My Chicken of an EV

Yes, that's my chicken atop my car.

Yes, that’s my chicken atop my car.

A little over two years ago, my wife and I entered a new phase of life in two respects: we got three chickens, and we got a plug-in hybrid vehicle. They have more in common than I would have thought. We see flagging performance in both (egg-laying and battery capacity). We knew the chickens would only last/live for something like 4 years. It’s looking like the EV battery may be similar! Both are happiest pipkining around: plodding about at a leisurely pace. And perhaps like some children, they both disappoint us at times, but we are fond of them all the same. They’re good girls, we tell ourselves.

It may come as no surprise to you that I’ve been collecting data (yes, on both “experiments,” but I’ll spare you egg masses and laying schedules). It takes a little time to do, but recording/resetting the trip meter for every charge, noting charge time and energy delivered, and convincing the wife to go along does pay off, as you will hopefully be convinced.

From the data, I see that the battery capacity is at about 85% of its original condition. While extrapolation is highly risky, it would seem that I can expect zero capacity on the scale of six years, based on its accelerating decline. At this point, we have put about 500 full-cycle-equivalent charges on the battery in about 700 charge events (just shy of one per day, typically about 70% depth). So perhaps it’s not surprising: few batteries can withstand more than 1–2000 charge cycles before giving out.

Want to see some data?

Basics first. The car is a 2013 Ford C-Max Energi, with a nominal electric range of about 20 miles, plus a gasoline range around 600 miles. The 7.5 kWh battery provides nominally about 5.5 kWh of capacity for the user. The following plot shows the historical usage profile for our vehicle.

gasoline vs. electrical consumption over time

Gasoline vs. on-board electrical consumption over time

The horizontal axis tallies gasoline usage in gallons, while the vertical axis is the electrical energy used, in kWh (as reported by the car: charging supplies 22% more than this). Road trips shoot over to the right, while long stints of around-town driving are more vertical tracks. Color coding signifies progress through time (the same scheme is used for many of the plots to follow). Soon after getting the car, we took a ~4000 mile road trip to the Pacific Northwest (charges along the way), and a more recent one to Yosemite. The black line represents an approximate parity between EV driving and gasoline driving. Traveling a total of 24,200 miles using 280 gallons means a literal MPG of 86 (37 km/L).


Rather than focusing on miles per literal gallon of gas, the car also reports MPGe: miles per gallon-equivalent. Reverse-engineering, it uses a conversion of about 33 kWh per gallon of gasoline, which is consistent with the thermodynamic lower heating value of gasoline.

Looking only at “pure EV” trips in our car, we get the following scatter relationship between kWh reported used by the car and miles driven. The upper, middle, and lower black lines correspond to 170, 140, and 110 MPGe, respectively.


So 140 MPGe is typical for us. Note a greater preponderance of blue (early) points at lower MPGe, and more red (recent) above the center line: we’re driving more efficiently over time. The direct conversion of 140 MPGe is 4.27 miles per kWh, or 23.4 kWh/100 mi (a suggested metric in this old post on EV MPG). But we should not be so hasty to declare this a marvelous feat.

Firstly, charging efficiency (at a 3.4 kW rate) for our car is around 82%. By this, I mean that Delivering 5.0 kWh from the wall outlet results in only 4.1 kWh kept/used by the battery. That’s not a bad energy efficiency, as batteries go (note that energy efficiency is always lower than charge efficiency, which just counts charges—electrons—ignoring the fact that charging takes place at higher voltage than discharging). So the true effective efficiency is 113 MPGe, or 29 kWh/100 mi, which is in line with other EVs. The same (our) car on gasoline tends to get about 47 MPG, so EV mode uses about 40% as much energy as would gasoline to propel the car (far less wasted as heat). If the electric drive is 80% efficient (guessing), this implies a 32% efficiency in gas/hybrid mode.

Also, I should remind readers that electricity doesn’t come out of wall sockets without some less-than-perfectly-efficient process behind the scenes. A coal plant at 33% efficiency needs three times as much thermal energy as the amount delivered in the form of electricity. So the 40% EV miracle goes up in a puff of smoke, now taking 20% more thermal energy compared to direct burning of gasoline, and producing an even larger toll on climate change, given coal’s higher carbon intensity. If your power is coming from solar, wind, or hydro, then fine. Fossil fuels: flirting with break-even.

