In a pioneering study, the Danish Energy Agency concluded that it would be technically possible to construct a secure and reliable national energy system based on 100 per cent renewables by 2050. The report, "Energy Scenarios for 2020, 2035 and 2050", compares the feasibility and cost of replacing coal, oil and natural gas with various sources of green energy, ranging from a wind powered electric production system to a biomass system. According to the report, all of the scenarios meet the vision of a fossil fuel independent energy system for Denmark by 2050, as well as the government's goal of fossil fuel independent electricity and heating by 2035. To meet the 2050 target, however, the report notes that a decision on the shape of Denmark's energy future would need to be made shortly after 2020.