Pumped storage for electrical generation. Total output is enough to power a city of 1.4 million people.
Description of the Process
The Ludington Pumped Storage Plant is a hydroelectric plant and reservoir in Ludington, Michigan. It was built between 1969 and 1973 at a cost of $315 million and is owned jointly by Consumers Energy and Detroit Edison and operated by Consumers Energy. At the time of its construction, it was the largest pumped storage hydroelectric facility in the world. It consists of a reservoir 34 m deep, 4 km long, and 1.6 km wide which holds 100,000,000 m3 of water. The 3.4 km2 reservoir is located on the banks of Lake Michigan. Because impervious bedrock is more than 240 m below the reservoir, the builders had to line the reservoir with a layer of asphalt and clay to prevent water seeping into the ground. The power plant consists of six reversible turbines that can each generate 312 megawatts of electricity for a total output of 1872 megawatts. Water is delivered from the upper reservoir to the turbines by six penstocks each 340 m long that taper from 8.5 to 7.3 m in diameter. At night, during low demand for electricity, the turbines run in reverse to pump water 110 m uphill from Lake Michigan into the reservoir. The plant takes advantage of the natural steep sand dune landform of eastern Lake Michigan. During periods of peak demand water is released to generate power. Electrical generation can begin within 2 minutes with peak electric output of 1872 MW achieved in under 30 minutes. Maximum water flow is over 120,000 m3 per minute. This process was designed to level the load of nearby nuclear power plants on the grid. It also replaces the need to build natural gas peak power plants used only during high demand. The Ludington Pumped Storage plant is connected to three 345,000 kWh Transmission lines, all owned and maintained by METC, a subsidiary of ITC Holdings.
Result of project
Consumers Energy discussed plans in 2008 to extend the life of the facility and upgrade the pumps to increase efficiency by up to 9%.Consumers Energy also planned to tap the wind power resources along the eastern Lake Michigan shore with wind farms. Because wind is an intermittent power source and may inconveniently deliver large amounts of power during periods of low electric demand, pumped storage facilities are desirable to have on the same grid with large-scale wind farms. The available pumped storage capacity, along with the wind characteristics, partly determines the maximum contribution wind power can make to the overall electricity use in a region. Consumers Energy and Detroit Edison announced an $800 million upgrade on February 7 2011. The six year project would begin in 2013 and extend the plant's life by at least forty years and upgrade the generating capacity from 1,872 megawatts to 2,172 megawatts.