Kenya's hydro cascade sits above full supply level, and thermal dispatch has room to fall.

For an offtaker buying Kenyan power, and for anyone holding a thermal plant that earns on the same grid, the cheapest units on the system are currently running hard. Hydropower sent 9.57 million kilowatt hours into the national grid on 4 May 2026, according to an operational update published by KenGen the following day.

The reservoirs behind that figure are at the top of their range. Masinga, the largest, measured 1,057.43 metres above sea level on the night of 4 May, sitting above its full supply level of 1,056.5 metres, with overflow being released under control. Kiambere was marginally over its own threshold of 700.0 metres, at 700.91, and under active management. Kamburu, Gitaru and Kindaruma were all inside their operating bands.

Scale matters here. The company reports installed capacity of 1,786 MW, of which 826 MW is hydro, 754 MW geothermal and 25.5 MW wind, with the remainder thermal. A single day's output of 9.57 million kilowatt hours averages a little under 400 MW across 24 hours, close to half the nameplate of the hydro fleet. Read together, full dams and a large geothermal base leave the system operator less reason to call on expensive thermal units to hold the reserve margin, and that is where the cost of the merit order moves for a buyer.

The other half of the operation is water rather than electricity. With rain still falling over the Mt Kenya and Aberdare catchments, the cascade is moderating downstream flows while it generates, residents in low-lying ground near the Tana River have been told to keep clear of the banks and follow instructions from local officials, and the company has said further updates will follow as conditions change.

Storage this high is drawn down over months, not weeks, so the question is duration rather than any one day's number. The implication is that what a buyer should be pricing is how long the cascade holds above its normal band once the rain stops.