district system operated by Enwave, in Seattle. Enwave also operates district heat system in Chicago, Houston, Las Vegas, Los Angeles, New Orleans, and Portland along with additional Canadian cities. Detroit Thermal operates a district system in Detroit that started operation at the Willis Avenue Station in 1903, originally operated by Detroit Edison. Citizens Energy Group in Indianapolis, Indiana, operates the Perry K. Generating Station, a gas-fired power plant that produces and distributes steam to about 160 downtown Indianapolis customers. Lansing Board of Water & Light, a municipal utility system in Lansing, Michigan operates a heated and chilled water system from their existing coal plant. They have announced their new natural gas cogeneration plant will continue to provide this service. Cleveland Thermal operates a district steam (since 1894) from the Canal Road plant near The Flats and district cooling system (since 1993) from Hamilton Avenue plant on the bluffs east of downtown. Veresen operates district heating/co-generation plants in Ripon, California, and San Gabriel, California. Veolia Energy, a successor of the 1887 Boston Heating Company, operates a district system in Boston and Cambridge, Massachusetts, and also operates systems in Philadelphia PA, Baltimore MD, Kansas City MO, Tulsa OK, Houston TX and other cities. District Energy St. Paul operates the largest hot water district heating system in North America and generates the majority of its energy from an adjacent biomass-fueled combined heat and power plant. In March 2011, a 1 MWh thermal solar array was integrated into the system, consisting of 144 20' x 8' solar panels installed on the roof of a customer building, RiverCentre. The California Department of General Services runs a central plant providing district heating to four million square feet in 23 state-owned buildings, including the State Capitol, using high-pressure steam boilers. Historically, district heating was primarily used in urban areas of the US, but by 1985, it was mainly used in institutions. A handful of smaller municipalities in New England maintained municipal steam into the 21st century, in cities like Holyoke, Massachusetts and Concord, New Hampshire, however the former would end service in 2010 and the latter in 2017, attributing aging infrastructure and capital expenses to their closures. In 2019, Concord replaced a number of remaining pipes with more efficient ones for a smaller steam system heating only the State House and State Library, mainly due to historic preservation reasons rather than a broader energy plan. District heating