Apart from the more obvious problems presented by physical obstacles such as bridges, tunnels and tightly bending roads to extra-large components, an increasingly global market and stricter regulations are all keeping heads of logistics and transport planning on their toes.
These days longer blades, heavier nacelles and bigger tower sections mean that wind-turbine components are often considered "super loads" by transport authorities. This means that transporting them from manufacturing facilities to project sites requires close co-operation between turbine manufacturer or component supplier, transportation and logistics providers, state or local-authority transport officials and ports and port authorities if any part of the journey is carried out by sea.
Transportation can represent as much as 10% of the capital outlay of a wind project, which, according to the American Wind Energy Association (AWEA), is why manufacturers in the US now want to set up shop as close as possible to the ultimate point of turbine delivery to improve competitiveness.
Transport and logistics is one of the main reasons why the US market shifted to 67% domestic content for wind turbines, with more than 550 manufacturing sites across the country supplying components, according to AWEA.
However, this is not the case everywhere. The industry has come a long way from being centred around Denmark and components are sourced worldwide. But a global supply-chain network requires a very flexible approach to transport. Timing of deliveries, customs controls, restrictions on dimensions, port regulations and road permits can all pose obstacles that need to be overcome without adding significant costs.
More red tape
In addition, as the market matures, the advantages of greater knowledge and experience in transporting wind components have been counterbalanced by more regulations, observes Holger Erhardt, project manager at Siemens responsible for onshore logistics in Europe, the Middle East and Africa. He believes more restrictions will be imposed on the heights, loads and lengths of equipment to be shipped and that, from a logistical standpoint, the 154-metre rotor diameter for its 6MW machine is the current size limit.
Towers present one of the greatest challenges for transportation because the largest part of the flange is too big to pass through many bridges in Europe. German manufacturer Siemens is working on new tower design concepts, such as a bolted steel structure consisting of easily transportable sections to install on location.
Erhardt says anything above 4.3 metres diameter will be challenging for a lot of projects. "In order to get permits to transport goods by road, all of a sudden you have to do bridge calculations," he says. "In Germany, where bridge calculations had not been requested before, they are becoming better educated, but also more concerned and conscious of them." The same applies for ports and harbours. Siemens has a project in Morocco where the port authorities only allow a limited amount of ships into the port because of the length of the blades.
New regulations have cost implications. Since 2008, ships emissions are more tightly regulated, meaning that ship owners are having to upgrade their fleets to comply - an expense passed on to the wind industry reliant on ships to transport equipment.
Components sometimes end up travelling much further because of bureaucratic obstacles. Erhardt recalls an instance of having to take a long detour offshore purely because the permits were easier to get for shipping than for road transportation.
AWEA's transport and logistics working group is working with the American Association of State Highway and Transportation Officials to harmonise the permitting process across states.
Efficient transportation is hampered by the differing state permitting rules for oversize loads, according to Amanda Fortner, who leads the group: "These differences may be as small as different coloured flagging required on loads. By harmonising state-by-state permits, the time and cost of highway transportation can be decreased." So far, there is no move towards harmonisation of permitting in Europe.
In the US, transport and third-party logistics providers are seeking closer co-operation with manufacturers to ensure that efficient and cost-effective solutions are available. The working group is drafting a guide that will help turbine manufacturers' research and development and engineering teams understand and work within existing transportation constraints.
Another challenge is knowledge of the business relationships between countries. Erhardt explains how Siemens had to negotiate getting equipment into Morocco when supplies from a Ukrainian sub-contractor were viewed with suspicion by Moroccan authorities as there was no existing business relationship between the two countries.
While most equipment is transported via road and sea, German manufacturer Enercon has been using rail where possible since 2002. It has revitalised a disused railway network near its headquarters in Aurich and its railway company transports goods between production facilities and nearby Emden harbour for export, as well as between its manufacturing sites in Aurich and Magdeburg. The company claims that one train trip from Aurich to Magdeburg and back replaces 40 lorry trips, helping Enercon achieve CO2 savings of about 72% and save on fuel costs.
And Enercon is not the only one. In September last year, Danish manufacturer Vestas carried out one of the first transportation of blades by train in Europe, from its manufacturing plant in Lauchhammer, Germany, to Esbjerg harbour in Denmark for shipment. The delivery consisted of nine 55-metre blades for Vestas' V112-3.0MW turbine and the train of cars was almost 700 metres long. It plans to transport 700 blades a year in this way.
Rail cost reductions
Vestas claims that using rail could reduce costs by 10-15% compared to transporting them by road and would be far quicker - it takes one locomotive 20 hours to transport nine 55-metre blades from Lauchhammer to Esbjerg. By road, it takes nine trucks and 18 pilot cars 36 hours to cover the same distance.
It could also reduce CO2 emissions by 30% as the main part of the rail route is electrified. Vestas says it is planning to design rail connections between other manufacturing facilities in Europe.
Transport and logistics company SNCF Geodis and transport engineering company Captrain Solutions worked with Vestas on the project. They altered carriages and developed special equipment to ensure the safe passage of blades through tunnels and bridges and around curves in the tracks.
Ischtar El-Radhi, who manages heavy and oversize transports for Captrain Solutions, is confident that this transport technique can be transferred to other routes and confirms that projects with other turbine manufacturers are ongoing.
The company is targeting Eastern Europe because the greater gauge of the tracks, and much longer trains, mean there is the potential to transport more blades. The solutions could also be extended to other components such as nacelles.
Vestas is not the only manufacturer to use rail to transport goods. Siemens has used it to transport components in the US from its blade factory in Fort Madison, Iowa since 2009. However, Erhardt does not think that there is a trend towards using more rail than road. "Rail makes most sense where you have two distinct points and are moving a lot of components from one point to another. This means there needs to be a critical mass to make it a worthwhile and cost-competitive solution," he says.
Erhardt points out that there are solutions to most logistical challenges if you have the money to pay for them. Expensive solutions such as using cranes to lift equipment over obstacles before reloading it onto trucks can only be justified if the project can pay back the expense. "As a component provider we need to make sure we produce components we can transport," he says.