Property, plant and equipment and construction in progress (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 139,782,227	$ 136,109,235
Less accumulated depreciation	87,252,682	83,162,696
Property, Plant and Equipment, Net, Total	52,529,545	52,946,539
Construction in progress	3,705,681	710,863
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,488,400	3,316,537
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	23,280,880	23,255,925
Plant And Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	64,532,994	64,324,377
Distribution Systems [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	39,544,395	39,780,272
Office furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,109,546	3,051,814
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,525,576	2,079,874
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	287,980	287,980
Lab equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 12,456	$ 12,456