Where will surplus of energy come from? Even if fusion reactors will become mass-produced and cheap, well, it's easy to find a baseline there: they will never b

Where will surplus of energy come from? Even if fusion reactors will become mass-produced and cheap, well, it's easy to find a baseline there: they will never be cheaper than a coal boiler producing same steam energy, that's easy to see. Which means, because the rest of the system - turbines, generators, heat exchangers, condensers, steam separators, water treatment facilities, transformers, safety systems etc. - remains the same - a fusion power plant is the same thing as a coal power plant running on free coal. If you take cost of coal-produced electricity and subtract the cost of coal that went into it, it's still more than current costs of solar with storage.