Note that the upper right end of the plot above has no (recent) red points. The battery capacity is fading.

One more point before leaving the topic of MPGe. Our car has trained us to be more efficient drivers. The biggest effect happened over the first few months, but we see a slower improvement since then as well. The plot below tells the story.


This is the only plot for which dot color is not tied to the timeline. In this case, it represents the fraction of the trip energy provided by electricity. Dark blue is effectively gasoline-only, while dark red is pure EV mode. We see a steep initial “training” curve, especially in the EV-only points. One anomalous cyan point sits on the lower line. The car was in the shop at this time, and I can’t figure out what they did to use so much battery juice for not very many miles. I also detect a seasonal variation: more efficient in summer.


Okay, now for the bad news. We used to frequently pull into the garage on battery “fumes,” and note 5.5 kWh delivered by the car battery. But we have not seen this for many months now. Time to plot up all our hard-earned data. The plot below shows the energy expended on pure-EV trips (or collections of small trips) that ended with an estimated remaining range of three miles or less. For those trips with some range remaining, the “full” capacity was estimated by adding estimated range divided by 5.5 miles per kWh, which is the empirically-determined (optimistic) range estimate scaling the car seems to use. In other words, if we use 4.7 kWh and have 3 miles left, I report this as 5.2 kWh total capacity. The curve looks no different (just sparser) when including only points with 0 or 1 miles remaining.

Unmistakable decline in battery capacity

Unmistakable decline in battery capacity

In the early days, 5.0–5.5 kWh was the rule. Now it’s 4.4–4.8 kWh. The black curve is a fit-by-eye parabola that does a fair job of capturing the initially-flat behavior. But it may have been even flatter initially, and falling more steeply than the curve suggests now. In any case, that particular curve hits 80% in early 2016 (2.6 years in), 50% after 4 years of service, and would be dead within 6 years of purchase. I hope I’m wrong.

Could it be that the car is simply reporting less energy used by the battery, but that the actual energy has not changed?  After all, we seem to be getting better mileage.  Is this an illusion also connected to under-reporting of energy used on-board?

Short answer: no. I had hoped for something like this. We not only keep track of charge times, but our electricity monitoring system also tells us how much we’re actually delivering. Comparing initial charge efficiency to recent efficiency shows no change at the few-percent level.


Although there is a generous warranty on the battery (8 years or 100,000 miles; 10 years or 150,000 miles in CA and some other states), this does not apply to gradual capacity loss, since this is considered to be normal wear and tear. So if the $4,400 battery cost crops up in four years, my cost analysis ($3/gal gasoline, $0.15/kWh electricity, 5,000 miles/year in EV mode) indicates a propulsion cost savings of $100 per year (about 15% savings on yearly total propulsion cost, assuming 10,000 miles total per year). Compared to the $1100/year in battery premium cost, this saving is practically invisible/meaningless. Batteries becoming twice or even four times cheaper will not offset the differential.

Take Away

While obligated to point out the financials, I am the last to feel enslaved by a strict dollars-and-cents analysis. There are other reasons to go for an EV: reduced reliance on petroleum, solar charge capability, quiet, efficient, support of a nascent technology, etc. For me, energy is a hobby. I buy an expensive car and expensive solar batteries because I want to learn more about their pros and cons. In part, I am glad that I can export what I learn to the people. Most folks do not have the financial or technical capabilities to look into possibly-hyped technologies and report, free of financial agenda.

I am not yet personally convinced that we will see an EV revolution. Gasoline price fluctuations are a short-term killer of long-term planning. Batteries still do, and likely always will, disappoint. I am learning similar lessons on the nickel-iron battery front. We may have to face the fact that gasoline has been the ultimate transportation fuel, and the economists’ picture of universal substitutability may not apply. If EVs can never really outperform gasoline in cost, ease/simplicity, convenience, and robustness—and if they remain expensive to own and maintain, from where will the prosperity derive for us to all have such marvelous toys?

Meanwhile, I will continue to enjoy my EV and my chickens while they last, as a lifestyle choice. The cost per egg or cost per mile certainly do not justify them. So we need be satisfied by other reasons.

