CO2 Plume Geothermal (CPG) Systems for Combined Heat and Power Production: an Evaluation of Various Plant Configurations

Abstract

CO2 Plume Geothermal (CPG) systems are a promising concept for utilising petrothermal resources in the context of a future carbon capture utilisation and sequestration economy. Petrothermal geothermal energy has a tremendous worldwide potential for decarbonising both the power and heating sectors. This paper investigates three potential CPG configurations for combined heating and power generation (CHP). The present work examines scenarios with reservoir depths of 4 km and 5 km, as well as required district heating system (DHS) supply temperatures of 70°C and 90°C. The results reveal that a two-staged serial CHP concept eventuates in the highest achievable net power output. For a thermosiphon system, the relative net power reduction by the CHP option compared with a sole power generation system is significantly lower than for a pumped system. The net power reduction for pumped systems lies between 62.6% and 22.9%. For a thermosiphon system with a depth of 5 km and a required DHS supply temperature of 70°C, the achievable net power by the most beneficial CHP option is even 9.2% higher than for sole power generation systems. The second law efficiency for the sole power generation concepts are in a range between 33.0% and 43.0%. The second law efficiency can increase up to 63.0% in the case of a CHP application. Thus, the combined heat and power generation can significantly increase the overall second law efficiency of a CPG system. The evaluation of the achievable revenues demonstrates that a CHP application might improve the economic performance of both thermosiphon and pumped CPG systems. However, the minimum heat revenue required for compensating the power reduction increases with higher electricity revenues. In summary, the results of this work provide valuable insights for the potential development of CPG systems for CHP applications and their economic feasibility.

Life Cycle Greenhouse Gas Emissions of CO2-Enabled Sedimentary Basin Geothermal

“…Others assessed the reservoir heat depletion rates and well spacing designs, thermosiphon benefits in reducing pumping requirements, and increases in net electricity production. ,, Hansper et al analyzed the cost effectiveness of CPG systems and demonstrated that under preferred reservoir conditions and system layouts, they can be less expensive than brine-based systems in sedimentary basins. Schifflechner et al proposed combined heat and power (CHP) configurations for CPG systems, showcasing that such systems are suitable for deeper reservoirs (around 4 km) and can enhance the economic performance of CPG with revenues from heat compensating for reduction in power output.…”

Geothermal power generation and positive impact in the greater bay area: a case study of Huizhou City, Guangdong Province

“…In this context, geothermal energy holds significant importance as a clean and stable energy source 8 . Additionally, geothermal energy can reduce reliance on fossil fuels, decrease dependence on imported energy, and enhance national energy security 9 . Therefore, the research on the extraction and utilization of geothermal resources in China becomes increasingly urgent 10 , 11 .…”

Geothermal power generation and positive impact in the greater bay area: A case study of Huizhou city, Guangdong province

“…Geothermal resources, as vast renewable and clean natural resources on Earth, are estimated to have an energy storage of approximately 3.6×10 14 gigawatt-hours in the upper 10 kilometers of the Earth's crust [1]. Theoretically, these geothermal reserves can supply global energy consumption for approximately 2.17 million years, based on a global energy consumption rate of approximately 1.7×10 8 gigawatt-hours per year in 2012 [2,3].…”

“…China, as the world's largest energy consumer and the second-largest economy, faces challenges of an insu ciently rational energy structure and limited environmental carrying capacity [12].In this context, geothermal energy holds signi cant importance as a clean and stable energy source [13]. Additionally, geothermal energy can reduce reliance on fossil fuels, decrease dependence on imported energy, and enhance national energy security [14]. Therefore, the research on the extraction and utilization of geothermal resources in China becomes increasingly urgent.…”