Ghana's best shot at going green: sewage power
With solar and wind power costly and inadequate, Ghanaians are turning to some very alternative sources of energy – like human waste.
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There are more sanitary ways to make a megawatt in this country. Kwame Tufor came home from Florida to liquefy Ghana's coconut husks, cocoa pods, and palm nut shells into gas. But you'd need a lot of coconuts to turn a profit that way. So he and a business partner are eyeing an old paper farm the size of Brooklyn. Sometime between one 1970s coup and another, the owner ran out of money and political favor, abandoning acres of trees that were meant to be mulched into notepads 35 years ago.Skip to next paragraph
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Mr. Tufor intends to saw those trees down, replant them, then burn the timber and compress the smoke into a biofuel using dated World War II technology that's been dusted off by developing world power plants. At least 10 plants in China now gasify coal this way. Farmers in the Philippines run irrigation pumps on generators that gasify rice husks. If Tufor's $200 million project pans out, local farmers would also sell him their nutshells and cocoa pods for his incinerator.
Odder sources of energy are under review. They include leftovers. Ghana's trash, it seems, boasts curiously high food content – edibles account for 60 percent of this country's rubbish, according to senior researcher Robert Adu at England's De Montfort University, Leicester. He's finishing a technical proposal on how to goose a charge out of Ghana's garbage. One thing Ghana's got going for it: Locals love rice. One kilogram of the staple grain, Mr. Adu says, packs 17 kilojoules, a flicker compared with a kilo of kerosene, but great compared with a vegetable.
Ghana's government offers a subsidy for companies that can produce renewable energy at a cost closer to the African pay scale. For Adu, that means it might just be profitable to feed tons of rotten groceries every day into a fire that would boil a tank of water whose steam would lurch a turbine forward. The trouble? How to cull the grub from the garbage. Trash separation schemes do exist; Adu says he's reading a book on them. He points to a plant in Germany that's mastered the technique through a process made profitable by sales of hot air, a byproduct, to heat homes in wintertime. If Adu goes that route, he'll have to find buyers looking to purchase hot air in the tropics.
Otu-Danquah isn't quite sure how this burst of invention will wind up: At the day's end, economics on what Ghanaians and their government can afford will surely dash some dreams. But the proposals make for more interesting reading, he says, than the stack of hackneyed solar plant schemes he's stuffed into a corner. Plus, some big break just might occur.
“When the time comes,” he says. “we will have learned our lessons and developed our own technology.” At the very least, he adds, Accra might enjoy cleaner streets and cleaner sewers.