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34 thoughts on “My Chicken of an EV

  1. Thanks for taking the time to write this.
    Agree with your summery. For now, I am happy to commute in a gas powered Smart Car. Bought it used, so made a big saving there, and it seems no matter how much fun I have in it, I can’t get worse than 32mpg with 38 being typical. (This for a 12 traffic light 6 mile one way commute to work).

    Have just put some home spun solar on the house and am in the process of sourcing batteries for it (not going grid tie – in part due to your data).
    Going be very interested in seeing your blog on the likes of the Tesla Powerwall (or similar) when they arrive – again with the batteries).

    Bottom line, after looking into the ‘Duck Curve’, seeing the grid issues in Hawaii and then reading about your car, I am a bit of a loss to know where to turn next.

  2. This is great. We have a 2-1/2 year old Energi but we don’t do the math this deep.

    In sum, then, this reaffirms my own suspicion that battery-free electric transport is the future. Think electric trolleys, electric bus trolleys, and electric trains. Not only does this obviate the chemical costs and degradation of batteries, it also means not having to haul battery weight up hill and down dale.

  3. You also need to take into account the energy needed to create and recycle the batteries. If you buy and properly maintain a modern gasoline or diesel vehicle it should last a few hundred thousand miles before it makes sense to scrap. I don’t have any data to back this up, but I suspect that if you amortize the energy cost of production, maintenance, and scrapping a new Subaru or diesel Jetta against that of a Hybrid or pure EV the fossil fuel vehicle will come out ahead.

  4. Agree 100% with your economic argument. But not all energy transitions are purely based on economics – e.g. France’s decision to massively adopt nuclear power after the oil shocks, Germany’s “energiewende” to wind and solar.

    Is there any *technical* hurdle stopping California from subsidizing/regulating mass EV adoption into existence (see article)? I can imagine plenty of financial and political hurdles, but lithium seems like a fairly plentiful resource.

  5. Hi Tom,

    long time lurker of your site but this time I feel the need to comment.

    I recently bought a Mitsubishi Outlander PHEV (not sold in the US yet, I am Italian). I like measuring stuff too. My statistics for the first six months are here:

    I admit I am a biased fan of the PHEV concept, just for the reader to know my point of view.

    Some comments: with my car, which is heavier than yours and has 4WD, I get about 4km/kWh (2.5 Miles/kWh), and for kWh I mean metered at the wall plug (I put a meter for that plug only). Given that, officially, the Italian grid owner claims 400gCO2/kWh, this leads to a straightforward 100gCO2/km, which is something only small cars with diesel can achieve on the European NEDC test cycle, famous for being extremely mild. And I get this mileage with no local emission of pollutants, nor particulate from brakes or clutch (given strong regenerative braking). Once the battery is depleted, I get between 7 and 9l/100km or, in your units, between 30 and 40 MPG. Not a Prius level, but again we are talking about a 5 seater with huge boot and 4WD. In terms of CO2 per km, still the same, if not better than, a comparable diesel, again with very small amounts of NOx and PM (the engine is spark-ignited). So, I am quite happy with the choice, which of course is valid only if both conditions are met: little highway travel and lots of renewables in the grid.

    Second point, about battery depletion: your data took me really by surprise. There has to be some problem or systematic error. There is plenty of similar data I’ve seen and you are faring much worse than what I saw up to now, for example here the case of the Tesla:
    First, notice how the curve is concave rather than convex. The battery level should taper off and then decline very slowly.

    Furthermore, AFAIK, it is not true that this is not covered by warranty being “considered to be normal wear and tear”. Battery is considered faulty if, before the warranty period, goes below 80% capacity. I repeat, this is AFAIK, you should read the warranty conditions and, in case, contact Ford service to check the battery capacity. Car makers didn’t accept the usual battery limits of electronic appliances for their “experiments”, they used large safety margins in battery sizing. Depending on maker, they also switched completely the details of the electrodes for improved wear resistance. Thermal management was also considered (see for example the problems Nissan Leaf had). BTW Is your car exposed often to high ambient temperatures?

    Do you have the same plot available not from the car data, but from an external power meter? Do you actually charge less kWh now than you did two years ago? I wouldn’t trust car trip computer data too much, who knows the algorithms behind that display? And if in the shop they changed some parameters of the internal metering system? You’d never know. I think the only reliable metering is on the wall socket.

