How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

Thursday 1st September, 2011
It's almost impossible to miss the news that "old fashioned" incandescent 60 Watt light bulbs will soon be outlawed by the EU, forcing buyers to replace them with more energy efficient CFL units.

I'm all for saving energy, even though these replacement units do give off a rather odd light and most are useless with dimmer switches, but is it not a case of double standards if we aren't allowed to use 60 Watt light bulbs whilst an electric car owner up the road can happily plug in the 2400 Watt charger for his car?

I thought I'd do a bit of maths. How many 60 Watts light bulbs will we need to replace to save enough electricity for just one Nissan LEAF fully electric car?

For the purposes of the test, we'll assume that each 60 watt bulb is used for an average 3 hours each day. In Summer, electric lighting is hardly used at all. In winter, it will be used a little bit longer. In some rooms, like living rooms, usage may be high but in others such as dining rooms, bedrooms etc. there will be considerably less usage. We'll also assume the LEAF owner will drive 10,000 miles per annum and achieve an average 80 miles from each of their 24 kWh full charges.

At this point, make a guess for how many bulbs you think it might be, then see how close you were below.

Each 24kWh charge uses 24,000 Wh (Watt hours) of electricity. This moves the car an average 80 miles.
24,000 divide by 80 miles gives up a nice round figures of 300 Wh per mile.

Now we can work out that 10,000 miles  times 300 Wh per miles gives us 3,000,000 Wh per year. Yes, 3 million Wh per year, or 3 MWh (MegaWatt hours)

Our 60 Watt bulb is used for 3 hours a day but our replacement CFL bulb will still use 11W each hour too, so we're only saving 49Wh per hour, a total saving of 147Wh per day.

There are 365 days in a normal year, so our light bulb replacement will save us 147 x 365 = 53,655 Wh saved each year.

So now we just need to work out how many bulbs, at 53,655 Wh saving each we need to replace to save 3,000,000 Wh of electricity.

3,000,000/53,655=56 bulbs

So, based on living room, hallway, kitchen, downstairs toilet, 3 bedrooms and a bathroom, that's 8 bulbs per house.

So, if seven households replace every 60W lightbulb in their home, we may save enough electricity to power just one electric car for an average 10,000 miles.

With most households now having two cars that cover more than 10,000 miles between them, I think we'll need to do a little more than replace a few bulbs to reduce energy consumption in the future.

  1. 1) nemo20000 Said: (02/09/2011 16:54:40 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    “we may save enough electricity to power just one electric car”

    Yes, for free. Turning waste heat into thousands of miles travel. Great!

    “we'll need to do a little more than replace a few bulbs to reduce energy consumption in the future”

    Damn right. We need to reduce energy consumption hugely, eliminate waste (such as filament bulbs and petrol/diesel engines) and harvest as much free energy as possible (solar, wind, water).

    As for you eight bulbs per house theory, I have 14 bulbs in my lounge and my Mum has 18 60Ws in her hall alone.

  2. 2) Ben Rose Said: (02/09/2011 17:12:40 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi nemo20000,

    Thanks for the comment. I don't usually allow false identities on here but then I realised you were using a twitter ID!

    Interesting view point you give and some very valid comments. Obviously house sizes, and the number of bulbs, vary considerably - got rather a few myself - but we're just talking in average terms here.

    Many people who have a considerable number of lights in their rooms now use those little GU10 style bulbs which aren't covered by the I feel my estimation is fairly accurate.

  3. 3) Keith Ruddell Said: (02/09/2011 20:42:44 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    What a pointless exercise! Most people will charge their EVs at off peak hours when electricity demand is lowest. The Mini-E trials documented that fact. I'm not sure about the UK, but here in Ontario, Canada we usually have a surplus at those times.

    ieso publishes a forecast surplus baseload generation report. They didn't have an actual surplus baseload report that I could find. Since they are in the business of electrical power generation, I'm sure they have a good tools for making those calculations.

    Roughly the surplus is 1,000 MW per hour over an eight hour period during the work week. Doing the math, 1,000 MW * 8hr * 1,000 = 8,000,000 kWh. That would be enough power to fully charge over 333,000 LEAFs from surplus, wasted electricity. No light bulb changes required. No extra CO2 emitted.

    Get the smart grid enabled and I'm sure that 1,000,000 EVs could be supported here in Ontario, just on the surplus.

  4. 4) Ben Rose Said: (02/09/2011 21:45:34 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Keith,

    Thanks for the feedback.

    This is a UK site, I only really talk about the UK. Cars that are released in the UK. UK mpg and UK power generation. I know nothing about power generation in Canada.

    It's clear to me that Canada is very different. We don't have any surplus in the UK, none at all. Of course, the whole definition of "surplus" is rather insane. If you don't need electrical energy, don't generate it. Generating more than you need is wastage to the extreme.

    In the UK, we use everything we generate. Some of it gets consumed immediately. Some of it is used to pump water into massive reservoirs of water. On demand, when usage peaks in the early evening, they can open the flood gates to generate a massive amount of hydro-electric power in seconds. It's essential to fill a gap, without having to keep fossil fuel generators on-line.

