Modelling of flexibility-centric energy systems: Operation, planning and policy-making

The climate crisis, caused by air pollution through fossil fuel combustion, is an existential threat to billions of people. The global energy sector is responsible for a substantial share of this pollution, making its decarbonisation essential in stopping the climate crisis.
Decarbonised energy systems are supplied by renewable energy sources, which are largely variable and uncertain. To maintain the balance of demand and supply in these systems, flexibility across time, space and sectors must be utilised.
Such flexibility must be adequately represented in all stages of energy system analysis. Thus, this dissertation addresses the mathematical modelling and optimisation of flexibility-centric energy systems across their operation, planning and policymaking. This is done across different geographical scopes ranging from small-scale to large-scale studies.
Residential energy system operation is addressed in introducing a novel home energy management system model that optimises the operation of home battery systems under uncertain electric load. It allows smart home residents to make a trade-off between cost and emission minimisation without expressing their preferences a-priori.
District heating systems constitute a substantial source of energy flexibility. I propose an optimisation model for stochastic block bidding for combined heat-and power generation. Through that model, district heating systems can participate in electricity markets more efficiently.
Flexibility from energy end-use must also be considered in the planning stage. Yet, the existing body of research does not account for end-user characteristics in modelling demand response. Hence, Frigg, a modelling approach for integrating pricebased, non-linear demand response models into energy system planning, is introduced. This approach allows for better representation of end-user flexibility in energy system planning. It is applied in a case study on flexibility from electrified heating in a future Danish electricity system. Study results suggest both heat storage and demand response yield substantial cost savings.
Finally, ongoing research on cross-border energy flexibility is presented. Here, Ukrainian hydrogen exports to the EU are analysed. Main questions regard the competitiveness of such hydrogen exports in terms of their costs, as well as the impact of hydrogen exports on Ukrainian post-war energy system recovery and decarbonisation. Preliminary results suggest hydrogen exports to significantly impact the Ukrainian energy system, depending on their volume.