The plot thickens re: Friday’s blackouts. A very nerdy thread...
So: initial expert analysis suggested Little Barford gas plant tripped first, followed by Hornsea wind farm shortly after (as I pointed out here
https://twitter.com/emilygosden/status/1159919198900019207?s=21when some immediately blamed it all on wind farms)...
Subsequent analysis has also suggested this chronology, per these graphs yesterday from experts at Limejump and Aurora. Both show a drop in frequency blamed on Little Barford, a slight recovery, then further drop blamed on Hornsea. 
What’s interesting about these graphs is they suggest loss of Little Barford (~700MW) alone sent frequency below statutory minimum of 49.5Hz. Yet Grid is supposed to cope with a 1GW loss & has withstood similar drops before - hence questions over potential issues with inertia etc
HOWEVER... when I challenged National Grid on this point... its response was that these graphs are wrong. Duncan Burt @DBBurt says that “any analysis that is splitting the frequency trace into two discrete trips is incorrect”. thetimes.co.uk/edition/busine…
As I understand it, that means National Grid thinks it was only the combined loss of both Little Barford and Hornsea (up to ~1.4GW) almost simultaneously that sent frequency below 49.5Hz. The system is simply not set up to withstand a sudden loss on that scale.
Where does this leave us? Well, still nothing is confirmed yet, and we still don’t know what caused either plant to trip. Now apparently not even clear which plant tripped first.
There were lightning strikes near Little Barford, but RWE says not clear that was a cause. It says the “turbine generator automatic control system detected an abnormality and initiated a safety shutdown”.
Orsted is saying nothing yet about what caused Hornsea to trip, but investigations are understood to looking at the way it is connected to the grid and disconnection settings.
But if the conclusion is indeed that National Grid simply isn’t set up to handle a sudden loss of power on the scale seen Friday, the question is: should it be? How large an unexpected loss should it be able to cope with without risking any interruption?
As Aurora pointed out yesterday, if/when Hinkley Point comes on that will mean there are far larger single plants on the system that could potentially trip - while renewables will further reduce system inertia.
And that means if we want to prevent the risk of any blackouts, we potentially may need a lot more fast-acting backup - such as batteries, gas reciprocating engines and demand-side response. (/end of thread 🧵) thetimes.co.uk/edition/busine…
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