Improved Newcomen Engines
The theoretical efficiency of power stations is limited by the fact that the second half of the cycle from steam back to water is not used.
The steam turbines that are used in coal fired power stations generate a lot of waste heat and heat exchangers and cooling towers are employed to release this heat to the atmosphere. Waste heat represents the thermal inefficiency of the power station and can to a substantial extent be utilised using a retrofitted Newcomen engine improving overall efficiency in the order of 25-35%. Newcomen engines exploit the large volume differences that occur when water vapour collapses to form a liquid and the latent heat loss when water changes state from steam to water. Unlike conventional Rankine engine turbines they do not require pressurised steam to produce electricity and can therefore utilise bulky low grade steam.
More information can be found about Newcomen Engines under Gaia Engineering