Abstract: A method of managing energy supplied to a facility comprises monitoring a marginal cost of electricity from an electricity vendor; and determining a facility current electrical load and a facility current heating load. The method also comprises obtaining fuel to supply energy to meet the heating load when the marginal cost of electricity is greater than a marginal cost of a fuel or the current electrical load is greater than a peak billed demand threshold. When the marginal cost of electricity is less than the marginal cost of the fuel and the current electrical load is less than the peak billed demand threshold, electricity is obtained from the electricity vendor up to the peak billed demand threshold to supply energy to the meet at least part of the current heating load, and fuel is obtained to supply energy to meet any current heating load not met by energy from the electricity.