Missouri Solar in 2026: The 100 kW Cap, Full-Retail NEM & the Constitutional Property-Tax Lock

For most Missouri homeowners, yes - on the strength of full-retail net metering and a 100 kW cap that is the largest in the surrounding region. An 8 kW rooftop system costs about $21,600 (2.70/W - below the national average) and pays back in roughly 14.9 years. The constraint holding back faster payback is the below-average retail rate ($0.140/kWh - the lowest in this batch of state guides), which limits the offset value of each kilowatt-hour. The case strengthens for households with high consumption - particularly those heating with electricity or planning EV or heat-pump electrification - because Missouri's full-retail NEM with annual true-up makes forward sizing attractive and penalty-free.

Missouri's 100 kW residential net-metering cap under Public Service Commission rules is the largest in the central US region. Most states cap residential net metering at 20-40 kW - Wisconsin caps at 20 kW, Minnesota at 40 kW, Indiana at 1 MW but with avoided-cost export under EDG. Missouri's 100 kW cap means larger residential arrays (10-20 kW for big homes, shops, or small farms) can participate in the same full-retail NEM framework as standard residential systems. It also lets small-commercial customers use the residential framework rather than navigating a separate commercial tariff. Combined with full-retail export credits and annual true-up, this is the most permissive NEM structure in the central US.

Yes. Missouri mandates 1:1 full-retail net metering for systems up to 100 kW under Public Service Commission rules, with an annual true-up. Ameren Missouri, Evergy Missouri, Empire District Electric, and the cooperatives supplied by Associated Electric all implement it. Summer surplus is banked at the full retail rate and drawn back through winter - there is no avoided-cost penalty for overproduction. The state NemRate of $0.116/kWh (from <code class="font-mono text-xs">src/data/nem-policies.json</code>) is the full retail credit, not a reduced buyback. Customers retain their net-metering terms for the life of their interconnection. This is the structural pillar that keeps Missouri's economics workable despite the below-average retail rate.

Missouri's solar property-tax exemption is enshrined in the <strong>state Constitution</strong> (Article X, Section 6), not just a statute. That makes it notably harder to repeal than a standard statutory incentive - any repeal would require a constitutional amendment, which is a high political bar in Missouri. By contrast, most state solar incentives are statutory, meaning a hostile legislature or regulatory body can modify or eliminate them through ordinary legislation. Missouri's constitutional protection is the most durable state-level solar protection in this batch of state guides. The exemption means solar energy systems do not trigger a property-tax reassessment on the added value - your system will not raise your tax bill.

For most homeowners, a battery is a negative-ROI purchase in Missouri. With full-retail net metering already crediting exported surplus at the full retail rate, a battery's incremental value is small: it would let you shift consumption to avoid exporting at retail, but you would be exporting at retail anyway. The payback is negative. Batteries in Missouri are justified only for <strong>resilience</strong>: severe thunderstorm outages (the state sits in Tornado Alley and Dixie Alley overlap), households with medical equipment dependencies, or rural areas with less reliable distribution. If resilience is not a hard requirement for your household, skip the battery and put the savings into a slightly larger array sized to your consumption - or, in Missouri's case, into forward sizing for future electrification.

A typical 8 kW rooftop system in Missouri runs about $21,600 (2.70/W) before incentives - below the national average, reflecting strong installer competition in the Kansas City and St. Louis metros. The 30% federal residential credit (Section 25D) expired December 31, 2025, so owned systems placed in service in 2026 receive $0 federal credit. Leased/PPA systems may still capture Section 48E for projects that began construction before July 4, 2026. Missouri offers a constitutional property-tax exemption (Article X, Section 6) but, importantly, NO state sales-tax exemption - the 4.225% state rate plus local adders applies (budget roughly $970 on an 8 kW purchase).

Missouri's tax posture is thin on the incentive side but unusually durable on property tax. There IS a property-tax exemption, and it is <strong>enshrined in the state Constitution</strong> (Article X, Section 6) - not just a statute, which makes it notably harder to repeal than typical state solar incentives. Solar energy systems do not trigger a property-tax reassessment on the added value. However, Missouri does NOT exempt solar equipment from sales tax: the 4.225% state rate plus local adders applies to the equipment purchase. There is no state solar income-tax credit, and Missouri has no SREC market. The case rests on cheap hardware, full-retail NEM, and the constitutional property tax exemption.

Missouri's four major utility categories divide the state. <strong>Ameren Missouri</strong> serves the St. Louis metro, the metro-east, and the eastern tier. <strong>Evergy Missouri</strong> (created by the 2018 KCP&L-Westar merger) serves Kansas City and the western tier. <strong>Empire District Electric</strong> (now a Liberty Utilities subsidiary) serves the Joplin area and the southwest corner. And <strong>Associated Electric Cooperative</strong> supplies 51 local distribution cooperatives across rural Missouri. There are also municipal utilities (City Utilities of Springfield, Columbia Water & Light, Independence Power & Light) that operate within the same PSC framework. Check your electric bill to confirm your utility. All of them implement full-retail NEM 1.0 with annual true-up.

After the 2026 expiration of the Section 25D residential credit, the structure carries real federal-tax consequences. A cash purchase or low-interest loan keeps the full long-term savings and the constitutional property-tax exemption but receives $0 federal credit. A lease or PPA eliminates upfront cost and can still capture Section 48E (the developer claims the 30% credit and passes value through as lower payments) on projects that began construction before July 4, 2026. In Missouri, where the low retail rate already stretches payback, the choice between buy and lease has more impact on the timeline than in higher-rate states. The 100 kW cap also means small-commercial leases have more room than in cap-limited neighbors.

Missouri averages about 4.6 peak sun hours per day - the central US norm, with productive summers offset by shorter, often cloudy winter days. A south-facing 8 kW array tilted near latitude (~38-40°) typically produces on the order of $11,552 kWh per year (the state-database figure is 11,552 kWh). Production varies modestly by region: the Bootheel delta in the southeast runs marginally above the state average, while the Ozark highlands and the northern tier sit slightly below. Hot, humid summers drive heavy air-conditioning load that aligns well with peak solar output. Because Missouri retains full-retail NEM with annual true-up, the optimal strategy is the classic maximize-and-bank model - size 100-115% of annual consumption to hedge against future load growth.

Yes - Missouri customers retain their net-metering terms for the life of their interconnection, under PSC rules. The 100 kW cap and the full-retail NEM 1.0 framework have been stable since 2007, and there has been no serious legislative push to follow the net-billing transition that other states have made. The constitutional property-tax exemption is even more durable - repeal would require a constitutional amendment. That said, no policy is permanent, and interconnecting sooner rather than later locks in the current terms. Track any pending PSC proceedings with our <a href="/tools/nem-grandfathering-calculator/">NEM Grandfathering Calculator</a>.

Yes - Missouri is one of the best states in this batch for forward sizing. The combination of full-retail NEM 1.0 with annual true-up, a 100 kW cap, and penalty-free overproduction makes adding capacity for an EV, heat pump, or electric water heater straightforward and economical. If you size only for current consumption and add an EV in three years, you will wish you had installed more panels while the installer was already on the roof. Missouri's below-average retail rate ($0.140/kWh) limits the offset value of each kilowatt-hour, but full-retail NEM means there is no penalty for overproduction - any surplus is banked at the full retail rate for future use. The 100 kW cap means even substantial forward sizing stays well within the framework.