    Finally: yes, battery depletion costs are of an order of magnitude bigger than the cost of the energy that is stored in them. I fully agree on that point. What I am surprised of and I can’t accept is that batteries last less than the average car life. I’ve seen a Prius MY2000 just yesterday. I’ve read about Teslas doing 100k miles and more ( . I do think you either have a problem on your car or there is some systematic error in your data.

    Of course, I wish you good luck, I’ll keep reading you and, in four years, I’ll tell you how my PHEV is doing.

    Keep on writing!

    • Thanks for the comments and info. I was also under the impression that there was an 80% threshold in the battery warranty. But some investigation online and then reading the actual warranty language disabused me of that happy fantasy.

      As far as the systematic error: I address this in the post, but I have two other independent measures that uphold the car computer’s claim: recorded charge times (duration), and whole-house energy meter. All three measures are in mutual agreement.

      • Tom. Do you always charge to 100% and do you always discharge to 0% or close to that? My understanding of Li-Ion batteries are that they work best between 20% and 80% charge. It seems having a tiny battery (6.5kWh) means deeper charge/discharge cycles and therefore quicker depletion of capacity. If this is true then pure EV seems better than PHEV, and PHEV with a larger battery makes more sense. What are your thoughts?

        • We (almost) always charge to 100%. It’s how the car is designed: we’d have to monitor and interrupt to hit 80%, and the time to go from 80% to 100% is 24 minutes, so we’d have to be paying close attention.

          As for discharge, since we have done 700 charges and 500 full-cycle equivalents, our typical discharge is to 30%, but full depletion is common. Again, this was part of the design principle of the vehicle: return home on empty battery so that the maximum amount of electric assist could be had.

  6. I believe many Volts are over 250,000 miles without showing any loss of battery performance – any battery degradation is hidden within the locked out range of the charge cycle.

    Our chickens give us nearly free eggs and some lay for as many as 6 years, though we let them take winter off.

    • Correction: some Volts over 200,000 miles, not many over 250,000, show no battery loss.

  7. Hi:

    Long time lurker, first time poster in this excelent blog.

    Since I have some experience with Li-ion and Li-poly batteries, I think it is good to add some information here.

    Battery life is not only a question of cycles, but also an issue with temperature. Usually the worst case is the main drive behind the aging. Since batteries are chemical storage systems, they have a ‘chemical reaction speed’ that depends on temperature, following Arrhenius (empirical law). And there is some data worth reading:

    Li-batteries can be designed in two different ‘veins’: enhanced capacity (like Tesla’s ones, or laptop or cell phones), or enhanced power (EV’s, or more important, hybrids). The former use thinner electrodes in a cylindrical envelop, inteneded to be used with no cooling, while the later ones are usually Li-Poly, with really thick electrodes, prismatic, thin, with lots of surface allowing good coolin, usueally by some liquid.

    That means that high capacity have usually shorter cycle count (usually in the 500 cycles range) and shorter life, while high power have much smaller energy density (due the thick electrodes) but higher cycle count (1K to 1K5 – real) and longer life (due better cooling).

    Another point here, is the cost. For Renault Leaf (I tend to use it as an example, since one can compare the ICE with the EV versions easily, not incurring in bizarre comparations like the twizzy with an Indy Car), the battery costs I’ve estimated are like this:

    About 150€ of Lithium (I’m sorry, I’m Spanish).
    About 200€ aluminium.
    500€ Copper.
    About 1500€ Cobalt.

    Only in materials, but at 2013 costs, that, except for the strategic cobalt, had recently dropped.

    Since EV fluence is heavier, and it has even replaced the steel and aluminium engine by an aluminium and copper motor (since it doesn’t use neodimium neither disprosium), the result is that, just taking into account the cost of materials, it has to be much more expensive.

    Now, add the issues of manufacturing the whole battery pack, that scalates in volume in a much worse fashion than ICE, and you will find that battery electric vehicles will be a dead road, a no-go way except for the rich that can buy a Tesla.

