INFLUENCE OF THE HEAT-SOURCE COST ON GEOTHERMAL ORC'S

asme-orc2015 Tracking Number 90

One of the biggest costs in geothermal ORCs is the drilling of the wells. The costs of these wells depend on the region and they have an influence on the optimal configuration of the power plant. The higher the cost of the wells (for a given wellhead temperature), the higher the efficiency of the ORC has to be for a profitable project and thus the higher the cost of the ORC will be. In this work, it is investigated what the influence of the cost of the heat source is on the performance and configuration of the economically optimal ORC. This optimal ORC is obtained by performing a system optimization, as already performed in our previous work [1,2]. In such a system optimization, the configuration of the most important components (heat exchangers, cooling system and turbine) are optimized together with the configuration of the cycle. In this way, components are optimal to be used together and optimal to be used in the obtained cycle. Minimization of the LCOE (Levelized Cost of Electricity Production) is chosen as the objective function. This LCOE is the fixed electricity price needed to obtain break even at the end of the project. As a result, the LCOE for both water and air-cooled ORCs is given as a function of the heat-source cost and heat-source-wellhead temperature. With this data, an estimation of the LCOE of a geothermal project can be made based on the depth of the wells and the expected wellhead temperature. Comparison with expected electricity prices, the profitability of the project can be estimated. Other results, like the heat-exchanger surface, cooling-system cost, etcetera as a function of the heat-source cost, are also given.