    I drove past a massive power station in Nottinghamshire this weekend, Ratcliff-on-Soar. On Sunday there was no smoke or steam coming out into the atmosphere. It was the weekend, it was even a Bank Holiday (Labour Day) weekend, so demand was lowest. It was off-line. Off-line to reduce waste.

    At times of extreme need, the hydro reservoirs are there. At other times, we have a massive conductor under the English Channel to France which allows us to get in extra energy from the extensive French nuclear facilities. Uranium fuelled nuclear isn't so controllable so, whilst we turn off many of our fossil fuelled generators during times of low demand, the nuclear generally stays online.

    Whenever you charge an electric car, it uses the same energy. Whether that's when people are in bed at night, or in bright sunshine during the day. Energy use is energy use, whichever way you look at it.

    If you are swapping out all your light bulbs, to reduce electrical energy use, and then plugging in an electric car, the net result is that you use MORE electrical energy. That's the point.

    We're all buying standby saver devices and low energy computer monitors to reduce our demand. Around 50% of UK electricity supply comes from the combustion of natural gas. Another 30% comes from coal. So, whatever time of day, around 80% of it is coming from fossil fuels.

    Sure, in Canada you guys may be happy throwing a few more logs on the fire at the power station that you don't actually need. The solution isn't to build one million limited range EVs, with a massive carbon footprint, in order to soak up the excess. That's a bit like chopping down trees in rain forests to make paper towels that will soak up the water as the polar ice caps melt.

    The only solution here is to use LESS energy.

  5. 5) Clive Sinclair Said: (02/09/2011 22:23:57 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    I live in Scotland. We have the largest wind farm in Europe. I visited this farm two days ago. All but TWO of the turbines were 'feathered' and not producing electricity (even though the wind was capable of).

    The two turbines generating were doing so to power the visitors centre and the EV charging point.

    Tonight the UK is getting only 2.0% of it's power from wind, while we are getting 2.8% from French Nuclear plants - via the French Interconnector (which is the daily average we are importing).

    We are also building one of the largest offshore wind farms in the world and investing heavily in wave power (Scotland). Yet still the amount of energy from renewables is tiny and we certainly don't ever have a surplus.

    As Ben said, in the UK we use all we generate and need more - despite massive amounts of renewables.

    Bottom line is we need to use less energy and use what we have much more efficiently.

    We hear of people racing electric cars, trying to copy fossil car records, etc, etc. And many people are buying an EV as a second car?

    What I find strange is that the majority of people who buy an EV as their sole transport are prime candidates to be using public transport - short journeys in cities/towns. Yet they chose to add another/additional car to clog the roads and take up valuable real estate.

    Personal transport i.e. fossil or extended range cars are ideal for longer journeys not suited to pure EV's. A pure EV really does not make sense in it's current form.

  6. 6) Keith Ruddell Said: (03/09/2011 05:52:12 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Ben,

    After reading your and Clive's responses, I was left wondering, how could you possibly be using all electric generation if all but two turbines in a wind farm are sitting idle. After some research I found out why.

    Actually you do have surplus generation in the UK. It's just handled differently. In Ontario ieso has to accept all wind generated power and then try to get rid of it. In the UK they use wind curtailment, where the wind generating companies are paid not to produce by feathering the turbines. That is probably what Clive saw when he visited the wind farm. The only UK pumped storage is in Dinorwig, which has a 1.8 GW output for 6 hours. Not sufficient for the over 5 GW of UK wind capacity.

    Both policies are wasteful, but at least the UK method is safer for the grid. Ontario had to pay Michigan and Quebec to take an unsafe excess last New Years Eve.

    I have to disagree with you that electricity use is the same regardless of the time of day. Any wind turbines that are sitting idle in the UK at night, can be brought online to charge EVs. No point in throwing money away for nothing. Here in Ontario we are getting Time Of Use billing to encourage off peak usage of electricity. Obviously the government and power generation company are in agreement too.

    I also disagree that EVs have a massive carbon footprint. They're slightly higher than an ICE vehicle, but the fact they can soak up the excess wind energy surely balances that out.

    As Clive wisely stated "Bottom line is we need to use less energy and use what we have much more efficiently." I believe that in addition to conservation, renewables, EVs and the smart grid are important as well. EVs are the storage that renewables need and the smart grid ties them together.

  7. 7) Ben Rose Said: (03/09/2011 10:30:39 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Keith,

    The conversation seems to have digressed somewhat. To be honest, wind power represents such a small part of UK power generation that I think you're using it as too large a part of the argument. Even at maximum output, which we'll never achieve, it's a minority power source.

    I feel it important to point out that I'm not against electric cars in general. Indeed, I see a massive future for them - just not now.

    We've been trying to reduce our electricity usage for years as our power comes from a dirty grid. Instead of of throwing money into subsidising limited range electric cars that also have a rather limited life, I think all the "eco money" should be going towards cleaning up the National Grid and helping provide cheaper sources of energy.