    Only niche vehicles can have some results, but even in that case, many things have to change. EV leaf generates more CO2 in China (at 800gCO2/KWh) than the ICE variants in any case. China had substituted bycicles by EV scooters and motorbikes that create more CO2 than their ICE variants also, but that is progress. In Europe, switching from my Peugeot407 (that I buy for 6000€, 100000Km, less than the Leaf battery) to an electric motorbike that don’t allow me to do my daily commuting is anything but ‘progress’.

    Being a former R+D engineer in Hybrid and Electric Vehicle department of a big manufacturer in Europe (where BMW, Audi and other car manufacturers use our proposals), and still working in the same company, but in a different department (since the former is being dismantled – reduced), I can say that serious manufacturers are starting to leave the BEV concept, and working only with hybrids, and in different veins, and only to pay back the effort (more than 1000M€ losses in that field).

    Now, add the looming economic crisis (in fact, the same, the crash oil induced de-growth), and the most probable future is that cars, generally, will be declining in their use, and in two decades, only expensive EV’s, toys for the rich, may be produced, and only to flag the next target.

    You can find more info, in spanish (google translate may do a good job), that I wrote about EV’s here:

    I’m stuck at an entry regarding the wrong way called electrification, but I had written also about the lack of lithium as well as of rare earth materials, and other issues related, that may be limits to any effort to electrify everything, but avoiding the main drawbacks (tarifs, taxes, policy, monopoly, politics, power games between powerful power companies and politicians, etc).

  8. Not completely analogous, but a few years back I got a charge meter for free with some rechargeable cells. Since then I’ve checked cells when an electronic toy needs new ones, and in most cases only one cell needs to be replaced. You may just have a few weak cells. I can foresee a cottage industry of rejuvenating EV batteries…

    P.S.: I’m very interested in seeing your nickel/iron battery data; I’m considering those for a minimal PV system to keep my fridge running in the event Fate sends me a sibling of Superstorm Sandy.

    • Could be. It’s a likely scenario. The question is whether Ford considers this to be normal decline or a warranty issue…

  9. I think you have the right attitude, choose that technology because you like it and the lifestyle that it represents. Think of it as a hobby not an economic choice. Im still hopeful that this technology will come up to speed as time goes by. It seems like some combo of higher gas prices, longer battery life and cheaper batteries will eventually make EVs a smart economic choice, but that could be some time in the coming.

    Its pretty easy to see why Gasoline/diesel became the default choice for transportation. Despite what the conspiracy theorists think, gasoline really does solve the most technological hurdles of self contained transportation in the most economical manner possible.

  10. Your capacity falloff looks “bad” to me. It’s closer to what I see with my unmanaged ebike battery, not my Tesla battery. It looks like what you see with typical Li chemistries when they are not managed aggressively — SOC allowed to go to the rails, no thermal buffering.

    It may be that today it takes $3k worth of heating and cooling hardware to manage any battery of ($0, $40k) value, so for your small battery they decided to forgo much or all of it.

    While, like you, I am somewhat skeptical about Li chemistries getting us sufficiently far to declare victory with EVs, I do think that the battery lifetimes have easily been shown to be at least 5x – and probably an order of magnitude – better than your data suggest.

  11. That battery is behaving weirdly. Li-ion batteries generally decline in an exponential curve, not a parabolic.

    A quick search indicates that you have a 10 year warranty (that’s for California). If the battery is dying as quickly as you think, you’re due for replacement of many of the cells in the battery (apparently Ford replaces them individually).

    • Except the warranty explicitly does not cover gradual decline in capacity. Which is what batteries do.

  12. I suggest you not make assumptions here about exactly what’s happening.

    1st, you don’t know whether all the cells are gradually losing capacity, or whether individual cells have died (which I believe is covered).

    2nd, Ford has limited their liability on paper, but that doesn’t mean they won’t cover what’s happening. They may have an internal policy which is more lenient than the language of the warranty, or they may make exceptions. They may even change their explicit warranty: Nissan did with the Leaf.

    The bottom line is that the general rule in the industry is an automotive battery has reached it’s end of life at 70% capacity. No automotive battery should decline to 50% after 4-5 years, or go to zero at 6 years. There’s no way that Ford can afford to allow that to happen, even if there’s a way to interpret the warranty language in that way.

