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.

  1. 1) Michael Thwaite Said: (21/03/2011 17:46:21 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Ben, It looks like you're missing the well-to-wheel calcs for the emissions comparison.

  2. 2) Ben Rose Said: (21/03/2011 22:47:56 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Not really, Michael. I didn't really make any emissions comparisons to anything else, only to itself.

    Mike Boxwell's "Owning An Electric Car" website, that I linked, does show well to wheel figures though...and they are lower for some of the hybrids he displays than they are for my LEAF figures. His EV figures are based on maximum range, which we all know isn't achievable in many circumstances.

  3. 3) Michael Boxwell Said: (28/03/2011 18:40:41 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    I ran a test last week in a Mitsubishi i MiEV where I exceeded the official range of the car. Ok, only by 0.7 miles, but I exceeded it, which I wasn't expecting to be able to do.

    I've driven 86 miles in a Nissan LEAF, and the car was reporting 16 miles remaining, so I know that is possible too.

    To achieve these figures, you are carrying out inner city driving, with all the stops and starts and low speed chugging about that really doesn't work well with petrol or diesel powered cars.

    Go on higher speed journeys, and the electric car range goes through the floor. So an EV is the exact opposite to a petrol or diesel car - it will give you the best results in a congested zone and the worst on a clear run.

    I've done economy runs in hybrids such as the Toyota Prius and Honda Insight. In town, I found the Insight to be the most economical car, whilst on a run they were both pretty much the same. But my economy figures in town suggested a CO2/km of around 180-200 in both cases, which was far higher than the electric cars.

    Just as the official EV range is often on the high side, so is the economy figures of most combustion engine cars. Most car makers take their cars to Southern Spain in the summer in order to carry out the official emissions testing, in order to get the optimum performance out of their cars. Try getting those figures yourself, and you're unlikely to succeed.

    So if you're not going to accept the official EV figures, neither should you choose to accept the official combustion engine car figures either. Tell you what Ben, why don't we do some real world testing with a selection of different cars in different conditions and come up with some proper, real world figures?

  4. 4) Ben Rose Said: (28/03/2011 19:46:12 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Indeed, Mike, not going to disagree with you on any of that and I don't doubt whatsoever that 100 miles from the i-MiEV or LEAF is possible in optimum conditions when driven appropriately.

    Sadly, as you highlight, conditions aren't always optimum.

    Ultimately, for slow speed short journeys around town, an EV is easily likely to be the most efficient - i.e. the lowest CO2 footprint. For longer, or higher speed, journeys - the petrol hybrid becomes most efficient.

    For some, owning both types of car may be an option, they can then choose the vehicle that is most appropriate for their journey. For others, however, they need to choose the car that is the most efficient for their needs. All those savings on short journeys around town in an EV can soon be cancelled out a couple of long journeys.

    Ideally, what you need is a cross between both vehicles - which is why I am strongly recommending that people wait for the upcoming plug-in hybrid cars. A short range, efficient EV around town and a long range hybrid petrol vehicle when you hit the open road. Literally the best of both worlds. Until the CO2 footprint of the National Grid improves, they are going to be the most efficient option for a very long time.

  5. 5) John baldwin Said: (16/04/2011 11:14:02 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    CO2 emissions are much worse than this because any additional elec to charge an EV has to come from gas or coal. Renewables and nuclear are only 13GW total max, min elec demand on a summer night is 25 GW. So whenever you charge day or night needs coal or gas to be burnt. So Leaf significantly worse that petrol hybrid or similar sized much cheaper diesel.

  6. 6) jeffhre Said: (23/07/2011 14:08:21 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Mr Rose, will your calculations take into account the Co2 required to get a barrel of oil into petrol trucks and ready for retail sale? In the US oil refineries use a minimum of 39 billion Kwh of electricity to produce gasoline each year.

    Mr. Baldwin, the Petrol car then burns this at 24% efficiency, and the Leaf skips this process entirely using it's 92% efficient motor, with no petrol trucks, underground tanks, or electrically powered fuel pumps needed.

  7. 7) Ben Rose Said: (23/07/2011 17:31:20 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Hi jeffhre,

    Electric motors are efficient indeed, but first you need to inefficiently generate the power in a power station, transfer it over wires and then you can lose a huge % of energy, some say around 25%, in losses just getting the charge in and out of the battery. No method is flawless.

    My calculations are based on what I call "first stage" emissions. I've explained that in details here { Link }

  8. 8) jeffhre Said: (24/07/2011 09:25:21 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Ben Rose,

    Thank you for your reply.

    "So where do we draw the line? Well, that's up to you but I think we need to be realistic and put the line in a similar place for each type of vehicle. This, for me, is by looking at the emissions generated from the fuelling of each vehicle."

    I agree with this assessment completely. However,if you do not count the exploration, mining and delivery of coal, it is simpler yes, though not a complete analysis. For gasoline the same process would begin at the refinery, and not with exploration, extraction and delivery of oil to the refinery.

  9. 9) Ben Rose Said: (24/07/2011 09:42:50 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    I assume you're suggesting what I might call a "Stage Two" analysis - looking at both types at fuel one step earlier?

