Discontinued operations - Mexico project development (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets of discontinued operations	$ 21,340,805	$ 21,660,768
Discontinued Operations. | Mexico Project Development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	91,283	442,252
Accounts receivable		12,675
Prepaid expenses and other current assets	120,234	76,553
Land	21,126,898	21,126,898
Other assets	2,390	2,390
Total assets of discontinued operations	21,340,805	21,660,768
Total liabilities of discontinued operations	$ 364,665	$ 389,884