Distinguishing HEV Efficiency from Plug-in Vehicle Waste

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John Petersen

Over the last couple years I’ve frequently argued that plug-in vehicles are inherently wasteful on a micro-economic and a macro-economic level. Unfortunately complex economic proofs are hard to grasp at a glance and my biggest challenge has been finding a simple proof for a patently obvious truth that can’t be distorted by flimsy assumptions or misconstrued with rosy forecasts. I hope today’s article will drive a stake through the undead heart of plug-in vehicle efficiency claims.

To keep it simple, I’ll use the Camry Hybrid from Toyota Motors (TM), the Leaf from Nissan Motors (NSANY.PK) and the Roadster from Tesla Motors (TSLA) as examples.

The Camry Hybrid has an EPA fuel economy rating of 31 mpg city and 35 mpg highway while its conventional sister has an EPA fuel economy rating of 22 mpg city and 33 mpg highway. The Leaf and the Roadster both have EPA fuel economy ratings of 99 mpge. To achieve their fuel economy ratings, the Camry uses a 1.3 kWh NiMH battery pack, the Leaf uses a 24 kWh lithium-ion battery pack and the Roadster uses a 56 kWh lithium-ion battery pack.

If we assume that all three vehicles will have a 10-year life and be driven an average of 12,500 miles per year, the following table summarizes the electric drive miles achieved per kWh of battery capacity.

Camry Leaf Roadster
10-year mileage 125,000 125,000 125,000
Gasoline miles 88,710 0 0
Efficiency miles 36,290
Electric utility miles 125,000 125,000
Battery Pack kWh 1.3 24 56
Electric miles per kWh 27,916 5,208 2,232
Fuel saved per kWh 931 174 74

The first point that merits attention is that electric miles in a Camry come from using gasoline more efficiently. In contrast, electric miles in a Leaf or a Roadster come from an electric power plant that consumes coal, natural gas or uranium to make the juice that dives the wheels. Electric drive is more efficient than internal combustion if you start your analysis at a full gas tank or battery, but most of that advantage evaporates when you carry the analysis back through the supply chain and factor in all emissions and inefficiencies starting with the oil well or coal mine.

The second point that merits attention is that for every kWh of battery capacity, the Camry is 5.4 times more efficient than a Leaf and 12.5 times more efficient than a Roadster. Batteries are most valuable when they’re worked hard and cycled often. From the perspective of a battery, going to work in a Camry is full-time employment on an assembly line, going to work in a Leaf is a part-time job in a donut shop, and going to work in a Roadster is retirement on a beach in Belize.

The reason is simple. HEVs are an efficiency technology that uses a small battery to save 40% on fuel consumption. Plug-in vehicles, in comparison, are fuel substitution schemes that use batteries to substitute electric power for gasoline and replace the fuel tank at a capital cost of $3,750 to $7,500 per equivalent gallon of capacity.

Regardless of chemistry, advanced batteries are terrible things to waste because they require prodigious inputs of scarce mineral resources and are difficult, if not impossible, to recycle economically. They perform wonderfully when they’re used to improve fuel efficiency in an HEV, but they perform poorly when they’re used as fuel tank substitutes for a plug-in vehicle.

Future gas prices and battery costs will not change the fundamental truth that batteries are five times more efficient in HEVs than they are in plug-in vehicles. Batteries in HEVs eliminate the use of fuel while batteries in plug-ins can only add long tail pipes that substitute a mix of coal, natural gas and nuclear power for gasoline.

In the final analysis, plug-in vehicles are a luxury no nation and no investor can afford.

Disclosure. None


  1. 1. electricity to power ev’s is not only from “an electric power plant that consumes coal, natural gas or uranium to make the juice” but from renewable sources which are on track to reach 20 or even 30% of capacity by 2020.
    2. EV power trains replace not just the ‘replace the fuel tank’ but the internal combustion engine and power train as well.
    And in the final analysis, reliance on imported oil is a luxury no nation can afford.

