By Rikki Stancich in Paris

WindEnergyUpdate: In general, what are the key cost considerations for offshore
turbine operations and maintenance?

Axel Birk: Transfer of equipment and teams, marine costs, boats and equipments. Also, whether the operations and maintenance is scheduled or unscheduled, helicopter requirements, weather down time and major turbine failures.

WindEnergyUpdate: What cost is likely to be presented by materials fatigue and what is the best strategy to mitigate and/or resolve the issue?

Axel Birk: The cost of an unscheduled intervention is likely to be around ten times the cost of a scheduled intervention. As such, it is advisable that the component is changed before it fails. Each component should have a dedicated running time. In other words, you know that it will run for 12 months before failure.

WindEnergyUpdate: What are some of the best preventative maintenance systems out there?

Axel Birk: The best mainentance system is preventative – avoiding unscheduled interventions; anything planned is always less expensive than the unplanned.

With CMS you can analyse what needs to be done. You can carefully supervise the turbines – but you also need expertise on how to analyse that data. You need analysts who understand that wind turbine technology.

WindEnergyUpdate: To what extent is innovative turbine technology addressing some of the previous maintenance issues?

Axel Birk: Newer turbine designs have reduced the maintenance requirements. If you need O&M scheduled over 20 years, then every part should be exchanged before it fails.

We resolve this through working with big ships. We bring all the required parts on 3 vessels that are available between wind farms and can transport technicians of other service suppliers to nearby turbines.

Hotel ships could be shared, carrying technicians for several wind farms within the vicinity of one another. Of course, access codes would be required for restricted technical areas to prevent industrial espionage.

WindEnergyUpdate: What are the pros and cons of on-site vs off-site maintenance teams?

Axel Birk: For far offshore wind farms it makes sense to have a 24-7 offshore crew. Firstly, it is too expensive to have teams located onshore, where they have to travel 3 hours to reach the site. Instead, you accommodate staff for 10 days on hotel ships and 14 days off.

And secondly, during the shift change, you also bring out new material and equipment supplies. This way, you could have a vessel out for a minimum of 300 days.

I envisage that you would have one jack-up vessel and two supply vessels.

To respond to this article, please write to the editor:

Rikki Stancich: rstancich@gmail.com