The vast majority of people in Michigan are already connected to an extremely efficient distribution network for electricity. The marginal cost of delivering additional energy through this network does not round to zero, it is zero. Meanwhile heating oil is delivered by trucks with a large cost in depreciation, labor, and fuel (further fossil fuels burnt in support of a system which was designed to make economic sense with <$10 oil). Whereas domestically produced oil can never drop below $40-50 a (marginal) barrel at the refinery, and imported oil never realistically below $30 + the cost of fighting forever wars for resources, there is a clear and feasible convergence of the marginal cost of solar energy generated in the Southwest US to $0. All this would make solar a viable replacement even without the role of heat pumps, which reduce the raw energy cost of heating with solar to around 20% of that of burning fuel.