Capacitated Multi-Source Energy Optimisation with Time-of-Use Pricing

We investigate an energy optimisation problem at a European steel manufacturing facility. In this problem, the company seeks to integrate green energy with grid electricity using battery storage systems. The electricity drawn from the grid is subject to a time-of-use tariff, creating opportunities for cost savings through using solar or battery energy during expensive peak periods. A mathematical model is developed to minimise the energy usage cost from multiple sources, while ensuring the facility’s energy demand is met. The model accounts for constraints on solar energy availability, battery capacity, and charge/discharge rates. We conduct computational experiments using historical energy demand and time-of-use rates. Different sizes of energy storage systems up to 500kWh are considered. The results show up to a 23% reduction in energy costs relative to a baseline solution that relies solely on energy from the grid, demonstrating the value of combining on-site green energy generation with battery storage in reducing operational costs in energy-intensive industries. Finally, stochastic extensions that incorporate uncertainty pricing, energy supply and demand are provided along with the corresponding solution approaches.