Note 3 - Notes Receivable and Advances, Net - Notes Receivable and Advances (Details) - USD ($)	Mar. 31, 2025	Dec. 31, 2024
Total notes receivable and advances, non-current portion, net	$ 2,860,291	$ 2,430,291
RenFuel K2B AB Note Receivable [Member]
Total notes receivable and advances, non-current portion, net	1,880,000	1,450,000
Daney Ranch Sale Note Receivable [Member]
Total notes receivable and advances, non-current portion, net	$ 980,291	$ 980,291

Amortized cost, before allowance for credit loss, of financing receivable classified as noncurrent. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477011/948-310-45-1

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant