For wind farms, bigger really can mean better

WORLDWIDE: Setting the scene for this supplement on major projects has raised a number of questions about what constitutes a large wind farm and why we build them. Why, for example, develop a very large wind farm rather than several smaller ones? Do we build such large wind farms because they look more like conventional power stations and, if so, should we be taking a more progressive approach? Is ego or economics the main driver?

GL Garrad Hassan works across the world, providing services to projects of all sizes, at all stages and in a variety of different cultural, economic and political environments. We have been involved with every wind farm that has cost more than $1 billion, all the major wind farm portfolios, and the largest project in North Africa. In China, we have worked on a single farm rated at 3.8GW and another rated at 10GW – more than the combined installed capacity in France and the UK, and with an annual energy output comparable to a nuclear reactor. This makes every other wind farm look small.

In civil and mechanical design terms, a very large wind farm is not really special; to date they have used standard turbines designed to be suitable for a range of sites. There is an argument for large farms to use turbines tailored to the specific site: remote sites without residents might allow for a relaxing of noise criteria, for example. However, it remains to be seen just how large a project needs to be in order to justify such an approach commercially.

Electrical design certainly requires special consideration for larger wind farms. In particular, the effect that such a project has on the pattern of generation and its impact on the local or regional grid have been key considerations in China.

The electrical balance of plant design is also different for large projects. Their size offers opportunities to optimise reliability and efficiency; for example, incorporating features such as multiple substations and dual transformers can allow full or partial production to continue during certain outages of plant equipment.

A larger project can open doors to more sources of money precisely because of its size – it therefore offers a boost to local economies and allows politicians to point to a success story or the meeting of a target. Project finance remains a key source of investment for projects of any size but many larger ones in the US have used the bond market rather than the project finance route. In Asia, it is common to use corporate or equity-style finance. The search for alternative sources of investment or financial products is likely to be a continued trend for large projects and we expect to see ongoing innovation in this field.

There is no way to escape the fact that large projects require a lot of coordination and experience. Ultimately, the foundation for success is often the strength and experience of the project developer or owner/operator in the face of a combination of complex markets and high investment requirements. The increasing prominence of large industrial names in the wind market will have been obvious to observers over the past few years.

Logistical benefits

Purchasing power is a clear benefit of a large project, providing an opportunity to optimise construction and operations logistics. The construction business, by its very nature, is cumbersome because of the multiple skills required and the planning and managing of them. It often makes sense for a large project to use a dedicated team for a significant time, bringing cost and social benefits. The establishment of a large project in a single location also opens the way to a substantial operations and maintenance base, which should in turn make for better availability and lower costs. Such activity can also benefit the local area by offering a sustained source of employment.

Wind energy has the highly attractive characteristic of being able to be both large and small. In reality, the physical size of a single onshore wind farm is dependent on the available space; in places with an abundance of space, large projects are likely to be the norm. Large portfolios, on the other hand, are possible almost everywhere. This remarkable advantage of wind technology means that it can be sized to fit the opportunity; in the end, a successful project comes from understanding this opportunity in detail and maximising it by developing the best technical solution, rather than a one-size-fits-all approach.

On a personal note, though, having been in the wind business for 30 years, the reality of wind farms reaching the size of conventional power stations is something I have been anticipating for a very long time. There are still places that offer opportunities to develop extremely large single farms. In Inner Mongolia, for example, where ambient turbulence levels and winter minimum temperatures are very low, a site-specific turbine and an abundance of space could make for something really special. The thought of potentially being involved in a project of that nature is extremely exciting.

Dr Andrew Garrad is chief executive of GL Garrad Hassan

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