With many rivers, waterfalls, and lakes, Sweden has favorable conditions for waterpower. Northern and southern Sweden have their peak productions at different seasons; thus, they are complementary, and all large power stations are coordinated. In the north, underground installations provide power for iron-ore working, for iron smelting at Lulea, and for the Lapland railway. More than half the hydroelectric output is produced underground. Because of environmental considerations, high production costs, and low world market prices, Sweden's substantial uranium reserves—some 250,000–300,000 tons (or about 20% of the known world reserves)—have not been exploited.
Total installed electrical capacity in 2001 was 32,759,000 kW. In 2000 Sweden's electricity production totaled 141.4 billion kWh, of which 6.1%% was from fossil fuels, 53.8% from hydropower, 37.4% from nuclear power, and 2.7% from other sources. Consumption of electricity in 2000 was 139.2 billion kWh.
During the 1970s, as the price of Sweden's oil imports increased sevenfold, Swedes reduced their dependence on petroleum imports by conserving energy, so that their energy consumption rose by only 0.6% annually from 1973 to 1979. The share of oil in the primary energy supply declined from nearly 70% in 1979 to 30% in 2000. In the same year, nuclear energy accounted for another 24% of primary energy, hydroelectricity 36%, coal 4%, natural gas 1%, and renewable sources for the rest. Sweden embarked on an ambitious nuclear energy program, under which seven nuclear reactors came into operation between 1972 and 1980. By 1986, 12 units offered a capacity of 9.4 million kWh; by 2010, all 12 will be shut down. Plants fired by natural gas will replace nuclear energy's role. Energy conservation, development of alternative energy sources, and increased use of imported coal are also planned.