Survey Acquisition for Offshore Windfarms
The scale of these developments has been increasing by leaps and bounds in the last 5 years as offshore wind is now one of the cheapest energy sources.
New concepts such as energy transfer hubs on Dogger Bank Windfarm in the UK, with energy import and export abilities to 5 countries. In Denmark an artificial island to act as a gathering station is to be constructed. These conceptual leaps are warranted given the huge increase in the generating capacity of the wind turbine generators themselves and the number being constructed on each site. Wind Turbine Generators with a generating capacity of 14MW have already been built and will soon be commissioned but already we are planning for 20MW WTGs.
The first offshore windfarm our staff worked on in 1996 was just two 2MW WTGs. Plans for 800 x 20MW turbines on an East Coast USA development are now contemplated. A wind turbine of that size and value needs a firm footing- so supervision to ensure quality data acquisition is vital for every location.
Survey Acquisition Plans.
These plans can be of a size equivalent to the largest O&G development surveys.
This WTG size increase has resulted in the geotechnical drilling depths increasing and this last year (2020) we supervised boreholes to 120m on one project. The data quality requirements are improving too and that is one area Bluebird Geoscience can help, with our specialist knowledge. Just recently we have worked with P&S wave suspension logging/gamma logging combination tools on deep holes with great success.
The quality and penetration of the geophysical survey also needs to increase, it is no longer a mainly seabed survey.
Social and Environmental Challenges
Wind farm work is not just a technical challenge. The surveys plan needs to account for the Social and Environmental challenges. Experienced, knowledgeable and empathetic survey supervision is a must.
The fishermen were around long before windfarms and they are yet to be convinced that we are not endangering their livelihoods so we need social and environmental awareness with constant vigilance from the vessels’ crews to avoid inconveniencing or damaging fishing operations and tactful interaction is absolutely essential.
The critically endangered Northern Right Whales is the environmental flagship species on the East Coast of the USA and the monitoring of this species and all other protected species to avoid any detrimental interactions. The data being recovered on the cetaceans and sea turtles will be extremely useful for conservation, and we see the windfarms as an opportunity for the Northern Right Whale to recover numbers using the windfarms as a haven away from the main threat to their existence which is now ship strikes..
The next test will be the West Coast where environmental controls are even more essential and the geological challenges in deeper water on a tectonicly active coast cannot be understated.