    In the short term, I'd be diverting it towards the construction of new Nuclear facilities - preferably the potentially cleaner/safer Thorium powered type, not Uranium. This would be relatively quick and easy to deploy, remove some dependence on fossil fuel generation and put us in a better place to commence the roll-out of renewables.

    Things like PV solar panels are improving efficiency all the time. If we'd spent millions putting panels on every roof some years ago, we'd end up with our roofs full of redundant panels that we'd be better of throwing in the bin and replacing with better models that could generate 2-3 times more power in the same area. Very similar applies to wind turbines, the newer ones are considerably more efficient and waiting a while, using the Nuclear alternative, is perhaps a better bet. It's not the best option long term but, in the short term, it's air pollution free and independent of fossil fuel supply.

    I should clarify my point about current EVs having a limited life. It's well know that the battery packs aren't going to last a considerably length of time. They also cost a small fortune to replace. Sure, the cost of Li-ion fuel cells is dropping all the time, but I don't think it will ever be economically viable for a car like the Leaf to have its battery pack replaced.

    In circa 7 years time, many Leaf battery packs will likely have depleted to a level where its range is no longer sufficient for the owner. They will try to sell it on to a new owner but very few will be found who can live with a car that has such a poor range. This will make residual values of these cars drop like a stone after say year 5.

    It will swiftly reach a point that the cost of replacing the battery pack is more than the market value of the car. This is technically a financial write-off. Of course there may be somebody out there who is happy to buy a dirt cheap car with a limited range. Sadly, very few of those people have a private driveway on which to charge it.

    Those who have money, won't be buying 5+ year old Leaf cars with a limited range. By that time, EVs with 300 miles range will be more prevalent. That's where the money will go. Those without money who live in towns and have a short commute, where these used cars may be useful, generally don't have a driveway.

    So I predict we'll swiftly reach a point where they can't even give away these cars and they'll end up a big waste of carbon footprint on a scrapheap - the exact opposite to hybrid alternatives that are still happily running after over a decade and, should the worst happen, have a considerably smaller, cheaper, battery pack to replace.

    The biggest threat to current EVs is not petrol or diesel engined cars. It's future EVs. As soon as they appear, as soon as they have the range of a normal car, these over-priced "first gen" EVs are going to be shown to be a waste of money and a waste of resources. During their lifetime they will have used more carbon than they have saved and cost the owner considerably more than the other alternatives available.

  8. 8) Neil Stratford Said: (03/09/2011 12:41:56 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    So the reasoning here appears to be to do nothing because technology is improving all the time.

    By the same reasoning I'd be mad to buy a Prius because the model in 5 years might be slightly better.

    After 120,000 miles I just replaced the turbo on my BMW 320d. Just under £2000 and one of many things that can go wrong in a fossil car (including hybrids). Seems a replacement battery in 5 years isn't such a big cost after all when you compare it to the status quo.

  9. 9) Clive Sinclair Said: (03/09/2011 17:35:03 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Is battery technology really improving. A certain electric car 15yrs ago had a range of approximately 100 miles. We now have the Leaf - with a real world range of less than 100 miles.

    The reason current electric cars have no chance of meeting sales expectations is that people are now savvy to new technology and the rate at which it changes.

    People realise that things will improve and get cheaper. Spending a few hundred pounds on a HD DVD system - for it to be obsolete, is a lot more palatable than spending £25,000 on a car only to find a much better and cheaper one in 2-3 years.

    Electric cars are the future, but I doubt the long term power source will be batteries - as we know them now.

  10. 10) Ben Rose Said: (03/09/2011 19:22:20 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Neil,

    Thanks for the contributing to the discussion.

    Not sure anybody said the best idea was to do nothing? I'm simply proposing we move from an excellent energy source that emits carbon and other harmful emissions to another excellent energy source that doesn't.

    In the meantime renewable sources will have time to catch up and we'll be in a position to deploy solar/wind etc. that can match energy demands without requiring a massive physical footprint to do so.

    If we're going to create the massive concrete foundations that wind turbines require, it may as well be for significantly more efficient models. Likewise, if we're going to lock people into 25 year FIT tariffs for solar panels, I'd like those solar panels to be the most efficient available when we actually need them.

    We don't need renewable energy right now. We need to cut electricity consumption and find low carbon sources. Nuclear is one, has a small footprint and a high output. Until solar/wind become significantly more efficient, it's the best option.

    Incidentally, I don't know of any hybrid car currently on the market that includes a turbo. These tend to be used on stinky polluting diesels, in an attempt to give them the performance of a cleaner petrol engine. Either way, current EV owners can dream of a £2000 battery replacement cost - that simply won't be the case.

  11. 11) Neil Stratford Said: (03/09/2011 21:06:51 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Ben,

    When do you propose that we start moving seriously to renewables? How do you decide when they are efficient enough? It seems to me a usual delaying tactic. Keep saying it's not efficient enough and you never have to act.

