Decarbonising heavy industry operations with low-cost onsite photovoltaics and battery storage

• PV+ batteries enable 24/7 industry operations, cutting emissions by 35%–87%. • Levelised electricity cost: $90–$157/MWh today, $71–$92/MWh in future projections. • Grid interaction lowers electricity costs by 23%–42% compared to off-grid setups. • Load flexibility further reduces electricity costs to under one-third of gas-fired power. Decarbonising heavy industries, e.g., steel, aluminium, and cement, present unique challenges due to their high energy intensity and reliance on 24/7 continuous power supply. With volatile fossil fuel prices and increasing carbon regulations, the transition to renewable energy is critical for long-term economic and environmental sustainability. This study develops a new high-resolution energy modelling framework to assess the techno-economic feasibility of supplying 24/7 industrial electricity using low-cost onsite photovoltaic (PV) and battery storage systems. The model incorporates lifecycle degradation and intermittency with an hourly temporal resolution over a 25-year time horizon, integrated with grid interaction and load flexibility strategies. The results show that projected declines in PV and battery costs could lower electricity costs by 41% from $157/MWh to $92/MWh, though energy spillage constrains further savings. Grid interaction through bidirectional electricity exchange with the grid could reduce electricity costs by up to 42% and increase renewable energy integration from 37% to 100%. Load flexibility could reduce electricity costs by up to 80%, while achieving 100% renewable energy integration. Sensitivity analysis suggests that electricity costs are most sensitive to natural gas price and discount rate, while PV and battery degradation also have a measurable impact of $2–$5/MWh. The research findings provide quantitative evidence on the techno-economic feasibility of PV and battery integration for heavy industry operations, supporting strategic decisions for industrial decarbonisation.