Year: 2020
Type: other
Abstract: Electricity systems are planned so the supply and demand always meet. However, since the demand undergoes hourly, daily and seasonal variations, the electricity supply must be very flexible in order to adapt to the constant changes. Recently, a growing climate- and environmental awareness has driven the energy sector in a more sustainable direction. This means that renewable energy sources are increasing in number and importance. However, renewable energy generation is non-dispatchable, which means it cannot be generated on demand and thus lacks the flexibility that electricity systems require. This means that the flexibility must be achieved in other ways. One method that has been proven in practice is energy storage solutions. The subject of study in this thesis is the electricity system of Finland and the possibilities Finland has to commit to generation without fossil fuels before 2030. Two different cases were examined, one where Finland would rely completely on renewable electricity generation and one where electricity generation would be based on renewable energy sources and the three nuclear reactors in Olkiluoto, the already existing Olkiluoto 1 and 2 as well as Olkiluoto 3, which is nearing completion. All the calculations were based on data from 2018, which was scaled to match approximations for the situation in 2030. Existing studies and the current generation capacity were used as reference to approximate the generation potential of the different energy sources. A total renewable electricity generation potential of 89.5 TWh was identified, which means a 280% increase compared to the current generation would be possible. Based on the assumptions made in the study, the Finnish energy ssytem cannot be 100% renewable and self-sufficient yet in 2030. The remaining demand was 6.7 TWh, which would have to be imported from abroad or generated with other means. When the existing nuclear capacity in Olkiluoto was included in the generation, the capacity was enough to cover the assumed demand. An optimisation of energy sources was conducted with the objective to minimise the required energy storage need. The optimisation ruled solar power as too variable to be feasible in a electricity system with limited energy storage capacity. At the same time, wind power, bioenergy and hydropower were concluded as important generation technologies, together with nuclear power. The emission reduction potential in generation with renewable energy sources and nuclear power was also concluded as significant. Direct emissions in such a system would decrease to zero, while the life-cycle emissions would be reduced by 17% from the current level. However, since the generation was 28.7 TWh larger in the electricity system which was considered as self-sufficient, the emission intensity per generated TWh showed a reduction potential of 43%. A carbon-free electricity system is in line with the targets of the European Union to become carbon neutral in 2050. Still, the electricity system is not on its own able to reduce the total emissions by 55% from the 1990 levels, which is a goal set up by the Finnish government. The calculations in the thesis were based on data from Finland, but the results can also be applied to other countries which are similar in climate and consumption habits. For instance, the rest of the Nordic countries.
Source: Doria (University of Helsinki)
Author: Robert Puhakka
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3013611190