    I'm also not convinced by your battery doom predictions. At least a battery just degrades leaving a car with limited range. Typical (and common) problems with fossil cars often leave the car completely useless. I'm quite happy that I can afford a refurbished battery in 5 years for significantly less than I've spent on turbos, head gaskets, exhaust systems, catalytic converters, oil changes, filters, starter motors and timing belts etc in the last 5 years of car ownership. Maybe I'm unlucky, but it seems to be a myth that the internal combustion engine is reliable and cheap to maintain. In my experience it's a bit of a turkey that we should cast to history as an example of technology from it's time.

  12. 12) Neil Stratford Said: (03/09/2011 21:20:48 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Clive, I believe that most people will finance their new car with a guaranteed future value, exactly the same as they do for fossil cars. If you plan to only keep it 3 years with a guaranteed value, whats the problem with new technology arriving In 3 years?

    We have to assume that the people who work for car finance companies know what they are doing - they are taking a calculated risk on the technology rather than the end customer.

  13. 13) Ben Rose Said: (03/09/2011 23:41:07 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    @Neil - Sounds like you've been VERY unlucky with fossil fuelled car. Perhaps if you'd spent anything like you did on the Leaf on another C segment car then you wouldn't have had these large bills. Of course spending that much on another C segment car is pretty difficult.

    As for "guaranteed future value", you have to realise that current EV pricing is nothing short of a work of fiction. Even after taking off the £5000 subsidy provided by the tax-payer, these cars are nothing like profitable. From the answers Nissan gave in the European Press Launch for the Leaf, it seems like they are hoping that when their UK battery plant opens and local production of the Leaf comes on-line in 2013 it may be profitable at that point. We were given a strong impression that in the current market, with Li-ion being so expensive and the exchange rate so unfavourable with the Yen, that every Leaf is being sold at a loss.

    As for car finance companies, I think you'll find that Nissan are underwriting most of the policies themselves - their balance sheet may hurt a little in 3-5 years but I'm sure they've already set aside to handle the loss on returns.

    Incidentally, those past couple of paragraphs should be taken as observation, not criticism - it's not unusual for a car maker to throw cars into a new market at an initial loss, it's just how it needs to be sometimes. I'm sure the situation was similar at launch for the petrol hybrids and will be the same again for hydrogen fuel cell vehicles in the future.

    For those buying EVs on a "guaranteed future value" contract, more than half of all new buyers buy any new car this way, there is no DIRECT risk. But the risk to society is that these cars get returned after those 3-5 years and have extreme difficulty being remarketed, ending up with little value and only appealing to those who can't use them; as I highlighted above.

    As for when to switch to renewable. No delaying tactics, I just can't see the widespread adoption being anything like quick enough to meet our carbon targets. I'm led to believe that even if 1/10th of the entire UK land mass were covered in wind turbines, we still couldn't generate enough electricity to meet CURRENT demand - let alone future.

    That being the case, we need a proper interim solution until renewable options are ready. We're still approving new fossil fuelled power stations - if renewable were a proper scalable option at this point, we surely wouldn't be?

  14. 14) Neil Stratford Said: (04/09/2011 08:34:50 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?


    Your price argument is irrelevant. Although only slightly larger my 4 year old 320d cost significantly more than the Leaf when new, and I'm sure we all have a lot of respect for BMW engineering.

    The reality is that the Leaf makes the BMW feel like a bag of bolts to drive. Which car do we fight over driving each day? The Leaf.

    Financial institutions claiming that any loss they make is a 'risk to society'? That made me laugh :) Of course 'used' batteries still have value that can be offset against replacements, so any replacement cost will be significantly reduced anyway. Unlike the value of my blown turbo. That only has scrap value.

    I look forward to a hydrogen economy, though perhaps we've had enough of economies that make a squeaky pop when ignited.

  15. 15) Paul McCulloch Said: (04/09/2011 15:12:06 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Ben,

    I never think in terms of power for an EV, it's about dropping local pollution emissions and ultimately (when there are enough on the road) move to lower carbon emissions & when Renewables/nuclear finally replaces fossil fired near zero. The grid can take the EV ramp over this decade as it's reasonable predictable

    Replacing the standard light bulb is about driving people to stop wasting energy( although no one mentions low energy bulbs are more toxic than standard bulb), save money and give a knock on effect in the short term for less generation, saving 49 watts per bulb in the UK is a big saving. One thing is certain power price is going north in the short to medium term to fund the change from fossil fired to renewable, capital cost is higher per MW than fossil fired station (granted it will narrow)


  16. 16) Richard Lawson Said: (04/09/2011 18:31:48 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    "In the UK, we use everything we generate"

    "In the UK, we use everything we generate"

    Not so. 1% of grid electricity is burned off as heat, when supply exceeds demand. This process is marked by increased frequency. Smart chargers can use this increased frequency as a signal to put power into the EV.

    At the same time it will probably extend the life of grid components, since it cannot do them any good to overheat. This extra capacity will enable use of excess renewable production (see reference to wind turbine feathering above.)

    EV batteries can also feed back into the grid at tomes of undersupply. Thus EVs can act as an electricity storage facility.

    PS is it true you work for Toyota?

  17. 17) Keith Ruddell Said: (04/09/2011 20:06:04 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?


