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v3.23.1

Note 1 - Nature of Activities and Summary of Significant Accounting Policies (Details Textual) MMBTU in Thousands, gal in Millions | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Apr. 30, 2023 USD ($) | May 31, 2022 USD ($) | Oct. 31, 2020 USD ($) | Mar. 31, 2023 USD ($) MMBTU gal | Dec. 31, 2022 USD ($) | Dec. 31, 2022 USD ($)
Renewable Natural Gas in Storage (Millions of British Thermal Unit) | MMBTU |  |  |  | 31 |  |
Low Carbon Fuel Standard Credits, Per Metric Ton |  |  |  | $ 70 |  |
Low Carbon Fuel Standard Credits, Per D3 Cellulosic RIN |  |  |  | 1.96 |  |
Low Carbon Fuel Standard Credits, Estimated Market Value Per MMBtu |  |  |  | 53.37 |  |
Awarded Grants |  |  |  | 8,000,000.0 |  |
Proceeds from Grantors |  |  |  | 4,200,000 |  |
Matching Contribution |  |  |  | 1,600,000 |  |
U.S. Department of Food And Agriculture Forest Service [Member] |  |  |  |  |  |
Awarded Grants |  |  |  | 245,000 |  |
Proceeds from Grantors |  |  |  | 216,000 |  |
LCFPP [Member] |  |  |  |  |  |
Awarded Grants |  |  |  | 4,200,000 |  |
Proceeds from Grantors |  |  |  | 3,800,000 |  |
CDFAs[Member] |  |  |  |  |  |
Awarded Grants |  |  | $ 7,800,000 |  |  |
Proceeds from Grantors |  |  |  | 3,900,000 |  |
CEC [Member] |  |  |  |  |  |
Matching Contribution |  |  |  | 7,900,000 |  |
Actual Expenses Incurred |  |  |  | 5,000,000.0 |  |
Unearned Grant Proceeds |  |  |  | 1,700,000 |  | $ 1,700,000
CEC [Member] | Maximum [Member] |  |  |  |  |  |
Awarded Grants |  |  |  | 5,000,000.0 |  |
CAL FIRE Business and Workforce Development Grant Program [Member] |  |  |  |  |  |
Awarded Grants |  | $ 2,000,000 |  |  |  |
Proceeds from Grantors |  |  |  |  |  | 0
Matching Contribution |  | 5,800,000 |  |  |  |
CAL Fire [Member] |  |  |  |  |  |
Awarded Grants |  | 500,000 |  |  |  |
Proceeds from Grantors |  |  |  |  |  | $ 0
US Forest Service [Member] |  |  |  |  |  |
Awarded Grants |  | 642,000 |  |  |  |
Matching Contribution |  | $ 2,400,000 |  |  |  |
AAFK Plan [Member] |  |  |  |  |  |
Awarded Grants |  |  |  | 6,000,000.0 |  |
Matching Contribution |  |  |  | 5,300,000 |  |
PG&E SEM Incentive Program [Member] |  |  |  |  |  |
Proceeds from Grantors |  |  |  |  | $ 374,000 |
CEC PG&E Pipeline Interconnect [Member] |  |  |  |  |  |
Proceeds from Grantors |  |  |  | $ 5,000,000 |  |
Kakinada Plant [Member] |  |  |  |  |  |
GallonPerYear (Gallon) | gal |  |  |  | 50 |  |
Kakinada Plant [Member] | Subsequent Event [Member] |  |  |  |  |  |
Amount of Biodiesel, Offer To Ship | $ 34,000,000.0 |  |  |  |  |

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