Exergy Analysis Using a Theoretical Formulation of a Geothermal Power Plant in Cerro Prieto, México

The purpose of this research is the calculation of the exergy destruction of the single-flash and double-flash cycles of a geothermal power plant located on the ladder of the 233 m Cerro Prieto volcano, on the alluvial plain of the Mexicali Valley, Mexico. The methodology developed in this research presents thermodynamic models for energy and exergy flows, which allows determining the contribution of each component to the total exergy destruction of the system. For the case-base, the results indicate that for the single-flash configuration the efficiency of the first and second law of thermodynamics are 0.1888 and 0.3072, as well as the highest contribution to the total exergy destruction is provided by the condenser. For the double-flash configuration, the efficiency of the first and second law of thermodynamics are 0.3643 and 0.4983. The highest contribution to the total exergy destruction is provided by the condenser and followed by the low-pressure turbine.

Environmental and Social Impacts of the Increasing Number of Geothermal Power Plants (Büyük Menderes Graben - Turkey)

The use of renewable energy is critical to the long-term development of global energy. Geothermal Power Plants (GPP) differ in the technology they use to convert the source to electricity (dual, single flash, double flash, back pressure, and dry steam) as well as the cooling technology they use (water-cooled and air-cooled). The environmental consequences vary depending on the conversion and cooling technology used. Environmental consequences of geothermal exploration, development, and energy generation includes land use and visual impacts, microclimatic impacts, impacts on flora-fauna and biodiversity, air emissions, water quality, soil pollution, noise, micro-earthquakes, induced seismicity, and subsidence. It can also have an impact on social and economic communities. As geothermal activity progresses from exploration to development and production, these effects become more significant. Before beginning geothermal energy activity, the positive and negative aspects of these effects should be considered. The number of GPPs in the Büyük Menderes Graben (BMG) geothermal area is increasing rapidly. According to the findings, in order to reduce the environmental and social impacts of the GPPs in the BMG, resource conservation and development, production sustainability, and operational problems should be continuously monitored.

LCA and Exergo-Environmental Evaluation of a Combined Heat and Power Double-Flash Geothermal Power Plant

This study deals with the life cycle assessment (LCA) and an exergo-environmental analysis (EEvA) of the geothermal Power Plant of Hellisheiði (Iceland), a combined heat and power double flash plant, with an installed power of 303.3 MW for electricity and 133 MW for hot water. LCA approach is used to evaluate and analyse the environmental performance at the power plant global level. A more in-depth study is developed, at the power plant components level, through EEvA. The analysis employs existing published data with a realignment of the inventory to the latest data resource and compares the life cycle impacts of three methods (ILCD 2011 Midpoint, ReCiPe 2016 Midpoint-Endpoint, and CML-IA Baseline) for two different scenarios. In scenario 1, any emission abatement system is considered. In scenario 2, re-injection of CO2 and H2S is accounted for. The analysis identifies some major hot spots for the environmental power plant impacts, like acidification, particulate matter formation, ecosystem, and human toxicity, mainly caused by some specific sources. Finally, an exergo-environmental analysis allows indicating the wells as significant contributors of the environmental impact rate associated with the construction, Operation & Maintenance, and end of life stages and the HP condenser as the component with the highest environmental cost rate.