Impact of Renewable Energy Installations and Utilisation of Smart Energy Management Systems on low-voltage networks- a study case at Östergarnslandet, Gotland

Abstract: This thesis carries out an analysis of PV panel installations in the region of Östergarnslandet, situated in the Swedish island of Gotland. A low-voltage grid of 0.4 kV in the region is examined with the help of software Open DSS. This is done with the data provided by the distribution grid owner, Gotlands Elnät AB (GEAB). The potential impacts created by the PV installations in terms of exceeding currents, voltages and harmonics are assessed and thereby the hosting capacity of Solar PV in the houses and on the whole grid is studied.   Moreover, a theoretical review of the Smart Energy Management System (SEMS) is investigated about the performance and the devices involved in the system. Also, a battery which is a part of SEMS is modelled, taking into account the production and consumption of a single household connected in the grid. The battery sizes for various PV installations at the home is suggested via NPV analysis with the intention to increase the self-consumption and to reduce the cost of the electricity bill. In addition, a survey is conducted in the region with support from the Department of Earth Sciences, Uppsala University Campus Gotland. The survey is made to determine the attitude of the people in Östergarnslandet towards an energy transition. The results show that the maximum amount that can be installed or the hosting capacity of solar in the studied grid is 120 kW. From the simulations, it shows that the impacts created by these PV installations do not violate the specified Grid norms. From the theoretical analysis, SEMS is found to be a better solution for energy management at homes. The performance study done shows that 33 % of the solar energy produced in the home is directly used at the time of production. The remaining energy is used for battery charging for the future supply of power and feeding to the grid. The battery modelled for 10- kW PV installation in the home is found to be 9-kWh and the same for a 15-kW installation. Meanwhile, for a 20- kW installation, a 15-kWh battery is found to be ideal from the study. The survey conducted in the region has turned out to be positive as people are supportive of the energy transition. The responders have marked photovoltaics as the prime option for investment in energy production which assures that it has a good future in the area.