Commercial, Products, Regulatory

The Next Offshore Energy Revolution   

By By Andrew Drwiega, Military Editor | November 1, 2011

Operators Uni-Fly from Denmark and Bond Aviation Services have both selected the EC135 for wind farm support operations. Eurocopter

If money talks, then lots of money generated in an economic downturn shouts from the rooftops or, more appropriately, turbine tops. In this austere time the offshore wind farm market represents almost a rare windfall opportunity to create wealth, jobs and generate money—if those closely linked to its expansion are to be believed. None come more credible than the UK’s Crown Estate (CE). In March 2011, the CE announced a net profit of £230.9 million ($364.9 million), representing an increase of nearly 10 percent on the previous year. The marine sector alone saw a 32 percent increase in revenue, largely due to the leases given to offshore wind farm developers (and to a lesser extent tidal and tidal array). The CE is supporting developers in the wind/tide sector, not just because overall growth in the sector is good for the economy, but also “[to help] provide valuable jobs to local communities” and to support the UK’s “commitment to renewable energy and a reduction in CO2 levels, as well as an increase in energy security.” The CE’s business strategy was ratified in January 2011 and sets the UK Government’s course in this sector for the next decade. Over £100 million ($158 million) has already been committed to offshore wind projects and four offshore wind test sites were awarded in the summer of 2010 to test and demonstrate improved and new technologies. Ernst & Young has found that “from an investor perspective, the UK is the most attractive country in the world for offshore wind development.”

The CE has invested in a three-phase program of offshore wind farm development in the territorial waters around the UK. All the Round 1 (2010/11) projects are virtually complete and half the projects in Round 2 are also either under way or partially operational. According to the CE, Round 3 represents the true change of pace in that its developments (focused on nine separate zones) could result in a quarter of the UK’s total electricity needs being met by 2030. Inevitably plans are now being formulated for Round 4 to begin in 2016/2017.


While the current operational offshore wind farms are British-owned Thanet, producing 300 megawatts (MW) and Danish Horns Rev II and Rodsand II (209 MW and 207 MW, respectively) both owned by Denmark, there is more—much more to come. The two biggest under construction are both British; the London Array (Phase 1) and the Greater Gabbard (630 MW and 530 MW, respectively). Germany follows with the next two, both with a generating potential of around 400 MW each. These are all looking at completion dates of 2012, but London Array will be home to 175 turbine blades rather than the current 100 at Thanet and 90 or so at the Danish wind farms.

But the greatest leaps forward are still in the proposal stages, and the UK is leading the field here. The Dogger Bank offshore wind farm would have a capacity of 9,000 MW—30 times that of the current Thanet field. The next four as similarly impressive: Norfolk Bank (7,200 MW), Irish Sea (4,200 MW), Hornsea (4,000 MW) and Firth of Forth (3,500 MW).

RenewableUK is the leading renewable energy trade association in the UK, and has a focus on the land and maritime wind farm sector. Not surprising considering that wind energy is widely thought to be the world’s fastest growing renewable energy source, a trend that is expected to continue particularly following the nuclear tragedy in Japan—a factor that changed Germany’s focus away from nuclear energy and onto renewables for its future energy. Anne-Bénédicte Genachte, Regulatory Affairs Advisor for Offshore, with the European Wind Energy Association, stated at the recent Helitech conference held at Duxford in September that technically there could be enough potential wind energy generated—25,000 TWh (terawatt hours) by 2020 and 30,000 by 2030—to power Europe seven times over (putting Europe’s energy needs at 3,537 TWh and 4,279 TWh, respectively). Development will not happen at that pace, of course.

At the end of 2010, the UK had 45 percent of installed capacity in Europe for the production of wind power energy, Denmark had 29 percent and no other country registered over the 8 percent of the Netherlands. Peter Lloyd, Head of EHS Strategy with Siemens in Denmark, concurs that the offshore wind farm sector is only just beginning to see growth. His wealth of experience in helicopter operations (an ex-Chief of Staff within the Royal Air Force’s Search & Rescue Force) leads him to advocate a balance between maritime and aerial support for offshore wind farms. “There has to be a cost-benefit analysis scoping all operational scenarios.” Movements will depend on several factors: weather and sea state, urgency or requirement, cost of relatively speedy airborne delivery matched against cost of downtime while waiting for slower maritime delivery.

Helicopters can fly in windy weather and Danish helicopter service operator Uni-Fly claims deliveries of personnel to turbine platforms in wind gusting up to 60 knots—weather that would create waves that would negate any transfers by boat. Uni-Fly is the only civil Danish helicopter operator that uses Eurocopter EC135s to provide an aerial service to the Horns Rev I and Horns Rev II offshore wind platforms, located around seven miles off the Danish coastline. Uni-Fly states that it is the only such helicopter operator to do hoist operations—around 50,000 to date and counting —and has been providing this service to power company Vattenfall (then Elsam) for nearly a decade. Uni-Fly signed an agreement in late 2002 to support the wind farm fields from a base at Esbjerg Airport. 