    "The conversation seems to have digressed somewhat." Yes it has. I wish you could stay on track better.;)

    My point was, EVs will not have a significant impact on electricity use because they are mostly charged at night, when there is over supply and therefore wasted electricity. Yes, even in the UK it seems. "Wind farms operators "were paid £900,000 by the National Grid to disconnect their turbines for one night because the electricity was not needed"." Most efficient lights, TVs, computer screens, etc. will be turned off at that time and will not even factor into the equation.

    The point of your blog, is that every little bit makes a difference, then you go on to dismiss wind power as being insignificant. 5.7GW with 2GW to be added per year for the next 5 years is fairly significant. The lowest output for wind farms is during the summer at night. The capacity averages 13 percent at that time. Therefore the average output would be 741MW. That would fully charge over 220,000 LEAFs overnight on wind power alone, with over 78,000 being added each year over the next 5 years. If you were to limit each car to 10,000 miles per year, those numbers would more than double.

    Now if there were 440,000 fewer diesel and petrol cars, travelling 10,000 miles per year at 40 mpg (UK avg) that would be 440,000*10,000/40 = 110,000,000 gallons of gasoline and diesel not used. From NationMaster 5,624,000,000 kWh of electricity is used by UK refineries. From 40% of the refineries output, 9,798,299,980 gal(imp), goes to road transport. That would save 5,624,000,000kWh *.40 / 9,798,299,980 gal * 110,000,000 gal = 25,254,993 kWh. That's 25 GWh of electricity saved per year by using overnight wind power to charge EVs. Doesn't get any better than that.

    Since you brought up the topic of battery replacement, I'll add my thoughts. If your really worried about it, buy a Renault EV and lease the battery. When the term is up, you can lease a brand new battery that may even have a higher capacity, resulting in a longer range. Most significant range increases will come from battery improvement.

    Nissan is predicting the 2015 LEAF will have a 200 mile range. Current LEAF owners could trade in their car for the new model or swap out the old battery for the new improved battery. Although I would like it, I highly doubt there will be many dirt cheap EVs available in the future. The LEAF battery is modular, so swapping them out would be far easier than a engine job on an ICE car. In 7 years time there could be a thriving aftermarket for replacement batteries, with the cost much less than it is today.

    As I said before, conservation, renewables, smart grid and EVs will all have a positive effect when used together.

  18. 18) Ben Rose Said: (04/09/2011 20:15:00 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    You may just see is as "only slightly larger" but your Nissan Leaf and BMW 320d are chalk and cheese.

    1) You're comparing the C segment Leaf, in which BMW have the 1 series, with a D segment vehicle, where BMW have the 3 series.

    2) You're comparing what is regarded as a "Premium" brand with a "non-premium" brand. There are numerous reasons why premium brands command a higher price. Some even come from the same corporate umbrella. For example, the VW Golf and the Audi A3 are the same...but different. Both C Segment, but one is a premium model and the other is a VW. The Leaf competes with the Golf, not with the A3. Nissan's premium marque is badge Infiniti - the Leaf is not an Infiniti.

    3)You're comparing an old car with a new car. For a true comparison, you should be comparing the Leaf with what you BMW is worth NOW - or with a new BMW, that doesn't have spaceship mileage and still has a warranty.

    In reality, you only have to drive around one roundabout to feel the difference between these two cars. A high torque FWD electric car that scrabbles for grip vs. a RWD chassis that will slaughter most of the competition in side by side comparisons.

    Whatever you feel, the price argument is entirely relevant. Comparing the Leaf with a 3-series which, at 4 years old is likely a whole generation away, is a bit of a moot point. I think if you had the old 3-series and a new 1-series worth £30,990 you'd also fight over the 1-series.

    Financial institutions claiming that any loss they make is a 'risk to society'? That made me laugh :) Of course 'used' batteries still have value that can be offset against replacements, so any replacement cost will be significantly reduced anyway. Unlike the value of my blown turbo. That only has scrap value.

    "Financial institutions" are claiming that these cars are a risk to society. I am. I simply don't think they'll at all save their own carbon footprint in their lifetime.

    I look forward to hydrogen too. They're essentially electric cars but, instead of carrying around heavy overpriced batteries full of rare earth metals, they have a tank of compressed hydrogen gas. 2 of the 3 atoms in every molecule of water are hydrogen and 2/3rd of the world is covered in water - we're not exactly running short.

    I look forward to a hydrogen economy, though perhaps we've had enough of economies that make a squeaky pop when ignited.

  19. 19) Ben Rose Said: (04/09/2011 20:18:11 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    @15 - Paul,

    Will the grid clean up it's act in the 3-5yrs where the latest "100 mile range" generation of EVs are still on sale? I don't think so.

    That's my point. They will achieve something, one day, but not until the grid cleans up.

  20. 20) Ben Rose Said: (04/09/2011 20:32:34 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    @16 - Richard,

    Welcome to the blog and thanks for the comment.

    Very interesting information, do you have a source for that? Not doubting your claims just, if I reproduce it in future, somebody is bound to ask my source and "somebody posted it in a blog comment" isn't really going to cut it.

