Midwest Energy Emissions Corp. et al. v. Ameren Corp. et al.

This patent infringement litigation, Midwest Energy Emissions Corp. et al. v. Ameren Corp. et al., involves plaintiff Midwest Energy Emissions Corp. (now operating as Birchtech Corp.) and defendants Ameren Corp. and its subsidiary Union Electric Co. Birchtech Corp. functions as an environmental technology firm that specializes in patented "Sorbent Enhancement Additive" (SEA®) technologies for mercury emissions capture in the coal-fired utility sector, and is also developing water purification technologies. In the context of this and related litigations, Birchtech Corp. acts as a patent assertion entity (PAE), actively enforcing its intellectual property rights against numerous utility companies through lawsuits and seeking licensing agreements. Conversely, Ameren Corp. is a major American power company, serving as a holding company for various electric and natural gas utilities in Missouri and Illinois. Its subsidiary, Union Electric Co. (doing business as Ameren Missouri), is the largest electric utility in Missouri, providing services across central and eastern parts of the state.

The core of the dispute centers on the defendants' alleged infringement of Birchtech's patented mercury emissions reduction technologies at their coal-fired power plants. The specific patent at issue in this case is US Patent 10933370, which generally pertains to operational practices for coal plant exhaust systems, including methods for capturing mercury pollution using a combination of halogen additives and activated carbon. The plaintiff asserts that Ameren and Union Electric Co. have been utilizing these patented technologies without a license.

Filed initially in the Missouri Eastern District Court (4:24-cv-00980), the case was centralized on December 12, 2024, into Multi-District Litigation (MDL) No. 3132 in the Southern District of Iowa, where it is overseen by Judge Stephen H. Locher. This centralization is a significant procedural development, aimed at streamlining the numerous related patent infringement lawsuits filed by Birchtech against various power plant operators across different states. The MDL process is intended to prevent duplicative discovery, avoid inconsistent pretrial rulings (particularly concerning claim construction and patent validity), and efficiently manage the litigation by consolidating common factual questions.

This case is notable as part of Birchtech's broader and aggressive patent enforcement campaign within the coal-fired utility industry. The company has a history of successful patent litigation, including securing a $57 million jury verdict (which later increased to approximately $78 million with interest) in March 2024 against other defendants in a Delaware district court for willful infringement of its mercury-capture technologies. Birchtech actively seeks to convert unlicensed users of its technologies into licensees, highlighting its business model as a patent holder seeking to monetize its intellectual property. The consolidation into an MDL underscores the widespread impact of Birchtech's assertion patterns on the energy sector and means that the MDL court's rulings, especially on claim construction, will have far-reaching implications for all consolidated defendants.

Midwest Energy Emissions Corp. (now Birchtech Corp.) initiated a patent infringement lawsuit against Ameren Corp. and Union Electric Co. concerning U.S. Patent 10,933,370. This case, originally filed in the Eastern District of Missouri, was subsequently centralized as part of a larger Multidistrict Litigation (MDL).

Here's a chronological breakdown of the key legal developments and the current posture of the case:

1. Filing & Initial Pleadings

• Complaint Filed (2024-07-30): Midwest Energy Emissions Corp. (now Birchtech Corp.) filed its patent infringement complaint against Ameren Corp. and Union Electric Co. in the U.S. District Court for the Eastern District of Missouri, assigned case number 4:24-cv-00980. The asserted patent is US 10,933,370. While the prompt indicates a filing date of July 30, 2024, some docket information suggests a July 17, 2024 filing.
• Details regarding Ameren Corp.'s and Union Electric Co.'s answer or any counterclaims they may have filed prior to the MDL transfer were not immediately available through the provided search results.

