Most of the photovoltaic (solar cell) systems in Sweden today are installed on private houses and connected to the public grid. Photovoltaic (PV) power can be consumed directly in the house, called self-consumption, or fed in to the public grid. For the house owner self-consumed PV energy often has a higher economic value than sold excess PV energy, since the savings from not buying one kWh is larger than the income of selling one kWh. The self-consumption can be expressed as an absolute value; amount of produced/consumed kWh, or as a relative; absolute self-consumption divided with total PV production. The PV production and self-consumption were calculated on an hourly basis. In this Master thesis a MATLAB tool for calculating and optimizing the production, absolute and relative self-consumption and profit for PV systems with panels in one (1DPV), two or three directions (3DPV) was developed. The results show possibilities to increase especially the relative self-consumption with 3DPV. There is however no economic gain of using 3DPV instead of south-directed 1DPV for the studied case; a private house close to Västerås with a 1DPV system of 3360 W and variable electricity prices based on hourly Nord Pool Spot prices. The rated power of the inverter can be decreased with 3DPV compared to south-oriented 1DPV and still keep minimal production losses. A smaller inverter and other peripheral equipment such as cables might compensate for the lower yearly profit with 3DPV when calculating the payback period. Further studies of economic aspects and how to optimize them have to be carried out for 3DPV systems, since economy is very crucial for investment decisions.

Solar energy is resourceful for many purposes, for example, harvesting renewable electricity with photovoltaic (PV) technology. The number of new grid connections of PV is continuously increasing, and the Swedish PV market for residential prosumers is growing. Providing accurate information about PV’s benefits and the installation’s technical details is essential to attract more prosumers to the PV market. One outlet for such information is providers of PV, who are also responsible for the technical details. From a technical perspective, how much of the produced electricity the prosumer can self-consume impacts the profitability of the investment. Higher self-consumption is associated with more savings, and a battery storage system has the potential to increase self-consumption. Two different approaches were used to carry out this thesis. Communication was studied with a qualitative approach, and the technical term self-consumption was analysed quantitatively. A discourse analysis with a pragmatic approach was performed to study what meanings are created when retailers communicate about the two genres within the discourse of PV: the benefits and the technical specifications. Qualitative data used for this part was collected from the websites of PV retailers. The quantitative part involved calculations of self-consumption levels and simulations of a battery storage system in MATLAB using an extensive data set over households with real PV systems. The identified research gap indicates no previous studies on how PV retailers communicate and few studies of self-consumption using data from real systems. The results from the discourse analysis of the benefits showed that some of the central meanings were: “a prosumer's roof is worth money if they can afford the investment”, “PV has a positive environmental impact”, and “adoption of PV is a trend that prosumers should follow”. The central meaning from the analysis of the technical specifications was that “a prosumer does not need to be concerned about the technical aspect of the installation because the company takes care of it”. The results from the quantitative study showed that from the available data, self-consumption was dependent on how the PV system size is matched to the consumption of the household. Depending on the ALR groups, the households had different mean values of self-consumption, whereas the most common group ALR=6 had a mean self-consumption level of 38%. The simulations with battery storage showed that systems with lower initial self-consumption (below 40%) could increase self-consumption faster with increasing battery capacity but could not reach maximum self-consumption values.