    • You may well be correct, and this is reassuring. I had been operating under a vague assumption (based on verbal statements when I bought the car) that the warranty guaranteed 80% capacity for the period. Imagine my disappointment now that I read the warranty and the wording is pretty clear on gradual decline (no limit) not being covered (not a twisted interpretation of the words). Forums on the C-Max amplify this concern, rather than “correcting” it.

      But in fairness, I have not yet asked Ford to address the situation with my battery, so I don’t know what they would say. I may wait a few months until I am demonstrably below 80% and test it then.

      If Ford has to replace 10% of my cells per year, on average, they will essentially replace the whole battery in the warranty period, coming to many thousands of dollars in parts and labor. Seems like a loss to them.

      • Actual wording in warranty:
        Note: Lithium-Ion Battery Gradual Capacity Loss
        The Lithium-ion battery (EV battery) will experience gradual capacity loss with time and use (similar to all lithium-ion batteries), which is considered normal wear and tear. Loss of battery capacity due to or resulting from gradual capacity loss is NOT covered under the New Vehicle Limited Warranty. See your Owner’s Manual for important tips on how to maximize the life and capacity of the Lithium-ion battery. (emphasis in original)

        I will also note that my battery contains 84 cells, so my ~15% loss so far would imply at least 10 totally dead cells. Maybe. Still ominous.

        • Some thoughts:

          I was conservative when I said 70% is the rule: it’s more like 70% to 80%, so your assumption of 80% when you bought was reasonable. Nissan and GM explicitly limit the amount of gradual loss to 70%.

          EVs vary. Tesla and Volts show relatively little loss even after many miles, mostly because of very conservative design. The Leaf’s design is much less conservative, and they’ve had relatively much more loss.

          The Prius is very conservatively designed, and it’s battery seems to show no visible loss. Many have driven 300k miles.

          An “extended range” EV with short range, like yours, will tend to use it’s battery more heavily than one with greater capacity, like the Volt, and especially the Tesla. And, your usage has been relatively aggressive, with mostly deep cycles. It’s possible that Ford assumed lighter cycling, and that they simply built repair of outliers like yours into their business plan.

          Again, that parabolic curve is weird. If it’s accurate, then Ford probably screwed up the battery system design (or saved money by skimping on the battery chemistry and/or thermal management system).

          But…accurate and reliable testing is difficult – it’s very possible that the curve will straighten out and fly right as time goes on.

          Undoubtedly there has been some gradual, across the board battery loss – that’s normal. But, if your testing is accurate and that curve continues to decline, then some dead cells are also very likely. I’ll be very curious to see how it tests out at the dealer.

  13. Thank you for all your in-depth reports, I’ve been reading for almost 10 years now. I’m looking forward to the NiFe analysis, they have been on my list to add to my incomplete grid-tie system.

    Just in case you have not heard of this guy I though you might like this related discussion.

  14. I’m impressed with your usual high level of analysis.

    But there is mistake I so often see that you appear to have made in comparing EV to gas: gas also does not end up in the tank by magic.

    You rightly point out that the majority of electricity is generated from coal so using it to power vehicles cannot be said to be carbon free. You then went on to compare the end to end energy consumption of the electric powered vehicle with *just* the in-vehicle combustion of gas.

    But gas also has a long and energy-hungry supply chain. Crude oil is mined, then shipped to refineries, a hell of a lot of energy is used to refine the oil to produce gasoline. Then the gasoline is shipped to the gas stations, to which you have to drive your car to refuel.

    I would love to see a comparison for this complete end to end process, starting with coal mining, electricity production, distribution, charging and driving with the full oil mining, transport, refinement, transport again, refueling and driving.

    Those numbers would actually be useful.

    And that comes before we introduce the possibility of generating electricity via sustainable means. For instance, you have solar panels at home which will provide charge for your car with almost none of the generation factors you mentioned, but there is no way you can do that with gas.

    • Good point. My first reaction is to note that oil has an EROEI around 15-30, typically: it takes one unit to get 15, for instance. So the overhead in oil retrieval is small. I could bet that refining, etc. eats up another 25% or so, but this is just an off-the-cuff guess. I think I’ve seen numbers before, but they didn’t stick. Will have to look into it…

      • Not all crude ends up as gasoline, but I think it pretty much all gets used somehow — gas distillates, bunker oil, diesel, kerosene, plastics (a small fraction), asphalt (ditto.)

