This is a guest post from commenter JohnP
These days, most people are aware (often painfully so) of petrol prices being over $2 a litre, and much higher than they were a decade ago. It costs more to run cars than it used to, and consumers’ wallets haven’t really kept up with the cost increase. Unsurprisingly, there’s a heightened awareness about fuel efficiency, which we could also call “fuel economy” to highlight the fact that people are generally more worried about the cost implications.
The EPA did a fascinating study on fuel efficiency trends in US vehicles between 1975 and 2011, available at http://www.epa.gov/otaq/
Incidentally, Obama’s administration have tightened up US fuel economy standards for new cars starting in 2011, the first time this has been done since 1985. The improvements over the next 13 years will be major, assuming the Republicans don’t overturn them. Which they probably will.
This is what happened to the fuel economy of new American vehicles between 1975 and 2010. Note that this is in “litres per 100 km”, so a lower number means a more efficient car. I’ve calculated the figures for cars, trucks and both of them combined and weighted by production.
Source: EPA, John Polkinghorne
We don’t have a long-term data series like the US, but I would imagine that fuel economy in the NZ car fleet has followed a pretty similar path. Information from the Ministry of Transport shows that the NZ light vehicle fleet has on-road fuel economy of around 10 L/ 100 km, and this has remained stubbornly flat over the last eleven years.What’s the relevance for NZ? Well, most of our cars come from Japan, and fortunately they tend to be a bit more efficient – not that it’s helped us much. But we’ve jumped on board the SUV bandwagon, and we’ve got a higher proportion of those in our fleet than just about any other country besides the US. We’re also madly in love with big cars like the Holden Commodore and Ford Falcon. The average engine size for NZ cars is a pretty hefty 2.4 litres.
Source: Ministry of Transport annual vehicle fleet statistics
If we take a look at some Australian data, we can see that they’ve actually had no improvements in on-road fuel efficiency in the last fifty years. Australia’s a fair bit hotter than NZ so we can imagine that they took to air conditioning like a shrimp takes to a barbie.Two things to note there – firstly, the MoT data shows “on-road” fuel efficiency, or what our cars have actually achieved on our roads. The US data shown above is lab-tested, and cars tend to use more fuel on the road (congestion and air conditioning being the two main culprits). Secondly, the US data is for new cars produced in each year, so those fuel economy values can change much quicker than when you’re looking at the total fleet, as for the NZ data. If Priuses were the only new cars sold in New Zealand in 2012, it would still take quite a while before we’d see any noticeable difference to the fuel economy of our entire fleet of 3,000,000 vehicles.
More recently, New Zealand’s Ministry of Transport has started collecting fuel efficiency ratings for vehicles as they enter the fleet. This shows that the light vehicles coming into New Zealand (including cars, vans, light trucks etc) have been getting more efficient, which is a good thing. Cars entering the fleet today are at least 10% more efficient than in 2005, on average. You can see the downward trend in fuel use in the graph below. Actually, the graph shows CO2 emissions, but as we’ll see in my next post, these are directly proportional to the amount of fuel used.
Source: Ministry of Transport quarterly vehicle fleet statistics
So what are the takeaways here? New Zealanders have started buying more fuel-efficient cars thanks to higher prices since 2005 or so, but the improvement hasn’t been stunning – 10% is nothing to write home about, and there hasn’t been any noticeable effect on how much petrol the overall car fleet uses. In fact, international comparisons make it likely that decades of technological progress have done almost nothing to reduce how much petrol we use. Engines have gotten better, but cars have gotten bigger.
Jevon’s paradox?
Yes, exactly and the slow turn over of our fleet. Unfortunately only new car buyers will have the more efficient models.
Why? Average Commodore driver could swap for a same year Honda Jazz and get massive (40%) reduction in fuel bill. There’s issues of status and Kiwi male identity (which seems stuck in the 70s) here.
Two words: company car.
Maybe CSR needs to start with vehicle fleet? Maybe we need to be shaming large companies?
As someone who cycles and would love to see more PT and less driving, I don’t believe ‘forcing’ people into smaller, more efficient cars is useful. I do however, believe that our fuel tax could be higher but the only issue with that is the distribution of the funds under the current governing regime. Some people actually do need bigger cars (a Honda Jazz is not good at towing a boat for instance) and in the same way that we allow people to choose bigger, less efficient housing, the choice should be with the consumer but the scale of repayment should be scaled. Vehicle registration rates based on fuel economy, rather than type, could have a bearing on how people choose their cars?
The thing is, petrol is still relatively cheap. So a 40% reduction in the fuel bill doesn’t mean the overall cost of the car is massively cheaper. Maybe doubling yr fuel efficiecy (halving yr fuel usage) will save you about $1000-1500 per year for an average driver. Loads of people will pay that extra fuel bill for a bigger/cooler/faster car. Often bigger cars are cheaper too, certainly in the 2nd hand market, so the total cost of the car is the same.
