While National Grid have largely been absolved of blame here, one must question the quantity of reserve generation being held, which is a politically motivated choice regarding funding of balancing services not entirely in NG's control. The 1000GW reserve is a very-long-standing quantity. The widespread disconnection of generation in response to a frequency excursion has been known as a risk for a very long time, and known to be growing especially in line with the uptake of solar plant.
Contrary to some comments above, available generation in the UK is well in excess of 40GW so there is plenty of reserve available "right now" if we choose to run it. As demand increases for EV's, of course, generation has to increase too. There are 10's of GW's of generators applying to connect right now; though how many will actually happen is anyone's guess (see Westinghouse/Toshiba for examples of what happens to many generator applications).
Holding more in reserve means more CO2's and "dead" costs while the network is behaving normally so it is a political decision as to whether you want higher reliability and costs versus more risk but generally lower costs for 9999 days out of 10000.
Balancing services are already very, very expensive even at that historical level of reserve (over £1bn/year); and the real cost of running a distributed network is finally coming home to roost. The business model designed for big static generators isn't really compatible with distributed gen here there any everywhere. Dieter Helm's cost of energy review did recommend going as far as a COMPLETE re-write of the rulebook rather than sticking-plasters being stuck on top of sticking-plasters that we currently have. Windmills in the meantime are banking crazy subsidies whether they are generating or not while network operators effectively have to cover the costs of the windmills inadequacies..
The other really obvious tech to deploy (but still, more capex costs) are the widespread installation of flywheels and synchronous compensation capabilities. But, if they only benefit the world on 1 day out of 10,000 are they worth the expense going on your bill?
In the US the burden of reliability sits with the customer, if you need reliability, you buy a UPS and a generator. In the UK we've been very happy to let reliability burden sit with the transmission network and generators for the last 60 years. Perhaps, in an era of distributed generation everywhere we should be rethinking that policy.
Too bad our politicians have been lead down the road of debating utter garbage for the last 15-20 years rather than looking at real national interests.