Methods for Increasing Shares of Self-Consumption in Small PV Solar Energy Applications

The article analyses the possibilities of increasing PV electricity self-consumption, based on the data of a residential house. This is important for producing electricity from a PV station to the microgrid; to reduce the amount of electricity purchased from the grid, also to replace part of the electricity consumed with the electricity produced by the PV station. The article uses a previously measured consumption graph of an average Estonian residential house, which separately displays the consumption of hot water and non-shiftable load (white goods, lighting, TV set, etc.). The production graph of the PV station is the measured production of 2.5 kW solar station scaled to the annual consumption of this case. To increase the share of solar electricity in consumption, load shifting technology has been used, with both water and batteries deployed as storage devices. The PV station production and consumption data are recorded at 5-minute averaging intervals. The research aims to find the optimal capacity of the hot water tank and the battery, provided that the excess energy is stored after the non-shiftable load in both the boiler and the battery. In the case of a non-shiftable load energy deficit, it is provided from the battery, if there is a supply available. The energy production, scaled to equal the consumption, of the PV station was 3472 kWh / year, which was the basis for the energy capacity of 5 kWh for the optimized hot water tank and 3 kWh for the battery. In these conditions, the value of the demand cover factor is 0.657. Without storage devices, it would be 0.152. These results are scalable to bigger or smaller solutions.