Welcome to the fourth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’ll be crunching the numbers on wind potential in New Zealand. For the background to the work please our introductory post here. Also check out our earlier posts on the potential of hydro power and geothermal. Note: the units are in kWh/day/person – ie. if you ran a 40W lightbulb for 24 hours, it’d take ~1 kWh over the space of a day. We then divide it by person to give you a sense of the scale of the resource proportionate to the size of the population. Be sure to check out the methodology.
New Zealand has significant wind resources with much of the country having average wind speeds in excess of 6m/s. Even with the amount of development since the last report in 2009, we’ve only added around 0.64 kWh/day/person.
Another 1000 turbines (around 2 times the existing capacity) could deliver 4kWh/d/p while a reasonable upper limit (avoiding national parks, settlements, structures, waterways, steep slopes, low wind areas and assuming 50% willingness by landowners) has been calculated at 83kWh/d/p [cntnmby], with 32kWh/d/p available at competitive pricing. 33kWh/d/p would see windmills on 0.6% of total NZ land area, that is, if clustered, an area the size of Stewart Island.
Offshore wind hasn’t been studied seriously because it is twice the price of onshore wind, and thus will not be a viable option in the foreseeable future. Furthermore, most of New Zealand does not have wide shallow sea areas like the North Sea. This restricts opportunities, as wind power gets very expensive in deep water. An approximate estimate of offshore contributions based on shallow water extent might put the potential at 40kWh/d/p.
High altitude wind captured using kites is another bet, but we’ve yet to find a case study of this resource for New Zealand, and the technology for harnessing it is still in its infancy. We’ll assume a capacity of 0 kWh/d/p until proven otherwise.
Summary: There is a pretty substantial resource in wind for New Zealand – it helps that we’re windy and have a relatively low population. We think there is a reasonable argument for around 30 kWh/d/p. Also, it works well that our other main form of renewable power is hydro, as this can be used to balance out the variability of wind.
In the next post: we summarise the potential of wind, hydro and geothermal and discuss the implications of our findings.
UCSD prof. Tom Murphy of Do The Math assesses the scale of resource in both wind and solar.
Carlos de Castro, a professor of Applied Physics in the University of Valladolid in Spain has written an excellent paper published in the Energy Policy Journal called Global wind power potential: Physical and technological limits. It’s behind a paywall but he wrote a summary of the paper which can be found here. He disputes the overall size of the resource — not so important for New Zealand, but interesting nonetheless.