Operational Strategies of Wet-Cycle Micro Gas Turbines and Their Economic Evaluation

The simultaneous expansion of variable renewables and combined heat and power (CHP) plants in Europe has given rise to a discussion about their compatibility. Due to the concurrence of high wind power generation and high heating loads, it has been argued that only the flexible, electricity-oriented operation of CHP plants could go along with the extended penetration of renewables in the European energy system. The current work focuses on the wet-cycle simulation of a Turbec T-100. Three operational strategies are applied on the heat and electricity demand data of a public building, to assess the economic and environmental performance of the wet cycle. The operation of the micro gas turbine (mGT) is modeled in aspen plus, and the model is validated with data found in the literature. The economic aspects of the operational strategies are assessed with a financial model, which takes into account the current CHP policy incentives and price levels. Furthermore, the advantages and drawbacks of wet operation are highlighted by its comparison to the typical heat-driven operation of dry-cycle mGTs, with a reference to the same case study. It is shown that the wet-cycle turbines have a higher number of full load equivalent operating hours and can achieve higher investment payback, with minor drawbacks to their overall environmental performance.