... the no-nonsense name given to the situation where end-users of energy just stop using because the price is higher than they can justify paying. There are shades of this phenomenon: sometimes reduced demand for (e.g.) power or gas is actually fuel-switching; sometimes it's locational (switching production to another site). It shouldn't include short-term temporal flexibility, though, which is more properly "demand-side response / management", and if based on intelligent price signals and value-sharing, is just optimisation.
True demand destruction is demand just gone, totally unsatisfied. Like demand for haircuts: a haircut delayed is an absolute reduction in demand.
It's been happening at the industrial level ever since this energy crisis kicked off, i.e. in 1Q 2021 (sic) - ironic, since the initial cause was increased industrial demand arising from all nations' post-covid recovery efforts. Across Europe, demand for natural gas has fallen noticeably (5-10%) this year, not all of which will have been switching. But neither electricity demand, nor residential demand altogether, has really dropped off at all. Winter is likely to change all that.
So: gas and electricity, generally thought of as highly inelastic in most sectors, may be about to be stretched quite considerably. What will we find? Some BTL commenters here have suggested it could prove unprecedentedly elastic. That may be right: the price pressures are certainly unparalleled. And BG / Octopus et al are coming up with incentive-based schemes (long overdue) that will hopefully contribute a bit of intelligent assistance to end-user decision-making.
While the market evolves its new dynamics, in the UK for some reason politicians want no part of it. Truss won't hear the word 'rationing' mentioned, and Labour don't want to 'patronise' people by telling them to think about putting on the extra jumper. Commendable laissez-faire?
Well, Teenager Truss is certainly in the grip of some caricature drunken Speccie drinks-party doctrine: but I think it's rather that she doesn't want to be associated publicly with anything that smacks of failure or defeatism. Absolutely pathetic: all that happens is that the National Grid, by default, imposes whatever rationing regime it sees fit. And/or, a more considered form of rationing is indeed being hatched between Whitehall and the Grid, but nobody's to mention it in Her presence. These are the ways of the Court in absolute monarchies with very weak rulers. Even Thatcher made a proactive response to the AIDS crisis, and wanted to be told the facts (at least, until she went poll-tax potty after 1987).
And of course, end-users will form their own action plans, however blunt and sub-optimal they may be. We can only wish them all well, when cold weather afflicts us in the coming 6 months.