Trade-Offs Between Emissions, Cost and Resilience in Emerging Technologies Supporting Deep Decarbonization of the Electric Grid

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Bennett, Jeffrey, Civil Engineering - School of Engineering and Applied Science, University of Virginia
Clarens, Andres, EN-Eng Sys and Environment, University of Virginia

Decarbonization of the electric grid is necessary to limit the impact of climate change, however important questions remain about the architecture and operation of a grid heavily dependent on intermittent renewable generation. Four emerging technologies are evaluated here to understand their ability to support the decarbonization of electricity generation: distributed electric grids, supercritical carbon dioxide power cycles (sCO2), offshore compressed air energy storage (OCAES), and bioenergy with carbon capture and storage (BECCS). Distributed electric grids are expected to be more resilient to severe weather and may be well-suited to wind turbines and solar photovoltaics which are inherently distributed as they require large areas of land. sCO2 cycles offer high efficiencies and have compact machinery making them of interest for fast response. OCAES is a novel type of energy storage that combines isothermal thermodynamic cycles with aquifer air storage. BECCS power plants offer the ability to produce electricity while reducing atmospheric CO2 levels. These technologies could be deployed independently or in tandem. It is understood that energy technologies are not selected for technical feasibility alone, thus a systems perspective is used to interpret results, considering environmental impact, cost, and grid resilience.

This work makes the following contributions to the academic literature: (1) quantified the impact of grid topology (distributed vs. centralized) and fuel mix (natural gas vs. natural gas, wind and solar) on costs, emissions and grid resilience; (2) modeled the feasibility and cost of sCO2 power cycles for delivering load-balancing when integrated into a grid involving high deployment of solar photovoltaics; (3) evaluated the performance, cost and value of OCAES to the electric grid; and (4) identified locations off the United States Mid-Atlantic coast suitable for OCAES; (5) performed a life cycle assessment of power plant and carbon capture technologies for BECCS; and (6) projected the impact of emerging energy technologies on the cost of decarbonized electricity generation. These outcomes further the understanding of each technology and consider their ability to support the transition to a decarbonized electric grid. This understanding contributes to the discussion of what energy technologies should be deployed to meet the climate goals set by the United Nations. Additionally, the research used and developed open source models and datasets that enable verification of results by third parties and future collaboration.

PHD (Doctor of Philosophy)
Energy system modeling, Distributed electric grids, Supercritical carbon dioxide power cycles, Offshore compressed air energy storage, Bioenergy with carbon capture and storage
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