Greenhouse gas emissions from fossil power plants contribute significantly toward climate change. Simultaneously, the increase in ambient air and water temperatures reduces thermal power generation. Coal, nuclear and natural gas plants experience a 0.25%-0.72% reduction in power output for a 1°C increase in the ambient temperature. As ambient temperatures increase, generation losses from coal, nuclear and natural gas together are predicted to increase at an average rate of around 700 GWh/y. At this rate, average annual generation losses could add up to around 29 TWh for coal, nuclear and natural gas combined in 2050. Approximately ten additional 600 MW power plants might be needed to replace this lost electricity by 2050. Concurrently, average losses in generation income could total $1400 million for these thermal plants in 2050. Changes in solar and hydro power are also briefly compared. Finally, the importance of water availability and the effects of extreme climate events on thermal power plants are discussed.