Prediction of performance, energy savings and increase in profitability of two gas turbine steam generator cogeneration plant, based on experimental data

This study analyses three feasible regulation methods of an in-service cogeneration plant. The main task is to study the potential energy savings, CO2 reduction and the increase in profitability compatible with the lowest transformation costs.The cogeneration system is composed of two General Electric LM2500 gas turbines and a heat recovery steam generator (HRSG). Two plant localizations in Spain have been considered; San Fernando (Cádiz) where the current plant is located, and Burgos. The latter has been taken into account to analyze the effect of cooler weather on the regulation methods.The paper has been divided into three parts. First, a revision of the current legislation regarding cogeneration in Spain is shown. Second, a description of the power plant and the proposed regulation methods are set out. Then, the cogeneration plant is modelled with the objective of evaluating the effects of the regulation methods in power, generated steam and thermal oil flow. Finally, the model was applied to analyze the profit obtained from different regulation combinations and to compare the benefits of those regulation methods in the two locations with different climatic situations.The main conclusion reached is the importance to meet the requirements of Spanish legislation in order to obtain advantages in the sale of electricity; an increased profit of up to 60% was obtained in the simulation. In addition, it is evident that the regulation is more important when ambient temperature is lower.

Research highlights
► Gas turbine steam generator cogeneration plant performance prediction.
► Gas turbine steam generator cogeneration plant part load operation.
► Increase in profitability of gas turbine steam generator cogeneration plant.