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Does anyone mathematically proficient (no longer my case, I've been in banking too long) can take a look at that study (http://ref.org.uk/publications/280-analysis-of-wind-farm-performance-in-uk-and-denmark) and check what kind of torture has been inflicted on that data to come from this:

to this:

  1. Onshore wind turbines represent a relatively mature technology, which ought to have achieved a satisfactory level of reliability in operation as plants age. Unfortunately, detailed analysis of the relationship between age and performance gives a rather different picture for both the United Kingdom and Denmark with a significant decline in the average load factor of onshore wind farms adjusted for wind availability as they get older. An even more dramatic decline is observed for offshore wind farms in Denmark, but this may be a reflection of the immaturity of the technology.

  2. The study has used data on the monthly output of wind farms in the UK and Denmark reported under regulatory arrangements and schemes for subsidising renewable energy. Normalised age-performance curves have been estimated using standard statistical techniques which allow for differences between sites and over time in wind resources and other factors.

  3. The normalised load factor for UK onshore wind farms declines from a peak of about 24% at age 1 to 15% at age 10 and 11% at age 15. The decline in the normalised load factor for Danish onshore wind farms is slower but still significant with a fall from a peak of 22% to 18% at age 15. On the other hand for offshore wind farms in Denmark the normalised load factor falls from 39% at age 0 to 15% at age 10. The reasons for the observed declines in normalised load factorscannot be fully assessed using the data available but outages due to mechanical breakdowns appear to be a contributory factor.

  4. Analysis of site-specific performance reveals that the average normalised load factor of new UK onshore wind farms at age 1 (the peak year of operation) declined significantly from 2000 to 2011. In addition, larger wind farms have systematically worse performance than smaller wind farms. Adjusted for age and wind availability the overall performance of wind farms in the UK has deteriorated markedly since the beginning of the century.

Wind power
by Jerome a Paris (etg@eurotrib.com) on Sun Dec 23rd, 2012 at 07:56:06 AM EST

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