Accounting policies - Disaggregated revenue (Details) - USD ($)	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Total Revenue	$ 33,715,385	$ 39,689,390
Contracts in progress
Income from operations	4,610,763	7,313,994
Net Income (Loss)	$ 4,791,029	$ 6,474,348
Increase in basic earnings	$ 0.31	$ 0.44
Increase in diluted earnings	$ 0.31	$ 0.43
Retail revenue
Total Revenue	$ 9,411,342	$ 8,624,938
Bulk revenue
Total Revenue	8,411,716	8,342,094
Services revenue
Total Revenue	10,078,268	17,417,611
Services revenue | Transferred over time
Total Revenue	2,180,261	9,397,093
Services revenue | Transferred at point in time
Total Revenue	7,898,007	8,020,518
Manufacturing revenue
Total Revenue	5,814,059	5,304,747
Construction revenue
Total Revenue	2,218,230	9,203,662
Operations and maintenance revenue
Total Revenue	7,725,298	7,099,354
Design and consulting revenue
Total Revenue	$ 134,740	$ 1,114,595