Others in this category - known as senior rights holders - are irrigation districts, utilities with hydropower stations, and cities, including San Francisco.
The drought, affecting Brazil's southeast and central regions, has prompted rationing in 19 cities, undermined hydropower generation, pushed up greenhouse gas emissions and led to squabbles between states vying for dwindling water resources.
Hydropower, dams, diversions, expanding cities and irrigation schemes are all in the mix.
Despite air temperatures sometimes dipping as low as -32C, a hydropower dam on the city's river keeps the water flowing, which in turn encourages the creation of milky white freezing fog.
For example, the City of Lynch is exploring ways to generate hydropower from Looney Creek, as well as to retrofit city-owned buildings with energy efficient lighting, heating and cooling systems.
Amoskeag Falls has long provided hydropower for industry in Manchester, New Hampshire's largest city.
Each city's water price should rise; hydropower prices should also be raised to the level of fire-generated electricity.
The rest of Aspen's energy sources are domestic, too: The city receives wind energy from Nebraska and South Dakota and hydropower from within Colorado itself.
Underinvestment and ineptitude hit hydropower stations and the electricity grid, causing weekly blackouts that continue to darken cities, fry electrical equipment, silence machinery and require de facto rationing.
North Korea also plans to increase electricity generation capacity by building coal-fired power plants and hydropower plants, and to increase transmission capacity by extending grids to all secondary cities.