  2. Renewable energy will no doubt become more important in the future. The idea that it will reach 20% to 30% market penetration by 2020 is delusional. The EIA is predicting 14% by 2035.
    EV power trains replace more than just the fuel tank. The batteries, however, are the exact equivalent of a fuel tank, they just cost thousands of dollars per equivalent gallon of capacity.
    If you’re truly concerned about oil consumption, you should be infuriated by the reality that 1 Leaf will reduce oil consumption by 400 gallons per year, but the same batteries could be used to power a mini-fleet of 18 HEVs that would reduce oil consumption by a collective total of 2,880 gallons per year.
    I’m in complete agreement about imported oil and think it should be replaced by clean domestic natural gas wherever possible.
    Thank heavens for the fracking natural gas producers.

  3. The argument that Peterson advances is a strange one – he is claiming that batteries are such a scarce commodity that they should be concentrated in hybrids, where they will accomplish more per kilowatthour of capacity.
    Peterson’s assumptions are
    incorrect and he fails to see that simply increasing an average vehicle’s MPG
    it will not accomplish anything significant. Those gallons saved may seem like a lot, but they only amount to a few miles per gallon over the non-hybrid versions. Less than 10 percent, which isn’t enough to move any oil consumption needles very far. Peterson has invented an imaginary world in order to promote practically useless hybrid technology. This can easily be seen by comparing gas reduction using an electric like the Volt. Simple math shows the Volt to avoid 5 to 6 times more gasoline than the Toyota Prius, which is light years ahead of the Camry hybrid referred to here. The simple fact is that hybrids contain the worst of all worlds – they are completely inferior to electrics in terms of 1) innate cost – at price levels of $60K right now, and lower levels in a few years, as battery costs continue to drop 2) lowered maintenance costs 3) reliability 4) sheer number of manufactured parts 5) gigantic reduction in “wearable parts” – exhausts, trannies, radiators, etc. etc. etc. The automobile is going electric simply on the basis of low operating costs, low fuel costs, and lower build costs. If practical batteries were available way back when, no fool would ever have tried to build or sell an ICE powered vehicle. At this point in time, electrical vehicles at the $60K price level of the Tesla Model S are superior to their ICE competitors. But some folks just don’t seem to be getting the message.

  4. All commodities are scarce and will get a lot scarcer over the next few years. There are six billion people that want a small slice of the lifestyle you obviously take for granted. To bring them to 10% purchasing power with you we will have to increase global production of water, food, energy and every commodity you can imagine. Ignoring the problem can only make it worse.
    The Camry hybrid has a 9 mpg advantage in city driving (40%) and a more modest 2 mpg advantage in highway driving (6%).
    Every advantage you claim for plug-ins is an assumption rather than a proven fact. Some or even all of them may be proven by 2020 but until they are the plug-ins will be experimental vehicles and the purchasers little more than lab rats in a great experiment.
    I believe this new generation of plug-ins is likely to die of the same congenital birth defects that killed all earlier generations of plug-in vehicles. The material balance is unsustainable and it’s impossible to use prodigious quantities of scarce raw materials (metals) in the name of conserving far more plentiful raw materials (petroleum).
    I wish you the best of luck with your investing.

  5. I apologize if I sound critical – that is not my intent.
    I may be missing something, but I don’t follow the numerical logic of the analysis. Dividing mileage by battery capacity is the same as dividing mileage by the size of a fuel tank. It has no relevance, except for the number of charges/refills required.
    Wouldn’t you need to consider the efficiency of each vehicles drivetrain (i.e. miles per kWh or each vehicle’s range per fill) to get a meaningful distance per unit of energy number?
    Based on the above calculations, I can increase my ‘Electric miles per kWh’ by halving the capacity of thebattery pack (and the vehicles range).

  6. The entire purpose of adding electric drive to a vehicle is to conserve gasoline. The metric that let’s you measure how good a system is at accomplishing that goal is gallons of gasoline saved per kWh of electric drive capacity added.
    Using current HEV technology, it takes about $24 in capital investment to save a gallon of gasoline per year.
    Using current plug-in technology, it takes about $45 in capital investment to save a gallon of gasoline per year.
    Granted the plug-in can save more gallons per year for an individual user, but at a societal level it’s the worst misallocation of capital and natural resources imaginable.

  7. Still, one can’t help but wonder, especially following recent events, how will a hybrid car run, when we won’t have any gasoline? At least not poor people…


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