2. Pre-trial Motions & Centralization

• Motion to Stay Discovery (2024-11-06): Defendants Ameren Corp. and Union Electric Co. filed a motion to stay discovery, pending a decision from the Judicial Panel on Multidistrict Litigation (JPML) regarding a potential transfer of the case.
• Discovery Stay Granted (2024-11-06): Senior District Judge Catherine D. Perry granted the defendants' motion, staying all discovery in the case pending the JPML's decision.
• MDL Transfer Ordered (2024-12-12): The case was transferred via an MDL transfer order signed by Judge Karen K. Caldwell, Chair of the JPML, to the U.S. District Court for the Southern District of Iowa.
• Consolidation with MDL No. 3132 (2024-12-17): The case was formally consolidated with and became part of MDL No. 3132, "In re Midwest Energy Emissions Corp. Patent Litigation," in the Southern District of Iowa. The lead case for the MDL is 4-24-md-3132-SHL-WPK.

3. Claim Construction (Markman) & Discovery Milestones

• As of May 22, 2026, there is no specific information available regarding a Markman hearing or claim construction order for this particular case within the MDL. Given its recent centralization (December 2024), these proceedings would likely be governed by the MDL's consolidated schedule, which is still in its early stages.
• Discovery was stayed prior to the MDL transfer. Specific discovery milestones post-MDL transfer for this particular case were not found.

4. Trial Events, Verdict, and Post-Trial Motions

• No trial has occurred, nor has a verdict been rendered in Midwest Energy Emissions Corp. et al. v. Ameren Corp. et al.
• (Contextual Note: In a separate, earlier patent infringement lawsuit in the U.S. District Court for the District of Delaware, Birchtech Corp. (then Midwest Energy Emissions Corp.) secured a $57 million jury verdict in March 2024 against other defendants, which later resulted in a final judgment of approximately $78 million by December 2025. This case involved U.S. Patent Nos. 10,343,114 and 10,596,517, not 10,933,370.)

5. Settlement, Dismissal, Judgment, or Appeal

• The case remains active and is currently centralized within MDL No. 3132 in the Southern District of Iowa. While some defendants in other related lawsuits filed by Birchtech have obtained license agreements and been released from the broader Iowa lawsuit, leaving two remaining defendants as of December 2025, it is not clear from available information if Ameren Corp. or Union Electric Co. are among those remaining defendants or if they have reached a separate settlement.

6. Parallel PTAB IPR/PGR Proceedings

• IPRs for US 10,933,370: U.S. Patent 10,933,370, asserted in this litigation, has been challenged in inter partes review (IPR) proceedings. PacifiCorp and MidAmerican Energy Company filed IPR2025-00687 and IPR2025-00688, both challenging claims of US Patent No. 10,933,370. Trial institution was granted in these IPRs, and Birchtech Corp. subsequently filed a request for Director Review of the institution decisions.
• IPR2025-00688 Settlement: IPR2025-00688, specifically, shows a status of "Settlement" as of February 10, 2026, for some petitioners including Wisconsin Power & Light Company, WEC Energy Group, Inc., MidAmerican Energy Company, Interstate Power & Light Company, and PacifiCorp. It was "Not Instituted - Procedural" for others.
• No Direct IPRs by Ameren/Union Electric for 10,933,370 Found: While Union Electric Co. (a defendant in this case) did file IPR2025-01322, it challenged U.S. Patent No. 10,668,430, not U.S. Patent No. 10,933,370. No specific IPRs filed by Ameren Corp. or Union Electric Co. directly challenging U.S. Patent No. 10,933,370 were identified in the search.
• The existence of these IPRs, especially with institutional decisions, could potentially impact the litigation by staying the district court case or influencing claim construction, although no such stay directly attributed to these IPRs on the Ameren case docket was explicitly found beyond the initial MDL transfer stay.

Here is the counsel of record representing the plaintiff(s), Midwest Energy Emissions Corp. and Birchtech Corp., in Midwest Energy Emissions Corp. et al. v. Ameren Corp. et al.:

Lead Counsel (and Patent Licensing Counsel):

• Bradley W. Caldwell (Lead Trial Counsel)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Mr. Caldwell was lead trial counsel for Midwest Energy Emissions Corp. (now Birchtech Corp.) in a Delaware patent infringement case that resulted in a $57 million verdict in March 2024, later increased to approximately $78 million with interest. His firm has served as patent licensing counsel for Midwest Energy since 2018. He has also secured multiple other Top 100 Verdicts in patent infringement cases, including against Apple Inc. and Twitter Inc./X Corp.

