Discontinued operations - Mexico project development (Details) - USD ($)	Jun. 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	$ 21,554,992	$ 22,319,927
Discontinued Operations. | Mexico Project Development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	344,720	750,048
Prepaid expenses and other current assets	67,962	82,783
Value added taxes receivable (net of allowance of $1,657,871 and $1,279,757, respectively)	505	340,910
Land	21,126,898	21,126,898
Other assets	14,907	19,288
Total assets of discontinued operations	21,554,992	22,319,927
Total liabilities of discontinued operations	195,983	190,141
Value added tax, net of allowance	$ 1,657,871	$ 1,279,757