Monday, October 12, 2009

Wind Energy - Doctor Jekyll and Mr Hide

Wind energy's fortunes in New Zealand continue to be mixed. Most people's attitude to wind tends to be similar. Most people would say that wind power is a good thing but most would also say "don't build one anywhere near me!"

One of winds problems is that there tends to be a belief that a windfarm can be built just anywhere and that energy companies are just being difficult in wanting to build them where locals don't want them. The problem is that windfarms need to be built where it is windy. Of course lots of places are windy but being occasionally windy isn't good enough. A place has to be fairly constantly windy and this isn't as common as most people think.

New Zealand has such windy places. Places where it blows strongly regularly. New Zealand is a good place to build windfarms but not just anywhere. For example, very few windfarms look feasible in the upper North Island. Locations that can be very windy, such as round the Kaipara and Manakau harbours, don't tend to be consistently windy and no windfarm in this region yet looks economic.

Alternatively the Manawatu region blows not just a lot but often. In fact the problem in some of the Manawatu ranges is almost that it is too windy. Wind turbines are mechanical devices and can be overloaded. Most Manawatu windfarms require the highest specification turbines available to withstand the mechanical stresses. However, this adds relatively little cost (or input energy) to sites that can produce a lot of wind energy.

A big issue in the Manawatu ranges is not that windfarms here have been blocked but that there are now so many of them. Local residents have a reasonable point to make in that adding more and more windfarms to the skyline does make a difference. And, as more of the remote sites are developed, the newest project proposals must, necesarily, be closer to existing residents and amenities. The residents of Palmerston North and its environs might feel somewhat aggrieved that they are bearing considerable brunt for the development of New Zealand's energy future. They aren't alone, however, the Waikato, Waitaki and Clutha Rivers have been irrevocably altered and give more energy each than the Manawatu yet does. The Bay of Plenty region is also being heavily developed, although with geothermal plant which has less obvious local impact. Manawatu's main issue isn't that development hasn't been concentrated in a region before but that windfarm developments are so obvious.

Many might argue that small scale generation is the future and they could be right. However, there are currently three significant barriers to this:

  1. There are economies of scale
  2. Small scale generation still needs to be built where the resources are significant (a small wind generator in a place where it isn't windy may never recover the energy it took to manufacture and construct)
  3. The electrical networks have significant technical challenges before signficant small scale distributed generation can be safely and economically exported.

What are we to do? In the absence of fossil fuel use (which would currently need to be imported unless New Zealand makes a big commitment to coal) then the major development opportunities for large scale energy use are wind and geothermal. Both are practically limited relying on technology to deliver more developable areas. If wind is a major component of New Zealand's energy future, which makes sense, then someone has to put up with them. And if we are to make the most of the resource with the smallest overall disruption and least input resources then they need to be built where it is windy, consistently windy.