Missouri Clean Energy Guide

Missouri is the rare market that is booming and backsliding at the same time. Utility-scale solar nearly tripled in twelve months — from 570 MW in April 2025 to 1,561 MW in April 2026 — while the legislature passed a law that bars wind and solar from replacing retiring coal plants, and a bill to freeze all commercial solar construction statewide cleared committee before dying on the Senate calendar. Layer in a data center demand shock measured in gigawatts, and the Show-Me State has become one of the most consequential — and contradictory — energy stories in the Midwest.

Policy: A 2008 Ballot Floor Meets a 2025 Gas Mandate

Missouri's renewable policy framework is a period piece. Its foundation is Proposition C, the Missouri Clean Energy Act approved by voters in November 2008 and codified at RSMo 393.1020-393.1050. It requires the state's investor-owned utilities — Ameren Missouri, Evergy, and Liberty — to source 15% of annual retail sales from eligible renewables by 2021, with a solar carve-out of 2% of each requirement and a statutory customer cost cap, all overseen by the Missouri Public Service Commission. Co-ops and municipal utilities are exempt. The target has not been raised in the nearly eighteen years since voters approved it, and coal still supplied 58.1% of Missouri's generation in 2024, against 15.7% from the Callaway nuclear plant, 10.2% from wind, and 1.5% from hydro — roughly 29% carbon-free overall.

SB 4: The Watt-for-Watt Rule That Locks Out Renewables

The state's real energy policy was written in 2025. SB 4, the sweeping utility omnibus signed by Gov. Mike Kehoe on April 9, 2025, allows utilities to charge customers for new natural gas plants during construction (CWIP, sunsetting in 2035), makes integrated resource planning a statutory requirement filed every four years, and streamlines certificate review so the PSC must act within 120 to 180 days on projects in an approved IRP — a regime that begins in August 2027. The provision that matters most for clean energy is the "watt-for-watt" replacement rule: before retiring any thermal plant over 100 MW, a utility must secure equal or greater capacity, at least 80% of it dispatchable — and wind and solar are explicitly excluded from qualifying. In practical terms, Missouri has legislated that renewables cannot ride coal retirements into the rate base the way they have across MISO and SPP. Critics warned at signing that the law favors gas and will raise bills.

SB 4 also touched the RPS itself: it amended REC accounting so that "accelerated renewable buyers" — customers with loads of 80 MW or more buying post-2020 solar and wind RECs in SPP — cannot have those RECs counted toward Evergy's compliance; the utility must retire them.

The Property-Tax Hole Nobody Has Fixed

Missouri is also the unusual state where solar's tax treatment got worse by court order. In Johnson v. Springfield Solar 1, decided August 9, 2022, the Missouri Supreme Court unanimously struck down the state's 2013 solar property-tax exemption at RSMo 137.100(10) as unconstitutional. SB 4 restored favorable treatment only for systems constructed and producing before that August 2022 date — a grandfather clause, not a fix. County assessors have broad discretion under March 2023 State Tax Commission guidance, utility-scale solar is generally assessed as business personal property, and at least seven replacement bills have failed since 2022. Developers now routinely structure around the gap with Chapter 100 bonds or enhanced enterprise zone abatements — workable, but a deal-by-deal negotiation that most competing states don't require.

Net Metering

The Net Metering and Easy Connection Act of 2007 (RSMo 386.890) requires all Missouri utilities to offer net metering and free interconnection for solar, wind, or small-hydro systems under 100 kW, with monthly generation offsetting usage at the full retail rate and excess credited at the utility's avoided-cost rate. Compensation levels remain a recurring fight in PSC rate cases.

The Projects: Wind Flatlined, Solar Nearly Tripled

Missouri's operating fleet tells a clean before-and-after story. Wind capacity has been frozen at 2,392.9 MW — unchanged from April 2025 to April 2026 — while utility-scale solar nearly tripled over the same year. The growth has been driven by Ameren Missouri rate-base projects like the 300 MW Split Rail center, though merchant development is stirring too: DESRI and Ranger Power broke ground in early 2025 on the 250 MW Show Me State Solar project in Callaway County, backed by a Meta power purchase agreement and expected online in late 2026.

