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Wait, what? Coal plants operate with an upper temperature of under 600C, and they approach 40% efficiency. Why do you say it's only 20%?

Either way, it sounds as if a coal plant without the furnace wouldn't be able to compete with "conventional electricity". What is "conventional electricity" then? Open cycle gas turbines? Are they that much cheaper, even including fuel cost?

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Those temperatures will also be at higher pressures, while the waste heat I mentioned is at atmospheric pressures. 500-600C is the "crossover zone" where ORC versus steam cycle really depends on the details.

The plants we were looking at were either open cycle turbines (which means turbines in mechanical duty such as compressor stations, since all new turbine power plants are combined cycle) or other industrial processes such as cement production and steel manufacture.

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