Zeddy Sambu
2 December 2009
KenGen has reopened a section of a 40-megawatt power generation unit at Masinga Dam, signalling the high power tariffs linked to the recent surge in thermal power on the national grid may soon begin to ease.
KenGen officials said the water level at Masinga had climbed by 14 metres and attained the minimum operating level of 1040 metres to enable the reopening.
However, these volumes can only support generation from one of the dam's two units with the optimal target of 1,056 metres, highly dependent on the rainfall due in December.
"We have reopened Masinga and are generating 20 megawatts. However, the rains are not good and the inflows are not as expected for full generation," said Mike Njeru, KenGen's manager for corporate communications.
Masinga, which relays water to four other dams -- Kamburu, Kiambere, Gitaru and Kindaruma -- is one of the Seven Forks dams, which together produce 47 per cent of the country's electricity supply.
The unit was shut down at the end of June due to a long dry spell that had decreased water levels and capacity for power generation from one of the units situated in Kenya's main reservoir -- the Seven Forks Cascade.
The closing of the unit was expected to free up water for a second downstream unit and also will lessen the impact of the closure on the country's power grid.
Although part generation has now been made possible at Masinga, officials at power distributor KPLC warned that the current water volumes cannot sustain normal generation.
"We run the hydro power stations at night to meet peak hour demand (between 6 pm and 11 pm) and if the el-niño rains eventually come to fill the dams, you still need the water to meet your evening demand," said Mr Migwi Theuri, a KPLC manager.
"The generation mix has not changed because not much water is going into the Seven Forks dams to warrant enhanced generation. We are still in the water conservation mode for future use," he said.
Currently, other sources of electricity include costly emergency power sources that use diesel generators.
According to KPLC, over dependence on the thermal generation in place of the resilient hydro sources has led to frequent interruptions of power supply.
"The system is fragile because thermal generators is sensitive to even slight interruptions," said the KPLC official.
Presently, peak national demand for electricity stands at 1,089 megawatts.
While the demand can be met, helped by a diverse generation mix, weaknesses in the transmission system have caused leakages leading to frequent interruptions of power supply.
Statistics from the power firm show that of the total interconnected capacity of 1,523 megawatts of power, 48 per cent of the effective capacity is derived from water dams while the costly thermal sources account for 39 per cent.
The capacity of the thermal-powered generators include 286 megawatts of emergency power from the Aggreko plants in Naivasha and Nairobi.
At present, private investors -- including Aggreko, OrPower, Tsavo Power, IberAfrica and Rabai Power -- chip in close to 50 per cent of the country's power supply.
The short rainy season in Kenya starts in October to December, but it has currently produced lower-than-expected yields.
Businesses say frequent power blackouts increase costs.
But policy makers have been looking for alternative sources of power to maintain the electricity demand, which expands by about 8 per cent annually, on the back of a growing economy and population.
The expected el-Niño rains had raised hopes of lighter power bills on the back of increased use of less expensive hydro power generation sources and reduced reliance on thermal power that has delivered expensive electricity in recent months.
A drop in hydro power's contribution to the national grid on poor weather has seen electricity bills rise by about 60 per cent since March driven by fuel costs charges -- a varying item on the bills that is linked to the amount of power on the national grid that is generated from thermal sources.
Power economists at the industry regulator ERC reckon that for the costs to come down, the country must receive two months of continuous rain for the hydro power plants to operate at their optimal capacity.
With the country is heavily dependent on the rain-fed hydro power sources, power rationing was rolled out from August but it was withdrawn on October 5 as the expanded supply of emergency power from Aggreko, came on stream.
'A deepening of the drought has halved the contribution of hydro. Emergency power is up hence high power bills," said Energy minister Kiraitu Murungi.