Everybody paid very low energy prices, because new companies came into the market and bought cheap energy on a day-by-day basis, rather than forecasting and hedging future volumes properly.
Nobody complained about those very low prices, and the big energy companies lost billions of pounds because they ran their businesses properly, and couldn’t compete with the little cowboys. Ofgem encouraged the little cowboys to take on customers. The little cowboys didn’t care about going bust (often taking customers advanced money with them) because they knew Ofgem had a mechanism to transfer customers and cover the costs.
Then global energy prices shot up. All those little cowboy companies were caught swimming naked when the tide went out. They went bust because they had promised Mr Bloggs they could supply him at 12p a unit, and it cost them £3 to buy. The big companies had hedged their volumes (there’s a cost to this), they were safe.
Ofgem forced those big companies to take on people from bust suppliers. The big companies weren’t expecting them, so had to go out and buy extra £3 a unit energy to supply them. They could claim that money back from Ofgem and rightly so, it wasn’t their fault.
And Ofgem claims that money back from consumers everywhere, most of whom had originally benefitted from prices that were much lower than they really should have been.
The little cowboys don’t exist any more so they won’t pay, and global energy prices are much higher than they used to be, so this, and the cost of failed suppliers (effectively representing the prices that were unsustainably low three years ago) is what you are paying for now.
Even now, big suppliers over the last 5 years have made average margins of about 2.2%. So for every £102 of energy they supply, it costs them £100.
The people you should be most annoyed with are the little suppliers, and Ofgem/the Government, for allowing it to happen.
Meters and PAYG is a separate topic, but if people are allowed to default on their debt, that will also be spread across the population as a whole, so you will be paying the bill of your defaulting neighbour.