Heat Rate and Economic Evaluation of a Photovoltaic- Assisted Combine Cycle Power Plant

Abstract

Gas turbine combined cycle (GTCC) power plants are widely used as major power plants in grid systems, while world energy prices are rather high and renewable energy is now stepping in to replace conventional fossil energy. Therefore, the efficiency of the GTCC needs to be improved for both thermal efficiency and economic aspects. This concept will help GTCC improve its heat rate by bringing in renewable energy. In the present research, the installation of solar photovoltaics (PV) in the GTCC power plant for supplying the auxiliary equipment of the power plant was studied. The heat rate comparison between the proposed method and conventional GTCC, including an economic evaluation, was conducted through a case study of an independent power producer operating a 700 MW GTCC in Thailand. The performance test and calculation methodology followed the Performance Test Code 46 of the American Society of Mechanical Engineers, which eliminated the uncontrollable impact of environments. As a result, the PV system could replace some of the auxiliary power consumption by utilizing a PV system of 980 kW, the GTCC heat rate was improved to 59.17 kJ/kWh, and the electrical power generation was 1,393,379 kWh per year, which reduced the natural gas consumption by 10,086,671 MJ annually or 100,867 GJ for the remaining lifetime of the power plant.

Keywords

• combine cycle
• photovoltaics
• auxiliary power consumption
• economic