Undersökning av lönsamhet för batterilagring i kommersiella fastigheter tillsammans med solceller : Förutsättningar för lönsamhet vid optimal drift och vid drift baserad på prognoser

Sammanfattning: The majority of the existing photovoltaic (PV) systems are dimensioned in such a way that no or only a small part of the production exceeds the buildings internal consumption. This is done because sold electricity to the grid has a lower economic value than if used internally in the building. Therefore commercial buildings, with high consumption during sunny hours, are to prefer when installing PV. Implementing a battery energy storage system in these facilities can lead to higher self consumption of the PV energy and reduced electricity bills. To take full advantage of this potential it requires optimal management of the battery. In this study an optimized battery algorithm was developed to show the full potential a perfectly managed battery can have to reduce cost of electricity within commercial buildings. There are three main charge and discharge patterns for a battery which can reduce the cost on the electricity bill: 1) Charge and discharge at different prices, 2) peak shaving and 3) overproduced PV is stored for later use. By utilizing a battery in an optimal way to reduce the costs as much as possible, batteries will reach break even at battery prices between 1350-2100 SEK/kWh, depending on which scenario evaluated. By implementing forecast based desicion-making, in which the battery operation is optimized with respect to PV and consumption forecasts, the system profitability declines rapidly, especially when using a consumption forecast. A real system would probably profit from basing the battery operation on both forecasts and real time measurements.