Drax said its Scottish hydro operations had performed well during the six months to June 30.
The assets include the Cruachan Pumped Storage power station in Argyll and the Lanark and Galloway river-based schemes.
They were included in a portfolio that Drax acquired from ScottishPower in a £700 million deal in 2018, along with a plant at Daldowie that produces fuel pellets from sludge.
The company generated £34m earnings from the portfolio in the first half, compared with £35m in the same period last year.
In his business review, chief executive Will Gardiner said: “We are continuing to develop a long-term option for the expansion of Cruachan, which could create a 1GW pumped storage power station (currently 0.4GW) and commenced a planning application process in June 2021.”