Accounting policies - Disaggregated revenue (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Total Revenue	$ 39,689,390	$ 32,868,990
Contracts in progress.
Net Income (Loss)	6,474,348	3,813,626
Income from operations	$ 7,313,994	$ 4,528,336
Increase in basic earnings	$ 0.44	$ 0.26
Increase in diluted earnings	$ 0.43	$ 0.26
Retail revenue [Member]
Total Revenue	$ 8,624,938	$ 7,771,095
Bulk revenue [Member]
Total Revenue	8,342,094	9,004,373
Services revenue [Member]
Total Revenue	17,417,611	12,721,701
Services revenue [Member] | Transferred over Time [Member]
Total Revenue	9,397,093	8,588,584
Services revenue [Member] | Transferred at Point in Time [Member]
Total Revenue	8,020,518	4,133,117
Manufacturing revenue [Member]
Total Revenue	5,304,747	3,371,821
Construction Sevices [Member]
Total Revenue	9,203,662	8,693,516
Operations and Maintenance [Member]
Total Revenue	7,099,354	3,685,805
Design and Consulting Services [Member]
Total Revenue	$ 1,114,595	$ 342,380