Cutting transport costs down to size

US: Wind turbine transportation logistics can be a deciding factor in scheduling and costing a project. The challenge of moving equipment from ports and factories to wind plant sites will only become more formidable as the industry shifts to larger, multi-megawatt turbines. The additional hurdles to safe and timely delivery are likely to include pinch points in the capacity of the heavy equipment needed to move larger equipment, a shift to new modes of transportation and a limited labour force that may lack the required training.

On average, transportation amounts to around 10% of the upfront capital cost of a wind project. Prices are rolled into the purchase price of wind turbines and shipping costs dictated by geography can vary sufficiently between manufacturers to sway the choice of developers. For example, a developer with late-stage projects may be inclined towards a turbine manufacturer located close to its sites: it is no coincidence that Gamesa installs more turbines close to its manufacturing facilities in Pennsylvania than in other parts of the country.

Multi-megawatt turbines cost more to transport since more and bigger equipment is needed to move a single turbine and its tower sections. The major workhorses for carrying big wind equipment are the 19-axle trailers for nacelles and Schnabel trailers for tower sections. The 19-axle trailers, including a high-horsepower truck, cost around $1.5 million each. Depending on the weight of the nacelle and any slopes along the route or at the project site, a so-called push truck can also be required to help shunt the first trailer from behind, adding $175,000 to the cost.

Larger nacelles for 2.5MW machines weigh up to 195,000 pounds (88.5 tonnes). At these weights and beyond, new strategies are required, such as breaking down the nacelle and shipping the generator and gearbox separately, to be assembled at the project site. That is already the standard procedure for Mitsubishi's 2.4MW turbines, which are shipped in three pieces and assembled on-site by construction companies.

Typical tower sections for 1.5MW turbines require one-and-a-half Schnabel trailer units to deliver the tower sections. A turbine in the 2.5MW range will typically require two-and-a-half Schnabel units because the tower sections are wider and heavier to account for the additional nacelle weight and the hub height may be higher.

As with all bigger units, however, higher transportation costs are offset by the greater energy production from each unit. While it is natural to assess transport on a per-turbine cost, a developer can assess the cost on a per-megawatt output. A 100MW nameplate wind project can use either 40 units of 2.5MW or 67 units of 1.5MW.

Stretching the transport supply

While the transport costs may even out, the shift to larger turbines is likely to stretch the supply chain of the bigger equipment required. Truck fleets are ageing and a large capital expenditure will be needed to cover an increase in demand for larger components.

The existing supply of 19-axle trailers may not be able to handle the demand to transport nacelles. One project with a 1,500-mile (2,414km) route and delivery schedule of six per week would take at least 15 tractors and trailers. Multiply that by ten projects starting across the country at the same time and you would need 150 19-axle trailers on the road at any given time. At $1.5 million each, the magnitude of this hurdle becomes apparent, especially as there are only an estimated 300 of these trailers in the US now.

Another pressing consideration is the labour force and infrastructure required to operate the equipment. Over the past year, equipment carriers have made significant cuts in trucks and personnel. The majority of drivers are from the baby-boomer generation and are near retirement or have been forced into retirement by the economic slowdown. 

With recruiters and trainers being laid off, younger drivers are not being trained to fill these gaps. With fewer mechanics, ageing trucks and trailers are being worn out or taken out of service. All this leads to the question: Is adequate infrastructure in place to handle the upcoming demand associated with larger turbine sizes?

Another factor is that shipping by truck is not an easy process from a permitting standpoint. It can take four weeks to get one permit from a state agency, and most shipments cross multiple states with their multiple regulatory jurisdictions. As turbines get bigger, permits will become more complex and costly. A new risk in the current cash-strapped times is that state agencies or lawmakers in wind-rich states may see wind-equipment transport as a captive market, ripe for increased permitting costs.  

Moving off the roads

Two or more years ago, few wind components were moved by rail. Now, turbine manufacturers are designing components around the clearances available on standard rail routes. One major manufacturer has recently modified the nacelle of its larger unit to fit better on trains.

Rail trans-load facilities, or distribution centres, are popping up across the country, offering shorter last-mile hauls and the chance to reduce the quantity of equipment needed to fulfil delivery schedules. But these facilities will need to keep pace with growing component sizes by providing better ground compaction and through-site preparation.

The prospect of fewer trips is attractive to developers and turbine companies alike: 150 different truck deliveries, each with a nacelle, can be turned into a single train shipment. Train routes are designed for super-loads, whereas roads rarely see them and often present physical obstacles for trucks. For large projects, the cost savings can even justify a developer building a new section of rail, a spur line, off existing rail near the wind site.

Barge shipping is a new option for wind components and is expected to see increased use - the US has a vast network of shipping lanes through its Great Lakes and major rivers. Although shipping time can be double that of transport by truck, barge companies are increasing the attractiveness of this alternative by making it extremely cheap.

With the US market finally realising the benefit of larger turbines, the economic downturn may actually help to stave off a logistics nightmare. The slowdown, unwelcome as it may be, will give the market time to stay ahead of demand. More 19-axle trucks and Schnabel trailers could be put on order and other options weighed up. Manufacturers and developers can plan logistics strategies so they are ready when the next wind boom comes into full swing.    

Taylor Gosman is director of project development, wind energy group, Energy Transportation Inc