Balancing Supply and Demand in an Electricity System - the Case of Sweden

Abstract: In an electrical system there needs to be a constant balance between supply and demand ofelectricity and this is measured by the frequency in the grid. Due to the increasing awarenessof climate change, more renewable energy resources have been introduced in the Swedishelectricity system. This is, however, not solely positive since renewable energy sources areoften of intermittent character which entails more imbalances between supply and demand. Inaddition, statistics and data show that the deviation in the frequency in the Nordic system hasincreased during the latest years. Thus, in this thesis, the issues regarding the frequency havebeen addressed by examining the demand for frequency control in the Swedish electricitysystem and what balancing efforts that can be carried out on a local level to contribute to abetter balanced system. This thesis has been conducted at KTH Royal Institute of Technologywith collaboration with the commissioner Mälarenergi AB. A case study of the Swedish electricity system has been carried out to gather empiricalmaterial and this material has been analyzed using Geels theory on technical transitions, themulti-level perspective. The results indicates that it is likely the demand for frequency controlwill increase, and this is due to factors as more intermittent energy, current market design fortrading electricity, overseas transmission connections, decommissioning of nuclear powerand limited internal transmission capacity. Three other developments have been identified,which could have a large impact on the demand in the future, as an increasing use of electricvehicles, prosumers and the deployment of IoT in the energy sector. These developmentshave not been integrated to a large extent yet in the energy sector and thus have a moreuncertain impact. In terms of resources, the thesis has identified that it is likely that hydropower will continueto be the main resource for frequency regulation. Another source that could be used morefrequently than today and possibly compete with hydropower is combined heat and powerplants. Furthermore, the study has found that local actors can contribute by advertisingsmaller local resources on a market for trading regulating power called“reglerkraftmarknaden”, that balance providing companies collaborate, that the load iscontrolled in the local grids or that smaller local production facilities are operated in standalonemode during extreme situations.