Assessing the thermoeconomic performance and CO2 emission reduction of data center–assisted pumped thermal electricity storage

Abstract

Waste heat-assisted pumped thermal electricity storage (PTES) can improve energy storage performance by using low-cost thermal resources, and data center waste heat is attracting increasing attention because of its continuous availability. This study presents a thermoeconomic and environmental assessment of a data center waste heat-assisted PTES (DC + PTES) and compares it with industrial waste gas-assisted PTES (WG + PTES). The novelty lies in establishing a comparative framework that considers the thermoeconomic effects of an auxiliary waste heat storage system compensating for the temporal variability of both heat sources. Furthermore, unlike previous studies, the comparison was performed under the respective minimum levelized cost of energy storage (LCOS) operating conditions of the two systems. The effects of heat pump evaporator temperature, data center chip temperature, waste heat capacity, charging time, discount rate, and electricity price were systematically investigated. Increasing waste heat capacity (0.5–4 MW) reduced the LCOS from 0.562 to 0.295 $/kWh for WG + PTES and from 0.528 to 0.328 $/kWh for DC + PTES. Although WG + PTES achieved higher power-to-power efficiency, DC + PTES provided 11.7–17.7% higher cumulative net electrical energy output and 6.6–10.2% greater absolute net CO₂ emission reduction over the 25-year lifetime under the respective minimum-LCOS operating conditions of the two systems.