The Wind Fleet: A Northwest Missouri Legacy

• High Prairie Renewable Energy Center (Adair/Schuyler Counties): 400 MW and 175 turbines, operating since December 2020 — Missouri's largest wind farm, owned by Ameren Missouri and built by Terra-Gen
• Rock Creek Wind Project (Atchison County): 300 MW from 150 Vestas V110 turbines near Tarkio, online since November 2017 — a roughly $500 million Enel Green Power investment producing about 1,250 GWh per year
• Atchison Renewable Energy Center (Atchison County): 299 MW, acquired by Ameren Missouri in January 2021 as its second wind facility. Atchison County hosts roughly 800 MW of wind, the most of any Missouri county

The Solar Build-Out: Ameren's Rate-Base Sprint

• Split Rail Solar Energy Center (Warren County): 300 MW, in service April 2026 — now the largest solar facility in Missouri
• Huck Finn Renewable Energy Center (Audrain/Ralls Counties): 200 MW, operating since December 2024, part of a 500 MW, roughly $950 million three-project tranche (the other two sit across the river in Illinois)
• Vandalia (Audrain County) and Bowling Green (Pike County): 50 MW each, in service December 2025 and April 2026 respectively

Storage Finally Arrives

Missouri's operating battery fleet is minimal, but that changes in 2028. The Missouri PSC approved Ameren's Big Hollow Energy Center in Jefferson County on February 11, 2026 — 400 MW of batteries paired with 800 MW of natural gas, billed as the state's first large-scale battery storage facility at a single site. Ameren plans 1,000 MW of batteries by 2030 and 1,800 MW by 2042. That gas pairing is the SB 4 era in miniature: storage gets built, but as a rider on dispatchable steel.

Siting: 114 Counties, No Statewide Rules, One Near-Miss Moratorium

Missouri has no statewide siting board and no uniform permitting law for utility-scale wind and solar. Requirements differ across 114 counties and more than 900 municipalities, many rural counties lack countywide zoning entirely, and there are no statewide setback standards — every project negotiates its own local reality. Investor-owned utility projects need a certificate of convenience and necessity from the PSC (with SB 4's streamlined review arriving in August 2027 for projects in an approved IRP), while merchant projects face county-level review wherever zoning exists. Cass County's dedicated solar zoning regulations, drafted in May 2024, are one example of the county-level rulebooks developers now navigate. Track the county-by-county fights on our Missouri opposition tracker.

SB 849: The Moratorium That Almost Happened

The 2026 session produced the most aggressive anti-solar bill any state has seriously advanced. SB 849, from Senate President Pro Tem Cindy O'Laughlin (R-Shelbina), would have imposed an immediate statewide moratorium on new and ongoing commercial-scale solar construction until December 31, 2027 — or until the Missouri DNR issued statewide siting rules — complete with an emergency clause. Law firm BCLP warned clients it was a first-in-the-nation risk for utilities, lenders, and investors. The bill cleared the Senate Commerce Committee on a Do Pass vote February 10, 2026, then stalled on the Senate's informal calendar and died when the session adjourned May 15, 2026. Companion efforts — a similar moratorium from Sen. Sandy Crawford and a regulation bill from Sen. Travis Fitzwater requiring county commission approval and solar acreage caps — also failed. Expect all of it back in 2027.

The moratorium fight exposed a genuine split in rural Missouri. At February 2026 Senate hearings, Callaway County residents testified about noise, dust, and glare from a nearby utility-scale solar project, while farmers who lease land for solar income lined up against the freeze — a divide that separated Farm Bureau-aligned senators from their own constituents. The economics are not trivial: clean energy projects pay Missouri landowners $29.5 million a year in lease payments and $28.1 million in state and local taxes.