    In reality though, in the scheme of things, 1% is within the margin of error for the type of numbers we are talking about. So, should be burn off 1%, it's as good as using it all.

    Of course, if we do use it all, why are we constantly buying in grid supply from France, Ireland and the Netherlands?

    Why would be burn off 1% of our generation and then , as I type this, buy in 2.8% of our electricity from France and 2.5% of our electricity from the Netherlands? Doesn't really make sense to me. Perhaps you know otherwise and can explain?

    You claim that "EV batteries can also feed back into the grid at tomes of undersupply" - they can, but do they? I don't know of a single vehicle model on sale in the UK or indeed the whole EU that supports this. Can you name one?

    Finally, regarding the question in your p.s. - my employer has a communications policy that prevents me disclosing their identity on-line. I don't represent their opinion, it's all my own, so they're obviously keen that any opinions I have aren't misconstrued to be theirs not mine.

    The "about me" page on this site covers about as much about who I am and what I do as I can communicate in public but I'm always happy to discuss off-line with any interested parties. Feel free to use the "contact" page to do so, just as anybody else with an interest in this area is encouraged to do so by the text on the "about me" page.

    Thanks for asking.

  21. 21) Ben Rose Said: (04/09/2011 20:53:06 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    @17 Hi Keith,

    Thanks for coming back.

    Some very valid numbers there and I'm not going to challenge any of them.

    My summary response is simply that I don't believe that the lifetime carbon footprint of any of the latest "100 mile range" EV models is significantly less than some existing fossil fuelled powered models that would cost significantly less to own. Seeing as the whole world only seems to care about CO2, no matter how loud I shout, then I would expect the big CO2 solution to actually achieve something more than it does. At low speeds, say up to 40mph, I expect the EV is 10% lower CO2 at best - based on the average grid mix over its lifetime. Above 40mph, I expect it to be marginally worse than some alternatives. I just don't think the currently available models achieve anything, except a big hole in the buyer and taxpayers wallets.

    Regarding battery replacement, you couldn't be more right. Anybody who is thinking about buying an EV in the UK should be looking closely at the Renault Fluence and ZoE models. They're a little big greener than current options, e.g. achieving the same range as the Leaf using 22kWh instead of 24kWh , and the buyer is significantly less exposed to future battery problems and costs. The only risk is that the battery leasing price for the second owner may be rather high and push the value of the cars down but that remains to be seen. For the first owner at least, it seems to make a lot of sense. I did some numbers around the Renault battery leasing model in a previous article. { Link }

    I absolutely expect the LEAF with have 200 miles range in 2015 - this is what will kill the current model. Who is going to buy a used 100 mile model, with its dying battery back, when they are 200 mile models available that may meet the owners requirements a lot more. Sadly though, this may take charging times up to 22 hours from 11 on a standard home socket but it should at least then support a double speed 32Amp charging option - albeit at significant cost to the homeowner to install.

    I don't doubt current LEAF owners will be able to trade-in their existing model against a new one, why wouldn't they? My concern is for those old carbon footprints that nobody wants any more. I don't think there is any way in hell that owners will be able to upgrade the battery pack in any current LEAF model to give it 200 miles of range. If they did, they couldn't charge it in any practical way. This would be like Honda offering to install the engine from the new Insight into the old models, so they qualify for congestion charge exemption - simply not going to happen. Car companies are in the business of selling new cars.

    For sure Li-ion will be cheaper in future than it is today but you also need to appreciate that many Li-ion prices are also currently not reflecting their true cost. I'm told current pricing for Li-ion is about £500 per kWh - making a 24kWh battery pack have a cost of around £12,000. This is wholesale, not retail pricing though, you need to add a healthy margin and sales tax onto that.

    It will all be good in the future - just not now, that's my point.

  22. 22) chelsea sexton Said: (04/09/2011 22:11:27 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Ben,

    Thanks for instigating a really interesting discussion!

    Fascinating comparison between lightbulbs and EVs, but while entertaining, it's not the right one. Yes, EVs use much more energy than lightbulbs, but I can't drive a lightbulb to work.

    Since you focus on CO2 for your comparison with petrol/diesel vehicles, do you have a source for the conclusion that EVs don't offer any benefit at high speeds, and only 10% at low speeds?

    The 2008 study by DfT/BERR investigating the impact of switching to plug-in vehicles concluded that EVs offer a 40% reduction over a full life cycle, on the current UK grid mix.

  23. 23) Ben Rose Said: (04/09/2011 23:20:14 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?


    Hi Chelsea, it's good to see so much quality feedback in here lately.

    Believe me, I don't focus on CO2 through choice - I personally feel many of the other pollutants are a significantly higher threat. Sadly, all the world seems to truly care about right now is CO2, hence carbon based taxes etc. so it's those that are published and easiest to compare.

