On Friday 9th August 2019 the 727MW Little Barford gas-fired plant went off line in an unexpected outage, followed two minutes later by the 1,218MW Hornsea 1 offshore wind farm. This caused such a drop in the available power on the national grid that the grid went into "self-protect" state, cutting power to prevent further damage. The result of a widespread power cut across southern Britain for several hours.
The statements from the generators indicated that single generator failure is "common" - multiple times per day - and this can be coped with very well, but that almost simultaneous failure of one generator and one transformer is what caused the problem on Friday. I believe the inquiry will focus on why a dual failure was not coped with.
The other question I have is why the effects of this were apparently randomly distributed across the country. I live less than 30 miles from the Bedford gas station and not so very far from the entry point for the wind array and yet my house wasn't affected, and yet places from Essex to Lancashire and the West country were cut. For me it points to a need for a more resilient grid, with more connection options and possibly more effective / faster control systems. I hope, also, that more of the infrastructure can be buried, where it is safer from damage by wind and rain.
My own sentiment is that the UK needs to move towards a much, much more decentralized generating model, where generators of 1..10MW are far more common, whether from water, wind, solar or tide, as well as pushing large volume small scale battery storage -- of the form of the Tesla wall battery or electric vehicles. Some of these must be from new (smaller) reservoirs, which have the dual benefits of additional water and electricity, both of which will be needed in the near term. Some commentators have talked in terms of the far lower "inertia" of some modern generating methods, in reference to the continuing motion of turbines after the power input has died. A gas power station doesn't stop generating power immediately, even if you cut off the gas supply, while a solar power plant can be stopped very fast by a passing thundercloud.
One of the reasons for not creating more small scale storage and generation is that larger capacity generators are more economically efficient (and more electrically efficient as well), partly because there is low demand for small (50KW..1MW) turbines. My proposition is that the Govt. order from appropriate suppliers several thousand such items, which should enable good economies of scale, and then sell them for schemes within the country at roughly cost (to Govt) price. I would hope that would boost the economies of small scale generation and so buffer the grid in general. I accept this would not solve the efficiency problem, but it would help a lot economically and in this brave new world we have to match the generator capacity to the available power in an area because it is usually impractical to do otherwise.
By way of comparison, in electronic circuit design, engineers don't just include one large capacitor for (very necessary) power rail smoothing, because resistance gets in the way; instead we have large numbers (20..50 or more) of distributed small (perhaps even tiny) capacitors placed close to the power sinks.
The UK (probably the world) has a major shift to implement from small numbers of large power stations to very large numbers of smaller ones, which will require a significant change in the implementation of the electricity distribution network. (This is not my opinion, but that of the networks themselves). I hope this recent episode shines a light on this need and accelerates the diversion of funding required for it to happen here.