This data-file tabulates the ‘decline rates’ of 1,215 US wind power plants, which have reported data to the US EIA, using in-house web-scraping and aggregation software.
Across the entire data-set, we find wind farms take two years to ramp up. Generation peaks in year 3. It declines at 1.0% per year up to year ten (when production tax credits tend to roll off), then decline at 3.5% from year 10 to 18.
However, the data are highly variable. Hence this data-file gives full granularity on the underlying data-points, so you can stress test assumptions. We also discuss variables that may lower future decline rates.
The ‘Conclusions’ tab explores the consequences. US wind generation profiles are not dissimilar from well-managed oil and gas fields; some projects may suffer 2% lower IRRs versus forecasts if they have not factored in declines; and declines will also become more material over time, slowing the ascent of wind’s share in the power mix (chart below).