By Andrew Williams on Dec 13, 2013

So, when did the company first become aware of the technological challenges posed at the site? Were they foreseen before commencing the project - or did they become apparent as the scheme progressed? And what lessons might the Atlantic Array experience provide for future deep water projects elsewhere in the industry?

'Site Specific Factors'

A spokesperson for RWE Innogy told Wind Energy Update that the company faced a number of particular technological challenges in developing the Atlantic Array project, which were 'presented by a combination of site specific factors.' These include the fact that the area in the Bristol Channel Zone is a deep water site with 'significant areas of bed rock and large sand wave features,' as well as a 'high wave and strong tidal current climate.'

"This has an impact on the cost of foundation and cable design, fabrication and installation, as well as long term operation," says the spokesperson.

As a result, RWE Innogy's current view is that 'significant' technical developments would be required to lower costs in many areas of the project - particularly since 'additional risks are associated with the use of multiple new developments.' Instead, the company will now place a strong emphasis on progressing 'more technically and economically viable offshore projects.'

Detailed Site Investigation

The site was set to feature up to 240 turbines, with a total installed capacity of up to 1,200 MW - or 1.2 GW - while the maximum annual electricity that the company expected to generate from the wind farm site as a whole 'would have been equivalent to the approximate domestic needs of up to 900,000 average UK households.'

RWE Innogy also reveals that the full extent of the technological challenges posed by developing an offshore array in the Bristol Channel Zone only became apparent following a period of detailed investigation into the conditions and characteristics of the site.

"Naturally, at the start of the project we had some awareness relating to the conditions of the project. However, it was not until we completed the many detailed and varied surveys that we began to get a fuller picture of the technical challenges," says the spokesperson.

"Once we had this information, we then needed to look at the technology options available to make the wind farm economically viable. As you can imagine this takes some time and takes place as the project progresses," they add.

Crown Estate

News of the cancelled deep water project is also a blow for the Crown Estate, which leases the sea bed for tidal ad offshore wind projects. A recent news article by the North Devon Journal reported that the Crown Estate has said there are no plans for any further development in the Bristol Channel for the foreseeable future, despite local business leaders attempting to revive Atlantic Array plans.

The Devon and Cornwall Business Council were hoping that a new developer could step in to revive the scheme, claiming that the project could create 500 jobs, and would require a further 500 staff to maintain and run it.

Johnny Gowdy, director of Regen South West, said the Bristol Channel is a prime location for development, according to the North Devon Journal report. "The Bristol Channel is the right location for renewable energy, and we could be looking at a larger number of smaller developments and mixture of wind and tidal projects, but any future schemes will need to have more governance at a local level.”

Supporting 'Marginal Projects'

Although it is difficult to deny that the move represents a setback for the company, other commentators in the offshore wind sector are keen to stress that the pull out may have been influenced more by financial considerations than technological hurdles - and some have used the RWE Innogy decision to call for an industry-wide consideration of how best to support deep water projects.

According to Nick Medic, Director of Offshore Renewables at RenewableUK, 'when we talk about overcoming the challenges mentioned it’s important to understand that we are actually discussing costs.' In his view, the issues associated with the Atlantic Array project did not come about because challenges are 'beyond current engineering or O&M capabilities - but rather because support levels 'might not be sufficient for a project of this nature.'

"Perhaps the answer here would be to consider how to properly support marginal projects, as they are crucial for implementing new procedures and expanding our store of knowledge in offshore," says Medic.

Charting the Deep Waters

Looking ahead, Medic points out that, in the longer term, the broader offshore wind industry might learn a number of important lessons about developing deep water projects in the light of RWE's experience with the Atlantic Array project.

“Beyond the immediate questions of overall profitability, we are likely to see the offshore industry taking an ever increasing interest in reducing costs, and applying some of the cost reductions solutions from shallow water project to deeper waters," he says.

In addition, Medic predicts that 'we are likely to see more of a focus on installation techniques, devices and materials,' which he says have not been applied 'in an industrial way in the UK’s offshore wind sector.' In concrete terms, he believes this could well take the form of 'trials in test sites, followed by mass roll outs.'

"So really it’s about ensuring that the deeper water projects are properly supported by adequate policy, exploring opportunities for reducing costs and then ensuring that ‘depth specific’ new mass deployment technologies are in place," he adds.