By Paul Homewood
h/t Stuart Brown
https://www2.bmreports.com/bmrs/?q=generation/windforcast/out-turn
It is claimed that although wind power is variable, it is also predictable. After all, we are assured, weather forecasts are now so accurate that they can predict wind speeds.
It turns out that this not the case. Above is the chart from BMRS, showing the initial wind power forecast with the actual outturn over a two-day period.
Below is the explanation of the National Grid forecast:
Based on historical outturn data and detailed local wind forecasts, National Grid forecasts likely levels of wind generation for windfarms visible to National Grid, i.e. those that have operational metering and that are included in the latest forecast process. The forecasts are produced for the period from 21:00 on the current day (D) to 21:00 D+2.Wind Generation forecasts are produced by National Grid’s own second generation windpower forecasting tool. The predictability of the wind varies with atmospheric conditions and so there may be periods where National Grid’s forecast and outturn values differ significantly. Please note that the downloadable data will contain gaps for Original and Updated Forecast values in Settlement Periods that National Grid do not provide forecast values for.
Even yesterday, we can see that wind output was overestimated by more than 3GW, or a third of the forecast.
The “Latest Forecast”, which presumably is made a day before, is naturally more accurate, but has still been up to 2GW adrift.
Fortunately we have plenty of CCGT capacity around to fill these gaps. But when wind capacity has been tripled or quadrupled, such we could be looking at shortfalls of 10GW or more.
via NOT A LOT OF PEOPLE KNOW THAT
February 14, 2020 at 05:21AM
Iowa Climate Science Education 