Three Utility IRPs Land With Battery Storage Front and Center

Ameren Missouri, DTE Energy in Michigan and Black Hills Energy in Colorado have each recently filed integrated resource plans with state regulators that highlight battery energy storage system additions, according to Energy Storage News.

Three US utilities operating in three different state regulatory regimes have filed long-range supply plans that put battery energy storage systems near the top of the build list. Ameren Missouri, DTE Energy in Michigan and Black Hills Energy in Colorado each recently submitted integrated resource plans, or IRPs, with highlighted BESS project additions, as reported by Energy Storage News.

An IRP is the document a regulated utility files with its state commission setting out how it intends to meet customer demand over a planning horizon that typically runs a decade or two. It is not a purchase order. It is a ranked argument about which mix of generation, storage, transmission and demand-side measures produces reliable service at the lowest reasonable cost, and it is the document against which every subsequent request to spend money gets measured. When batteries move from a footnote in an appendix to a highlighted portion of the plan, that is a signal about what the utility intends to ask permission to build.

Why the filing venue matters more than the press release

The reason these three filings are worth grouping together is that they come from unrelated utilities answering to separate commissions in Missouri, Michigan and Colorado. Storage economics that clear the bar in a Colorado proceeding are not automatically transferable to Missouri, where resource adequacy accounting, capacity accreditation rules and the local wholesale market construct all differ. When the same technology shows up as a headline item in three unconnected dockets at roughly the same moment, the more plausible explanation is that the underlying cost and performance case has improved broadly rather than that one regulator has been unusually receptive.

Batteries have earned that position by doing several jobs at once. They shift solar output into the evening peak, provide fast-responding reserve capacity, defer transmission and distribution upgrades in constrained pockets of the system, and — critically for planners — can be sited and energized on timelines far shorter than a thermal plant or a major line. For a utility facing load growth it did not forecast five years ago, speed to service is itself a resource.

What an IRP does to the rate base

For investors, the mechanics are straightforward even when the megawatt totals are not yet public. A regulated utility earns an authorized return on the prudently incurred capital it puts into service — its rate base. Storage that is owned rather than contracted through a power purchase agreement lands on the balance sheet and, once approved and in service, becomes earning capital. An IRP that leans on utility-owned BESS is therefore a forward indicator of capital expenditure, and capital expenditure is the engine of earnings growth in this sector.

The offsetting consideration is the customer bill. Commissions weigh storage against alternatives that may be cheaper per unit of energy but slower or less flexible, and against the option of buying capacity from third parties instead of owning it. Approval of an IRP is not approval to spend; certificates, competitive solicitations and prudence reviews all sit between the plan and the meter. The filings tell you what each utility wants to do, and where the argument will be had.

How the three stocks closed before the filings drew attention

All three parent companies finished the most recent session higher, in a broad tape that was mixed. As of the last trade at 20:00 GMT on 29 September 2026, AEE closed at 100.25, up 0.87% from a previous close of 99.39, having traded between 98.75 and 100.62 on the day. DTE closed at 122.39, up 1.29% from 120.83, with a day range of 119.68 to 122.91 — the strongest single-day move of the three. BKH closed at 70.27, up 0.77% from 69.73, in a range of 69.18 to 70.52. The currency of quotation is not specified in the data supplied.

Those gains came against a benchmark that slipped. The S&P 500 tracker SPY closed at $764.20, down 0.18% from $765.61, while the Dow 30 proxy DIA fell 0.22% to $512.88. The Nasdaq 100 tracker QQQ was the exception, up 0.19% to $737.93. A single session proves nothing about the reception of a regulatory filing, but the direction is at least consistent with the defensive bid that regulated utilities tend to attract when the broad index is soft.

What to watch as the dockets progress

The substance of these plans will emerge in the procedural record rather than in the filing-day coverage. Several things are worth tracking:

• Stated capacity and duration. Storage is measured in both power (MW) and energy (MWh). A four-hour system does a different job from a two-hour system, and the ratio between the two numbers tells you what the utility thinks it is solving for.
• Ownership structure. Utility-owned assets grow the rate base; contracted capacity does not. This is the single most consequential detail for equity holders.
• Intervenor positions. Consumer advocates, industrial customer groups and environmental intervenors will each test the modeling assumptions that produced the storage selection, particularly capacity accreditation and assumed installed costs.
• Load forecast drivers. If data center or electrification demand underpins the plan, the durability of that forecast becomes the central contested question.
• Interconnection and supply chain timing. A plan that assumes rapid deployment depends on queue positions and cell availability that sit outside the utility's control.

The through-line is that battery storage has stopped being the experimental line item in these documents. Three utilities in three states, filing independently, have put it in the foreground. Whether the megawatts survive contact with three separate commissions is the part that has not been decided yet.

Key facts

• Utilities filing: Ameren Missouri, DTE Energy (Michigan), Black Hills Energy (Colorado)
• AEE last close: 100.25, +0.87%, as of 20:00 GMT 29 Sep 2026
• DTE last close: 122.39, +1.29%, as of 20:00 GMT 29 Sep 2026
• BKH last close: 70.27, +0.77%, as of 20:00 GMT 29 Sep 2026

Frequently asked questions

What is an integrated resource plan?

An integrated resource plan, or IRP, is a long-range supply plan a regulated utility files with its state public utility commission. It sets out how the company intends to meet forecast customer demand over a planning horizon using generation, storage, transmission and demand-side measures, and it explains why the chosen mix is the lowest reasonable cost option available.

Which utilities filed the plans highlighting battery storage?

Ameren Missouri, DTE Energy in Michigan and Black Hills Energy in Colorado each recently submitted integrated resource plans that highlight battery energy storage system additions. The three utilities are unrelated and answer to three separate state regulatory commissions, so the filings were made independently of one another.

Does filing an IRP mean the batteries will definitely be built?

No. An IRP is a planning document, not a spending authorization. Between an approved plan and an operating asset sit competitive solicitations, siting and certificate proceedings, interconnection queue positions, equipment procurement and prudence review. Regulators can accept a plan in principle while later rejecting or modifying specific projects proposed under it.

Why does utility-owned storage matter to shareholders?

A regulated utility earns an authorized return on the prudently incurred capital it places in service, known as the rate base. Storage the utility owns outright is added to that rate base and becomes earning capital. Capacity bought from a third party under contract is an operating cost instead, so it does not drive earnings growth the same way.

How did the three stocks perform in the most recent session?

As of the last trade at 20:00 GMT on 29 September 2026, AEE closed at 100.25, up 0.87%; DTE closed at 122.39, up 1.29%; and BKH closed at 70.27, up 0.77%. All three rose while the S&P 500 tracker SPY fell 0.18% to $764.20 and the Dow proxy DIA fell 0.22%.

What is the difference between MW and MWh for a battery system?

Megawatts measure how much power a battery can deliver at one instant; megawatt-hours measure how much energy it can store in total. Dividing energy by power gives duration. A four-hour system can cover a long evening peak, while a two-hour system is better suited to short reliability events and fast-response services.

Sources

• US utilities Ameren Missouri, DTE Energy in Michigan, and Black Hills Energy in Colorado submit IRPs with highlighted BESS additions — Energy Storage News

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