Electric Cars – a solution to Climate Change?

TL;DR: No.  A 4 kWp photovoltaic installation   saves much more CO2 for the difference in lifetime cost with a conventional car.

Electric cars have been talked up as a potential solution, or part of a solution, to climate change and dependency on fossil fuel.  At first sight, they have many good characteristics:  Zero emissions in use, running on electricity which can be made from renewable sources.  So can they solve at least part of the climate change/ renewable energy challenge?

Fuel economy.  A typical electric car will travel 5 miles per kilowatt hour, whereas a comparable internal combustion engine (ICE) car might do 66 mpg.  I picked a Fiesta 1.0T Ecoboost http://tinyurl.com/p9vrkpb .

It’s difficult to compare 66 mpg with 5 miles per kWh, so we need to get to using the same units for energy.  Also, we need to take account of the raw energy needed to produce 1 kWh of electricity.

There are 4.5 Litres in a gallon and one  litre of petrol produces about 10kWh (http://www.withouthotair.com/c3/page_29.shtml ), so 1 gallon of petrol produces 4.5*10 = 45 kWh.

 So the equivalent calculation for the ICE car is 66/45 miles per kWh, 1.5 miles per kWh.  This looks like the electric car travels over 3 times as far for the same energy.

 However, in order to compare like with like, we must take into account that we don’t actually have sufficient renewable energy in the UK to power our normal usage, let alone additional for electric cars, so the marginal kWh for the electric car will at best  come from a gas fired CCGT power station, which will typically burn 2 kWh of gas to produce the 1 kWh required for charging the vehicle.  So for each  kWh of raw energy, the electric car will only  do 2.5 miles.  It’s still significantly more thanthe 1.5 for an economical ICE vehicle, 66% more, so it’s worth having.

   Or to be more precise, it’s worth having if that benefit doesn’t cost too much.  The Fiesta selected above costs £15k, while a typical electric car costs £25k, with a £5k government subsidy.  Even without the government subsidy, that £10k difference in price would buy a lot of fuel.  At 14.5 miles to the litre, and around £1.40 per litre, it would buy 100,000 miles at 10p/ mile.  That’s a lifetime supply of fuel – in fact at the RAC’s estimate of an average of 8.2 k annual miles per car, it would last for 12 years.  

Energy saved

 The total electrical energy used by the electric car  over 100k miles would be 20 megawatt hours (MWh), or 40 MWh of raw energy.(methane gas).  By comparison, the ICE car would use 67 MWh of raw energy ( petrol)

So the energy saved is (67-40) MWh or 27 MWh.  Assuming a 12 year life for the 100k milies that equates to 2.4 MWh per year of raw energy.. 

Range

Electric cars have a typical range of 100miles and a long refuelling time:  8 hours on a normal domestic power circuit,4 hours on a fast charge point,  down to 30 minutes on a “rapid” DC charging point.  At present, the charging infrastructure is fairly sparse, although with good planning and a willingness to wait for at least half an hour while charging, reasonably long journeys are possible in the UK.  But for most people, the certainty of fuel availability, and a range of over 300 miles, would mean that their main car, the one used for long journeys, will be ICE.  So an electric car, if bought, will be a second car, and used for relatively short trips, typically 40 miles out and back as a maximum, and mostly for even shorter runs.   Electric cars score here, as ICE vehicles are particularly inefficient for the first few miles when the engine is cold, while it makes little difference to electric cars.  However, this restricts the market largely to households that can afford to run 2 cars, and also of course reduces the likely annual mileage.  Each car in a 2 car household will typically do fewer miles each year than a single car, while a designated short range car would do less again.  If the average annual mileage for an electric car is less than the 8,200 miles per year used for the calculations above, then the annual energy saving would be less.

Financial savings

We calculated above that the cost of fuel for the ICE car over 100k miles would be £10k.  By comparison, the electric car would use 20 MWh of electricity at the plug for the same distance.  Domestic electricity costs about 12p/ kWh, so the cost of the fuel for the electric car for 100k miles would be 20,000 * 12p, which works out to £2,400.

