| Explanation of Responses: |
| (1) | On December 13, 2021, 656,300 OpCo Class A Units held by Aria Renewable Energy Systems LLC ("Aria RES") were redeemed on a one-for-one basis for 656,300 shares of Class A Common Stock, par value $0.0001 per share ("Class A Common Stock") of Archaea Energy Inc. (the "Issuer") pursuant to a Redemption Notice from Aria RES dated December 8, 2021 and 656,300 shares of the Issuer's Class B common stock, par value $0.0001 per share, held by Aria RES were surrendered to the Issuer and canceled. |
| (2) | On December 8, 2021, Aria RES entered into share purchase agreements (collectively, the "Salient Share Purchase Agreements") with certain entities affiliated with Salient Capital Advisors, LLC (collectively, the "Salient Purchasers") pursuant to which Aria RES agreed to sell to the Salient Purchasers and the Salient Purchasers agreed to purchase from Aria RES 656,300 shares of Class A Common Stock of the Issuer at a purchase price of $17.95 per share, subject to certain conditions. In accordance with the terms of the Salient Share Repurchase Agreements, on December 13, 2021, Aria RES completed the sale of 656,300 shares of Class A Common Stock to the Salient Purchasers. |
| (3) | These shares are directly held by Aria RES. The Reporting Persons may be deemed to beneficially own, these shares by reason of the direct or indirect beneficial ownership of such shares, except as follows: (i) United States Power Fund III, L.P. ("USP Fund III") may be deemed to beneficially own 10,351,432 of these shares, (ii) EIF United States Power Fund IV, L.P. ("EIF USP Fund IV") may be deemed to beneficially own 8,821,907 of these shares, (iii) EIF US Power III, LLC may be deemed to beneficially own 10,351,432 of these shares, and (iv) EIF US Power IV, LLC may be deemed to beneficially own 8,821,907 of these shares. |
| (4) | This statement is being filed jointly by (i) Aria RES, (ii) USP Fund III, (iii) EIF USP Fund IV (together with USP Fund III, the "Ares Funds"), (iv) EIF US Power III, LLC, (v) EIF US Power IV, LLC, (vi) Ares EIF Management LLC, (vii) Ares Management LLC, (viii) Ares Management Holdings L.P. ("Ares Management Holdings"), (ix) Ares Holdco LLC ("Ares Holdco"), (x) Ares Management Corp. ("Ares Management"), (xi) Ares Management GP LLC ("Ares Management GP"), (xii) Ares Voting LLC ("Ares Voting"), and (xiii) Ares Partners Holdco LLC ("Ares Partners") (collectively, the "Reporting Persons"). Due to the electronic system's limitation of 10 Reporting Persons per joint filing, this statement is being filed in two parts. |
| (5) | Aria RES is indirectly controlled by the Ares Funds. The general partner of USP Fund III is EIF US Power III, LLC, and the managing member of EIF US Power III, LLC is Ares EIF Management LLC. The general partner of EIF USP Fund IV is EIF US Power IV, LLC, and the managing member of EIF US Power IV, LLC is Ares EIF Management LLC. The sole member of Ares EIF Management LLC is Ares Management LLC. The sole member of Ares Management LLC is Ares Management Holdings and the general partner of Ares Management Holdings is Ares Holdco. The sole member of Ares Holdco is Ares Management. Ares Management GP is the sole holder of Class B common stock, $0.01 par value per share, of Ares Management and Ares Voting is the sole holder of Class C common stock, $0.01 par value per share, of Ares Management. (continued in next footnote) |
| (6) | Pursuant to Ares Management's Certificate of Incorporation, the holders of Ares Management's Class B common stock and Class C common stock, collectively, will generally have the majority of the votes on any matter submitted to the stockholders of Ares Management if certain conditions are met. The sole member of both Ares Management GP and Ares Voting is Ares Partners (together with Aria RES, the Ares Funds, EIF US Power III, LLC, EIF US Power IV, LLC, Ares EIF Management LLC, Ares Management LLC, Ares Management Holdings, Ares Holdco, Ares Management, Ares Management GP and Ares Voting, the "Ares Entities"). Ares Partners is managed by a board of managers, which is composed of Michael Arougheti, Ryan Berry, R. Kipp deVeer, David Kaplan, Antony Ressler and Bennett Rosenthal (collectively, the "Board Members"). Mr. Ressler generally has veto authority over Board Members' decisions. |
| (7) | Each of the Ares Entities (other than Aria RES with respect to the shares held directly), and the Board Members, and the other directors, officers, partners, stockholders, member and managers of the Ares Entities, expressly disclaims beneficial ownership of any equity securities of the Issuer, except to the extent of any pecuniary interest therein, and this Form 4 shall not be deemed an admission that any such person or entity is the beneficial owner of, or has any pecuniary interest in, such securities for purposes of Section 16 of the Exchange Act, or for any other purposes. |