National Grid’s Preliminary Report On Blackout

By Paul Homewood

The National Grid has just published its preliminary report into last week’s blackout:

Key points:

Lightning was the original cause, even though such strikes are perfectly common, and do not usually result in such catastrophic blackouts
Hornsea wind farm tripped first, contrary to original reports.
They still don’t seem to know exactly why either Hornsea or Little Barford tripped, though it was obviously due to the lightning.
Along with the loss of 500MW of small embedded generation (wind and solar), the total loss was about 1878MW
National Grid has 1000MW of automatic back up power available, incl 472MW of battery storage. Clearly this was not enough.
Following the lightning strike, the grid’s protection systems worked properly

Certain aspects don’t seem to have been highlighted:

When Hornsea wind farm is fully operational in the next year or so, it will have capacity of 1200MW. In addition, Hornsea Project 2, due on line in 2024, will have an additional 1386MW capacity. It is not clear whether it will share the same transmission lines, but to have so much capacity at risk of tripping off is clearly far too big a risk.
The importance of inertia, provided by heavy rotating turbines, is not discussed. If more gas and coal power had been running at the time, would the blackouts have occurred. Just as importantly, what will happen in a few years time, when gas is no longer part of the normal baseload and is simply turned on when the wind is not blowing?
While the National Grid claim that their backup power worked properly, such measures are only useful for a short period of time, maybe an hour. The report does not mention that gas power very quickly made up the shortfall, within about half an hour.