Sec Form 3 Filing - Figueira de Chaves Frederico @ Fusion Fuel Green PLC - 2026-03-18

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Figueira de Chaves Frederico 2. Issuer Name and Ticker or Trading Symbol Fusion Fuel Green PLC [ HTOO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Interim CFO (Last) (First) (Middle) C/O FUSION FUEL GREEN PLC, 9 PEMBROKE STREET UPPER 3. Date of Earliest Transaction (MM/DD/YY) 03/18/2026 (Street) DUBLIND02 KR83 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Ordinary Shares 6,352 I Held by Key Family Holding Investimentos e Consultoria de Gestao, Ltd

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Share Option (Right to Buy) $ 367.5 ( 1 ) 01/01/2029 Class A Ordinary Shares 5,715 D Share Option (Right to Buy) $ 4.53 ( 2 ) 10/09/2032 Class A Ordinary Shares 400,000 D Restricted Share Units $ 0 08/18/2021 ( 3 ) Class A Ordinary Shares 143 D Restricted Share Units $ 0 05/10/2024 ( 3 ) Class A Ordinary Shares 286 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Figueira de Chaves Frederico C/O FUSION FUEL GREEN PLC 9 PEMBROKE STREET UPPER DUBLIND02 KR83 X Interim CFO Signatures /s/ Frederico Figueira de Chaves 03/18/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Vested equally over three years. ( 2 )Vests in three equal installments on December 31, 2025, December 31, 2026, and December 31, 2027. ( 3 )Does not expire.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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