Midwest Energy Emissions Corp v. Ameren Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Midwest Energy Emissions Corp. (Delaware)
  • Defendant: Ameren Corp. and Union Electric Co. (d/b/a Ameren Missouri) (Missouri)
  • Plaintiff’s Counsel: Simon Law Firm, P.C.
• Case Identification: 4:24-cv-00980, E.D. Mo., 07/17/2024
• Venue Allegations: Venue is alleged to be proper as Defendants are incorporated and reside in the district, maintain regular and established places of business, and commit the alleged acts of infringement at specific, identified energy centers within the district.
• Core Dispute: Plaintiff alleges that Defendants' operation of coal-fired power plants infringes five patents related to methods for removing mercury from flue gas emissions.
• Technical Context: The technology addresses the removal of mercury, a toxic pollutant, from the emissions of coal-fired power plants to comply with environmental regulations.
• Key Procedural History: The complaint references a prior lawsuit in the District of Delaware against refined coal producers ("CERT"), which concluded on March 1, 2024, with a jury finding of willful contributory and induced infringement of two of the patents-in-suit ('114 and '517). The complaint alleges this verdict implicitly found direct infringement by power plants supplied by CERT, including certain of Defendants' facilities.

Case Timeline

Date	Event
2004-08-30	Earliest Priority Date for all Patents-in-Suit
2016-12-31	General compliance deadline for EPA's MATS rule
2019-07-09	U.S. Patent No. 10,343,114 Issues
2019-07-31	Plaintiff files related infringement suit in Delaware
2020-03-17	U.S. Patent No. 10,589,225 Issues
2020-03-24	U.S. Patent No. 10,596,517 Issues
2020-06-02	U.S. Patent No. 10,668,430 Issues
2021-02-05	Plaintiff alleges it contacted Defendants to negotiate
2021-03-02	U.S. Patent No. 10,933,370 Issues
2021-08-31	Plaintiff serves subpoena on Defendant Union Electric Co
2021-12-31	Refined Coal Tax Credit program expires
2024-03-01	Jury verdict finds infringement in Delaware litigation
2024-07-17	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,343,114 - "Sorbents for the Oxidation and Removal of Mercury" (issued July 9, 2019)

The Invention Explained

• Problem Addressed: The patent's background describes the challenge of removing mercury from the flue gas of coal-fired power plants, noting that existing sorbents like activated carbon are often "relatively unreactive toward mercury," must be used in large amounts, and can contaminate the collected fly ash, preventing its commercial use ('114 Patent, col. 2:10-19).
• The Patented Solution: The invention is a method using a "halogen/halide-promoted sorbent" to more effectively capture mercury ('114 Patent, col. 3:36-40). A base sorbent, such as activated carbon, is treated with a promoter like a halogen or halide (e.g., bromine). This process creates highly reactive sites on the sorbent surface that can efficiently oxidize elemental mercury into a form that is more easily captured, thereby reducing the amount of sorbent needed ('114 Patent, col. 3:52-col. 4:21).
• Technical Importance: This approach was developed to provide a more economical and efficient solution for power plants to meet increasingly stringent federal environmental regulations, such as the EPA's Mercury and Air Toxics Standards (MATS) (Compl. ¶17, 24).

Key Claims at a Glance

• The complaint asserts claims 1-30, with a focus on independent claim 25 (Compl. ¶74, 76).
• Essential Elements of Claim 25:
  • A method of separating mercury from a mercury-containing gas.
  • Combusting coal in a combustion chamber to provide the mercury-containing gas, wherein either the coal comprises an added bromine-containing substance (Br2, HBr, or a bromide compound) upstream of the chamber, or the combustion chamber itself comprises an added bromine-containing substance.
  • Injecting a sorbent material comprising activated carbon into the gas downstream of the combustion chamber.
  • Contacting mercury in the gas with the sorbent to form a mercury/sorbent composition.
  • Separating the mercury/sorbent composition from the gas to form a cleaned gas.
• The complaint reserves the right to assert dependent claims (Compl. ¶74).

U.S. Patent No. 10,596,517 - "Sorbents for the Oxidation and Removal of Mercury" (issued March 24, 2020)

The Invention Explained

• Problem Addressed: Similar to the '114 Patent, the '517 Patent addresses the inefficiency and high cost of conventional mercury sorbents used in coal combustion facilities, which require high sorbent-to-mercury ratios and can create solid waste disposal problems ('517 Patent, col. 2:11-19).
• The Patented Solution: The patent describes a method for reducing mercury in a gas stream by combusting coal that includes a halogen-based additive to facilitate the oxidation of mercury ('517 Patent, col. 3:5-15). The resulting oxidized mercury is then collected from the gas stream using a sorbent, such as activated carbon, that is added to the gas ('517 Patent, col. 4:9-15). This two-part chemical process (oxidation via additive followed by capture via sorbent) is designed to improve mercury removal efficiency.
• Technical Importance: The method aims to enable power plants to meet regulatory requirements for mercury emissions more effectively and economically than prior art methods (Compl. ¶17, 22).

