skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Probabilistic Estimation of Levelized Cost of Electricity from Using Geologically Stored CO2 for Geothermal Energy Production
The use of geologically stored CO2 as a geothermal heat extraction fluid can take advantage of the beneficial thermophysical characteristics of CO2 that can render it a more effective heat extraction fluid than the brine that exists in the aquifers. Some of these characteristics include a higher mobility (inverse kinematic viscosity) in reservoir conditions and a highly temperature-dependent density that can result in a naturally self-convecting thermosiphon between injection and production wells. This thermosiphon may reduce or eliminate the need for subsurface pumps—and the associated parasitic pumping power—for fluid circulation. Part of the utility of such a CO2 capture, utilization, and storage (CCUS) system is the possibility to generate baseload or dispatchable electricity with levelized costs of electricity (LCOEs) that are on par with the LCOEs of other energy technologies of regional electricity systems.  more » « less
Award ID(s):
1739909 1922666
PAR ID:
10350881
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Proceedings of the 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. null (Ed.)
    With the fast evolution in greenhouse gas (GHG) emissions (e.g., CO2, N2O) caused by fossil fuel combustion and global warming, climate change has been identified as a critical threat to the sustainable development of human society, public health, and the environment. To reduce GHG emissions, besides minimizing waste heat production at the source, an integrated approach should be adopted for waste heat management, namely, waste heat collection and recycling. One solution to enable waste heat capture and conversion into useful energy forms (e.g., electricity) is employing solid-state energy converters, such as thermoelectric generators (TEGs). The simplicity of thermoelectric generators enables them to be applied in various industries, specifically those that generate heat as the primary waste product at a temperature of several hundred degrees. Nevertheless, thermoelectric generators can be used over a broad range of temperatures for various applications; for example, at low temperatures for human body heat harvesting, at mid-temperature for automobile exhaust recovery systems, and at high temperatures for cement industries, concentrated solar heat exchangers, or NASA exploration rovers. We present the trends in the development of thermoelectric devices used for thermal management and waste heat recovery. In addition, a brief account is presented on the scientific development of TE materials with the various approaches implemented to improve the conversion efficiency of thermoelectric compounds through manipulation of Figure of Merit, a unitless factor indicative of TE conversion efficiency. Finally, as a case study, work on waste heat recovery from rotary cement kiln reactors is evaluated and discussed. 
    more » « less
  2. Abstract Thermoelectric generators convert heat energy to electricity and can be used for waste heat recovery, enabling sustainable development. Selective Laser Melting (SLM) based additive manufacturing process is a scalable and flexible method that has shown promising results in manufacturing high zT Bi2Te3 material and is possible to be extended to other material classes such as Mg2Si. The physical phenomena of melting and solidification were investigated for SLM-based manufacturing of thermoelectric (Mg2Si) powders through comprehensive numerical models developed in MATLAB. In this study, Computational Fluid Dynamics (CFD)-based techniques were employed to solve conservation equations, enabling a detailed understanding of temperature evolution within the molten pool. This approach was critical for optimizing processing parameters in our investigation, which were also used for printing the Mg2Si powders using SLM. Additionally, a phase field-based model was developed to simulate the directional solidification of the Mg2Si in MATLAB. Microstructural parameters were studied to correlate the effects of processing parameters to the microstructure of Mg2Si. 
    more » « less
  3. Abstract We present a mechanism for thermal cycling that does not require electricity; instead, the device functions as a heat engine and requires only a generic heat source and a shape memory alloy (SMA) spring. The SMA spring mechanically translates to a low-temperature reservoir when heated, and the subsequent cooling of the spring causes translation back to a high-temperature reservoir. The usefulness of the mechanism is displayed by performing the quantitative polymerase chain reaction (qPCR), an important biological assay that requires thermal cycling for amplification of nucleic acids. The ability to perform qPCR with a generic heat source enables a variety of significant health diagnostic tests to be performed in resource limited settings, where electricity access may not be available or reliable. We demonstrate robust thermal cycling using a direct flame, sunlight, and electricity as heat sources, with maximum heating and cooling rates of 4.4 °C s−1and −2.7 °C s−1, respectively. 
    more » « less
  4. Combining thermopreference (Tp) and CO2-gated heat-seeking assays, we studied the thermal preferendum and response to thermal cues in three Culex mosquito species exhibiting differences in native habitat and host preference (e.g., biting cold and/or warm-blooded animals). Results show that these species differ in both Tp and heat-seeking behavior. In particular, we found that Culex territans, which feed primarily on cold-blood hosts, did not respond to heat during heat-seeking assays, regardless of the CO2 concentration, but exhibited an intermediate Tp during resting. In contrast, Cx. quinquefasciatus, which feeds on warm blooded hosts, sought the coolest locations on a thermal gradient and responded only moderately to thermal stimuli when paired with CO2 at higher concentrations. The third species, Cx. tarsalis, which has been shown to feed on a wide range of hosts, responded to heat when paired with high CO2 levels and exhibited a high Tp. This study provides the first insights into the role of heat and CO2 in the host seeking behavior of three disease vectors in the Culex genus and highlights differences in preferred resting temperatures. 
    more » « less
  5. Sedimentary basins are attractive for geothermal development due to their ubiquitous presence, high perme­ ability, and extensive lateral extent. Geothermal energy from sedimentary basins has mostly been used for direct heating purposes due to their relatively low temperatures, compared to conventional hydrothermal systems. However, there is an increasing interest in using sedimentary geothermal energy for electric power generation due to the advances in conversion technologies using binary cycles that allow electricity generation from reservoir temperatures as low as 80 ◦C. This work develops and implements analytical solutions for calculating reservoir impedance, reservoir heat depletion, and wellbore heat loss in sedimentary reservoirs that are laterally extensive, homogeneous, horizontally isotropic and have uniform thickness. Reservoir impedance and wellbore heat loss solutions are combined with a power cycle model to estimate the electricity generation potential. Results from the analytical solutions are in good agreement with numerically computed reservoir models. Our results suggest that wellbore heat loss can be neglected in many cases of electricity generation calculations, depending on the reservoir transmissivity. The reservoir heat depletion solution shows how reservoir tempera­ ture and useful lifetime behave as a function of flow rate, initial heat within the reservoir, and heat conduction from the surroundings to the reservoir. Overall, our results suggest that in an exploratory sedimentary geothermal field, these analytical solutions can provide reliable first order estimations without incurring intensive computational costs. 
    more » « less