ScotWind: Pains of plugging budget holes with renewables windfall

Each winning bid still carries significant technical risks for developing offshore in wild waters. Of the 20 areas, 13 are to use floating wind turbines, which are much less mature in their design.

There is financial risk. These auction bids were ahead of interest rates going up, inflation applying to supplies and bottlenecks in the development process.

There is, for instance, a shortage of the huge barges required to install turbines which now reach more than 200 metres (656ft) above sea level. They have to be booked well in advance, and competition for them has pushed up prices.

The ScotWind windfall could have been more if conditions had not been applied. Crown Estate Scotland chose bids that looked most credible as well as being lucrative, with a large share of the supply chain close to home, and a clear route to being installed within 10 years, which is when the development rights run out.

Crown Estate Scotland has an interest in seeing these plans progress, because it will eventually be charging windfarm owners an annual rent for the seabed once the power and the cash begin to flow.

It has the same financial interest as the Scottish government. Although its name is derived from the estates owned historically by kings and queens, it is wholly owned by Scottish ministers, and all its profits flow into their coffers.

So that is where the windfall reaches Shona Robison. This is a one-off payment, to be followed, in 10 years or so, by more modest annual leasing profits.