Assessing the Economic Impacts of Spot Market Electricity and Cost Factors on Financial Feasibility of Electric Heat Storage for Process Steam

To match the fluctuating renewable energy generation with varying industrial process steam demand, electric heat storage is a viable solution for energy transformation. However, the adoption of this technology by companies hinges on its economic feasibility. Proponents often argue that leveraging spot market electricity prices provides a competitive edge over conventional energy systems without storage. However, additional factors, such as grid fees, levies and taxes can substantially inflate storage charging costs. This study investigates the integration of an electric latent heat storage for process steam within a conventional natural gas boiler system in a paper manufacturing case study under German industrial electricity price regulation to evaluate the effects of electricity prices alongside various operational energy cost factors and rebates through a mixed-integer linear program. Three storage sizes (1 MWh, 100 MWh, 100 GWh) and four electricity procurement configurations (status quo, optimized fixed-price contract, day-ahead only, and a mixed fixed/day-ahead strategy) are analysed. For 100 MWh, the mixed strategy cuts energy costs by about 10% versus day-ahead pricing and around 13.5% versus the status quo contract, lowering the specific electricity price from 6.2 to 5.3 ct/kWh, while emissions range from the slight increases to 23% reductions when grid fees are removed.