FOR IMMEDIATE RELEASE

OPAL Fuels LLC Announces Joint Venture with GFL

Environmental Inc. to Develop New RNG Facilities

New projects to produce 3 million MMBtu of pipeline quality RNG annually

WHITE PLAINS, N.Y. – (December 14, 2021) – OPAL Fuels LLC, a leading vertically integrated producer and distributor of renewable natural gas (RNG), today announced a 50/50 joint venture with GFL Renewables LLC, an affiliate of GFL Environmental Inc. (NYSE: GFL) (“GFL”), the fourth largest diversified environmental services company in North America, to develop new RNG production facilities in the United States.

The JV agreement will include the development, construction, and operation of two new RNG production facilities, which will capture methane emissions from landfill facilities owned and operated by GFL. These methane emissions will then be converted into clean, renewable energy for use as a transportation fuel for heavy-duty trucking fleets.

Adam Comora, co-CEO of OPAL Fuels said, “OPAL Fuels is extremely excited to be a part of this joint venture with industry leader GFL on these RNG facilities. This is truly a win-win scenario as we are able to close the loop on methane emissions from GFL’s landfill facilities from its capture, processing, delivery and utilization as RNG in their fleet to replace diesel.” Comora continued, “We look forward to other potential development opportunities with GFL to assist them in unlocking value within their business and advancing their sustainability goals.”

Patrick Dovigi, Chairman, President and CEO of GFL Environmental noted, “The development of these new RNG facilities is the first step in our stated goal of unlocking the value of RNG within our business operations while also significantly advancing our own internal sustainability goals. We are excited to enter into this joint venture with OPAL Fuels.”

The first new project, located in Michigan, is expected to produce 2 million MMBtu of pipeline quality RNG each year. This will be one of the largest RNG projects in the country based on volume of landfill gas. The project is expected to begin commercial operations in early 2023. The second project, located in North Carolina, is expected to produce more than 1 million MMBtu of RNG annually with anticipated commercial operations beginning in mid-2023. For these projects, OPAL Fuels will be responsible for overseeing the development, construction, and operation of these facilities as well as marketing the RNG. OPAL Fuels also currently operates an RNG facility located at a GFL landfill site in Pennsylvania that produces approximately 890,000 MMBtu of RNG per year.

About OPAL Fuels LLC

OPAL Fuels LLC, a FORTISTAR portfolio company, is a leading vertically integrated renewable fuels platform involved in the production and distribution of renewable natural gas (RNG) for the heavy-duty truck market. RNG is a proven ultra-low carbon fuel that is rapidly decarbonizing the transportation industry now while also significantly reducing costs for fleet owners. OPAL Fuels captures harmful methane emissions at the source and recycles the trapped energy into a commercially viable, low-cost alternative to diesel fuel. OPAL Fuels also develops and constructs RNG fueling stations. As a producer and distributor of carbon-reducing fuel for heavy-duty truck fleets for over 15 years, the company delivers best-in-class, complete renewable solutions to customers and production partners. To learn more about OPAL Fuels and how it is leading the effort to capture North America’s harmful methane emissions and decarbonize the transportation industry, please visit www.opalfuels.com and follow the company on LinkedIn and Twitter at @OPALFuels.

OPAL Fuels also previously announced an agreement for a business combination with ArcLight Clean Transition Corp. II (Nasdaq: ACTD), which is expected to result in OPAL Fuels becoming a public company listed on the Nasdaq Stock Exchange in second quarter of 2022, subject to customary closing conditions.

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Forward-Looking Statements

Certain statements in this communication may be considered forward-looking statements. Forward-looking statements are statements that are not historical facts and generally relate to future events or ArcLight’s or the Company’s future financial or other performance metrics. In some cases, you can identify forward-looking statements by terminology such as “believe,” “may,” “will,” “potentially,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “target,” “plan,” “expect,” or the negatives of these terms or variations of them or similar terminology. Such forward-looking statements, including the identification of a target business and a potential business combination or other such transaction are subject to risks and uncertainties, which could cause actual results to differ materially from those expressed or implied by such forward looking statements. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. These forward-looking statements are based upon estimates and assumptions that, while considered reasonable by ArcLight and its

