Economic analysis of geothermal combined heat and power processes

Despite huge potentials of geothermal energy the share on worldwide electricity and heat provision is small, which is mainly caused by unfavorable economic boundary conditions. In this study, combinations of combined heat and power systems and working fluids, which perform best from a thermodynamic point of view, are evaluated by means of economic parameters based on VDI standard 2067. The objective is the evaluation of levelized cost of electricity and heat respectively. In detail, effects of electricity and heat price factors, thermal water temperatures and drilling costs on economic efficiency are focused. A trade-off between economic and thermodynamic goals is discussed. Based on a realistic cost structure of geothermal energy systems economic operations are feasible within typical life spans of projects. Annual energy sales are strongly influenced by the applied drilling cost correlation and are calculated to three to five Mio. Euro. In order to generate heat and electricity sales the heat generation represents the limiting process.