Operators in the offshore export and inter-array power cables market make use of different O&M strategies of the submarine transmission cables. They also draw on some experience from the oil and gas sector and civil marine sector.
A critical element of the offshore export grid will be the availability of reliable remote and automated condition monitoring systems for such key assets.
Compared to existing offshore sectors (oil & gas and maritime), the preventive maintenance strategy and “de factum” planned active integrity management processes for the offshore wind industry are extremely demanding, due to a higher number of operation days, and repetitive inspection regime processes. Many of the widely known techniques are not ideal for such conditions. The equipment is often not up-to-date to meet the new challenging operational and financial requirements of this new industry.
The deployment of the offshore wind energy requires a dedicated offshore electricity system. Such a system is expected to allow grid access for the more remote wind farms, and additional interconnection capacity to improve the trading of electricity between the different markets. Building an offshore grid is different from the well known onshore infrastructure, not only technically but especially economically.
The capacity and availability of the export cable should be sufficient to transport the maximum expected output of the connected wind farm. However, this maximum is only produced for a certain amount of hours per year. Moreover these periods cannot be predicted. That’s why the active condition-based monitoring of such cables must be functioning regardless of weather condition, crew availability, etc. Otherwise the return on the investment will simply be pushed further into the future.