For 45 years, DTE has tapped a distinctive technology to generate reliable, affordable and cleaner electricity. The Ludington Pumped Storage Power Plant on Lake Michigan in Mason County generates hydroelectric power using a simple technology capitalizing on the daily cycle of energy supply and demand.

Located on a 1,000-acre site south of Ludington, the plant is an engineering marvel, a key part of DTE’s commitment to reduce carbon emissions by more than 80 percent, and an energy source now being upgraded to increase its output and extend its life for 50 more years.

The plant consists of a man-made reservoir located 363 feet above six 300-ton turbines. It works by pumping Lake Michigan water uphill to the 27 billion-gallon reservoir at night when energy demand and costs are lower and releases the stored water downhill through the turbines to generate electricity during the day when energy demand is higher. The reversible turbines work as pumps at night and power generators during the day.

The Ludington Pumped Storage Power Plant, with the reservoir at left and Lake Michigan at right. When the plant went online in 1973, Ludington was the largest facility of its kind in the world. It now ranks fifth worldwide in terms of energy output for pumped storage facilities.

The huge reservoir – covering 639 football fields – serves as a natural battery of stored power. Because Ludington uses pumped water storage, it doesn’t impact fish or wildlife. Nets are annually installed to prevent fish from being drawn into plant intakes.

“Ludington provides energy at a moment’s notice,” said Ryan Randazzo, a 15-year DTE employee who manages the company’s “peaker” power plants, which generate electricity when demand soars. “We can hit peak output in only 30 minutes. Ludington is a sustainable, clean, reliable energy source that quickly responds to the daily, weekly and seasonal highs and lows of Michigan’s energy demand. The plant helps keep energy bills lower because we avoid having to buy expensive outside electricity when demand peaks.”

An $800 million upgrade project to replace each of the six turbines is on schedule and budget. The work started in 2013 and will be complete in 2020. Ludington will then produce enough power for 1.65 million residential customers – an increase of 250,000 over the current output.

Ludington is co-owned and jointly managed by DTE and Consumers Energy. While the 41 employees who keep the plant running are Consumers employees and the plant is located in the electric service territory of Consumers, the energy produced at Ludington goes to customers of both companies. DTE and Consumers have jointly applied to the Federal Energy Regulatory Commission (FERC) to operate Ludington for another 50 years.

Michigan doesn’t have other pumped storage power plants along its nearly 3,000 miles of Great Lakes shoreline because Ludington possesses a unique combination of environmentally-appropriate shoreline and geography. It was built in the perfect place at the perfect time.

The Ludington Plant is taking on added importance as DTE continues its transition from fossil fuels to renewable energy generation. The primary technological challenge to wind and solar sources replacing fossil fuels, especially in states like Michigan, is how to store energy when the wind is blowing and the sun is shining to provide the grid with 24/7 energy. As Ludington’s new turbines produce more output, the plant will continue serving well into the future, providing power when demand peaks and as a 24/7 battery supporting wind and solar.