        Wait, I has data!
        Crude inputs of about 17k; motor gasoline 10k, distillate fuel (aka diesel) 5k, kerosene 1.7k, propane 1.7k… hmm, output seems to be larger than input. Oh, it’s volume, not mass.

    • I know the Alberta oil sands is around 5:1 thermodynamically but around 20:1 if you calculate it using the Net External Energy Return method, meaning that instead of using natural gas to extract bitumen they instead burn a lot of the lower quality liberated goo to extract further goo (consisting of a range of high to low quality goo, the higher quality being used to make oil for sale and the lower quality being fed back in to liberate more goo). That alternative method is great in terms of reducing dependence on external natural gas but it doesn’t make any difference in the long run to decreasing EROEI as the quality of the remaining bitumen goes down because you still need a significantly positive overall thermodynamic EROEI to make the activities worthwhile.

      That’s just extraction, then you have to further refine and transport and deliver it. I did some calculations once showing that the electricity generated from burning the natural gas used to provide the power merely to extract Alberta oil sand could power an EV the same distance as the final refined gasoline could… so the whole oil extraction step could be avoided by driving EV’s (except for the oil needed in their manufacture). That was a while ago and it would be good to revisit it.

      The US shale oil boom is a totally different process and I think the energy inputs have more to do with the energy and labour needed to manufacture and use the complicated drilling rigs, and then haul the oil out since it is scattered all over the landscape and can’t be piped. The wells are so short lived that they have to drill new ones all the time. Each oil extraction process is so different they need to be individually analysed and the energy inputs to every single process driving that extraction need to be quantified. IMO the US shale oil boom has a very low or negative EROEI when you factor it all in since they can’t make a profit doing it; it is all financed by Wall Street ponzi schemes that have unravelled with the crashing oil price.

  15. My Leaf has lost about 20% of its range although this is impossible to accurately quantify because a couple years after I had it Nissan took it back on a recall and reprogrammed the computer to “hide” a lot of the range to prevent extreme high and low battery states. It essentially lies to the driver about the state of charge now. I get confirmation of this when I go to the CHAdeMO high capacity chargers and it says I have something like 40% left but based on the bars in my dashboard it says I have more like 20% left! Quite a difference.

    I’ve had my car for like 4 years now and this is decent battery degradation, I was expecting it. I am however very careful to keep the car from heating up, I always park it inside and if outside I always crack the windows open. The Leaf has no thermal management system for the batteries, which was criticized by Tesla, which does have thermal management. Apparently a lot of Leaf owners in the southern US were having big battery degradation problems from the heat.

    I am seeing so many EV’s here in Vancouver, you can see a Model S every few minutes driving around. I even saw one in an accident yesterday! Leafs and Volts are not quite as popular here.

  16. Hi,

    I’m interested in your experience with NiFe batteries.
    I’m currently experimenting with a small off-grid solar PV setup, utilizing outdated NiCd batteries from the 1960s (I bought them because the had the logotype “Nife”, wasn’t aware of the cadmium at that point.) , I note that I can get around 500Wh from them, they where rated at around 1000Wh new.

    No panacea at all, the way I see it, we have to change the way we do things, so that we use other types of energy, to perform the bulk of our “needs”, such as utilizing thermal energy to cook for example, and use mechanical energy for mechanical tasks.

    The roundtrip to electricity must be avoided.

  17. Tom,
    I’m not sure your EV experience is typical, which is unfortunate, as many people read and respect your opinion. My wife and I each have Nissan Leafs, we power them nearly completely with solar, and we’ve driven them at total of probably 70,000 miles over the last three and half years, including a long-distance trip from Vermont to St. Louis and back this summer. I find the cars to be speedy, fun, quiet, smooth, and nearly maintenance free. I have noticed a very slight loss in capacity in very cold weather (well below zero). As we power them with solar, our carbon emissions from transportation have plummeted to near-zero since we acquired the cars (I drive 80+ miles every day). This is clearly a viable path forward with respect to our environmental problems. Maybe you should trade your Ford in for a Leaf?
    I enjoy your posts, keep them up.
    Best, tb

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