Solar in Michigan

Michigan's inflow/outflow tariff is the defining policy framework. Public Act 342 of 2016 directed the Michigan Public Service Commission to transition away from full retail net metering, and the resulting structure separates consumption (inflow, billed at retail) from exports (outflow, credited at a utility-specific avoided-cost rate). This two-channel billing means homeowners see the full retail value of solar they consume on-site but a reduced rate for surplus sent to the grid — a design that, in effect, prices self-consumption above export and predates similar moves in California and North Carolina.

The property tax exemption shields solar systems from assessment-driven tax increases, and Michigan Saves — the nation's first state-level green bank, established in 2009 — provides low-interest loans and financing products that lower the barrier to residential adoption. There is no state income tax credit and no sales tax exemption for solar equipment. The state's renewable portfolio standard and broader clean energy goals, expanded under 2023 legislation, keep the policy direction supportive of distributed generation.

DTE Energy and Consumers Energy, the two dominant utilities, each publish their own outflow rate, which is the figure that most affects the value of exported surplus. Homeowners should obtain their specific utility's current inflow/outflow rates and size the system against them — leaning toward self-consumption given the structural preference the tariff builds in. The Upper Peninsula's smaller utilities and cooperatives implement their own versions of the framework, so territory-specific verification is essential.

Michigan's 4.3 peak sun hours reflect a genuinely northern solar resource: long, productive summer days offset by short winter days where output drops sharply and snow cover can persist on low-angle arrays. The Lower Peninsula is fairly uniform, with the lakeshore (Grand Rapids, Traverse City) seeing marginally different cloud patterns than the interior. The Upper Peninsula has both a weaker solar resource and a heavier snow load, making winter production particularly low.

Snow management is a real operational consideration in Michigan. Pitched-roof arrays shed snow within a day or two of sun returning, and the lost winter production is a small fraction of annual output, but low-slope or ground-mount arrays can hold snow longer. Most of Michigan's annual production comes from April through September, so a system should be sized to capture that productive season fully while accepting that winter contribution is modest.

Because the inflow/outflow tariff pays less for exports than for self-consumed energy, optimal sizing leans toward matching the productive-season daytime load rather than maximizing raw output for export. A system sized to 80–100% of annual consumption, oriented south at a moderate tilt, generally outperforms an oversized array that exports a large surplus at the lower outflow rate. Michigan's high retail rates make the self-consumed portion especially valuable, reinforcing the self-consumption bias.

Michigan's $3.00/W installed cost sits near the national average, with a typical 8 kW system around $24,000 before incentives. The federal 30% ITC (~$7,200) and the property tax exemption are the structural offsets. The state has no income tax credit or sales tax exemption, but Michigan Saves offers below-market financing that can meaningfully reduce the monthly carrying cost of a project — relevant for homeowners who finance rather than pay cash.

The payback math lands at roughly 12.9 years on the 8 kW model, faster than the national average, and the reason is the retail rate: at ~$0.172/kWh, Michigan's electricity is expensive, so each kilowatt-hour a solar system offsets is worth more than in lower-rate states. This high offset value compensates for the modest solar resource and the reduced export compensation under inflow/outflow billing. Households with high consumption — particularly those heating with electricity or running multiple air conditioners in humid summers — see the fastest payback.

The outflow (export) rate is the key variable that determines how much surplus production is worth, and it differs by utility. DTE and Consumers set their own outflow rates, which are updated periodically. Systems sized to minimize surplus and maximize self-consumption are less exposed to that variable and tend to produce more predictable returns.