Nissan LEAF - One Year Later

Monday 21st March, 2011
It's a year since I wrote my first article which discussed the running costs of the Nissan LEAF based on real life theory, not marketing numbers. I followed up with an article which discussed its emissions and then another piece which analysed ownership for those on an Economy 7 electricity tariff. These are some of the most read articles on my blog - many new readers hitting the site each day searching for information on Nissan LEAF running costs of Nissan LEAF CO2 output - and, with a year being a long time, I figured it was time to post an update which takes into account all of the information that has come into the public domain since then.

So what's changed in the last year?

1) The Price

From 1st March, the already quite expensive LEAF has gone up in price. A £2000 rise, from £28,990 to £30,990, makes the LEAF more expensive than the Audi S3 Quattro. Whilst the experience of driving a car is very subjective, I recommend you try both to get an idea for what a £30k should drive like. If you're desperate to compare it to another environmentally friendly car, you could afford a new Lexus CT-200h - arguably the cleanest petrol/diesel powered car in the <100g/km CO2 category. Even after the £5000 subsidy that's currently available from the government for new electric cars, bringing the LEAF down to £25,990, you could still buy the Lexus CT-200h SE-I for £23,485 on the road - some £2500 less than the LEAF. With the Lexus currently able to do 15 miles per litre of unleaded, that means the Lexus effectively gives you a current saving of 28,900 miles worth of unleaded - based on £1.30/litre - probably around 3 years of fuel for those in the market for a limited range electric car. The Lexus has a quoted range of 682 miles, almost 7 times that of the LEAF.

2) The Range

Nissan claim a range of around 100 miles for the LEAF in normal use. Of course, however, that "normal use" varies considerably between drivers. If you're doing a slow speed journey around town, on a warm day, you may hit this range but if you drive a little bit quicker, or need the lights, heater or air conditioning; this range can be significantly reduced. The owner of the first Nissan LEAF claims just 60 miles of range on the US highway. This is rather less than the 100 miles range that people may have been expecting when they forked out the money for their electric car. He's not alone and there have been reports of owners being stranded when their LEAF unexpectedly did considerably less miles than the car's own display led them to believe. Even when you read a little more explanation of why those problems occurred, it doesn't take away from the the fact that, ultimately, many owners are getting considerably less than 100 miles in normal driving. I've been monitoring daily temperatures in the UK for the last 6 months as part of my winter tyre ownership and, if the LEAF range really is affected by external temperature as much as claimed, then that's going to leave you with reduced range for around 6 months of the year. Even in March, we're having sub-zero overnight temperatures which will likely reduce the range of the Li-ion battery pack. Some manufacturers, like Tesla, use a battery warmer to get around this problem but no such function is currently available on the LEAF.

So, you can expect 100miles on a warm, clear day around town with no traffic. A bit of stop/start traffic, range is going to reduce. A bit too hot, requiring the A/C, range is going to reduce. Cold, requiring the heater, range is going to reduce considerably. If you're prepared to sit in lane 1 of the motorway at 50mph being overtaken by HGVs, you may get some decent range but drive at a normal motorway speed and range is going to be more like 70 miles from a full charge, or more like 50 miles on a cold day after an 80% DC fast charge.

3) Charging

Last year, I did a lot of my charging stats with theoretical "best case scenario" numbers based on a standard 3kW UK power supply. Now we know a bit more, the maths can be adjusted.

The LEAF's battery is actually larger than 24kWh, some claim around 27kWh, the 24kWh quoted is simply a usable size. Some of the battery is reserved to ensure the battery can't be completely drained by the driver. Those 24kWh will take a different amount of time to charge, depending on how you charge it.

There are 3 main charging types available to electric cars - low speed AC mains charging at up to 16 Amps, high speed AC mains charging at  32 Amps and high speed DC charging. Only two of these are available to LEAF owners - either high speed DC charging, providing 80% charge in around 30 mins, or low speed "16 Amp" charging. You'll get the full 16 Amp if you have a special pod charger installed at home for an additional cost of around £1000. 32 Amp charging pods are available and, whilst you can plug the LEAF into one for charging, it will still only charge at the slower 16 Amp rate.

