figure 2. Incineration plant ovens, 1903. (Source: Frederiksberg Forsyning; used with permission.) These collective heat infrastructure networks and CHPs are fundamental for the energy efficiency of the Danish energy system and for the top WEC ranking of the country. In the 1960s, prel imina ry explorations for oil and gas had taken place in the Danish part of the North Sea, and the private entrepreneur A.P. Møl ler-Maersk was awarded the concessional rights to these fossi l-fuel reserves. Oil was first extracted from the oil platform Danfield in 1972. That same year, the commercial transmission company for natural gas (D.O.N.G., now known as Ørsted) was established with the Danish state as the only shareholder. figure 3. The incineration plant, 1903. (Source: Frederiksberg Forsyning; used with permission.) 100 ieee power & energy magazine The Global Energy Crisis and NationalScale Collective Heat Infrastructure Planning The energy import-dependent country suffered during the global energy crisis in the 1970s. Short-term and long-term remedial measures targeting energy efficiency were introduced. All members of society felt their effects and limitations. Thus, policy makers-and the Danish public-warmly welcomed the newly discovered oil and gas reserves within national sea territories. These were an alternative to the unstable imported oil, and the discovery sparked hopes for energy independence in the future. november/december 2021