The question for this blog post is a rather simple minded one. But sometimes simple questions are worth asking. So, let’s answer a couple.
How big is the average wind turbine in America?
Oddly, Google does not throw up an answer to this question. So, I will have to estimate this here.
We can do it using data from the United States Geological Survey, which I discussed last week. They publish a data set covering most of the wind turbines in existence in America in July 2013. This provides geographical co-ordinates, turbine height and capacity of each turbine, more than enough to provide an answer to the question above.
The data set covers turbines of a total capacity of 60.7 GW. According to BP, the total capacity of America’s wind farm fleet was 61.3 GW at the start of 2013. So, we can be reasonably confident that this data can be used to get a reasonable estimate of the average size of America’s turbines.
In total, there are 41,058 turbines. This means that the average capacity of America’s wind turbines is approximately 1.5 MW. Similary, the average height is 113 metres.
Has the average size of American wind turbines increased over time?
USGS also tells us when a wind turbine came online. As a result, we can estimate the average size of wind turbines that came on each year for the last 20 years.
Here is a time series of the evolution of the size of American wind turbines.
Average turbine capacity doubled between 2000 and 2010. However, the average capacity of new turbines appears to have reduced slightly in recent years.
Turbine height did not double, but rose by just under 50%. Keep in mind that the kinetic energy that flows through a wind turbine is proportional to the swept area of the turbine blade.
In the long run there is no technical reason the average turbine height will not keep rising. 10 MW wind turbines are now planned for offshore locations. However, it is likely that there will be a cap on the maximum size because of NIMBY opposition to turbines – no one likes to live near a 200 metre tall wind turbine. So another doubling in average turbine capacity may be off the cards.