Going green in Ghana with sewage power

How might the world’s poorest continent go green? Kwabena Otu-Danquah’s job is to crack that riddle. The renewable energy czar for Ghana ranks among the handful of bureaucrats across Africa tasked with picking which forms of green energy might prove affordable on a continent where most people don’t pay for the electricity they sometimes receive.

Last year the Ghanaian parliament signed a pledge to derive 10 percent of the country’s electricity from alternative sources come 2020.

Sun? Forget it. Solar costs 40 cents to 50 cents a kilowatt hour, while Ghanaians pay just 5 cents to 10 cents for electricity from conventional sources. Wind? Too slow. Breeze ambles through this tropical doldrum at a leisurely average of five kilometers an hour (3.2 miles per hour).

That’s forced Ghana to consider a more imaginative set of choices. Among them, sewage. Flush with a $1.5 million grant from the Bill and Melinda Gates Foundation, local Waste Enterprisers Ltd. is building Ghana’s first “fecal sludge-fed biodiesel plant.” That’s longhand for cooking human excrement into generator fuel, Chief Operating Officer Tim Wade explains. The transformation would serve a dual purpose. Open sewers sweep 1,000 tons of slurry each day into the ocean off Accra. Outside the upland city of Kumasi, roughly 100 trucks dump tens of thousands of liters of septic tank sewage daily into what used to be a small pond.If all goes according to plan, next month one truck a day from Kumasi will dump its payload into a warm and massive vat that will skim lipids – fat – off the top. “That’s your biodeisel,” he explains.

At $7 a gallon, he can sell the muck to local mining companies, who are keen to buy because they too have been required by parliament to power 10 percent of their private electric plants from green sources. Normal diesel does sells a few bucks cheaper, he admits, “But we’re still optimizing the process.” If he can get costs down, Mr. Wade intends to build four plants in Accra and lecture sub-divisions back home in Colorado on the folly of treating their waste.