Key Claims at a Glance

• The complaint asserts claims 1-30, with a focus on independent claim 1 (Compl. ¶94, 96).
• Essential Elements of Claim 1:
  • A method for reducing mercury in a mercury-containing gas.
  • Combusting coal in a combustion chamber, where the coal comprises an additive (Br2, HBr, a bromide compound, or a combination thereof), to form the mercury-containing gas.
  • Collecting mercury from the gas with a sorbent comprising activated carbon that is added to the gas.
• The complaint reserves the right to assert dependent claims (Compl. ¶94).

U.S. Patent No. 10,589,225 - "Sorbents for the Oxidation and Removal of Mercury" (issued March 17, 2020)

• Technology Synopsis: The patent describes a method for treating a mercury-containing gas by combusting a mixture that includes coal, pyrolysis char, and a halogen-based additive (such as HBr or a bromide compound). A particulate sorbent comprising activated carbon is then added to the resulting gas to capture the mercury ('225 Patent, Abstract; Claim 1).
• Asserted Claims: At least one of claims 1-29, with claim 1 identified as exemplary (Compl. ¶110, 112).
• Accused Features: The process of combusting coal with an additive and adding a sorbent containing activated carbon at Defendants' power plants (Compl. ¶115, 117).

U.S. Patent No. 10,668,430 - "Sorbents for the Oxidation and Removal of Mercury" (issued June 2, 2020)

• Technology Synopsis: The patent describes a method of separating mercury from a gas stream. The method involves combusting coal with a pre-added halogen additive (such as Br2 or HBr) or adding the halogen additive into the combustion chamber itself. A sorbent comprising activated carbon is then injected downstream to contact and capture the mercury, which is subsequently separated from the gas ('430 Patent, Abstract; Claim 1).
• Asserted Claims: At least one of claims 1-29, with claim 1 identified as exemplary (Compl. ¶126, 128).
• Accused Features: The process of combusting coal with a halogen additive and injecting an activated carbon sorbent downstream at Defendants' power plants (Compl. ¶131, 133).

U.S. Patent No. 10,933,370 - "Sorbents for the Oxidation and Removal of Mercury" (issued March 2, 2021)

• Technology Synopsis: The patent describes a method for separating mercury from gas by combusting a mixture of coal and a halogen-based additive. A key feature of the asserted claim is the addition of a particulate sorbent (activated carbon) in a specific weight ratio relative to the amount of additive used, specified as between 1:100 to 30:100 ('370 Patent, Claim 1).
• Asserted Claims: At least one of claims 1-29, with claim 1 identified as exemplary (Compl. ¶146, 148).
• Accused Features: The process of combusting coal with a halogen additive and adding a particulate sorbent at Defendants' plants, which allegedly satisfies the claimed weight ratio (Compl. ¶151, 153).

III. The Accused Instrumentality

Product Identification

• The methods for mercury removal employed at Defendants' coal-fired power plants, specifically identified as the Labadie Energy Center, the Rush Island Energy Center, and the Sioux Energy Center ("Accused Coal Plants") (Compl. ¶42, 52).

Functionality and Market Context

• The complaint alleges the Accused Coal Plants perform a multi-step process to comply with federal and state mercury regulations (Compl. ¶77). This process involves: (1) combusting coal in a combustion chamber with an added bromine and/or bromide compound (e.g., Br2, HBr); (2) injecting a sorbent material comprising activated carbon into the flue gas downstream of the combustion chamber; and (3) using equipment such as baghouses or electrostatic precipitators (ESPs) to collect mercury that has become bound to the activated carbon (Compl. ¶43-52). The use of these mercury control technologies was allegedly necessary for regulatory compliance and coincided with a federal tax credit program designed to incentivize emissions reduction (Compl. ¶24-28).
  No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

10,343,114 Infringement Allegations

Claim Element (from Independent Claim 25)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method of separating mercury from a mercury-containing gas	The Accused Coal Plants are alleged to perform this method to comply with mercury regulations.	¶77	col. 3:52-54
combusting coal in a combustion chamber to provide the mercury-containing gas, wherein the coal comprises added Br2, HBr, a bromide compound, or a combination thereof, added to the coal upstream of the combustion chamber, or the combustion chamber comprises added Br2, HBr...	The Accused Coal Plants allegedly burn coal with added bromine-containing compounds and/or add such compounds directly into the combustion chamber.	¶79	col. 16:35-40
injecting a sorbent material comprising activated carbon into the mercury containing gas downstream of the combustion chamber	The Accused Coal Plants allegedly inject activated carbon sorbent downstream of the combustion chamber.	¶81	col. 18:15-25
contacting mercury in the mercury-containing gas with the sorbent, to form a mercury/sorbent composition	Mercury in the flue gas exiting the combustion chamber allegedly contacts the injected sorbent, as both are contained in the same gas stream.	¶83	col. 4:52-54
separating the mercury/sorbent composition from the mercury-containing gas, to form a cleaned gas	The Accused Coal Plants allegedly use equipment such as baghouses or electrostatic precipitators to collect the sorbent with captured mercury from the flue gas.	¶85	col. 2:3-9

