With the continuing drive for savings in offshore wind during 2017, the team here at CPNL thought it might be a good idea to share a brief outline of the 10 most common pitfalls/myths associated with design, procurement, delivery and maintenance of Cable Protection Systems for the renewable market.
Be more pessimistic
Being more pessimistic at the procurement stage will make sure that you question everything. Sales pitches are invariably based on the best case conditions. Ask a salesman about safety margins, and they'll refer to safety over the 'norm' or 'best base' conditions, not the worst case. By being more pessimistic you should see through this, and other sales gimmicks or tricks. Do not forget to ask suppliers to prove their claims!
There is no such thing as a 'Universal Cable Protection System'
What is ideal for one location is not necessarily what you need for the next project. Cable design requires careful consideration per project, so too does CPS.
Risk perception levels
In some cases, when it comes to Cable Protection Systems, risks are perceived to be of higher relevance than the ones you should really be concerned about. If the CPS does not meet your technical requirements, than why look at the commercial requirements anyway?
A CPS is for Life, not just for Christmas
Ok, so we unashamed hijacked the strap line of the Dogs Trust, but the principle is similar. Just like a dog will be with you for life, your selected CPS will be present throughout the lifetime of your windfarm. Making sure your CPS will physically last the distance, and that it does not become an encumbrance for your O&M team will pay dividends, don't just concentrate on the short construction period.
'Diverless' solutions, really?
If you do not want diver intervention, be clear on the criteria for the phrase, Diverless installation is not the same as Diverless retrieval. Make sure you validate the evidence of any diverless claims.
With offshore windfarms now having been operational since 1991, there is a world of experience available from the O&M divisions, which may not necessarily be public/general knowledge. Liaise carefully with O&M and take their concerns/feedback into account during technical/commercial evaluations.
Compare Apples with Apples
When performing your evaluation (regardless of stage), make sure you are comparing apples with apples. Simple things such as CPS length, design life, safety margins, seabed stability, heat transfer capabilities and warranty all provide the ability to make a 'real' comparison. There are some real horror stories out there of warranties expiring before a years use, damage to cables due to poor stability. Do not let your CPS be the cause of an extra work campaign on site.
What is 'maintenance-free'?
In lie with the other suggestions, be sure to consider the cost of inspections throughout the lifetime of the field. The costs associated with ad-hoc inspections during O&M are costs which can be avoided, as are costs associated with replacement after a big storm.
After purchasing a Cable Protection System it may be a sobering thought that you have to put all your efforts into selecting a cost effective solution for your project, only to find out that the product you selected has a defect warranty of only 1, 3 or 5 years, starting from the delivery date, also known as before it was even wet! Your project is based on 25-years. Why would you limit yourself with short term product visions when your own vision is for the long term?
As a freelancer once questionned: "If the supplier does not have the confidence to provide a warranty for the 'design life' of the system, why should you have the confidence to buy it?"
As with some other areas of offshore renewables, there is currently no obvious certification process for cable protection components to verify the product lifetime of 25 years. Just because it may not seem to be obvious, this does not mean it is not there!
Products can be independently empirically tested to provide a certain level of confidence in the ability to deliver on claimed design life.
Be careful, ask questions, as some perceive this lack of obvious certification as a reason to certify only a part of the cable protection system or even production processes of the product. Being certified for quality is not the same as design certification, nor is it the same as empirical evidence.