Re: Still a problem though
"Major power supply upgrades may not be needed, if local energy storage is available."
Sorry to burst your bubble, but....
You might not have to overbuild the GRID to such an extent, but the charge/discharge losses through battery cycles mean that this stuff really is intended for peak trimming or emergency backup _only_ otherwise you're doubling the cost of power for no good reason other than to increase overall generation requirements.
And that brings us to overall generation requirements. Taking the amount of carbon-sourced power generation in the UK in any given year 2000-2010 and calling it "N" TWh.
Renewables can slightly outproduce N, but only by a small amount. Beyond that the law of diminishing returns kicks in extremely hard (and you really don't want wind turbines nearby, blades have been recorded travelling over a mile when they break) and by the time you hit 1.5 x N you can effectively invest an infinite amount for no increase in capacity.
That's fine, but electricity only accounts for about 1/3 of carbon emissions and getting rid of the other 2/3 is where it gets hairy:
An electric domestic (as in privately owned) vehicle fleet will require about N TWh per year by itself.
An electric commercial vehicle fleet will require 1-2 N TWh
Eliminating gas/oil from domestic heating will require about N TWh to replace it, even with better insulation and if planning laws are changed to allow superefficient stuff on "listed buildings"
Commercial premises heating will be about the same N TWh
Replacing carbon in industrial processes apart from steel and cementmaking will be 1-2N
Replacing carbon in steel and cementmaking (especially kilns!) will be 2-4N
All that means
A lot more generating capacity will be needed
Greater grid capacity to hanlde those average flows
All those vehicles charging overnight is likely to turn "night rate" on its head
And there's the "slight" problem of UK mains distribution being predicated on residences drawing 1kW at most for sustained periods.
Add a few 7kW car chargers - every house in my area has 1-2 cars as the public transport is lousy and UNsuited to anyone except bankers heading into London - and you'll have more than few exploding footpaths and subterranean tunnels as stressed feeders blow out, along with most of the street-level submain distribution transformers. The idea of streetside chargers in most urban areas falls apart when you realise you essentially require a COMPLETE OVERBUILD of the existing mains distribution system in any given area to handle them - something that I simply can't see happening in only 15 years when you factor in the costs.
Batteries can help allieviate local short term issues but they don't deal with the elephant in the room - current approaches are on par with handling local flooding by building better drains to dump it in the river - ensuring more flooding for the folks downstream - deeper, faster flowing and faster rising. We can't make this "someone else's problem" and it increasingly looks like we'll be at rolling blackouts by the time politicians admit a serious energy planning disaster took place in the late 2010s/early 2020s