Scientists from Halmstad University demonstrated the potential Swedish energy industry by 2050 – the deadline for achieving carbon neutrality. To do that, they created a mathematical model describing the operation of the entire power system with an hourly accuracy – from electricity generation to supplying heat to major cities. The calculations show: by mid-century wind will remain the basis of electricity generation: the installed capacity of wind power engineering will reach approximately 41 GW making about 60% of all generating capacities of the country (68 GW). The wind is unstable by its nature; hence, such a shift will inevitably result in abrupt growth of energy storage systems allowing for mitigating the fluctuations of generation and decreasing the need for redundant backup capacities.
According to the researchers, the most dramatic changes in Swedish energy industry will take place in the heating sector. This is where the model shows gradual refusal from modern co-generation CHPPs, which today are playing the key role in municipal heat supply networks. Their share in heat generation is going down from 43% to 24%, while heat pumps are coming to the fore. By 2050, they will be providing circa 61% of heat becoming the main instrument of sectoral link between electricity generation and heat supply. The logic is simple: in the fall, when there are a lot of winds, and the demand for electricity still remains not very high, the redundant electricity is channeled to heat pumps operation. The generated heat is not used immediately, but goes to the storage facilities including major subsoil tanks, which can accumulate up to 11% of annual needs. These strategic reserves are used in the winter, in January and February, when heat pumps performance goes down, and the need for heat reaches maximum.
Heat supply networks upgrade provides for additional effect. Decreasing temperature in the centralized heat supply systems (transition to the so-called 4th and 5th generation networks) secures the success of heat pumps even more: their share may grow up to 80% of the overall heat generation. Simultaneously the economic attractiveness of major seasonal storage facilities goes down, because with higher performance of the pumps there is no need for lengthy storage. The model also shows that the growth of accessibility of stable sources of industrial waste heat results in additional decrease of the need for seasonal storage.
Analyzing the alternative scenarios, when certain elements of the system become inaccessible, is especially interesting. If we exclude electrical storage facilities, the economic feasibility of seasonal heat storage facilities practically disappears. Without the possibility of mitigating daily fluctuations in generation, the system is forced to rely more on co-generation plants, and the redundant electricity is used for heating immediately via short-term (one-day) heat storage facilities. Such option is noticeably more expensive: the cumulative energy costs grow approximately by 11%.
Overall, the study showed that the sustainability of future power system will depend on the combination of different tools. In addition to heat pumps and storage facilities, scientists emphasize the need of engaging other “flexible consumers”, first of all, e-vehicles, as well as the need for developing Power-to-X technologies allowing for transforming redundant energy into gas and synthetic fuel.
