Optimal utilization of geothermal heat from abandoned oil wells for power generation

Unlike other types of renewable energy, geothermal resources represent a stable energy source because they can be exploited regardless of meteorological conditions. In geothermal systems, heat is exchanged between the surrounding rock and the geofluid. Thus the energy potential strongly depends on the temperature of the geofluid, which in turn depends on the working parameters (WPs). The objective of the current work is to specify the optimal WPs (i.e., heat extraction rate, geofluid flow rate, and the temperature difference between the well inlet and outlet) in order to maximize the exploitation of the geothermal resource. The ground thermal properties, geothermal temperature gradient, and well dimensions based on realistic conditions in Qatar and neighboring countries were used to model electricity generation from a geothermal power plant. The simulation shows that the proper selection of the WPs can considerably increase the electricity generation of the power plant. Also, this work shows that the optimal WPs guaranties a sustainable utilization of geothermal sources, which means a constant electricity output of the Rankine turbine over time. For the working conditions in Qatar, it is determined that the maximum electricity generation would be 11 kW during the 25 years (analysis time). To get this maximum electricity generation, the optimal WPs should be as follows: 275 kW for heat extraction rate, 3.7–4.4 kg/s for geofluid flow rate, and 15–17 °C for the temperature difference.Scopu

Utilization of oil wells for electricity generation: Performance and economics

There is a general agreement that the climate change, which is the most important challenge facing humanity, is anthropogenic and attributed to fossil fuel consumption. Therefore, deploying more renewable energy resources is an urgent issue to be addressed. Geothermal refers to existing heat energy in deep rock and sedimentary basins. Traditionally, geothermal energy has been exploited in places with plentiful hot water at relatively shallow depth. Unfortunately, the high exploration and drilling costs of boreholes is the main barrier to the commerciality of geothermal worldwide. In oil producing countries, such problems can be overcome by utilizing oil or gas wells. The current study presents thermodynamic and economic analyses of a binary geothermal power generation system for commercial electricity generation. Two different source temperatures (100 and 120�C) and constant sink temperature (29�C) were considered. The optimal working fluid and optimal design that improve the performance of the plant are determined. For the current costs in Qatar, the economical analysis of 5MW geothermal plant shows that the levelized cost of electricity for the plant varies from 5.6 to 5.2�/kW. Whereas, the payback period of such plants lies between 5.8 and 4.8 years.(NPRP 7�725�2-270) from the�Qatar National Research Fund�(a member of The�Qatar Foundation)Scopu