10,596,517 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method for reducing mercury in a mercury-containing gas	The Accused Coal Plants allegedly perform this method to comply with mercury regulations.	¶97	col. 3:5-6
combusting coal in a combustion chamber, the coal comprising an additive comprising Br2, HBr, a bromide compound, or a combination thereof, to form the mercury-containing gas	The Accused Coal Plants allegedly combust coal with an additive comprising Br2, HBr, a bromide compound, or a combination thereof.	¶99	col. 16:35-40
collecting mercury in the mercury-containing gas with a sorbent added to the mercury-containing gas, the sorbent comprising activated carbon	The Accused Coal Plants allegedly add an activated carbon sorbent to the gas exiting the combustion chamber and collect the mercury.	¶101	col. 18:15-25

Identified Points of Contention

• Scope Questions: The term "bromide compound" appears in the asserted claims of multiple patents. The dispute may focus on whether the specific chemical additives used by Defendants fall within the legal construction of this term. A potential point of contention could also be the interpretation of claim language distinguishing between an additive "added to the coal upstream of the combustion chamber" and one that "the combustion chamber comprises" ('114 Patent, Claim 25), as this could affect where and how infringement occurs.
• Technical Questions: A primary evidentiary question will be what proof Plaintiff offers that Defendants' operational processes at the Accused Coal Plants meet every limitation of the asserted claims. The complaint's allegations appear to be based, in part, on inferences from the Delaware litigation against a supplier (CERT) (Compl. ¶41). The factual connection between CERT's activities and the specific, day-to-day operations inside Defendants' power plants will be a central area of inquiry.

V. Key Claim Terms for Construction

The Term: "bromide compound" ('114 Patent, Claim 25; '517 Patent, Claim 1)

Context and Importance

• The core of the infringement allegation is that Defendants combust coal with an "added" halogen substance. The definition of "bromide compound" is critical, as Defendants' liability depends on whether the specific additives they use are found to fall within the scope of this term. Practitioners may focus on this term because it directly maps to the accused instrumentality.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The specifications provide a non-exhaustive list of promoters, including "molecular halogens, Group V...halides, Group VI halides, hydrohalides, and combinations thereof" ('114 Patent, col. 4:28-32). This suggests the term is meant to be inclusive of a variety of chemical structures containing bromine.
• Evidence for a Narrower Interpretation: The claims specifically list "Br2" and "HBr" alongside "a bromide compound." A defendant might argue that under principles of claim differentiation or ejusdem generis, the general term "bromide compound" should be construed as limited to compounds of a similar class or simplicity as the specifically enumerated examples.

The Term: "added" ('114 Patent, Claim 25; '517 Patent, Claim 1)

Context and Importance

• This term's construction is important for determining the infringing act. It raises the question of whether infringement requires the power plant operator to perform the physical step of adding the substance, or if using coal that was pre-treated by a third party also constitutes infringement. This could distinguish direct infringement from indirect infringement theories.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The patent's focus is on the resulting chemical composition of the combusted fuel, not necessarily on who performs the act of addition. Language describing the coal "comprising an additive" ('517 Patent, Claim 1) could support a reading where the state of the coal is what matters, not the actor.
• Evidence for a Narrower Interpretation: The specification describes various methods for introducing the promoter, such as in-flight injection into the flue gas stream or reacting it with the base sorbent ('114 Patent, col. 6:1-10; col. 5:1-5). These descriptions of active processes could support an argument that "added" implies an action performed as part of the patented method itself.

VI. Other Allegations

Indirect Infringement

• The complaint alleges that parent company Ameren Corp induces its subsidiary Union Electric to infringe. The alleged basis for inducement includes Ameren's exercise of control over Union Electric, provision of technical and financial services, shared executives, and participation in the "supply contract process for activated carbon and bromine-containing additives" (Compl. ¶55-58, 87, 103).

Willful Infringement

• Willfulness is alleged based on pre-suit knowledge of the patents and the infringing conduct. The complaint alleges that Defendants knew or should have known of their infringement based on: (1) direct contact from Plaintiff on February 5, 2021, to negotiate a license; (2) a subpoena served on Union Electric in August 2021 related to the Delaware litigation against its supplier; and (3) general due diligence that would have uncovered Plaintiff's patent portfolio (Compl. ¶62, 64, 65-67).

VII. Analyst’s Conclusion: Key Questions for the Case

• A core issue will be one of evidentiary proof: What direct evidence will Plaintiff provide to demonstrate that the specific operational methods and chemical inputs used at each of the three Accused Coal Plants satisfy every limitation of the asserted claims? The case will likely test the extent to which findings of indirect infringement against a supplier in a prior case can be used to establish direct infringement by that supplier's customer in a subsequent case.
• A key legal question will be one of willfulness: Given the allegations of multiple pre-suit contacts, including a subpoena related to prior litigation, the dispute will likely focus heavily on the timing and nature of Defendants' knowledge. The analysis will turn on whether Defendants' continued operations after these alleged notice events constituted objective recklessness.
• The case may also hinge on a question of definitional scope: Can the term "bromide compound," as used in the patents, be construed to cover the specific additives allegedly used by Defendants? The outcome of claim construction for this and other key terms will be critical in defining the boundaries of infringement.