Eminent Domain and the Grain Belt Express

Transmission is Missouri's highest-profile energy land fight. Invenergy's Grain Belt Express — a 5 GW, 800-mile HVDC line from Kansas across Missouri to Illinois — holds PSC approval and filed dozens of eminent domain petitions in Missouri in February 2025, prompting the state's attorney general to call it "a multi-billion-dollar green energy scam." DOE canceled its $4.9 billion conditional loan guarantee on July 23, 2025, but Invenergy says it will proceed on private financing, having awarded $1.7 billion in construction contracts to Quanta Services and Kiewit in May 2025, with Kansas-Missouri construction expected to begin in 2026 and operations in late 2029. The backlash has legislative legs: the Missouri House voted 115-27 in May 2024 to ban eminent domain for wind and solar facilities (HB 1750), and though that bill never became law, successors like 2025's HB 457 keep returning.

The Demand Shock: Data Centers Rewrite the Load Forecast

Missouri's utilities spent a decade planning for flat load. That era ended abruptly. Ameren Missouri signed confidential contracts with multiple large data centers totaling 2.2 GW of new demand in February 2026 — nearly the output of Labadie, its largest coal plant. The average size of a new project seeking service has ballooned from 3.2 MW in 2019 to 181.2 MW, and data centers had already paid Ameren $28 million in study and deposit fees by October 2025. The marquee name is Google, which announced $15 billion of Missouri infrastructure investment on May 20, 2026, including a new data center in New Florence and a pledge to bring more than 1 GW of new generation capacity to the state — over 500 MW of it under a Capacity Commitment Framework with Ameren.

On the SPP side, Evergy reported 2.5 GW of signed large-load agreements in May 2026, including data centers for Meta and Google, plus 450 MW more under contract with customers like Panasonic's EV battery plant; Meta's roughly $1 billion Kansas City data center is already online. Evergy expects retail sales to grow 7-8% per year through 2030. But note how it plans to serve that growth: 4.7 GW of new gas-fired generation by 2044, cancellation of earlier plans for 2.4 GW of wind, and a cut in planned solar additions from 2,415 MW to just 465 MW — citing reduced federal tax credit eligibility, higher costs, and local permitting challenges. Missouri is a live case study in what happens when the federal tax-credit phase-down meets a hostile siting map: the load growth gets served either way, but by gas.

SB 4's large-load tariff framework is doing real work here. Ameren and Evergy filed tariffs for customers over 100 MW designed to keep data-center costs off other ratepayers — the approved Ameren tariff requires 12-to-17-year contracts, collateral equal to two years of minimum bills, and 80% minimum monthly demand charges. Google says it pays 100% of the power it uses and covers the infrastructure costs its operations drive.

Challenges & Outlook

The near-term buildout is already on the books, and most of it burns gas: Ameren's 800 MW Castle Bluff simple-cycle plant in 2027, Big Hollow's 800 MW of gas plus the 400 MW battery in 2028, and a combined-cycle plant targeted for 2031. Ameren's earlier announcements pointed to 2,800 MW of renewables by 2030 and 4,700 MW by 2036 — roughly $9.5 billion of potential investment — but gas and batteries now lead the near-term plan, and SB 4's watt-for-watt rule guarantees renewables cannot substitute for retiring coal on paper even where they could on the grid.

Still, the bear case has limits. Solar capacity nearly tripled in a year, Missouri ranks 23rd nationally with 4,039 MW of operating clean capacity and $8 billion invested, and the demand story is the strongest in the state's modern history. The open questions for developers are structural: whether the legislature revives the SB 849 moratorium push in 2027, whether anyone fixes the post-Springfield Solar 1 property-tax gap, and whether merchant projects like Show Me State Solar can scale in a market where the highest-profile new solar is utility rate-base. Missouri will build a lot of generation this decade. How much of it is clean is still being decided — county by county, and session by session.

Frequently Asked Questions