Sir,
Your 11th February article "Electric cars mean UK could need 20 new nuclear plants" by Graham Paton shows both a lack of understanding of charging patterns of electric vehicle drivers and a failing of basic arithmetic.
Ninety per cent of all electric vehicle charging is done at home (source: OLEV) and of this the vast majority is done at night. Like many EV drivers, I programme mine to charge during the Economy 7 period to take advantage of cheap electricity rates of 8p per unit (kilowatt-hour). That charge is enough to cover my typical daily needs. Nationally, 73% of all vehicles are garaged or parked on private property overnight and even in urban areas the majority of cars are parked on private property (source: RAC Foundation), so there is scope for much of the fleet to be charged at off peak times today, even in cities.
Your article states that "At the maximum level of uptake in the city green cars would demand between seven and eight gigawatt-hours per year" and "Experts said this was equivalent to the output of more than two nuclear power stations similar to that being built at Hinkley Point in Somerset". Hinkley C will have an output of 3.2 gigawatts, meaning that in one hour, two such power stations would produce 6.4 gigawatt-hours. Clearly 8 gigawatt-hours in a year is not going to trouble such a facility, but in fact your total is very wide of the mark.
An electric vehicle like mine typically drives 4 miles with one kilowatt-hour. Therefore, taking average annual mileage of 7,900 miles per year (source: RAC Foundation), annual usage is just under 2,000 kWh or 2 megawatt-hours per car. Thus the 8 gigawatt-hours quoted in your article equates to only 4,000 cars' worth of electricity in a year. This is clearly incorrect, as London already has more electric vehicles on the road than that. Furthermore, it is 0.8% of the just over 1 Terawatt-hour (1,000 Gigawatt-hours) Transport for London states London Underground uses in one year (source: TfL).
More importantly, the article also completely misses the point that demand on the National Grid is not constant, but during the winter period varies from approximately 30 gigawatts at night to 50 gigawatts in the daytime peak (source: National Grid Demand). It is even less during the summer. Average annual mileage is under 22 miles per day, equating to a demand of under 6 kilowatt-hours per car, per day. If everyone recharged 90% of their needs during the seven hour Economy 7 period, each car would require under 1 kilowatt (or about 4 amps, less than a single electric heater). So today, during the Economy 7 period, 20 million cars can recharge before electricity demand reaches the same as the daytime peak. If all 31 million cars in the UK were electric, peak overnight demand (including existing demand) would be approximately 62 gigawatts - which was the peak demand in 2007 before LED lights and A+ appliances were commonplace. The other 10% of "away from home" daytime charging, which the government's proposed new initiative is aiming to meet by rolling out new fast chargers, will also comfortably remain within this historical threshold.
As the National Grid currently has a total generating capacity of 75 gigawatts and a further 3 gigawatts of foreign interconnectors (source: National Grid Winter Outlook Report 2016/17), it is therefore apparent that
no new capacity is needed for a mass uptake of battery electric vehicles (note this is not true of electrolysed hydrogen, also mentioned in your article, which requires over three times as much electricity per mile to manufacture). In fact, a mass uptake of electric vehicles benefits the grid by allowing assets that would be idled overnight to continue to operate at full capacity. An electric vehicle fleet is complementary to existing National Grid domestic and industrial demand, not a burden to it.
What is needed is demand management - the so-called "Smart Grid" - to ensure that 31 million drivers do not arrive home and immediately recharge during the evening peak. To an extent this is done today through tariffs like Economy 7, but overnight charging should be the default option rather than merely encouraged (of course, like with a heater, this would not preclude an immediate boost if essential). As many domestic charging stations already include remote management via cellular links, by comparison this is relatively easy to implement and certainly not comparable to the expense and complication of an unnecessary build of 20 new nuclear power stations.
Yours faithfully,
David Peilow
OLEV:
Drive an EV and you may never have to visit a petrol station again - Electric cars, low emission motoring - Go Ultra Low
RAC Foundation:
Mobility
TfL:
http://content.tfl.gov.uk/london-underground-carbon-footprint-2008.pdf
National Grid Demand:
G. B. National Grid status
National Grid Winter Outlook Report:
http://www2.nationalgrid.com/WorkArea/DownloadAsset.aspx?id=8589937050