In deciding what to do about the cost of energy, it's important to understand how markets work, what will happen if we do nothing, and what effects various interventions would have.
The problem is that the supply is insufficient to meet demand. This is because of a mismanaged interventions in the market which were motivated by green goals. The sensible way to manage a transition would have been to subsidise green energy sources and then let fossil fuels gradually go out of business as they cannot compete with green energy (whether because of the subsidies or because technology has improved to the point where green energy is cheaper). Instead the policy has been to suppress fossil fuel supply, sometimes with dishonest policies, such as buying gas from Russia so that merely domestic production of fossil fuels can be reduced - which obviously is not in any way green as green policies need to take into account global effects.
What would happen if we left the market to sort it out?
More demand than supply causes the price to rise until the imbalance is corrected. There are two complementary effects - the price rise directly suppresses demand as people buy less either because it is no longer good enough value for them or because they simply cannot afford that price. The rise also means that supply becomes more profitable, leading to sources that previously were not profitable to become so, contributing to the supply, but also it stimulates investment in new sources (possibly by spending money that would otherwise have been invested in something else).
So the market will fix the imbalance by itself. However, unless you're a right-wing idiot who worships the market, this may be unsatisfactory and require intervention. In the case of energy, the obvious problem is the hardship caused to poor people who cannot afford the high prices.
Compared to not intervening, what effects will various interventions have?
So what happens if we subsidise energy prices generally - such as by cutting VAT on fuel? This means that someone who has only £100 to spend on energy gets more for their money, so they use more. And anyone who has a choice over how much they spend, similarly has an incentive to use more. That's bad. It means that in the face of insufficient supply we have increased demand. The good news is that some of the money that would have gone in tax may instead go to suppliers, which will tend to increase supply, but unless all goes to suppliers (which is surely not the intention) it is overall bad.
What if we subsidise prices for only the poorest? Well, this will make them use more energy. The price will rise to a higher equilibrium, which may make the subsidy insufficient (both for those receiving it but also by causing hardship for those just over the threshold for receiving the subsidy). A big problem with this intervention is matching the poorest with the energy they pay for.
What if we simply give the poorest more money? This will allow them to spend more on energy, so it does not suppress demand as much, but some of the money might be spent on other things, so demand may not be as high as with direct price subsidy. The great advantage of this intervention is that we (presumably) already know who the poorest are through the benefits system, so it should be easy and cheap to implement (though anyone who has interacted with the benefits system will know that it doesn't actually work very well) - or, at least, easier and cheaper than constructing a separate parallel system for handing out money. The problem with this is finding the money to hand out.
What if we give the poorest more money and increase VAT on energy to raise the necessary funds? This may seem crazy, but it actually works. The increased tax suppresses demand from everyone, countering the effect of the poorest having more money (which must account for the increased tax) and therefore not reducing their demand (as much as doing nothing). It also redictributes money from the richest to the poorest, which is often seen as a good thing in itself.
What about giving the poorest more money funded by a windfall tax on very rich energy suppliers? Well, since the rich energy suppliers are foreign companies (and may be owned by foreign governments) they are outside the reach of the UK government (short of invading and seizing them), so it's impossible to tax them. UK sources, such as the North Sea oil fields are already heavily taxed and increasing tax will obviously reduce supply (tax is currently 30%+10% - https://obr.uk/forecasts-in-depth/tax-b ... -revenues/
). If you ever want to see an example of gross profiteering, look at how much tax has been paid on oil production.
And finally, what about a price cap? This is the most insane and disastrous intervention of all, and why the current situation is as bad as it is. Without price rises, demand is not suppressed, and supply is not increased, so the gap inevitably leads to failure of supply. Suppliers will refuse to sell where they can sell abroad at higher prices, so their energy must be taken by force. Where the energy is imported, suppliers will either refuse to sell at a loss or go bankrupt as has heppened to lots of suppliers already. If suppliers are nationalised, as has effectively happened with Bulb Energy Ltd, ever increasing subsidy must be provided to allow for the continuing losses. If this intervention is continued, it will result in all suplliers being nationalised and requiring ever increasing subsidy until the nation as a whole is bankrupt or actions by sane foreign governments to increase supply result in the crisis gradually ending. Since the cost of Bulb alone is approaching £2bn already, we could be paying the cost of this for a very long time. The current price cap should be abolished urgently.
Remember that however bad things are, it's always possible to make it worse.