his clients to be in industries that need large power plants in remote areas, such as energy and mining companies, which could save millions of dollars’ worth of fuel for their generators.
The E1 is also modular, in that it can be made larger to accommodate even more waste heat and therefore generate more electricity. And Scullin says Alphabet Energy already is working on yet another thermoelectric material that could reclaim a greater percentage of waste heat into electricity.
So far, though, it appears that no amount of tinkering with tetrahedrite can make it efficient enough to reduce fuel consumption by more than 5 or 10 percent.
Ali Shakouri, a professor of electrical and computer engineering at Purdue University, has been following the development of tetrahedrite as a thermoelectric material. He says Alphabet Energy’s estimates of the E1’s cost savings appear to be sound, though he hasn’t had an opportunity to assess it properly.
Nevertheless, Shakouri says, tetrahedrite is so abundant that initial investment in a heat converter is minimal -- something he said is “kind of quite unique in thermoelectrics.”
By Andy Tully of Oilprice.com
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Andy Tully is a veteran news reporter who is now the news editor for Oilprice.com