Accounting policies - Disaggregated revenue (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Accounting policies
Total Revenue	$ 35,118,706	$ 33,390,557	$ 102,425,170	$ 105,559,105
Contracts in progress
Number of days after consumption billings are considered past due			45 days
Retail revenue
Accounting policies
Total Revenue	7,770,344	7,585,992	$ 25,819,712	24,392,814
Bulk revenue
Accounting policies
Total Revenue	8,394,614	8,767,168	25,081,146	25,557,220
Services revenue
Accounting policies
Total Revenue	14,289,315	12,677,837	35,815,785	42,017,917
Manufacturing revenue
Accounting policies
Total Revenue	4,664,433	4,359,560	15,708,527	13,591,154
Construction revenue | Services revenue
Accounting policies
Total Revenue	6,360,333	4,251,237	11,404,500	17,632,772
Operations and maintenance revenue | Services revenue
Accounting policies
Total Revenue	7,715,000	7,492,121	23,695,704	21,660,396
Design and consulting revenue | Services revenue
Accounting policies
Total Revenue	213,982	934,479	715,581	2,724,749
Transferred over time | Services revenue
Accounting policies
Total Revenue	6,462,508	4,246,506	11,752,695	17,631,774
Transferred at point in time | Services revenue
Accounting policies
Total Revenue	$ 7,826,807	$ 8,431,331	$ 24,063,090	$ 24,386,143
Minimum
Contracts in progress
Number of days after consumption billings are collected			30 days
Maximum
Contracts in progress
Number of days after consumption billings are collected			45 days