Crude oil is processed in two refineries, located at Burgas and Pleven, with daily throughput capacities of about 16,500 tons and 5,500 tons, respectively. Except for the small domestic output, crude oil for the Pleven refinery is moved by rail from Black Sea ports. A pipeline network that will connect the refinery with the ports is under construction and is scheduled to enter into full operation in 1975. By that date the capacity of the Pleven refinery is planned to attain 16,500 tons per day. A pipeline under construction for the transport of petroleum products from the Burgas refinery to consuming centers at Stara Zagora and Plovdiv is to be completed sometime in 1973. The refinery output has not been sufficient to cover all the country's requirements for petroleum products. Net imports of petroleum products in 1970, including gasoline, fuel oils, and lubricating oils, amounted to 2.5 million tons. Ninety percent of the imports originated in the Soviet Union. Electrical Energy Installed electric generating capacity and production of electrical energy increased more than fourfold in the 1960-71 period but failed to keep pace with the country's growing requirements. Installed capacity in 1971 was 4.48 million kilowatts, including 3.65 million kilowatts in thermal and 0.83 million kilowatts in hydroelectric stations. During the period the proportion of hydroelectric capacity declined from 50 to 18 percent, and the production of electricity per kilowatt of hydroelectric capacity dropped by more than one-third. The utilization of thermal capacity declined by 13.5 percent. New power from generating plants scheduled to begin operation in the 1971-75 period totals about 3 million kilowatts. Major power stations to be commissioned include: hydroelectric stations--with a capacity of 1 million kilowatts--on the Sestrimo cascade, in the upper reaches of the Maritsa River and at the Vucha cascade, southwest of Plovdiv; a thermal power plant with a capacity of about 620,000 kilowatts at Bobov Dol, fueled by local coal; and an atomic power station with a capacity of 880,000 kilowatts at Kozloduy on the Danube River, in the northwestern corner of the country. According to government plans, total generating capacity is scheduled to reach 7 million kilowatts in 1975 and 12 million kilowatts in 1980. The more distant plans include the construction, jointly with Romania, of a hydroelectric power complex on the Danube, at Belene on the Bulgarian bank of the river and Ciora on the Romanian side. The Soviet Union has provided large-scale technical and material assistance in the development of the electric power system.