Significant benefits are shown to be possible in the province of Ontario by implementing utility-based cogeneration using die facilities of the main provincial electrical utility, Ontario Hydro. Six cogeneration scenarios are assessed, and show that cogeneration can provide significant technical, economic and environmental benefits to the province and its electrical utility. The first three scenarios assume implementation of utility-based cogeneration to satisfy a minor portion of the heat demands of the residential-commercial (including institutional) sector, the industrial sector, and both of these sectors. The other three scenarios are similar, but assume a larger portion of the heat demands of the sectors are satisfied using utility-based cogeneration. It is shown that the implementation of utility-based cogeneration in Ontario offers significant opportunities to reduce annual energy use and related emissions.