    The question is, where to align those steps? Delivery of the Crude to the refinery may look like a natural place but Crude Oil is simply unrefined raw material. If we tried to do the same for coal, we'd be looking at coal lying in the ground, mixed with dirt and other impurities. Coal already gets separated at the mine before delivery.

    Also, we need to recognise that in the UK (where this site is focussed) over 40% of power actually comes from natural gas, more than double that from coal. This has a very different footprint to petrol/diesel although they are often drilled and extracted at the same location.

    Sure, refining Crude Oil requires a lot of heat energy. it's basically boiled in a big pot and different components, or fractions boiled as they boil off at different temperatures. Getting components that boil at low temperatures, like petrol, to boil off takes a fair amount of heat - but not as much as other, heavier, fractions. For example, petrol boils around 95C at normal atmospheric pressure whereas diesel boils around 150C - considerably higher. The figures that are thrown around, like the "7kWhr" you quoted above are often derived from the entire energy required to separate ALL the fractions of the crude oil, not just the lighter petrol portion which is easier to boil than it is to boil water for a cup of tea. The other fractions are used for things like paints, detergents, solvents, adhesives, rubber and even bitumen for tarmac - all required for Electric Vehicles. Quite simply, if we don't refine Crude Oil, we aren't able to build or use Electric Vehicles. When refining, the petrol is one of the first things to come out of the pot, so it doesn't actually cost us any energy to refine petrol - as we need to do it to get the other fractions out anyway.

    Additionally, once boiled off, all these fractions are, of course, VERY hot. 1000 litres of diesel boiling at 150C can obviously boil more than 1000 litres of water - this generates steam, lots of it. High pressure steam can be used to generate electrical, it's exactly what they do in a coal, natural gas or even nuclear power station.

    Oil refineries are very similar and they too can set-up Combined Heat & Power stations...except they don't need coal or gas to power it...they already have hot oil products. End result is that companies like Conoco have, I believe, recently commissioned a 450MW CHP at their Humber site. 450MW of electricity generated as a by-product of the refining process and energy that can be used to power their refinery or, at quiet times or when the price is right, they actually feed the grid!

    Imagine that - chances are that your electric car might be powered by energy from an Oil Refinery. Based on the current energy mix, there's actually over 3 times as much chance of this than there is of getting your power from from wind turbines which are currently only supplying the UK with 113MW of electricity.

    So yes, refining fuel takes a lot of energy...but it doesn't all come from the grid.

  10. 10) jeffhre Said: (25/07/2011 01:09:54 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Much like moths circling toward a flame we could eventually near a similar point of view.

    There is little processing of oil or coal at the extraction stage. Yet, petrol is clearly not ready for consumption until refined. There is not enough to sate demand, by orders of magnitude, which is discovered seperate from oil. Oil can be cracked to get a larger percentage of petrol, though my concern is with the large electrical input required at the refining stage, not the process complexity or pollutants created.

    Therefore, I am not convinced that arrival at refineries is not the proper stage for this analysis.Prior to this stage the only processing for coal or oil is to prepare for transport. Though, I agree that the kWh in common use for refineries are often for gross processing and generally are not specific to gasoline production.

    Refineries taking advantage of cogeneration opportunities are creating a net reduction in energy use by recycling waste heat. They are not however generating new electricity greater than that which is consumed to refine petroleum. Coal conversely, must again be processed after electrical generation for disposal. I have not addressed NG electricity generation, since it seems to have become an often common notion that a petrol car is more efficient than an EV using electricity from coal.

  11. 11) Ben Rose Said: (25/07/2011 07:11:15 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    Hi jeffhre,

    You seem to be quoting stats and information from the US. It's a very different picture here in the UK. I wrote some info on Crude Oil from a UK perspective a little while ago.

    { Link }

    In summary, Petrol (Gasoline) appears to have a significantly larger carbon footprint during extraction in the US. Also, your electricity supply has a lower carbon footprint. The end result of this is that ICE cars in the US are generally dirtier to use than those in the UK and EVs are a little cleaner. It makes quite a difference to the overall picture.

  12. 12) jeffhre Said: (25/07/2011 07:50:06 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    "In summary, Petrol (Gasoline) appears to have a significantly larger carbon footprint during extraction in the US." I Agree.

    Although my analysis is not well(extraction)to wheel(stage one), but extends from the post extraction stages to consumption. In summary, I am not including the efforts of deep water wells, tertiary extraction methods, or tars sands production, only the refining of petrol itself.

  13. 13) Ben Rose Said: (25/07/2011 07:55:04 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    We're in a position in the UK where a large majority of our petrol comes directly from North Sea Brent Crude. On top of that, most of the Natural Gas that produces most of our electricity also comes from the very same off-shore wells. It makes the picture a little clearer.

  14. 14) jeffhre Said: (26/07/2011 16:31:43 GMT) Gravatar Image
    Nissan LEAF - One Year Later

    "It makes the picture a little clearer." Perhaps. Yet, the energy required to get the petrol from the front gate of the refinery into vehicle tanks seems to do a remarkable anti-thermodynamic disappearance trick. Perhaps the picture could be even more clear.

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