How much SHOULD household energy bills be?
One possible benchmark is to combine the traditional ten percent definition for FUEL POVERTY, which means a household is deemed to be in fuel poverty if it needs to spend more than 10% of household income on fuel and the definition for POVERTY meaning 60% of median household income
In the UK in 2019 the median disposable income is £29,400 according to The Office for National Statistics
Ten percent of 60 percent of the median (or 6% of the median if you prefer) = £1764; compare this to the actual average household spend on energy: £1254
This suggests the domestic consumer could afford to pay a modest premium for more renewable / low carbon household energy … but multiples of 3X, 5X, 10X would plunge large numbers of people into fuel poverty