Cost of revenues and general and administrative expenses - Cost of revenues (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	$ 43,356,311	$ 45,859,671
Electricity [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	5,698,148	5,389,361
Depreciation [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	5,855,073	6,202,012
Fuel oil [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	5,742,056	4,157,393
Employee costs [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	12,439,042	11,465,514
Maintenance [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	2,092,776	2,859,262
Retail license royalties [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	1,418,820	1,489,862
Insurance [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	1,625,862	1,491,799
Materials [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	1,952,764	5,786,698
Other [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of revenue	$ 6,531,770	$ 7,017,770