In the wake of the Crown Estate’s round-three allocations for offshore wind last week, industry body Scottish Renewables estimates developers will spend £7.2 billion a year on capital expenditure between this year and 2030. About £1.8bn of this outlay will be in Scotland. This is compared to the less than £5bn a year spent in the North Sea by oil and gas companies, in a sign that offshore wind is now poised to come of age.

Niall Stuart, chief executive of Scottish Renewables, said: “Oil and gas is obviously a huge industry and will continue to be a massive driver of the economy, but these figures show the scale of the investment in offshore wind over the next 20 years.”

The Crown Estate’s round three allocations, which will be further from the coast than their predecessors, take the total planned build-out of offshore turbines to 45GW across the UK and 11.1GW in Scotland. The two Scottish allocations went to Aberdeen-based SeaEnergy and Portugal’s EDPR (a 1.3GW site in the Moray Firth zone) and Scottish and Southern Energy and Fluor (a 3.5GW site in the Firth of Forth zone), adding to nine previous allocations worth 6.4GW in which many of the same companies, plus others such as ScottishPower, Dong of Denmark and Norway-based Fred Olsen Renewables, were involved.

The allocations are likely to be the last for a number of years, meaning there is complete clarity about who will be working on which sites around the territorial waters over the coming years. Although work is unlikely to begin on the round three sites until around the middle of the decade, some previous allocations are in the early stages of development and two huge demonstration turbines have been stationed by the Beatrice oil field in the Moray Firth for some time. In England and Wales, where allocations were made earlier, some smaller concessions are already operational.

Malcolm Watt, chief executive of Oil and Gas UK, pointed out his sector’s inferior capital expenditure could not be considered in isolation from the additional £6bn it spends on operating existing installations.

But he said: “Renewables have got a strong part to play, but oil and gas is hugely important too. This is not a competition, really, and I would point out that several of my members, such as RWE and Statoil, have been among the winners in round three.”

David Watt, director of the Institute of Directors Scotland, said the announcements about the round three allocations and also the Beauly-Denny power line were “extremely welcome” in that they showed the country was finally taking decisions and moving forward with projects. He pointed out, however, that people tended to forget all of the subsidies for renewable energy to make it commercially viable would be borne by consumers and businesses through their electricity bills.

He said he was optimistic about the future of the oil and gas industry, since he expected new discoveries in the deeper waters off West Shetland and also opportunities from carbon storage once the sequestration technologies being developed for power stations were commercially viable in a few years’ time.

The rapid development of offshore wind capacity is central to the delivery of the UK’s share of the EU target of 20% renewable energy by 2020.

Rob Hastings, The Crown Estate’s Director of Marine Estates, said: “The new approach to the deployment of offshore wind that the Crown Estate has set out requires us take an important facilitating role in which we will share developer’s risk. For the first time we will be investing directly in offshore windfarm development. We will be helping to identify suitable sites and working closely with commercial partners who we expect to make considerable capital investments in offshore windfarm assets.”

Energy Minister Malcolm Wicks said: “The expansion of wind energy is already a real success story for the UK. We will shortly become the leading country in the world in terms of the number of windfarms operating offshore. The potential for round three will add to that success.