• Justin T. Nemunaitis (Principal)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Mr. Nemunaitis was part of the trial team that secured the $57 million patent infringement verdict for Midwest Energy Emissions Corp. in Delaware and is listed as counsel for the plaintiff in the transferred MDL.

• Richard A. Cochrane (Attorney)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Mr. Cochrane was also a vital member of the trial team that secured the $57 million patent infringement verdict for Midwest Energy Emissions Corp. and is listed as counsel for the plaintiff in the transferred MDL and in an IPR filing.

• Daniel R. Pearson (Principal)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Mr. Pearson presented witnesses at the Delaware patent infringement trial for Midwest Energy Emissions Corp.

• Warren J. McCarty, III (Principal)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Mr. McCarty presented witnesses at the Delaware patent infringement trial for Midwest Energy Emissions Corp.

• Adrienne R. Dellinger (Attorney)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Ms. Dellinger played a vital role in the trial team that secured the $57 million patent infringement verdict for Midwest Energy Emissions Corp.

• Aisha Mahmood Haley (Attorney)

  • Firm: Caldwell Cassady & Curry P.C., Dallas, TX
  • Note: Ms. Haley played a vital role in the trial team that secured the $57 million patent infringement verdict for Midwest Energy Emissions Corp.

Local Counsel:

• Jeremiah W. Nixon

  • Firm: The Simon Law Firm PC
  • Note: Listed as counsel for Midwest Energy Emissions Corp. in the PacerMonitor entry for the MDL-transferred case.

• Anthony G. Simon

  • Firm: The Simon Law Firm PC
  • Note: Listed as counsel for Midwest Energy Emissions Corp. in the PacerMonitor entry for the MDL-transferred case.

Other Counsel Mentioned (Role not specified as lead, local, or of counsel in search results but listed as part of Caldwell Cassady & Curry P.C. for plaintiff):

• Austin Curry
  • Firm: Caldwell Cassady & Curry P.C.
  • Note: Listed as counsel for Midwest Energy Emissions Corp. in the PacerMonitor entry for the MDL-transferred case.

The case, originally filed in the Eastern District of Missouri, was centralized as part of MDL No. 3132 in the Southern District of Iowa.

The following counsel represent the defendant(s) Ameren Corp. and Union Electric Co. in this patent infringement case:

Richard Bennett Walsh, Jr.

• Role: Lead Counsel
• Firm: Thompson Coburn LLP, St. Louis, MO
• Experience Note: Mr. Walsh's firm, Thompson Coburn LLP, has an intellectual property practice with attorneys experienced in patent litigation at both trial and appellate court levels, and in strategic planning of patent infringement suits, as well as post-grant proceedings before the USPTO. The firm's attorneys have experience across various technical disciplines including electrical, mechanical, chemical engineering, biotechnology, and software.

Robert M. Evans, Jr.

• Role: Lead Counsel
• Firm: Thompson Coburn LLP, St. Louis, MO
• Experience Note: Mr. Evans is associated with Thompson Coburn LLP, a firm known for its intellectual property litigation practice that handles patent infringement, ownership, and validity cases in federal district and appellate courts nationwide, as well as before the Patent Trial and Appeal Board.

In-house Counsel (Ameren Corp.)
Ameren Corporation has an in-house legal department. David M. Feinberg was appointed Executive Vice President, General Counsel and Corporate Secretary in November 2025. While Ameren has in-house counsel, specific in-house attorneys dedicated to this particular patent litigation have not been identified in the public docket information. In-house counsel often manage litigation processes by coordinating with external counsel and overseeing case strategy.

Note: While searches returned information about UB Greensfelder LLP as a firm with patent litigation experience and offices in St. Louis, the provided docket information does not explicitly link them as counsel of record for the defendants in Midwest Energy Emissions Corp. et al. v. Ameren Corp. et al. (4:24-cv-00980).