    The "10%" argument was from my own analysis published previously on the blog. One example is here -> { Link }

    At lower speeds, inefficiency is generally caused by the process of having to speed up and then slow down the mass of the vehicle as you accelerate and brake. The weight of the vehicle is an important factor here and it's why the Prius full hybrid I borrowed the other week was significantly more efficient around town than my big Lexus full hybrid. The Lexus is much heavier and takes much more effort to pull away from junctions and stop for traffic lights. In much the same way, EVs (despite carrying a heavy load of batteries) are reasonably light as you lose all the heavy gearbox, petrol tank etc. that form the drive-train of a normal ICE vehicle. Also, as that battery charge is so precious due to limited range, they have been built to regenerate as much battery power as possible under deceleration/braking - the hybrid can currently afford to be a little more wasteful and still achieve the lowest tax bracket.

    At higher speeds, however, mass is less important and it's all about wind resistance and aerodynamics. In my recent experience, the Prius efficiency dropped significantly in both EV and HV modes at higher speeds whereas my Lexus actually becomes more efficient in these areas. At high motorway speeds, the Prius and Lexus aren't that far apart.

    In a similar way, the slippery Prius will likely be aerodynamically more efficient than the blobby Leaf at high speeds. If the Leaf had the excellent aerodynamics of something like the Mk1 Honda Insight, then it may be a different story, but it doesn't. The Insight is still a perfect example of this argument with an mpg that proved how seriously efficient it was - at least for fuel economy and CO2.

    As for the 2008 DfT/BERR study, you don't link it but I think I know the one. If I remember correctly, it compares different vehicle types, comparing the full life cycle of each, but uses an extremely high annual mileage of 20,000 miles. 20k miles p.a. may now be a lot in a normal ice car but, in an EV with restricted range, I find it a tad unrealistic.

    These cars aren't being purchased to do regular long distance journeys and, whilst there are always exceptions to the rule, I can't see many of them breaking 10k miles a year, let alone twice that.

    All of the Leaf owners I know of have retained an ICE vehicle to handle their longer distance trips. Unfortunately, in every case I know of, this is also an older polluting diesel. Using an EV for commuting and then a stinky diesel for your long journeys is highly likely to emit more emissions overall than simply have a single petrol hybrid vehicle.

    The results of the study, if I remember correctly, were highly dependent on this theoretical higher mileage to give the EV a chance for the lower CO2 emissions in use to outweigh those of manufacture and disposal. If the mileage had been restricted to the likely limited use of 10k miles, I believe the petrol hybrid vehicles would likely have a smaller Carbon footprint.

    Finally, it's important to note that CO2 based transport taxation wasn't as significant back in 2008 and most manufacturers only really optimised for low CO2 with their Euro 5 compliant models that were launched ready for this legislation to be introduced in 2011. As a result, CO2 emissions from standard ICE vehicles have dropped like a stone since then.

    In 2008, EVs may have looked a lot more favourable next to the current rolling stock and even some of the new options available at the time than they do now.

  24. 24) chelsea sexton Said: (05/09/2011 00:46:55 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?


    Hi Ben,

    Sorry, here's the link: { Link }

    It calculates based on a 180,000km life cycle, which is reasonable even in an EV. The earliest MY calculations are 2010, so I'd assume that CO2 improvements have been taken into account- though it also projects for 2020 and 2030.

    The long distance trips are a fair point if you have data on what that average mileage is per year, and average length of trip and exclude any that could be accomplished reasonably in a 100-mile EV. Obviously you'd have to separate out those that would likely be accomplished by train or plane for drivers of either vehicle type as well. But it would be easy enough to figure a reasonable number of miles/yr you think would be travelled in a traditional vehicle, and extrapolate the added CO2 based on the lifetime numbers for the liquid-fueled vehicles in the study.

    It's less valid to use a comparison of a specific EV to a specific traditional vehicle- nor to assume that the second vehicle to an EV will always be one of the dirtier diesels, for the purposes of drawing a conclusion about an entire technology. If evaluating only for your own personal situation, fine.

    I understand the difference in efficiencies based on speed and aero- though Cd difference between Prius and Leaf is only ~.3, which isn't egregious. Still, to draw a conclusion about the group, you can't pick just one of each vehicle type, and certainly not the best example of a petrol vehicle.

    But there may be better studies out there, and I'm happy to look at one you like more?

  25. 25) Ben Rose Said: (05/09/2011 01:21:57 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Chelsea,

    Thanks for the link, will take a look when I find a moment - little point in responding to that part until I have. As it's 1am here, not going to be tonight.

    180,000km is 112,500 miles - seems to be quite a distance if we're talking the original battery pack. Or maybe it takes replacement battery modules into account in the life cycle? I'm not saying a new EV isn't capable of doing that distance on one battery pack but I do feel that the range at that point, after normal usage, may be so decreased that the car is somewhat unusable. I'm basing this on both the total distance and the time it would take to hit that mileage based on short journeys in a low range EV.

    Average mileage and average length of trip is an interesting stat but doesn't always tell the full story. I could easily manage my work commute each day in an Electric Vehicle. So 52 weeks, 5 times a week, that's 260 journeys a year. Many of my other local journeys are also achievable. However, when I recently borrowed a plug-in hybrid, my EV miles were actually less than 25% of the total mileage. I may do a large percentage of journeys under a long distance but most of my miles are clocked up on journeys over the typical range of an EV. So on paper, an EV looks good. In practice, I'd do more miles in my "other" car.

