Presentation Open Access

# Feasibility study for 100% renewable energy microgrids with medium-sized wind turbines in Switzerland

Sarah Barber; Simon Boller; Henrik Nordborg

The growing worldwide levels of renewable power generation require innovative solutions to maintain grid reliability and stability, due to their variability and uncertainty. The implementation of microgrids in small regions can help with these challenges, by intelligently storing or releasing electricity to the grid, depending on the loads and the grid requirements at any specific time. Renewable microgrids are also good solutions for regions wishing to produce green electricity independently from the grid, saving potentially high cable laying and grid connection costs.

Switzerland does not yet have a large number of installed wind turbines (0.2% penetration level in 2016), and despite the ambitious Energy Strategy 2050, not a single wind turbine was installed in 2018. This lack of progress is mainly due to large delays, costs and risks associated with the permitting procedure for wind turbines higher than 30 m. Whilst wind turbines lower than 30 m require a much easier permitting procedure, they are less economically viable than large wind turbines, generally having average installed costs of about 4,400 $/kW compared to 1,400$/kW for MW-size wind turbines.

The implementation of renewable microgrids consisting of small wind turbines below 30 m, photovoltaic panels and a storage system may be a potential solution to help Switzerland to reach the goals of the Energy Strategy 2050. In this work, twelve sites in Switzerland were chosen for a 100% renewable energy microgrid feasibility study. Five of these sites were found to be economically viable, assuming that organisations / municipalities are prepared to make extra investments up to 0.2 \$/kWh for electricity independence. The Self-Sufficiency Ratio (SSR) was between 1 and 2 for each site, reflecting the extra installed capacity required in order to fully cover every hour of demand (island operation). Reduced battery costs (up to 50%) reduce COE (up to 11%) but reduce SSR only minimally (<1%). Reduced wind turbine costs (up to 75%) reduce COE (up to 46%) but increase SSR (up to 30%). Reduced PV costs (up to 33%) reduce COE (up to 66%) but increases SSR (up to 81%). However, the implementation of 100% renewable energy microgrids is strongly limited by the area required / available. Furthermore, a suitable solution was found for a High Performance Computing Centre test site in Canton Glarus. The next step is to look at some real test cases with real costs and wind measurements.

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