Energetic and exergetic performance evaluations of a geothermal power plant based integrated system for hydrogen production

The purpose of this study is thermoeconomic performance evaluation of alkaline water hydrogen production assisted by geothermal energy. In this study energy, exergy and cost balances of combined systems of each component for hydrogen production assisted by geothermal energy will be written. Exergy of each involved stream will be calculated and the exergetic balance of each subsystem will be assessed, as well as the global system, identifying and quantifying losses. This will allow thermodynamic performances of combined systems and each component. This information will be relevant to optimize the system performance from an economical point of view. We consider a geothermal resource at 230°C available at a rate of 230 kg/s. Under realistic operating conditions, 21545 kW power can be produced in a power plant. The produced power is used for the electrolysis process. The electrolysis water can be preheated to 67.6°C by the geothermal water leaving the power plant and hydrogen can be produced at a rate of 0.1125 kg/s. Also, combine flash binary geothermal power plant energy and exergy efficiencies are calculated to be 12.1% and 57.4% at this condition. Electrolysis system energy and exergy efficiencies are calculated to be 71.4% and 60.7% of geothermal water temperature at 230°C and geothermal water flow rate at 230 kg/s. We evaluated at unit exergetic cost of electricity combined flash binary system is 10.1$/GJ (0.0364 $/kWh) and unit exergetic cost of hydrogen is 34.6$/GJ (4.16 $/kg H2).

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Report on 20 MW Geothermal Power Plant with Steam Gathering and Brine Injection at Roosevelt Hot Springs, Utah: Preliminary design, construction cost, financial study

10.2172/883355 ◽

1980 ◽

Author(s):

Keyword(s):

Power Plant ◽

Hot Springs ◽

Construction Cost ◽

Preliminary Design ◽

Geothermal Power Plant ◽

Geothermal Power ◽

Brine Injection ◽

Design Construction

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

Sustainability ◽

10.3390/su13041935 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1935

Author(s):

Vitantonio Colucci ◽

Giampaolo Manfrida ◽

Barbara Mendecka ◽

Lorenzo Talluri ◽

Claudio Zuffi

Keyword(s):

Life Cycle ◽

Power Plant ◽

Environmental Analysis ◽

Combined Heat And Power ◽

Hot Water ◽

Environmental Cost ◽

Published Data ◽

Geothermal Power Plant ◽

Geothermal Power ◽

Double Flash

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.

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