KenGen eyes power storage facility to cut costly thermal

KenGen is planning to build a battery energy storage system that will store excess energy from its geothermal power plants in Olkaria to be used when demand goes up. 

The government said recently it needs such energy storage facilities to enable the national electricity grid to cope with an increase in power plants that use energy sources such as wind and solar, which are not available in the evenings when there is a surge in power consumption. 

State-owned electricity generating firm KenGen on Tuesday started the search for a consultant to undertake a feasibility study to guide it in the installation of a battery energy storage system (BESS).

The system is expected to store electricity generated using geothermal power, which according to KenGen, is left idle during off-peak consumption hours.

This is particularly the case when electricity from wind and solar feeds the grid and displaces geothermal. 

“The current grid network is experiencing challenges that were not present in the recent past. There is significant generation from intermittent renewable energy sources, especially wind and solar,” said KenGen in the invite to firms for an expression of interest for a utility-scale BESS feasibility study.

It added that while enhanced generation from variable renewable sources such as wind and solar was good as it is displacing costly and polluting thermal power, they have exposed the grid to some key challenges.

These include the fact that they are only available when demand is low such as late in the night for wind and during the day for solar.

The result is that they displace geothermal energy, during the off-peak hours but are not available during peak times when the system experiences firm capacity deficiencies and sees power the country relying on expensive thermal plants.

“At these low peak times, it is difficult to throttle geothermal wells with the aim of reducing steam generation so the only option available is to vent the excess geothermal steam. The situation is worsened by the fact that vented steam cannot be recovered for reinjection into the resource area, so it reduces the sustainability of the geothermal field,” said KenGen.

“Another concern is the stability of the grid. Intermittent sources of power tend to be unpredictable and so they require other energy sources that can compensate for the intermittency of the resource.

“This means that  for the integration of renewable energy in the network, other forms of energy generation or ancillary services are needed in the network to help improve the stability of the grid network.”

Kenya’s Least Cost Power Development Plan (LCPDP) 2024-2043 recommends expediting the development of 250MW BESS by the year 2026.

KenGen said the capacity of the electricity storage facility as well as its location will be informed by the feasibility study.

“It is noteworthy that all diesel and gasoil power plants are expected to be decommissioned by 2035. In line with the government target towards 100 per cent green energy by 2030,” said KenGen.

While the country has slowed down on licensing thermal power producers over the high cost to consumers, power plants using wind and solar to generate electricity have been on the rise.

Major wind plants feeding the national grid include KenGen’s plant at Ngong Hills, which has a capacity of 25.5MW, Lake Turkana Wind Power (310MW) in Marsabit and Kipeto Power (100MW) in Kajiado.

Among the major solar power plants are the State-owned Garissa Solar plant with an installed capacity of 52MW, Globeleq’s Malindi Solar Plans (40MW), Selenkei (40MW), Cedate (40MW) and Alten Kenya Solarfarm (40MW).

Wind and solar power accounted for about 20 per cent of the country’s installed power-generating capacity, which stood at 3,243.6MW in 2023, according to data from the Kenya National Bureau of Statistics (KNBS).