Prepaid and other current assets (Additional Information) (Details) $ in Millions	Dec. 31, 2023 USD ($)
Prepaid Expense and Other Assets, Current [Abstract]
Short-term Interest Bearing Loan & Customer dvance	$ 3.0	[1],[2]

[1] a non-interest bearing customer advance, both of which are for pre-project construction financing activities. The amounts are secured by customer assets and, additionally, in one case by a financial guarantee.

[2] a short-term interest-bearing loan to a customer, as well as