The Fierza Hydroelectric Power Station is a large hydroelectric power station on the Drin River, in Albania. Fierza is the upper HPP (Hydro Power Plant) of the Drin River cascade followed by the power stations of Koman and Vau i Dejës downstream. Based on the installed power capacity, position and the volume of the reservoir, Fierza plays a key role in the exploitation, regulation and safe operation of the Drin cascade. Work for its construction began in 1970. The first power unit became operational in 1978 and the plant was fully operational in 1980. Fierza HPP was built with equipment mostly from China but on the concepts of Albanian engineers. Around 14,000 workers, engineers and specialist were involved in the construction of the plant. Fierza is a HPP with a rock-fill dam with a clay core and reservoir. When it was built, Fierza was the second in Europe for the height of its type. The dam has a total volume of 8 million m3. This rock-fill dam measures 167 m in height, and 380 m in length along the crest. Construction began in 1971 and was completed seven years later in 1978. The dam is one of the three hydroelectric dams on the Drin River. The reservoir was filled with water between 1978 and 1981. The four units installed in the plant have "Francis" vertical turbines with 125 MW power each; 3-Phase synchronous generators of 13.8kV voltage; and lifting transformers 13.8kV/242 kV for the connection with the transmission substation. The annual output of Fierza HPP averages in 1,330 GWh, that represent approximately 33% of Drin cascade production. The importance of Fierza, beside energy production, relates on the capacity of its lake which regulates the annual inflows and increase the efficient use of the Drin cascade.