Discontinued operations - Mexico project development (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets of discontinued operations	$ 21,640,235	$ 22,319,927
Value added tax, net of allowance	1,657,871	1,279,757
Discontinued Operations. | Mexico Project Development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	432,002	750,048
Prepaid expenses and other current assets	67,882	82,783
Value added taxes receivable (net of allowance of $1,657,871 and $1,279,757, respectively)	777	340,910
Land	21,126,898	21,126,898
Other assets	12,676	19,288
Total assets of discontinued operations	21,640,235	22,319,927
Total liabilities of discontinued operations	$ 238,366	$ 190,141