Mark Fleming, Ph.D.
Assistant Professor
- Milwaukee WI UNITED STATES
- S200D
- Mechanical Engineering
Mark Fleming’s areas of interest include thermodynamics and fluid mechanics with a focus in geothermal and renewable energy.
Education, Licensure and Certification
Ph.D.
Mechanical Engineering
University of Minnesota
2019
M.S.
Mechanical Engineering
Rose-Hulman Institute of Technology
2012
B.S.
Mechanical Engineering
Rose-Hulman Institute of Technology
2011
Biography
Areas of Expertise
Social
Selected Publications
Combining brine or CO2 geothermal preheating with lowtemperature waste heat: A higher-efficiency hybrid geothermal power system-temperature
Journal of CO2 UtilizationNagasreeGarapatiaBenjamin M.AdamsbMark R.FlemingcThomas H.KuehncMartin O.Saarbd
2020
Hybrid geothermal power plants operate by using geothermal fluid to preheat the working fluid of a higher-temperature power cycle for electricity generation. This has been shown to yield higher electricity generation than the combination of a stand-alone geothermal power plant and the higher-temperature power cycle. Here, we test both a direct CO2 hybrid geothermal system and an indirect brine hybrid geothermal system. The direct CO2 hybrid geothermal system is a CO2 Plume Geothermal (CPG) system, which uses CO2 as the subsurface working fluid, but with auxiliary heat addition to the geologically produced CO2 at the surface. The indirect brine geothermal system uses the hot geologically produced brine to preheat the secondary working fluid (CO2) within a secondary power cycle.
Increased Power Generation due to Exothermic Water Exsolution in CO2 Plume Geothermal (CPG) Power Plants
GeothermicsMark R. Fleming, Benjamin M. Adams, Thomas H.Kuehn, Jeffrey M. Bielickic, Martin O. Saarbe
2020
A direct CO2-Plume Geothermal (CPG) system is a novel technology that uses captured and geologically stored CO2 as the subsurface working fluid in sedimentary basin reservoirs to extract geothermal energy. In such a CPG system, the CO2 that enters the production well is likely saturated with H2O from the geothermal reservoir. However, direct CPG models thus far have only considered energy production via pure (i.e. dry) CO2 in the production well and its direct conversion in power generation equipment. Therefore, we analyze here, how the wellhead fluid pressure, temperature, liquid water fraction, and the resultant CPG turbine power output are impacted by the production of CO2 saturated with H2O for reservoir depths ranging from 2.5 km to 5.0 km and geothermal temperature gradients between 20 °C/km and 50 °C/km. We demonstrate that the H2O in solution is exothermically exsolved in the vertical well, increasing the fluid temperature relative to dry CO2, resulting in the production of liquid H2O at the wellhead. The increased wellhead fluid temperature increases the turbine power output on average by 15% to 25% and up to a maximum of 41%, when the water enthalpy of exsolution is considered and the water is (conservatively) removed before the turbine, which decreases the fluid mass flow rate through the turbine and thus power output. We show that the enthalpy of exsolution and the CO2-H2O solution density are fundamental components in the calculation of CPG power generation and thus should not be neglected or substituted with the properties of dry CO2.
Benefits of Using Active Reservoir Management During CO2-Plume Development for CO2-Plume Geothermal (CPG) Systems.
In 44th Workshop on Geothermal Reservoir Engineering. Palo Alto, CaliforniaFleming, M. R., Adams, B. M., Kuehn, T. H., Bielicki, J. M., & Saar, M. O.
2019
Grid scale energy storage using CO2 in sedimentary basins: The cost of power flexibility.
European Geothermal Congress, Den Haag, NetherlandsAdams, B. M., Fleming, M. R., Bielicki, J. M., Hansper, J., Glos, S., Langer, M., Wechsung, M., & Saar, M.O.
6-2019
CO2 Plume Geothermal (CPG) is a CO2-based geothermal energy technology that generates electricity typically using a sedimentary reservoir. We have expanded this technology into a CO2 Plume Geothermal Energy Storage (CPGES) system by adding a second, shallow reservoir. The CPGES system can separate and time-shift its generation and parasitic powers, allowing for energy storage. Energy storage may be done for periods ranging from hours to months.
