Discontinued operations - Mexico project development (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets of discontinued operations	$ 21,660,768	$ 22,319,927
Discontinued Operations. | Mexico Project Development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	442,252	750,048
Prepaid expenses and other current assets	12,675
Value added taxes receivable (net of allowance of $1,657,871 and $1,279,757, respectively)	75,826	82,783
Property, plant and equipment, net	727	340,910
Land	21,126,898	21,126,898
Other assets	2,390	19,288
Total assets of discontinued operations	21,660,768	22,319,927
Total liabilities of discontinued operations	389,884	190,141
Value added tax, net of allowance	$ 1,711,234	$ 1,279,757