Kenya leads way in Africa with major biogas power plant
A COMMERCIAL farm in Kenya has become what is believed to be Africa’s first electricity producer powered by biogas to sell surplus electricity to the national grid.
The process cuts carbon emissions associated with oil-powered generation.
The Gorge Farm Energy Park in Naivasha produces two megawatts of electricity – more than enough to cultivate its 706ha of vegetables and flowers, and with sufficient surplus to meet the power needs of 5 000 to 6 000 rural homes.
The new plant generates not only electricity, but also heat for the farm’s greenhouses, with fertiliser as a byproduct.
Gorge Farm, 76km northwest of Kenya’s capital, Nairobi, is owned by the Vegpro Group, a leading East African exporter of fresh vegetables and its second largest exporter of roses.
Biojoule Kenya, the independent power producer that operates the Gorge Farm plant, signed an agreement to sell electricity to Kenya Power and Lighting Company (KPLC), the country’s sole power distributor, last year.
Biojoule Kenya sells the power to Gorge Farm and to KPLC for 10 US cents (R1.18) per kilowatt hour (kWh). Diesel-generated power, by contrast, costs $0.38 (R5.38) per kWh to produce. “The Gorge Farm plant is physical proof that locally produced feedstock can be used to generate clean and cost-effective power for all Kenyans,” Tropical Power chief operating office Mike Nolan said.
The company specialises in developing biogas and solar plants.
The operation produces biogas through anaerobic digestion, a process in which crop residue from the farm is digested by micro-organisms.
The biogas produced is burnt in two engines, producing both electricity and heat in a process called cogeneration.
Producing the same amount of energy using diesel would require five million litres of fuel annually, Nolan said, plus the extra fuel required to transport the diesel inland from the port of Mombasa.
Tropical Power says the biogas plant contributes to a 7 000-ton reduction in carbon dioxide emissions ayear.
Cogeneration currently makes up a tiny fraction of renewable power sources in Kenya, at 0.7% in 2015, according to the Kenya Electricity Generating Company.
Geothermal was the biggest contributor to the electricity generation mix with 49%, followed by hydropower at 44%.
Even though anaerobic digestion of waste to produce biogas is an established technology in Europe and Asia, the large-scale use of the process is still new in Africa.