Thermal electricity generators have increased their output by 70 per cent over the first five months of the year, loading on additional costs to power bills.
Data for the period shows thermal power produced amounted to 1,303.19 million kilowatt-hours compared to 764.3 million kWh over a corresponding period last year.
Kenya Power, the State-run electricity vendor, turns to the expensive thermal power to bridge shortfalls in hydro generation, which has been low over the period due to poor hydrology.
Using diesel-fuelled thermal electricity has meant that households and businesses have to pay more due to a higher fuel-cost charge, one of the components of power bills.
"There has been a gradual rise in the fuel-cost charge since December. We have made some changes to accommodate the poor hydrology in the period," Ben Chumo, Kenya Power's chief executive, told The Star.
"This is the third month that we are charging our customers Sh7.22 per unit compared to Sh5.19 in December because we were initially cushioning them. We are passing through the cost of thermal power."
Hydro power produced over the period amounted to 1,453.58 million kWh compared to 1,779.84 million kWh in the first five months of last year, a 18.3 per cent decline. Water levels at Masinga and Turkwel dams were at 1,049.62 metres and 1,126.2m respectively as at Thursday.
It is anticipated that the hydrology situation will improve by November, Chumo said. Households, businesses and manufacturers therefore have to brace for a longer period of expensive power bills.
"The higher fuel charge is estimated to end by November in the unlikely event that nothing changes before then. We are however expecting an additional 70 megawatts of geothermal power next month, which will displace some of the thermal power," Chumo said.
The Kenya Electricity Generation Company, a quasi-public corporation which produces over 80 per cent of electricity consumed in the country, owns three thermal power stations - Kipevu Diesel Plant, Kipevu Gas Turbine and Nairobi South Gas Turbine.
Independent power producers running thermal generation plants include Tsavo Power (74 megawatts), Rabai Power (90MW) and IberAfrica Power (108MW).
More thermal power was loaded on to the national grid despite a surge in geothermal power generated by 167.85 million kWh over the five months, to 855.8 million kWh.
The additional thermal power taken on board has pushed total electricity generation up by 11.8 per cent to 3,612.57 million kWh over the period from 3,232.08 million kWh.
This matches an almost equal rise in consumption, which was up 11.6 per cent to 2,941.71 million kWh over the five-month period, including Kenya Power sales and rural electrification, from 2,635.79 million kWh.
Emergency power producer Aggreko in addition generated 43.4 million kWh over the period, but this was however a 161.8 per cent reduction compared to last year's 113.62 million kWh up to May.
Chumo said Aggreko's supply is not being retired but being gradually reduced under an "exit strategy that includes paying it a capacity charge". Chumo said the country is looking to other sources of energy as a two-prong approach to save on costs and avail cheaper power while reducing over-reliance on hydro generation.
"About 50 per cent of our 1,600MW generation capacity is rain-dependent. We must look at this to avoid energy crisis as the economy grows and as hydrology changes," he said.
Power loss over the period surged by 19.64 million kWh over the period to 754.03 million kWh from 734.39 million kWh, a 2.7 per cent increase.