The concept of self-consumption of photovoltaic (PV) electricity from grid-connected residential and industrial systems is becoming widely popular among PV system owners and in the scientific community. Defining self-consumption, it is the share of the total PV production that is directly consumed by the PV system owner. With decreased subsidies for PV electricity in several countries, increased self-consumption could contribute in raising the economic viability of PV systems and lower the stress on the electricity distribution grid. The present thesis consists of the study that is required to be carried out, in a summarized form, for the installation and operation of a PV self-consumption system. The owner of the system is an industrial building that is located near the city of Limassol in Cyprus and it is therefore subjected to the respective legislation scheme. The realization of this study was combined with a 3-month internship in the company Limcen ltd, which was the company that undertook performing the study for the owner of the industrial building. The main challenge of the thesis was to select a PV system under the optimal technological and economical parameters by performing simulations, according to previous data acquired from the customer (industrial building owner), relevant to the electricity load distribution of the building during a year. This study shows that even when a PV self-consumption system owner cannot benefit from excessive electricity produced from his system, this type of investment can be significantly profitable.