The two are quite different. In the case of Trans Mountain, as you alluded to, construction costs are difficult to predict until they're completed, whereas in the case of the contracts for Stellantis and Volkswagen the government has committed to.... Even for Northvolt, from what I heard, the government is providing some support for the construction, but the difference is that if there are costs overruns they are on the private sector to bear. The vast majority of the subsidies are production-linked. They're an amount per kilowatt of battery power, so it's limited to the capacity of the production.
