Techno-economic assessment of an air-source steam-generating heat pump with optimal PV–BESS integration

This study evaluates the techno-economic performance of an air-source steam-generating heat pump supplied by a cost-optimized combination of grid electricity, on-site photovoltaics, and battery energy storage. A continuous baseload demand of 2 t/h of saturated steam at 15 bar is considered. The minimum levelized cost of heat and cost-optimal electricity-supply configurations are evaluated for electricity purchase prices from 20 to 200 €/MWh in Cagliari, Italy, and Berlin, Germany, selected as contrasting European cases with different solar-generation and ambient-temperature profiles. Hourly lifetime simulations account for component degradation and replacement. The minimum levelized cost of heat ranges from 55 to 109 €/MWh in Cagliari and from 55 to 149 €/MWh in Berlin. As electricity prices increase, the optimal supply configuration shifts from grid-dependent operation to photovoltaic-supported hybrid systems and eventually to higher-autonomy configurations with daily-scale battery storage. These transitions occur earlier in Cagliari, where photovoltaic and storage investments become attractive at lower electricity prices. Photovoltaic deployment precedes battery adoption, reflecting the higher economic value of direct self-consumption. Cross-combined meteorological scenarios indicate that differences between the cases are mainly driven by their solar-generation profiles, while ambient temperature has a smaller effect. Broad near-optimal regions indicate limited sensitivity to photovoltaic and battery sizing. Overall, photovoltaic-battery integration can limit heat-production costs and reduce exposure to high grid-electricity prices, although its benefits remain location-specific. The economic performance of steam-generating heat pumps therefore depends not only on heat-pump performance but also on electricity-supply design, with more favourable meteorological profiles enabling earlier investment and greater cost-optimal energy autonomy.