While smaller helicopters are the best choice for turbine hoist operations, larger helicopters may come into the scenario to support operational/accommodation platforms for the larger, more distant wind farms when they are developed. Uni-Fly

The majority of missions are to transport technicians offshore to work on the turbines. The company supports the operating principle that it can continue providing a transportation service to the platforms when wave levels are prohibitively high for ships to perform the task. The helicopters will also transport cargo when required to do so, again usually if it is too rough for sea transportation, as well as operations to support vessels. One of the more unusual tasks is ice reconnaissance. Uni-Fly recently became an industry member of the Danish Wind Industry Association. Stating Uni-Fly’s belief in the future of the wind farm business, company manager Bjarne Peterson said, “We believe that the positive development in offshore will continue and then we might as well make sure that we are where it happens,” referring to the DWIA membership.

The German energy wind farm owner EON is planning that most of their personnel transfers will be undertaken by helicopter, but with boat back-up. Bond Air Services purchased an EC135 in late 2008 to support operations into the Greater Gabbard wind farm in the North Sea, but to date reports indicate that this service is still to begin. Some of the large wind farms are also going to have to be designed with helicopters in mind. This is not only to ensure safe and easy access to the maintenance platforms on top of each turbine, but also to allow helicopter ingress into the farm in cases of emergency [potentially people in the water due to some kind of incident]. Lloyd has studied the cost vs. benefit equation regarding access to turbines against weather conditions usually experienced in the North Sea. Typically a smaller crew transfer vessel (CVT) will have access around 53 percent of the time and a downtime of 47 percent. A bigger service operation vessel (SOV) fares a lot better with around 83 percent access and only 17 percent when it cannot operate. He summarized helicopter access by looking at two limiting factors: with a wind limit of 18 meters (59 feet) per second, access is around 92 percent of the time, although with a higher limit of 25m/s (82f/s) accessibility rises to around 94 percent.

Lloyd also produced figures estimating the cost of downtime of a wind turbine (perhaps through the need of a part) against the cost of paying for a helicopter mission to resolve the problem:

Turbine     1 day lost revenue could be
3.6 MW 3.9 flying hours
6.0 MW 6.5 flying hours

Helicopters, especially light ones such as the EC145 operated by both Danish operator Uni-Fly and British company Bond Aviation Services, offer a number of attractive features. They can carry up to seven passengers and hoist up to four while carrying tools or smaller spare parts. While being able to deploy medically qualified people and rescue teams they are not a substitute for fully equipped and crewed specialist medevac helicopters such as those provided by the Royal Air Force Search & Rescue force. They are quick, flexible and can hover and conduct hoist operations in close proximity to the turbine blades. However they have relatively smaller cabins, do have limited weather operations and are a day-only service.

Anne-Bénédicte Genachte, with the European Wind Energy Association, speaks at Helitech 2011. Photo by Andrew Parker

A medium helicopter such as the EC225, already strongly linked with offshore oil and gas operations, offers much more. More people, around 19, internal cargo space and external cargo lifting (up to around 2,000 kg, or 4,000 lbs., depending on the aircraft and distance). They also have greater comfort when fitted for a specialist role, longer range and endurance and better overall operational capability with day/night/IMC/VMC. However, the drawback is that they would be unsuitable for operations over hoist platforms, suggesting that they would be more appropriate when the offshore wind farms are coordinated from a central platform in permanent residence within the field.

Lloyd says that specialist helicopters such as those from the SAR Force will still be required for urgent medical rescue where continuing treatment and monitoring of a patient is required and for the usual search and rescue emergency tasks within offshore wind farm fields. Although operating largely heavier aircraft, such as the existing Sikorsky S-61 Sea King, the SAR Force is already working on ways that it can extract injured people by hoist from turbine platforms and to perform other operations within them. Those crews will come with their specialist knowledge of not only the medevac roles they will be asked to perform, but an understanding of the operational area and the weather conditions that prevail at any time of the year. Again the rescue helicopter would be capable of day/night/IMC/VMC operations.

His conclusions are that helicopters and supply vessels are complimentary to one another and that helicopters will become more important as offshore distances increase.

Finally, it would be a mistake to forget onshore wind farms in terms of the relevance of helicopter support, especially during the build phase. Aircraft such as the Erickson Air Crane could well have a use when it comes to installing turbines in geographically challenging locations, such as on mountainsides and ridgelines.

Ground transport could be used to position the structures and the machinery to the nearest road-side location, but a heavy lift helicopter could be employed in the final stages of transporting the turbine up a mountainside to its final location. This could also be a green-friendly option if the ground needed to be physically protected.

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