The High Efficiency-Coal and Gas (HE-C&G) is a hybrid power plant concept integrating Conventional Steam Power Plants (CSPP) and gas turbine / combined cycle plants. The gas turbine exhaust gas energy is recovered in the HRSG providing partial condensate and feedwater preheating and generating steam corresponding to the main boiler live steam conditions (second steam source for the ST).
The concept, exhibiting very high design flexibility, integrates the high performance Sequential Combustion gas turbines GT24/GT26 technology into a wide range of existing or new CSPP.
Although HE-C&G refers to coal as the most abundant fossil fuel resource, oil or natural gas fired steam plants could be also designed or converted following the same principle.
The HE-C&G provides very high marginal efficiencies on natural gas, up to and above 60%, very high operating and dispatching flexibility and on-line optimization of fuel and O&M costs at low capital investment.
This paper emphasizes the operating flexibility and resulting benefits, recommending the HE-C&G as one of the most profitable options for generating power especially for conversion of existing CSPP with gas turbines.