Energy Storage in Luleå Energi's power grid

This thesis will investigate possible energy storages in Luleå Energi’s power grid within a five-year period. The transition to a more sustainable and efficient energy system, in response to climate change, creates new challenges for the power grid. Energy storage has, according to many sources, the potential to contribute to meet the challenges that arise from a larger share of intermittent renewables, a growing number of electrical vehicles and increased demands for reliability and stability. Several reports conclude that currently energy storages are most profitable in customer applications, especially in combination with micro-production, e.g. solar cells. Therefore, this report will investigate if battery storages could be installed in three multi-residential properties with solar cells, with the purpose to increase self-use of electricity generated from the solar cells and peak-shaving. Batteries have been chosen as storage technology, since they currently seem to be the technology with the most potential. Possible savings for the customer as well as potential benefits for the grid will be considered. Based on data for the properties’ consumption and solar power production, an analysis has been made to see how much excess electricity the solar cells generate and to identify peak demands. Regarding the solar cells, data has only been available for a few months. For other days, the production has been estimated base on measurements of global radiation over Luleå municipality. A simulation in MATLAB has then been carried out to dimension the battery. When customers connect micro-production to the grid, the voltage may rise above permissible limits, especially in weaker rural grids. As a result, reinforcements of the grid may be necessary, which means expenses for the grid owner. Installation of a battery, that can store energy and keep the voltage within permissible limits, could be an alternative. The report considers such a case and makes a comparison between reinforcements of the grid and installation of a battery. The results of the report show that energy storages have several potential benefits, both for customers, grid owners and system operators. Forecasts point to a strong growth, as well as lowered battery prices, which could lead to investments that are more profitable. The study of installing a battery in properties with solar cells shows that an increased self-use and peak shaving is possible. However, the economic results show negative net values. This means that currently the investment is not profitable. Approximately, battery prices must be cut in half to reach profitability. The calculation concludes that power tariffs enables most savings for the customers and gives them incentives for peak-shaving. The report also shows that the amount of micro-production in a rural grid can be limited by the strength of the grid. If five customers in the investigated part of the grid each would install 8.6 kW solar power, the voltage rise at the point of common coupling would go above permissible values, and the grid would have to be reinforced. The economical comparison between investing in new cables and installing a battery storage shows that currently, a battery storage is more expensive than a new cable. The overall conclusion from the report is that energy storage has the potential to contribute to the transition of the energy system. However, regulations and battery prices currently limit the possibilities for profitable investments. It is recommended to do an oversight of regulations and new business models to enable more investments in energy storage. Studying alternative tariffs is also important, to create incentives for a more efficient use of the power grid