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UK needs 7,000 specialist charging stations for its switch to electric cars

Image: Kārlis Dambrāns

Taken alongside the Paris climate targets, the UK government decision to ban new internal combustion engine vehicles (ICEVs) from 2040 implies that almost all of the cars on Britain’s roads will be electric by 2050.

Insofar as anyone has focused on the impossibility of achieving this aim, they have tended to home in on Britain’s electricity supply problems (although these are far from the only show-stoppers).  However, even if we overlook the financial dire straits that the nuclear power industry is in and the probable lack of profitable shale gas beneath the British Isles, it turns out that even apparently trivial charging issues may be sufficient to stop electric vehicles (EVs) in their tracks.

According to a recent discussion paper from the National Grid – the organisation that will somehow have to conjure up the additional energy to power EVs while continuing to keep the lights on – just two issues – home charging and fast charging – are currently impossible on the scale needed.

At present, charging is the EV’s Achilles Heel.  It takes just a few minutes to refuel an ICEV, but according to the National Grid paper:

“If you assume you have an average size battery charger; it is a 3.5 kW device (equivalent to a fast boiling domestic kettle’s electricity usage). It would take about 19 hours to charge one of these batteries from being 25% full to 100% charged.

“This time could be halved to 10 hours with a 7 kW charger. This size of charger is already available and will soon become more prevalent than the 3.5 kW versions.”

The trouble is that domestic electricity systems begin to struggle as both batteries and chargers grow more powerful:

“The average household is supplied with single phase electricity and is fitted with a main fuse of 60 to 80 amps. Using a 3.5 kW battery charger requires 16 amps. If one were to use an above average power charger, say 11 kW, this would require 48 amps. When using such a charger it would mean that you could not use other high demand electrical items (such as kettles, oven, and immersion heaters) without tripping the house’s main fuse. Using an 11 kW charger would take 6 hours to fully charge a Tesla Model S, which also has a 90 kWh battery, from the 25% full state.”

One solution would be to retrofit domestic properties with new main fuses:

“If your house had fitted the maximum 100 amp main fuse then a more powerful 22 kW charger could be used. It would take only 3 hours to charge the battery (or 5 hours if the battery was completely flat); but all the other electrical equipment in the house would have to be turned off as the charger requires 96 amps. In reality an 11 kW charger, with an above average main fuse, is likely to be a good compromise.”

Even if this were done – most likely at the householder’s expense – more than a third of UK properties lack a safe domestic charging space:

“In a survey 57% of households had access to off street parking and it is assumed that 43% did not.  With 20 million EVs on the road that means that there will be 8.6 million vehicles without the necessary facilities to charge from home. So these consumers will require alternative charging facilities.”

Alternative charging facilities will also be required to avoid excessive pressure on the local electricity distribution infrastructure:

“Another ‘pinch point’ would be the substation and the peripheral routes and branches within a local distribution network. Pilot projects, such as My Electric Avenue, were reporting potential issues at the distribution level. In one more extreme example they were identifying voltage issues when five 3.5 kW chargers were connected to a network cluster (with 134 dwellings) and were charging at the same time. The project concluded that across Britain 32% of low voltage circuits (312,000) will require reinforcing when 40% – 70% of customers have EV’s based on 3.5 kW chargers. These problems will only be exacerbated when 7 kW chargers are used.”

Even if these problems could be fixed, the charging times achieved would still leave EVs woefully behind ICEV refuelling times.  An 11kW charger could charge 75% of one of today’s top of the range batteries (which is likely to be the standard in a few years’ time) in a little over six hours – fine for overnight charging, but little use for a (relatively) quick turnaround.  A 50kW charger – of the kind offered by national suppliers like Ecotricity and Tesla – by contrast, could do the job in one and a half hours.  However, these are far too powerful for domestic use, and may soon by overtaken by even more powerful fast chargers:

“Recent announcements by VW, Ford, Daimler and BMW have indicated that they plan to build a network of at least 400 rapid EV chargers across Europe. These are likely to be 150 kW units and may be capable of supporting 350 kW chargers in the future.”

A 350kW charger would take just four minutes to three-quarter charge an average EV battery and a little over ten minutes for a top of the range one.  The trouble is that contemporary batteries cannot support this level of charging.  However, assuming battery technology could be improved, EV chargers of this kind would have to operate at a Grid scale:

“… nine pumps of 350 kW capabilities would require an infrastructure capable of handling 3.1 MW. This is enough power to supply 1,000 average households. In current forecourts, having 20 pumps is not unknown. Such EV charging stations would require a 7 MW infrastructure to support them. All these megawatt sites will be significant connections and would warrant a direct connection to the distribution network which would be above the domestic 240 volts.”

According to the paper, somewhere close to 7,000 of these new charging sites would have to be installed around the UK if the dream of simply swapping from ICEVs to EVs is to become a reality.  Some manufacturers are constructing charging stations; but not in the volumes needed, and primarily to sell their EVs:

“Ultimately a network of forecourts may grow organically, as it did when cars were first introduced; but perhaps in this modern world someone may need to take the lead.”

The trouble is that petrol filling stations were able to grow organically because petrol (gasoline) was an abundant waste product of the kerosene industry (and is today a waste product of the diesel, kerosene and chemical industries).  Electricity, in contrast, is an increasingly scarce and expensive commodity whose suppliers are already struggling to meet demand.  Capital expenditure is unlikely to be available for new EV infrastructure for which a secure and continuous supply of electricity cannot be guaranteed.

Massive cuts in exploration and recovery investment – which point to shortages in the 2020s – in the oil industry in the wake of the 2014 collapse in world oil prices is likely to bring forward the day when UK motorists hand back the keys to their ICEVs.  But it is highly unlikely that they are going to be swapping them for shiny new EVs.  The best we can look forward to is the end (for all but the very wealthy) of private motoring, a return to mass transit systems, and a re-localising of the economy.  A switch from ICEVs to bicycles and walking is far more likely than the mass adoption of EVs.

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