    I'm comparing to a specific EV as it's the most well know of the few that are available in the UK. It's also the best range/charge balance of those currently on sale, until the Renaults hit the market - which will do the same range on less electricity. I think it's fair to use the Leaf for comparative purposes.

    I'm not assuming that the second vehicle will always be a dirtier diesel, that was just a personal observation based on all the current owners that I know of - nothing more. There does appear to be a bit of a pattern there though.

    Be careful comparing the Cd of 2 vehicles, they aren't at all directly comparable. The Cd measures the air resistance of the vehicle vs. a block of the same cross sectional area and length. It's very easy for 2 cars to have the same Cd but total different wind resistances. Likewise, a car with a low Cd may actually have a higher wind resistance to one with a high Cd. Being half the resistance of a small block is obviously better than being half the resistance of a large block.

    The Prius and Leaf have a very different cross sectional area so the Cd aren't directly comparable. What you need to use is the CdA figure, which also takes that cross sectional area into account.

    For example, a 2004 Toyota Prius has a Cd of 0.26 and a CdA of 6.24 sq ft. The Opel Calibra from 1989 also has the same Cd of 0.26 but a CdA figure of 5.40 sq ft - considerably less as the Opel is actually more aerodynamic overall.

    So whilst the current Prius has a better Cd of 0.25 compared to the Leaf's 0.29, the CdA may show more difference between the two as the Leaf's high roofline creates a rather large cross sectional area.

    My conclusions simply compare the "best" EV with petrol vehicles that can be bought for the same or less money. When buying the Leaf, the customer is already well into the price bracket of some of the best petrol hybrid options so I see no reason not to compare them.

    If I was suggesting the customer spent more on my proposed alternative option, I could see your perspective, but I'm pointing out "better" options that actually cost less.

  26. 26) chelsea sexton Said: (05/09/2011 02:37:40 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?


    Hi Ben,

    Ok, so this sounds more like a speculative or philosophical assessment than an objective one. I understand the types of things you're citing to speak of efficiency differences, and yet as a technology, EVs are proven to be better in terms of CO2 than you think. If you want to talk price per gram of CO2 savings, that might be a different story- but I was responding to your original premise of whether EVs were better on CO2 to begin with.

    Given that the minimum warranties were seeing on the Leaf and Volt are 8 years/100k miles (which next year become 10yr/150k miles for Volt, Prius, and Ford Energi at least), it's fair to assume 112k miles is possible on the original pack. Range will degrade some, but not enough to render the car unable to accomplish a average daily driving.

    Finally, I see the point about you, in particular, using the 2nd gas car more. But again, if we're assessing the merits of the technology for the typical consumer, we have to use what those driving patterns generally are. I'm happy to add in the gas car use to the EV to make a true comparison, but we'd need to determine what trips we're talking about that are truly out of the range of the EV (and I'm not talking about charging a bunch of times in the middle to make it) but that also aren't likely to be accomplished by another form of transport. Here, even the Volt drivers are averaging around 80% of their miles in EV mode. I'm sure some of those are taking actual long trips with the other 20%, while others are probably just exceeding the Volt range but still staying within the range of an EV. So if we meet in the middle and assume that 10%, or 1200 mile/year are done with a second car, and add the respective CO2 use to the EV based on the data in the study, the EV comes out 28% better than a petrol car, and 22% better than a diesel. That 10% may be high or low depending on average UK driving patterns, which is why I was asking if there was any data anywhere on the longer trips.

    Whether that 22 or 28% is worth paying the incremental cost for a plug-in, depends on whether CO2 is your main motivation for the purchase. Given how much vehicles are and emotional purchase, that tends not to be the primary (or even secondary) motivating factor for EV purchases in the US market over the last 15 years, but perhaps it's different there?

  27. 27) Richard Lawson Said: (05/09/2011 13:16:50 GMT) Gravatar Image
    How Many Electric Car Owners Does It Take To Change a 60W Lightbulb?

    Hi Ben

    The 1% wastage figure comes from data sent personally to me by someone in a Grid balancing agency. As you know the Grid has to do a delicate balancing act to match supply and demand - ready for half time in a Cup match, when everyone puts their electric kettle on &c.

    From the data I found that the grid is 1% of the time in overproduction, 1% is underproduction.

    In reality though, in the scheme of things, 1% is within the margin of error for the type of numbers we are talking about. So, should be burn off 1%, it's as good as using it all.

    I dont think it can be explained away as margin of error: these were precise real-time figures, applying to an acknowleged effect that absorba a lot of grid supply effort.

    Why are we constantly buying in grid supply from France, Ireland and the Netherlands?

    I guess to match up gross disparities that occur, for instance, when nukes go down (talk about "intermittent"...)

    "EV batteries can also feed back into the grid at tomes of undersupply" - they can, but do they?

    This is just a gleam in the engineers' eye at the moment, but it is being discussed, and will come through eventually.

    Finally, regarding my question of your employer, if you did not work for Toyota, you would have said so, so I infer that you do. Now why would Toyota want to dis the EV?

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