Kenya last week cut off a third of cheaper geothermal power from the national grid due to lines maintenance, setting the stage for higher electricity bills next month.
The Energy Regulatory Commission (ERC) said construction works at Suswa substation on the Maai Mahiu-Narok highway prompted the country to temporarily withdraw 200 megawatts of geothermal from the national grid.
The supply shortfall was plugged by increased intake of hydropower and expensive diesel-fired electricity, signalling higher fuel charge in consumer bills.
The energy regulator reviews the fuel levy monthly and the surcharge is influenced by the amount of thermal power injected into the grid.
A unit of thermal power costs more than Sh18 per kilowatt hour (kWh) compared to hydro (Sh3) and geothermal at Sh7.
“This is sacrifice we have to make at the moment to stabilise electricity costs in future,” said ERC director-general Joseph Ng’ang’a.
“There was a one week outage of up to June 12 (Sunday) that arose from Suswa substation due to works carried out by Ketraco (Kenya Electricity Transmission Company) to improve geothermal energy evacuation, necessitating a shutdown in one of the Suswa-Nairobi transmission line.”
The fuel levy in power bills has remained at Sh2.31 per unit of electricity consumed since January. The levy was at Sh7.22 in July 2014 before the country added 280 megawatts of geothermal energy from Olkaria fields to the grid.
Suswa is Kenya’s largest substation and receives electricity from geothermal plants at Olkaria in Naivasha and hydroelectric plants.
Substations convert electricity coming from plants through high voltage transmission lines — 120 kilovolts or above — to lower voltage for distribution to homes and businesses. Reinforcement of the stations aims to cut transmission losses and reduce blackouts.
The Ketraco is in charge of constructing and maintaining high-voltage transmission lines of above 132 kilovolts alongside their substations with Kenya Power handling lower voltage lines.
A restricted transmission capacity has recently curbed supply of increased cheaper hydro power and geothermal to the national grid, denying homes lower bills.
“Much as we have surplus cheaper energy, we can’t increase generation as we have limited lines. Otherwise they can overheat and trip the whole system,” said Mr Ng’ang’a.
The switch-off of the 200 megawatts of geothermal energy saw Kenya Power increase its purchase of hydropower by 100 MW and expensive thermal power by another 100 megawatts.