Restricted Cash	12 Months Ended
Dec. 31, 2023
Restricted Cash and Cash Equivalents [Abstract]
Restricted Cash	7. Restricted Cash As of December 31, 2023, current restricted cash of $77.3 million consists of amounts held as collateral for letters of credit to provide financing support for development and construction of the NW Iowa RNG and NZ1 projects. The Company entered into an irrevocable direct pay letter of credit (the “Bond Letter of Credit”) with Citibank N.A (“Citibank”) in April 2021 to support the 2021 Bonds (as defined below) for the development and construction of NW Iowa RNG. See Note 14, Debt, for additional information on the 2021 Bonds. The Bond Letter of Credit has a 0.5% annual fee and expires April 4, 2024 (unless terminated earlier). The Company deposited $71.2 million with Citibank as restricted cash to secure any amounts drawn under the Bond Letter of Credit. As of December 31, 2023, no amounts have been drawn under the Bond Letter of Credit. In September 2022, the Company entered into a Pledge and Assignment agreement with Citibank to provide credit support in the form of a letter of credit (the “Power Letter of Credit”) from Citibank to a local electric utility company in order to induce the utility company to design and construct the power transmission and distribution facilities that will serve NZ1. The Company deposited $6.6 million of restricted cash in an account with Citibank to collateralize the Power Letter of Credit, which has a 0.3% annual fee and expires September 30, 2024 (unless terminated earlier). As of December 31, 2023, no amounts have been drawn under the Power Letter of Credit. In January 2024, Citibank was notified by the local electric utility company to close the letter of credit, as the Company has discontinued its relationship with the local utility, and fulfilled all obligations under the Power Letter of Credit. The Company is entitled to receive interest income on the restricted cash, and recorded interest income of $3.4 million and $0.5 million for the years ended December 31, 2023, and 2022, respectively, included in “Other income, net” in the Consolidated Statements of Operations.

Restricted Cash

12 Months Ended

Dec. 31, 2023

Restricted Cash and Cash Equivalents [Abstract]

7. Restricted Cash

As of December 31, 2023, current restricted cash of $77.3 million consists of amounts held as collateral for letters of credit to provide financing support for development and construction of the NW Iowa RNG and NZ1 projects.

The Company entered into an irrevocable direct pay letter of credit (the “Bond Letter of Credit”) with Citibank N.A (“Citibank”) in April 2021 to support the 2021 Bonds (as defined below) for the development and construction of NW Iowa RNG. See Note 14, Debt, for additional information on the 2021 Bonds. The Bond Letter of Credit has a 0.5% annual fee and expires April 4, 2024 (unless terminated earlier). The Company deposited $71.2 million with Citibank as restricted cash to secure any amounts drawn under the Bond Letter of Credit. As of December 31, 2023, no amounts have been drawn under the Bond Letter of Credit.

In September 2022, the Company entered into a Pledge and Assignment agreement with Citibank to provide credit support in the form of a letter of credit (the “Power Letter of Credit”) from Citibank to a local electric utility company in order to induce the utility company to design and construct the power transmission and distribution facilities that will serve NZ1. The Company deposited $6.6 million of restricted cash in an account with Citibank to collateralize the Power Letter of Credit, which has a 0.3% annual fee and expires September 30, 2024 (unless terminated earlier). As of December 31, 2023, no amounts have been drawn under the Power Letter of Credit. In January 2024, Citibank was notified by the local electric utility company to close the letter of credit, as the Company has discontinued its relationship with the local utility, and fulfilled all obligations under the Power Letter of Credit.

The Company is entitled to receive interest income on the restricted cash, and recorded interest income of $3.4 million and $0.5 million for the years ended December 31, 2023, and 2022, respectively, included in “Other income, net” in the Consolidated Statements of Operations.