Re: If have the extra power to refine more petrol...
Not even close - the majority of the energy used in an oil refinery is thermal energy - and guess what - it is an oil refinery so they get the thermal energy by burning oil.
The push to EVs has the following major problems
1) The cost of EVs is still far higher than the cost of ICE vehicles
2) There is insufficient generation to handle a significant proportion of EVs even in windy periods where wind farms deliver maximum output (and during calm weather wind farms produce zero electricity).
3) Even if by some miracle the electricity generation was available, the distribution system is not sized to handle the additional load. The biggest problem is with local distribution in towns and cities - the cables and transformers are not sized for the additional load. As (in the UK) urban electricity distribution is done with underground cables the majority of urban roads would need to be dug up to replace the cables with bigger ones.
Current UK peak electricity demand is just under 50GW - approximately 0.75kW per person in the UK. Medium rate domestic EV chargers charge at about 7kW. There are over 33 million cars in the UK - if all were EVs charged with domestic chargers overnight the peak electricity demand by the EVs alone would be well over 200GW - over 4 times the current peak demand.
Because wind power is unreliable (the UK does get some calm days most years with very little wind power available) there has to be sufficient conventional generation (coal,oil,gas,nuclear) to cover shortages.
One further note - EV ranges are always quoted for mild conditions when the vehicle is not using heating or cooling - with an ICE vehicle heating is effectively free as it uses the waste heat from the engine - for an EV the power for heating comes directly from the same battery that powers the motor reducing the range considerably.