(Internal Combustion Engine, Plug-in Hybrid Electric Vehicle (like my GTE!) or a pure Electric only Vehicle)

I have been playing around with a few figures relating to the overall costs of running these three different vehicles and trying to compare them – it is a difficult task! Here is what I have done so far, comments and ideas are welcome:

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The cost of charging an EV battery depends on the size of the battery, how depleted the battery is and how quickly you charge it. As a guide, charging a pure-electric car from flat to full will cost from as little as £1.00 to £4.00. This is for a typical pure-EV with a 24kWh battery which will offer around 100 miles range.

This means the average cost of ‘fuel’ will be approximately £0.03 per mile. Similar costs will apply to PHEVs and E-REVs, and because the batteries are smaller, it will cost less to charge them. See also the figures in table 2.

In some cases it may be possible to charge overnight and take advantage of cheaper electricity rates. Other options include charging from domestic solar panels. At this time it is calculated that the total cost of ownership of an electric car is similar to an ICE because of the additional purchase costs. However, this will change and if other advantages are included such as congestion charges (currently £11.50 per day in London for ICE but zero for EVs), the EV will be significantly cheaper in the longer term.

Table 1 Comparison of costs

Term, mileage, fuel cost	ICE	Pure-EV	PHEV	Notes
Annual mileage	10,000	10,000	10,000
Cost of fuel (£/gallon or £kW/h)	£5.70	£0.05	£5.70 / £0.05	Electricity (£/kWh) average standard/cheap/solar used for calculation
Official combined cycle mpg	68 mpg	150 Wh/km	166 mpg	Electricity consumption (Wh/km)
‘Real world‘ mpg	50 mpg	175 Wh/km0.28 kWh/mile	100 mpg *1	Real world consumption
Total fuel costs	£1,140	£140	£570	(annual miles * fuel cost / mpg)(annual miles * fuel cost * kWh/mile)
Vehicle cost information
Purchase price	£28,000	£34,000	£35,000	Estimates based on current list prices
Plug-in car grant		-£5,000	-£5,000	A grant to reduce cost by 25% (up to £5,000)
Net purchase price	£28,000	£29,000	£30,000
Depreciation cost/year	£8,400	£8,700	£9,000	30% used – this will vary however
Residual value	£19,600	£21,300	£21,000
Service, maintenance and repair	£190	£155	£190	Based on average of published figures.
Other information
Vehicle Excise Duty and Registration Fee	£30	£0	£0
TOTAL COST	£9,760	£8,995	£9,760	Per year

Important note: the figures used in this table are ‘best guesses’ but none-the-less give a reasonable comparison. The bottom line is that the three cars have broadly the same overall total cost even though the Pure-EV and the PHEV have much lower fuel costs. The key factor will be how the depreciation cost of the EVs pan out. However, over subsequent years the fuel savings associated with the EVs will become more significant.

Being able to programme EVs to charge during the night will allow drivers to take advantage of cheaper electricity prices, whilst using any surplus electricity. In addition, the development of smart metering systems which can automatically select charging times and tariffs can also help to manage demand on the grid. The National Grid manages the grid on a second by second basis to ensure that supply and demand are met and to indicate to the market if there is a shortfall or surplus of power.

*1 Very much depends on the length of journey – an average value was used

…we’ll almost, at least very cheap motoring is the plan!

On the 7th August 2015 I took delivery of the (almost) final part of the puzzle that when put together will result in big savings – I hope. I still need to get the proper charging point together with gadgets to monitor energy use etc., but I am nearly there. Here is my new Golf GTE (from Inchcape in Chelmsford) taking its first charge on my drive:

The Golf GTE 1.4 TSI produces 204PS (Pferdestärke, abbreviation of the German term for metric horsepower).  It is a PHEV (plug-in hybrid electric vehicle) 5dr DSG boasting 0–62mph in 7.6 seconds. and up to 166.0 mpg. The electric range is 31 miles and when electric and petrol combine, the total range is 580 miles. The previous data are laboratory figures of course, I will report back on what happens in the real world in due course. However, its performance is very impressive so far. Because the car is a plug-in hybrid it attracted the £5000 government grant. More on overall prices later though because cheap mileage is all very well but initial and running costs still have to be considered.

The other part of my cunning plan involves solar panels (actually photo-voltaic or PV panels) and these will be used to charge the 8.8 kWh lithium-ion battery in 3.75 hours from a domestic mains outlet, or 2.25 hours from a domestic wallbox.

My PV array has saved me buying a lot of electricity and has further resulted in an income. So far this year I have received about £400, by selling the excess energy back to the grid (using what is known as a feed-in tariff). In addition, my electricity bill has reduced as shown in the following chart:

As you would expect, we pay much more for the electricity we use than the price we get when selling it (something like 14p per unit when buying and 3p per unit when selling). The way the feed-in tariff works is that the electricity generation company pays us for 50% of the amount generated by the PV panels. So the more we generate the more we get but of course the other advantage is gained because the more of the PV energy we use, the less electricity we purchase. This is where the new car comes in. The plan is that whenever we return home, we will make sure all the available charge in the car’s lithium-iron (Li-on) traction batteries has been used up. This will simply be done by switching the car to full e-mode when 35 miles from home. The car will now only be charged when enough solar energy is available (emergencies excepted of course). I am doing this manually at the moment but it will be automated in due course.

I have just completed a journey, by pure coincidence, to the UK VW headquarters where they have a charge point (well they should have shouldn’t they)! This was about a 170 mile round trip for me. I set off with a fully charged battery and managed to add 20 miles worth of charge while I was there. The car trip computer showed an overall average mpg of 68 – so just under 2.5 gallons. for the journey. My previous car (a modern Golf GTD 2.0ltr) would have done the same at an average of about 48 mpg (about 3.5 gallons). This journey was a good combination of country roads and motorway so probably indicates a good average. I did not try to save fuel or equally I didn’t accelerate/brake rapidly so the figures are probably quite a good start for real-world use. When used in hybrid mode only, the average was about 50 mpg .

I am expecting to win much more on the shorter journeys we do, which will use no petrol or very little. My journey to the office at the IMI for example, is about 42 miles each way. We have a free charging point! My hope therefore is to only use about half a gallon of fuel for the return trip (60 miles on full electric and 25 miles at 50 mpg).

Watch this space, more details to come…

Tom