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Repurposing Coal Power Plants into Thermal Energy Storage for Supporting Zero-carbon Data Centers

Yifu Ding, Serena Patel, Dharik Mallapragada, Robert James Stoner

TL;DR

The paper tackles the challenge of decarbonizing power systems while maintaining reliability by proposing an integrated capacity-expansion model that co-optimizes retrofitted molten-salt thermal energy storage (TES), lithium-ion batteries (LIBs), co-located zero-carbon data centers (DCs), and local renewables, under hourly carbon-matching constraints and DC workload flexibility. Using a case study anchored in the ERCOT system, the authors examine retrofitting 12 coal plants near Texas DC sites and deploying three 1 GW DCs by 2030, with detailed TES and LIB cost parameters. Key findings show that retrofitted TES can complement LIBs to lower system costs under carbon constraints, while zero-carbon DCs require more renewable capacity but can outperform unconstrained DCs in certain scenarios, achieving 13–23% carbon reduction. The work demonstrates a viable pathway to reuse existing coal assets and grid interconnections to accelerate data-center decarbonization and broader renewable integration.

Abstract

Coal power plants will need to be phased out and face stranded asset risks under the net-zero energy system transition. Repurposing coal power plants could recoup profits and reduce carbon emissions using the existing infrastructure and grid connections. This paper investigates a retrofitting strategy that turns coal power plants into thermal energy storage (TES) and zero-carbon data centers (DCs). The proposed capacity expansion model considers the co-locations of DCs, local renewablewith the system-generation, andlevel coal retir energy storage ement and retrofitting. We optimize the DC system configurations under the hourly-matching carbon policy and flexible operations. Results show that under hourly-matching carbon constraints, the retrofitted TES could complement the operations of lithium-ion batteries (LIBs) to reduce system costs. This could render DCs with optimal co-located renewable generations and energy storage more cost-effective than unconstrained DCs.

Repurposing Coal Power Plants into Thermal Energy Storage for Supporting Zero-carbon Data Centers

TL;DR

The paper tackles the challenge of decarbonizing power systems while maintaining reliability by proposing an integrated capacity-expansion model that co-optimizes retrofitted molten-salt thermal energy storage (TES), lithium-ion batteries (LIBs), co-located zero-carbon data centers (DCs), and local renewables, under hourly carbon-matching constraints and DC workload flexibility. Using a case study anchored in the ERCOT system, the authors examine retrofitting 12 coal plants near Texas DC sites and deploying three 1 GW DCs by 2030, with detailed TES and LIB cost parameters. Key findings show that retrofitted TES can complement LIBs to lower system costs under carbon constraints, while zero-carbon DCs require more renewable capacity but can outperform unconstrained DCs in certain scenarios, achieving 13–23% carbon reduction. The work demonstrates a viable pathway to reuse existing coal assets and grid interconnections to accelerate data-center decarbonization and broader renewable integration.

Abstract

Coal power plants will need to be phased out and face stranded asset risks under the net-zero energy system transition. Repurposing coal power plants could recoup profits and reduce carbon emissions using the existing infrastructure and grid connections. This paper investigates a retrofitting strategy that turns coal power plants into thermal energy storage (TES) and zero-carbon data centers (DCs). The proposed capacity expansion model considers the co-locations of DCs, local renewablewith the system-generation, andlevel coal retir energy storage ement and retrofitting. We optimize the DC system configurations under the hourly-matching carbon policy and flexible operations. Results show that under hourly-matching carbon constraints, the retrofitted TES could complement the operations of lithium-ion batteries (LIBs) to reduce system costs. This could render DCs with optimal co-located renewable generations and energy storage more cost-effective than unconstrained DCs.
Paper Structure (11 sections, 15 equations, 7 figures, 1 table)

This paper contains 11 sections, 15 equations, 7 figures, 1 table.

Table of Contents

  1. Introduction
  2. Background and motivations
  3. Related works
  4. Model formulations
  5. Capacity expansion problem considering coal retrofitting
  6. Retrofitting coal power plants into TES
  7. Zero-carbon and flexible operations of DCs
  8. Case study
  9. Results
  10. Conclusions
  11. Acknowledgment

Figures (7)

  • Figure 1: The locations of (a) operating coal plants of three weather zones highlighted in red us_energy_information_administration_coal-fired_nodate and (b) the existing DCs baxtel_texas_nodate as of 2022 in Texas
  • Figure 2: The annualized investment costs for charging, discharging, and energy capacity of the retrofitted TES considering the remaining lifetime of 12 eligible coal power plants by 2030
  • Figure 3: Changes in power capacity (GW) in five scenarios compared to the 2030 ERCOT system without the additional DC loads and coal retrofitting
  • Figure 4: The map of individual retrofitting results in scenario (a) zero-carbon DCs with retrofitted TES, LIB, and co-located renewable generations; DCs are assumed co-located with retrofitted TES
  • Figure 5: Energy storage cycle and renewable generation profiles of two scenarios (a) TES & LIB zero-carbon DC systems (b) LIB zero-carbon DC systems; Battery discharging power is positive, and charging power is negative
  • ...and 2 more figures