Improving the Environmental Sustainability of Flash Geothermal Power Plants—A Case Study

Bruscoli, Lorenzo; Fiaschi, Daniele; Manfrida, Giampaolo; Tempesti, Duccio

doi:10.3390/su71115262

Cited by 12 publications

(6 citation statements)

References 15 publications

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“…A flow rate of 122 kg/s is assumed to be available at an enthalpy level of 1200 kJ/kg, corresponding to about 275 °C at 250 bar, which are the estimated reservoir conditions for the deep reservoir in the Mt. Amiata region at a depth z>3000 m. The CO2 content of the brine is evaluated at 2% mass fraction [40]. The current power plant applies a wellhead separator set at 20 bar, determining a saturated steam flow rate of 36 kg/s (with 7% CO2 content), while a hot brine (enriched with salts causing considerable scaling problems) of about 86 kg/s is directed to reinjection.…”

Section: Reference Casementioning

confidence: 99%

Energy, Exergy and Exergo-Economic Analyses of Super-Critical CO2 Cycles for the Exploitation of a Geothermal Resource in the Mt. Amiata Region

Fiaschi,

Talluri,

Di Michele

et al. 2023

36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 20

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An alternative powerplant layout to the commonly applied flash technology is proposed for the geothermal location of Monte Amiata, Italy. The reservoir conditions correspond to a pressurized brine field, with relevant contents of CO2, acid gases/contaminants, and dissolved salts. The present solution avoids flashing the brine stream, proposing instead to install a borehole pump capable of maintaining pressurized conditions. By applying this solution, the amount of non-condensable gases released when reaching the ground level with reduced pressure can be conveniently limited; the gas stream is recovered, compressed and reduced in liquid conditions, suitable for complete reinjection into the reservoir. The necessity of a gas treatment section is thus completely avoided. The heat recovered from the hot brine, placed at ground level, is transferred to the supercritical CO2 cycle. Different CO2 cycle configurations were considered. Exergy and exergo-economic analyses of the whole system are carried out. The optimal calculated exergy efficiency of 45.5% was achieved for the recuperative cycle with intercooling and reheat configuration and the lowest obtained produced cost of electricity was 7.4 c€/kWh for the recuperative cycle configuration. Furthermore, the influence of the pressure losses to the heat exchanger has been assessed, allowing evaluating of the loss in efficiency for each cycle.

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Section: Reference Casementioning

confidence: 99%

Energy, Exergy and Exergo-Economic Analyses of Super-Critical CO2 Cycles for the Exploitation of a Geothermal Resource in the Mt. Amiata Region

Fiaschi,

Talluri,

Di Michele

et al. 2023

36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 20

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“…The use of the heat of exhaust gases with a temperature from 250 ºC to 350 ºC ensures the generation of electricity, which increases the efficiency of energy supply systems for agricultural enterprises. The hybrid power system consists of three circuits, including an evaporator boiler, a steam separator, a steam turbine and two organic working fluid turbines [6][7][8][9][10][11][12][13].…”

Section: Problem Statementioning

confidence: 99%

Heat recovery in hybrid flash/orc power plants

Redko

Ujma

Павловська

et al. 2021

20th International Scientific Conference Engineering for Rural Development Proceedings

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The usage of exhaust gas heat in WHR (Waste Heat Recovery) systems and its conversion into electrical energy using ORC technologies is limited by the thermal stability of working bodies at a temperature of exhaust gases above 270-300 ºС. Therefore, thermal schemes of hybrid power plants, in which water vapor and organic heat carriers are used as working fluids, are being developed. Numerous studies indicate that the efficiency of the thermal scheme of energy conversion is significantly influenced by the properties of working bodies and their parameters. Due to the large number of working bodies, the problem of their thermodynamic parameter effect has not been sufficiently studied. This paper [13] presents a review on hybrid renewable energy power generation systems focusing on energy sustainability.

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“…For instance, in Italy, the AMIS® (Hydrogen Sulfide and Mercury Abatement System) technology [3] is utilized for chemical scrubbing and adsorption and effectively removes H2S, NH3, and Hg. However, this approach does not solve the problem of greenhouse gas emissions, estimated at around 122 mg/kWh [4,5]. For this reason, other geothermal solutions were studied to reduce the environmental impact.…”

Section: Introductionmentioning

confidence: 99%

Exergo-economic and exergo-environmental analysis of a binary geothermal power plant with solar boosting

Giusti

Ciappi

Ungar

et al. 2022

J. Phys.: Conf. Ser.

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The exploitation of renewable energies is a solution to the energy, economic and environmental issues related to the massive use of fossil resources. Thus, investing in renewable technologies is essential to achieve the carbon-neutral scenario within 2050. In this framework, geothermal energy may have a key role. In particular, power plants with a closed binary cycle are suitable for harnessing geothermal resources with low and medium enthalpy levels. They are prone to be integrated with other renewable devices to increase the global power output. Geothermal fluid can be drawn constantly from underground throughout the day and seasons. Conversely, the availability and intensity of solar energy depend on weather conditions and the time of year. In Italy, geothermal energy is currently harvested for continuous electricity generation, while solar energy is mainly used for photovoltaic generation. For small-to-medium size plants, rated between 5 and 20 MWe, the geothermal and thermodynamic solar hybridization may lead to relevant benefits for the economic competitiveness regarding separate photovoltaic or thermodynamic solar systems. This article aims to investigate the economic and environmental aspects of geothermal power plants with a closed binary cycle coupled with a topper cycle fed by linear parabolic solar collectors. The system operation in both design and off-design conditions was analysed, and exergo-economic and exergo-environmental simulations were conducted. The application site was selected near Torre Alfina (Italy). It has a water-dominant reservoir with a pressure of 44 bar, a temperature of 140 °C, and content of non-condensable gases (NCGs) approximately equal to 2% by weight. At the design point, the net power is 8.4 MW and the first and second principle efficiencies are 9.31% and 18.45%, respectively. The exergo-economic and exergo-environmental analyses indicate that the components with the highest economic and environmental impact are the condenser, the field of solar collectors, the evaporator, and the low-pressure turbine. The levelized cost of electricity (LCOE) is equal to 14.19 c€/kWh.

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Improving the Environmental Sustainability of Flash Geothermal Power Plants—A Case Study

Cited by 12 publications

References 15 publications

Energy, Exergy and Exergo-Economic Analyses of Super-Critical CO2 Cycles for the Exploitation of a Geothermal Resource in the Mt. Amiata Region

Energy, Exergy and Exergo-Economic Analyses of Super-Critical CO2 Cycles for the Exploitation of a Geothermal Resource in the Mt. Amiata Region

Heat recovery in hybrid flash/orc power plants

Exergo-economic and exergo-environmental analysis of a binary geothermal power plant with solar boosting

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