Cutting edge expertise

15 November 2019

David Collett is president of ESTA, the European mobile crane and special transport association, and MD of the eponymous UK special transport firm. Will North interviewed him about the challenges posed by longer, heavier, wind farm components, and collaboration between the transport and wind energy industries.

In recent years, ESTA has organised a series of wind energy summits, connecting the lifting and transport sectors with representatives of the wind power sector. By bringing together representatives of ESTA, the FEM, and the power generation group of the VDMA, these events have fostered dialogue that had previously been missing.

Collett says, "The summits were a great success. They offered a focal point for the wind turbine generator OEMs to talk to the transport and crane operators on a European-wide basis, as well as to the crane and trailer manufacturers. They presented the OEM’s with an organisation (ESTA) that has a knowledge and expertise base, and can offer opinions, experience and communications with the transport and crane operators.

“They raised safety issues in an unbiased way. This is an industry-wide problem, not a specific manufacturer or operator's issue.

“And, the summits also acted as a sort of springboard to accelerate work on the best practice guide on the safe transport an erection of onshore wind turbines that you will see published very soon.”

PROPER PLANNING While the summits have helped bring the industry together at the top, on the ground careful planning remains a pressing concern. Collett has given presentations showing the challenges posed to transport service providers by some wind farm road layouts, and how they may be better planned.

He says, “Poor site infrastructure plays a very large part in crane and transport incidents on wind farm sites. We see examples of this in everyday practice on an ongoing basis. The problem starts with the developers that design the site in the first place. When budgets are squeezed, infrastructure and access considerations are usually some of the first things that gets reduced.

“Early engagement with a reputable transport company or consultant that has the capability to assess the requirements of the project [is essential]. This should be done before the road construction begins and then checked as the site is built.

“The new Best Practice Guide that ESTA/VDMA are producing will offer a standard of road dimension that should be considered and used at the design stage.”

The need for planning extends beyond the ‘last mile’ of the wind farm, to the public road network. Collett says, “Every wind farm project brings its own challenges and problems due to length of route, type of roads required to get to site, and the infrastructure on the route.

“The best answer is a well prepared transport management plan (TMP) that illustrates times and days of movement, use of convoys, day and night time movement schedules, local press/information dissemination, along with a well-planned route where all alterations have been made before hand to reduce time on the road at pinch points. With this in mind the ESTA/VDMA Best Practice Guide gives guidelines for the minimum required content of such a TMP.

“Early engagement with a reputable transport company or consultant allows for alternatives to be sought or different transport techniques proposed to gain access to the site. This should be considered at the planning stage. No available route, means no wind farm.”

DRIVING ON The transport and erection of wind turbines will remain a pressing issue for many years. At the most recent ESTA cranes group meeting, manufacturers’ experts warned that it may become increasingly hard to erect turbines using standard crawler designs: at a certain height, stabilising a crane on crawlers alone at a wind farm becomes a real obstacle.

Similarly, for transport companies, there are looming challenges as the market takes a step up to substantially longer blade lengths. Thankfully, through the dialogue prompted by forums like the ESTA Wind Energy Summits, these challenges are being considered earlier. Collett says, “As blade lengths increase, it is clear to the manufacturers that transport and shipping is a major consideration at the design stage.

“Blade manufacturers now work directly with trailer manufacturers and transport companies at the design stage. The strength and integrity of the blades is now a large consideration, not just for capturing and transferring wind into energy, but also for being supported or selfsupporting for their transport.

“Some manufacturers have split blades, but with varying success. Further development of this split blade technology will be required to continue constructing longer blades. As these blades continue to grow, trailer manufacturers will continue to develop trailers to carry them.

“What is clear is that the road infrastructure across Europe will not change to suit the blades, therefore technology will have to change first. In many cases the present road infrastructure is at its limits with the current blade lengths.”

Beyond the logistical challenges, there is a business challenge. Once larger turbines with longer blades are developed, the industry will, on the whole, switch over to this design. That is a problem from transport firms who have invested heavily in specialised trailers: “This is an ongoing problem,” Collett says, “Since the blade carriers are of a very specialised design and suited for a specific use, their resale possibilities into secondary markets are limited.”

Whether for the good of consumers, or for the planet, the efficient and effective development of new wind generating capabilities is vital. All of these challenges will have to be overcome, and dialogue between industry sectors will be key.

Collett concludes, “Power generation and requirement is a problem. The demand for energy is still increasing. The growing demand for clean sustainable energy is even more important. Renewables are a credible way of providing that. Wind energy is the best renewable source that we currently have and so more wind farms will have to be constructed, both on-shore and off-shore.” 

When Collett delivered these 58.7m blades to Phase 3 of the Muirhall wind farm in Lanarkshire in November 2015, they were the longest to have ever been moved on UK roads. The job relied on Collett’s careful planning and consultation with a range of authorities and stakeholders. Today, even longer blades are becoming standard, reinforcing the need for proper planning.