With the heat produced by the cogeneration plants in Moncalieri and North Turin and the waste-to-energy plant TRM, a volume corresponding to more than 57% of the total potential volume is served; thus, Turin is the most district-heated city in Italy and one of the most district-heated metropolises in Europe. More than 90% of the energy fed into the network is produced by cogeneration plants, an outstanding figure achieved through the use of heat accumulators installed in power plants and along the network. The remaining thermal energy is produced by means of integration and recovery boilers. In Piedmont, in addition to the municipality of Turin, the Iren Energia metropolitan district heating network also serves the municipalities of Beinasco, Collegno, Grugliasco, Nichelino, Moncalieri and Rivoli.