Costs in £k	ICE	Electric
Customer price	15.0	25.0
Subsidy	0	5.0
Lifetime fuel cost	10.0	2.4
Total cost	25.0	32.4

So financially the Electric car costs £7.4k than the ICE car, or £2.4k if we deduct the subsidy.

Who will buy?

We’ve already determined that the most likely purchasers will be for a second car, not the first.  There is also a problem for some people with overnight charging.  While many people park their cars in a garage, or on a drive near to their house, some 37% have to park their cars on the street. (UK government National travel survey 2010 http://tinyurl.com/noekobw ).  And it’s not reasonable to trail power cables out into the street, nor to trail them out of windows for flat-dwellers, so these people would not be able to charge an electric vehicle overnight.   We come down to some fraction of the 63% who would want an electric vehicle for a second car, and are willing to pay a sizeable premium for a perceived aura of green-ness.   One might suspect that there wouldn’t be all that many people in this category; in 2013 1,100, out of the 2.2 million new cars were sold in the UK.  That’s less than 0.05% of the market.

Alternatives

The electric car seems like an attempt by the car makers to hang on to a dying market.  There have been a number of articles on “Peak Car”:  the idea that car miles per person per year is starting to decline, rather than increase.  For example http://tinyurl.com/6hbtvdr.  The alternatives, public transport and cycling, are considerable more economical than cars (in the case of buses and trains, when reasonably fully loaded). 

Transport type	Energy for 100 passenger kilometres
Normal speed train	6
Bus	19
Car (1.6 passengers)	26
Bicycle	1

Note that as a bicycle engine is a human,  the fuel for is food, which is a bit more expensive to produce than fuel.

A problem with both buses and cycling is the competition for road space with cars.  Relatively inefficient cars use up the road space, delaying buses and intimidating cyclists so that neither form of transport can effectively use the road space.   Groningen in Holland has a cycling modal share of around 50% http://tinyurl.com/nb9zkfk;  if this could be replicated in the UK it would produce a very much larger fossil fuel and CO2 output saving than a few electric cars. 

In order to save energy/ CO2, arguably a better option would be to spend the £7,500 additional cost of the electric car (including subsidy) on PV installations. For about £7k(between £5.5k and £9k) you could install a 4 kWp photovoltaic system, which would produce about 3.5 MWh per yea rhttp://www.energysavingtrust.org.uk/Generating-energy/Choosing-a-renewable-technology/Solar-panels-PV#3 ,  The 2.4 MWh/ year of energy saving by the electric car is raw energy, so to compare like with like we need to double the electricity generated by the PV system to find the raw energy saved    So we are comparing 7MWh/ year raw energy saved by the PV system with 2.4MWh /year for the electric car; 4.6 MWh/year.

Policies

The £5,000 / car subsidy is roughly £5 million pounds/ year for the UK, but it is not producing a worthwhile effect in numbers of cars, nor in CO2 output reduction.

One alternative would be to spend that money directly on PV installations or house insulation.  £5 million is enough for at least 500 4kWp PV installations, which would generate 2 GWh/ year, which is 0.8 GWh per year more than is saved by 1,000 electric cars.

Another possibility would be to spend £50/head per year on cycling infrastructure.  This is double what is spent in the Netherlands, so would enable catch up to their quality of infrastructure over time.  £5million per year would only cover 100,000 people at that rate, so a demonstration town of about that size would be needed.  Perhaps a competition where cities and towns  could bid for the funds for a period of ten years, as political will is important as well as money?

To reducie overall car fuel consumption, apart from reducing the mileage travelled by better planning of the urban landscape, it would be sensible to adjust VED rates to further encourage new car buyers to buy more economical vehicles, and to increase fuel duty which would tend to both reduce mileage and encourage more economical vehicles.