I based all my numbers last year around charging from a standard mains power socket at 3kW. I estimated that this would take 8 hours to charge full, as 8 hours at 3kW would provide 24kWh of charge. In practice, however, this isn't the case - to avoid potential overheating and overloading of sockets, the plug-in charger only runs at 2.2kWh. Whilst this is safer, it does considerably increase the expected charging times, and you're now looking at more like 11 hours for that full overnight charge. This brings the theoretical charging rate down to 9 miles range for every hour plugged in to the charger but, based on our range expectations above, that will be more like 4.5 miles of range every hour for motorway drivers. In real terms that means, if you drive 60 miles to Mum's for Sunday lunch, you may as well have a few drinks with your roast beef - you'll easily have sobered up before you have enough charge to drive home - in fact, you might want to pack an overnight bag.

The DC fast chargers are nice, but availability is poor. There's a fast charging point at many Nissan dealers but, sadly, these are often only available during normal working hours. Also, as DC fast charging will only bring you to 80% of maximum charge to avoid battery damage, you're theoretical maximum charge will reduce from 100 miles to 80 miles or, if you normally get 70 miles from a full charge, a 30 minute fast charge will only get you 56 miles. At the current 70mph speed limit, you're likely to need to stop for 30 minutes after every hour you drive on the motorway - this easily turns a 3 hour drive into a 5 hour one - not including any time you may have waiting for a charging point to become available if it's being used by another EV owners.

4) Costs

I did the numbers last year based on 100 miles of range but we now know many owners are unlikely to see this number of miles, even from a full battery.

Looking at current electricity pricing from British Gas in my postcode area I see a unit price of 21.859p/kWh for tier 1 and 9.205p/kWh for tier 2 - this is based on their cheapest "online only" tariff.

So this gives us a theoretical cost of £2.21 to £5.25 for a full, 11 hour, 24kWh charge. In the comments for last year's article, I worked out my average unit cost to be 11.78p/unit - a theoretical charging cost of £2.83 but this won't give us 100 miles.

So, this gives up a cost per mile of 2.8 pence if you see the 100 miles range but this will increase to 4p/mile based on 70 miles range and 5p/mile on 60 miles range and around 6p/mile if you're unfortunate enough to only see 50 miles of range like some owners. It's still less than the expected 9p/mile in the Lexus I mentioned above, but remember that the Lexus was almost 30,000 miles cheaper to buy in the first place.

5) Economy 7

I did the Economy 7 numbers last year but, in reality, you aren't going to be able to fully benefit from such a tariff. Discounts are provided from 10:30pm-12:30am and then from 2:30am to 7:30am - 7 hours a day. Cheap charging hours vary between providers, making it more confusing. Regardless of the hours, you're only going to get a maximum of 7 at the cheap rate, assuming you set it to charge at exactly the right time, and you need 11 hours. 4 of them are going to be at full day rate, which is higher than on a normal tariff. Installing a faster 16A pod charger at home might help get more of your charging done during cheap hours but, in reality, this charger is going to cost you an extra £1000 which will wipe out any savings.

As a result of all this, I'm not going to update my economy 7 numbers as I don't see it as entirely viable for the purpose.

6) Emissions

We did some eye opening emissions figures last year but now we know that we aren't actually likely to get that many miles from a full charge. We worked out that 24kWh of charging gave us 13kg of CO2 emissions somewhere in the UK. But now let's do the emissions based on the shorter range expectation.

13kg/70 miles = 185g per mile. There are 1.6km in a mile, so that's equivalent to 116g/km for a normal driver. Take that down to 60 miles from a full tank and you're looking at 135g/km or 162.5g/km for those who only manage 50 miles.

Essentially, if these cars were treated like normal ICE cars, they would not be exempt from the congestion charge as they actually create more CO2 pollution than many modern petrol or even diesel cars.

These numbers are provided for equivalence to the numbers I calculated last year but I've since found better grid CO2 figures on this website. Based on the current figure of 600gCO2/kWh, that gives us a 14.4kg footprint for charging the LEAF. Converting that into emissions per mile, we're looking at 90g/km for 100 miles range, but 129g/km, 150g/km and 180g/km based on 70, 60 and 50 miles range.

Overall, I didn't think the LEAF was particularly green when I looked at the figures last year. Now, based on real life owner stories, I actually think it may have a CO2 footprint higher than that of a modern petrol, diesel or hybrid car that usually costs much less.

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