This post provides details of the financial analysis of a wind farm in New York which I prepared in writing a piece for the National Center for Energy Analytics where I am a Senior Fellow.
Thank you Gordon for another informative, authoritative and transparent article.
I have a few simple questions: is the decline in capacity factor of a wind farm over time due to increasing down time for maintenance and repair, as one would expect, or are other things at work? If so, one would expect to see a decline in capacity factor and increase in operating costs correlate hand-in-glove. Are figures for operating experience to date available, or is there a lack of transparency to which you referred?
The answer to your question is that we don't know though I suspect that your explanation is correct. What I have observed is that the probability of breakdowns - as measured by extended periods of low or no production - certainly increases with age. Even a few turbines out of operation for 2-3 months at a wind farm substantially lowers the average capacity factor.
We have to rely upon an analysis of reported monthly output by either turbine (in Denmark) or wind farm in the UK, so the resolution of the data is not great. Wind farms certainly don't report outages in the way that larger power plants are required to do. It might be possible to examine day-ahead bidding behaviour of what are called BM Units but only the larger wind farms are not registered as BM Units and in any case the data is quite hard to handle.
In referring to a lack of transparency I had in mind the failure by New York State to give any detailed reasons as to why it had increased the offtake price by so much.
Sorry, I forgot to mention. My analysis of wind turbine/farm performance is contained in my papers for the Renewable Energy Foundation - www.ref.org.uk - on Wind Power Economics in 2020.
Thank you Gordon for another informative, authoritative and transparent article.
I have a few simple questions: is the decline in capacity factor of a wind farm over time due to increasing down time for maintenance and repair, as one would expect, or are other things at work? If so, one would expect to see a decline in capacity factor and increase in operating costs correlate hand-in-glove. Are figures for operating experience to date available, or is there a lack of transparency to which you referred?
The answer to your question is that we don't know though I suspect that your explanation is correct. What I have observed is that the probability of breakdowns - as measured by extended periods of low or no production - certainly increases with age. Even a few turbines out of operation for 2-3 months at a wind farm substantially lowers the average capacity factor.
We have to rely upon an analysis of reported monthly output by either turbine (in Denmark) or wind farm in the UK, so the resolution of the data is not great. Wind farms certainly don't report outages in the way that larger power plants are required to do. It might be possible to examine day-ahead bidding behaviour of what are called BM Units but only the larger wind farms are not registered as BM Units and in any case the data is quite hard to handle.
In referring to a lack of transparency I had in mind the failure by New York State to give any detailed reasons as to why it had increased the offtake price by so much.
Sorry, I forgot to mention. My analysis of wind turbine/farm performance is contained in my papers for the Renewable Energy Foundation - www.ref.org.uk - on Wind Power Economics in 2020.
Thank you for all of that - clear, enlightening and appreciated.