Abstract. Photovoltaic installations are becoming an increasingly important player in the global renewable energy production market. The biggest disadvantage of photovoltaic installations is their high price, and relatively low efficiency. Photovoltaic cells achieve a theoretical efficiency of 30%, but in real conditions this efficiency is much lower at roughly 15%. Photovoltaic installations are particularly recommended in locations where the amount of solar radiation is high and where photovoltaic installations will be able to work at full capacity for most of the year. The paper presents an analysis of the work of a photovoltaic installation built for a roofed car park located in eastern Cairo, the capital of Egypt. The installation is built for a car park located at the Schlumberger company. The installation is built of 1344 Hanwha Q.Power L-G325 silicon polycrystalline cell modules, each module has a power of 325 Wp, and the total area of the installation is 2,611 m 2 . Effective irradiance on collectors is 1922 kWh/m 2 . The array's nominal produced energy was 840 MWh/year, the amount of electricity injected into the grid was 587 MWh/year, which means that the calculated performance ratio was 0.62.