For energy markets, and this includes gas and electricity, one must distinguish between the spot markets, and longer term agreements. The former ones have very

For energy markets, and this includes gas and electricity, one must distinguish between the spot markets, and longer term agreements. The former ones have very high volatility during the day, while the latter ones base on long term contracts usually with fixed prices. The spot markets are generally only there to cover any additional demand that one didn't want to make long term commitments for, while the longer term contracts create the base load. That's why it's profitable to keep the gas turbines running. You must also consider the price of the turbine and surrounding infrastructure: if it can only run profitably 10% of the time it will be a much harder sell than running it 30%.