And the limits to efficiency gains: http://physics.ucsd.edu/do-the-math/2011/07/100-mpg-on-gasoline/
Oh and nice post John, thanks.
Thanks Patrick, and thanks to Matt L for uploading and formatting! At least I’m assuming it was him
12kWh/kg is the energy density of petrol. Yet typically only 1% of that energy when burnt actually moves the driver. Li-Ion energy density is 160Wh/kg. Petrol then is 75 times more energy dense and then they go and waste it on 1.5 tonnes of steel.
The Nissan Leaf has 24KWh of battery with a curb weight of 1,521kg. Of which the batteries are about 150kg.
At the other end of the spectrum are pedal powered, enclosed, recumbent tricycles called velomobiles weighing 30kg that easily get to 40km/hr under human power. They could easily be engineered with Li-Ion batteries to go 60km/hr and have ranges of 200km+ with total weights of under 40kg.
And in between there are things like this: 300kg 3 wheelers – http://myersmotors.com/index.html
We as a society really don’t need Ford F150 trucks and Holden Colorados. We need innovative design with current battery technology and a few smart entrepeneuers who don’t have the rusty, prehistoric attitudes of car companies. “Cars” should weigh the same as a prop, and not the whole rugby team.
As for getting around a city – riding a foldable push scooter like a kids scooter with 300Wh of battery and a 150W motor (which all up costs less than $500) that you can fold and take on the train, and a fast frequent electrified railway is all anyone really needs.
I could not operate with out a AWD wagon of some sort. At present I have a Nissan X-Trail (petrol). With all my day to day requirements loaded it has averaged 9.1l/100km over 50,000 km’s. I could not operate out of a Leaf (or a Volt, which I prefer, for that matter).
For some of us the motor vehicle is a tool of the trade; we have a battered old Hilux for orchard work and 2 other vehicles for family and business use. A Leaf to replace one of the family cars and to be used as the vehicle of preference is highly feasible for our requirements. When it comes to selecting vehicle characteristics my priority is generally type of duty required, safety (crash rating), reliability (as well as that can be determined), depreciation, roadholding then maybe fuel economy.
I have owned a few AWD wagons in the UK and US. All Subarus and all good but not great for fuel economy. I understand that recent engine design changes have resulted in improvements.
Bryce, Yep it is a useful vehicle, but it does seem like overkill if you’re just going to the shops.
I have a car with a 3.5l petrol engine and get 8.7l/100km out of it. I am nursing it from WOF to WOF and hope to get something smaller in a couple of years. I too think I’d be lost without having access to far off trailheads, and I take my bikes on the back to go riding places.
I also have an electric bike with panniers which I can put a lot of groceries in (but usually get the groceries in the car when coming back from other things), and a foldable kick scooter for taking on the train.
I’d love a vehicle somewhere in between the size of my car and my bike for most daily commuting to the train station and running into town and stuff. I’m 20 minutes from town on my bicycle. 10 minutes by car. I’m too far from work to commute by bike, but my girlfriend commutes on it to her job.
It does seem there is a massive untapped market for anyone coming up with a small highway speed electric vehicle with a decent range at a reasonable cost.
Take a look at LIT Motors’ gyroscope-stabilised 2 wheeler:
http://techcrunch.com/2012/09/10/lit-motors-will-shake-up-the-electric-vehicle-market-with-its-two-wheeled-untippable-c-1/
Very cool. Ta.
I want one.
“Yep it is a useful vehicle, but it does seem like overkill if you’re just going to the shops”
That’s what my bike is for
. On a day to day basis, I’m in a different part of Auckland (or even further afield) every day and carry 40 kg or so, of ‘essentials’ everywhere I go.
Those are published fuel economy figures. Real-life figures differ depending on factors such as tyre pressure, use of AC, driving style etc. Substantial fuel economy improvements can be gained just by avoiding short trips from cold as there is a fixed fuel hit to heat up the engine block, manifolds. coolant etc. VW’s foray into small engines with turbo or supercharging is interesting in this respect. Less phyical and thermal mass and, of course, electric vehicles avoid this altogether.
Twincharging has its roots in the 1980s, although for entirely different reasons, but the idea of generating more power from smaller blocks isn’t new and we’ve had the technology to do so for some decades now. I’d be interested to see how these figures adjust for more common use of automatic boxes and congestion idle time. As far as electric vehicles are concerned, I would love to be able to build an electric car like I could build the ICE version of my favourite car, but the end user components are too expensive by a factor of ten and the end result wouldn’t be worth it.