Co-generation power plants are very popular in Europe compared to the U.S. market. It will be interesting to see if this type of application will take off in North America, but I’d like to share a little background information on co-generation first.
Co-generation, or combined heat and power (CHP), is actually the use of a heat engine or a power station to generate electricity and useful heat. Co-generation is considered as a thermodynamically efficient use of fuel. In separate productions of electricity, some energy must be discarded as waste heat, but in co-generation this thermal energy is put to good use.
Usually the CHP plant uses steam as a working fluid and has a flexible ratio of co-generation, which always depends on the season. In the warmer seasons when heat production is not required, the low pressure (LP) part of a steam turbine isn’t loaded. Likewise, it consumes power and reduces efficiency of the turbine and therefore the cycles. It should be noted that some technologies exist which help to reduce the mentioned negative effect but they still have some drawbacks.