Optimization of a Photovoltaic System at an Office Complex : A Case Study of Photovoltaics at PLAN4 Uppsala Sweden

Abstract: Photovoltaics is a method for converting sunlight into electricity by using PV devices. This report focuses on a pilot project of a PV system installed at the rooftop of an office complex, PLAN4 in Uppsala. The PV system has been evaluated with respect to the produced electricity and economic profitability. The report examines the possibility to optimize the facility in order to better match the electricity load profile at PLAN4. The optimization is done by changing the tilt angle and azimuth of the modules. A comparison between the existing and an improved system is done in order to determine the best match for the electricity demand. The electric power production was calculated with simulations in the software PVSYST, based on solar irradiation data and temperature from the year 2013. The result showed that the existing system has an annual production of 28 % of the electric power used at PLAN4. However, during midday on clear days, the production sometimes exceeds the demand and the produced electric power is used by someone else in the building, and does not generate any economic value for the office. This overproduction represents 17% of the total production, resulting in a self-sufficiency of 22%. The self-sufficiency represents the share of the electric consumption that comes from the PV production, calculated on an hourly basis. An optimization of the system would result in a small increase in self-sufficiency but the excess production would increase significantly. An optimization of the system does not generate enough savings to justify the investment required, although more electric power would be produced.