management, and the Company and its management, as the case may be, are inherently uncertain and subject to material change. Factors that may cause actual results to differ materially from current expectations include, but are not limited to, various factors beyond management’s control, including general economic conditions and other risks, uncertainties and factors set forth in the section entitled “Risk Factors” and “Cautionary Note Regarding Forward-Looking Statements” in ArcLight’s final prospectus relating to its initial public offering, dated September 22, 2020, and other filings with the Securities and Exchange Commission (SEC), including the registration statement on Form S-4 to be filed by ArcLight in connection with the transaction, as well as (1) the inability to complete the proposed transaction; (2) factors associated with companies, such as the Company, that are engaged in the production and integration of renewable natural gas (RNG), including anticipated trends, growth rates, and challenges in those businesses and in the markets in which they operate; (3) macroeconomic conditions related to the global COVID-19 pandemic; (4) the effects of increased competition; (5) contractual arrangements with, and the cooperation of, landfill and livestock waste site owners and operators, on which the Company operates its landfill gas and livestock waste projects that generate electricity and RNG prices for environmental attributes, low carbon fuel standard credits and other incentives; (6) the ability to identify, acquire, develop and operate renewable projects and RNG fueling stations; (7) the failure to realize the anticipated benefits of the proposed transaction, which may be affected by, among other things, competition, the ability of the combined company to grow and manage growth profitably, maintain relationships with customers and suppliers and retain key employees; (8) delays in obtaining, adverse conditions contained in, or the inability to obtain necessary regulatory approvals or complete regulatory reviews required to complete the proposed transaction; (9) the outcome of any legal proceedings that may be instituted in connection with the proposed transaction; (10) the amount of redemption requests made by ArcLight’s public shareholders; and (11)the ability of the combined company that results from the proposed transaction to issue equity or equity-linked securities or obtain debt financing in connection with the transaction or in the future. Nothing in this communication should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Both ArcLight and the Company expressly disclaim any obligations or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in ArcLight’s or the Company’s expectations with respect thereto or any change in events, conditions or circumstances on which any statement is based.

Important Information and Where to Find It

A full description of the terms of the transaction will be provided in a registration statement on Form S-4 to be filed with the SEC by ArcLight that will include a prospectus with respect to the combined company’s securities to be issued in connection with the business combination and a proxy statement with respect to the shareholders meeting of ArcLight to vote on the business combination. ArcLight urges its investors, shareholders and other interested persons to read, when available, the preliminary proxy statement/prospectus as well as other documents filed with the SEC because these documents will contain important information about ArcLight, the Company and the transaction. After the registration statement is declared effective, the definitive proxy statement/prospectus to be included in the registration statement will be mailed to

shareholders of ArcLight as of a record date to be established for voting on the proposed business combination. Once available, shareholders will also be able to obtain a copy of the S-4, including the proxy statement/prospectus, and other documents filed with the SEC without charge, by directing a request to: ArcLight Clean Transition Corp. II, 200 Clarendon Street, 55th Floor, Boston, Massachusetts 02116. The preliminary and definitive proxy statement/prospectus to be included in the registration statement, once available, can also be obtained, without charge, at the SEC’s website (www.sec.gov).

Participants in the Solicitation

ArcLight and the Company and their respective directors and officers may be deemed to be participants in the solicitation of proxies from ArcLight’s shareholders in connection with the proposed transaction. Information about ArcLight’s directors and executive officers and their ownership of ArcLight’s securities is set forth in ArcLight’s filings with the SEC. To the extent that holdings of ArcLight’s securities have changed since the amounts printed in ArcLight’s Registration Statement on Form S-1, such changes have been or will be reflected on Statements of Change in Ownership on Form 4 filed with the SEC. Additional information regarding the interests of those persons and other persons who may be deemed participants in the proposed transaction may be obtained by reading the proxy statement/consent solicitation statement/prospectus regarding the proposed transaction when it becomes available. You may obtain free copies of these documents as described in the preceding paragraph.

Non-Solicitation

This communication is not a proxy statement or solicitation of a proxy, consent or authorization with respect to any securities or in respect of the potential transaction and shall not constitute an offer to sell or a solicitation of an offer to buy the securities of ArcLight, the Company or the combined company, nor shall there be any sale of any such securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification under the securities laws of such state or jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of the Securities Act.

Contact information

Media

Jason Stewart

Senior Director Public Relations and Marketing

914-421-5336

jstewart@opalfuels.com

Investors

ICR, Inc.

OPALFuelsIR@icrinc.com