Cost of revenues and general and administrative expenses - Cost of revenues (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	$ 40,519,303	$ 38,977,570
Electricity [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	7,438,218	11,087,214
Depreciation [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	6,046,810	5,328,091
Fuel oil [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	5,315,676	5,434,995
Employee costs [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	6,597,755	5,127,831
Cost of plant sales [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue		1,059,520
Maintenance [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	2,076,501	2,481,095
Retail license royalties [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	1,701,724	1,687,010
Insurance [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	1,279,997	996,563
Materials [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	6,151,064	3,102,533
Other [Member]
Cost of revenues and general and administrative expenses [Line Items]
Cost of Revenue	$ 3,911,558	$ 2,672,718