Impact of thermal storage capacity, electricity and emission certificate costs on the optimal operation of an industrial energy system

Challenges arising from the transition to a more sustainable energy system require increased flexibility on demand and supply side. In energy-intensive industry optimal operation of energy supply systems and energy consumption from the electric grid is a promising contribution to flexibility enhancement. An industrial plant model derived from characteristics in pulp and paper industry was therefore implemented. A mixed-integer linear program was formulated to determine cost optimal operation of supply, conversion and thermal storage units for different electricity prices and carbon dioxide emission certificate costs at the level of year 2017 and of forecasts for year 2019. Furthermore, the capacity of the thermal storage was varied and cost savings could be obtained for increased storage capacities. Operation costs decreased around 5% for a storage capacity accounting for 7% of the total live steam conversion capacity. A further rise of 7% only accounted for another cost decrease of approximately 1%. Double emission certificate costs compared to 2018 had only a minor impact on the operation of the industrial test plant, but an average rise in costs of 5%. Furthermore, interaction of electricity demand, the thermal storage capacity and optimal operation could be reported.