Missouri Commercial Electricity: Ameren, Evergy, and Market Realities
Missouri's regulated electricity market is split between Ameren Missouri (St. Louis) and Evergy (Kansas City). In 2026, both utilities are executing rate cases before the Missouri PSC, driven by coal retirement costs and grid modernization capital. Commercial buyers have zero competitive supply options—cost control requires tariff optimization and demand management.
Executive Impact
- →The Bifurcated Wholesale Grid: Missouri is split between two distinct Regional Transmission Organizations (RTOs). Ameren Missouri operates in the Midcontinent ISO (MISO), which faces severe baseload capacity shortage warnings. Conversely, Evergy operates within the Southwest Power Pool (SPP), which boasts massive wind capacity but intense transmission congestion.
- →The Cost of the Coal Exit: Ameren's accelerated retirement of facilities like the Rush Island Energy Center creates a double-penalty for ratepayers: businesses must pay the un-depreciated "stranded asset" costs of the shuttered coal plant while concurrently funding the construction of the wind farms built to replace it.
- →Fuel Adjustment Clause (FAC) Dominance: Despite the push for renewables, both grids remain heavily dependent on dispatchable natural gas. The PSC generously grants Fuel Adjustment Clause riders, meaning volatile spikes in Henry Hub spot prices are passed immediately to commercial invoices with absolute 100% precision.
Combating Rate Inflation in a Regulated Market
Because businesses in Missouri cannot utilize market leverage to shop competitive block-and-index products, specialized tariff engineering and regulatory action form the core of commercial procurement strategy.
- Tariff Forensics and Re-classification: Missouri IOUs offer dozens of highly nuanced rate subclasses (e.g., Large General Service, Primary Metering, Large Power Service). Utilities rarely proactively place growing facilities on the cheapest available rate. Detailed engineering audits frequently discover that by absorbing the cost of a primary transformer directly, massive industrial sites can shift to "High Voltage" tariffs, generating immediate 8-12% annual savings.
- Interruptible Load and Demand Response: Because Ameren faces critical MISO capacity constraints, they pay huge premiums for dispatchable load relief. Manufacturing facilities that agree to curtail (shut down) operations during the 4 or 5 hottest summer hours of the year can negotiate specialized interruptible tariffs that slash their monthly peak demand charges systematically across the entire year.
- Aggressive Legal Intervention: The only mechanism to block rising Ameren and Evergy margins is direct intervention at the Missouri PSC. A single major rate case can lock in a decade of higher corporate costs. Industrial user groups must pool capital to legally challenge excessive utility Return on Equity (ROE) assumptions, demanding that rate classes are subsidized fairly rather than shifting the financial burden onto industrial corridors.
Targeting Corporate ESG: Green Tariffs
Missouri heavily restricts third-party corporate PPAs. To keep major corporate tenants who demand Scope 2 emissions compliance, both Ameren (via its Renewable Choice Program) and Evergy are expanding localized "Green Tariffs." These programs allow massive commercial users to subscribe to blocks of newly developed in-state solar generation, effectively achieving carbon neutrality without building risky, behind-the-meter generation assets.