Once they’ve established that it’s not prone to imminent explosion (if anything, hydrogen is safer to carry than petrol), the second thing people want to know about the Toyota Mirai is how fuel efficient it is.
After all, the Mirai is quite closely related to the Prius, which has economy at its core. Is the Mirai economical too?
We were keen to find a figure at the outset, but the more we thought about it, the more truth seemed to be carried in the words ‘depends how you measure it’. The easiest figure to give is miles per kilogram: the Mirai takes around 4.7kg of compressed hydrogen when the fuel gauge says it’s as near as we’re prepared to get to bone empty, at which point it has done around 270 miles. That calculation is easy: the car does 57.02 miles per kilo of hydrogen. Trouble is, this doesn’t help much, not least because compressed hydrogen is about eight times lighter than petrol.
Then we spotted a figure in the Mirai brochure stating that a tankful equates ‘roughly’ to 60 litres of conventional fuel capacity. That means 4.7kg of consumed hydrogen equates roughly to 56.4 litres, or 10.3 gallons. It gives you a range of 270 miles, thus in ‘petrol equivalent’ the Mirai returns 26.2mpg. Not impressive, if it matters.
We think a more interesting gauge of the Mirai’s efficiency is to measure fuel cost per mile and compare it with, say, a 40mpg petrol car. Hydrogen costs £9.99 per kilo, so our 4.7kg fill-up costs £47, give or take. Over 270 miles, that’s 5.74 miles per pound, or 17.4 pence per mile. Now consider a 40mpg petrol saloon fuelled at £1.20 per litre/£5.46 per gallon. Over 270 miles it would use 8.1 gallons, which costs £44.20 or 16.3p per mile, near enough.
Ergo, running a similarly sized petrol car costs roughly 90% of what we’re paying to run the Mirai.It seems a steal given that this is still very much an experimental car.
PREVIOUS REPORTS
First report
It’s weird how differently people react to the promise of hydrogen fuel cell cars – such as the 3000-mile white Toyota Mirai that joined our long-term test fleet and will be around for the next six months.
When, at a recent gathering, I mentioned to a few people that my odd-looking Toyota was powered by hydrogen and would travel through its entire life without emitting a solitary atom of noxious exhaust gas, one group fastened instantly onto the relatively pedestrian fact that filling stations are rare within the London area. They dissolved into laughter and dismissed the whole idea.
The others were quite different. For them, it was as if the holy grail of perpetual motion had landed on their doorstep. The fact that this car ran on electricity generated from non-polluting hydrogen, produced from a substance as ordinary and plentiful as water – well, that was magic. Especially when you learned that the hydrogen car is actually smoother and quieter than a vehicle powered by an internal combustion engine.
Join the debate
Add your comment
Information
Thanks to you for sharing this interesting, informative and impressive article with us. I've really very enjoyed it. Do you know about introduced updated Mercedes-Benz Marco Polo in Activity version. The new camper will gain access to more rough terrain. Mercedes-Benz has offered Europeans an updated Mercedes-Benz Marco Polo Activity. Buyers will receive several transmission options. So, the "older" Activity 300D develops 236 horsepower. To “hundreds” of such carzaamin(.)com/ accelerates in 7.9 seconds, and its maximum speed is more than 200 km / h. Also available for purchase are the 250d (188 hp), 220d (161 hp), 200d (134 hp) and 170d (101 hp) versions. The last gets front-wheel drive and 6MKPP. The rest of the modifications relies on a 9-speed automatic.
Efficiency best not measured in mpg
The quoted 26 mpg for the Toyota is misleading, since that figure is based on the current relative tax paid cost of hydrogen versus petrol. The only true way to compare the efficiency of cars using different fuels is to look at how far they travel on a fixed amount of energy. And since hydrogen has around 33 kWh of energy per kilogram weight, and the Mirai can travel around 57 miles on one kg of hydrogen, its efficiency is around 1.7 miles per kWh.
Using the same measure the efficiency of a typical petrol car of the Mirai's size (achieving 40mpg) is around 1 mile per kW, while a typical electric car achievs around 3 mile per kWh. So the fuel cell car is more efficient than a petrol car with the convenience and cleanliness of an electric car, but it is not as efficient as a pure electric one.
Really the fuel cell car is just another electric car, albeit one which generates its own electricity rather than having to be topped up from the grid - and that's the reason why it isn't as efficient, because there are energy losses in converting the hydrogen fuel into useful electric energy.
I don't think that big corporations like Honda, Toyota, Hyundai are daft. They would not be investing billions of pounds into fuel cell development if they were not confident of its long term viability. And let's face it, this approach has certainly paid off with the hybrid, despite the fact that the early models looked a bit shaky.
Efficient
or you could say it takes 30-35KWh of enegy to create 1 kilo of hydrogen (not including transport costs) which will propel a Mirra 50 miles MAX. That same enegy will propel a Leaf 150 miles MAX. Therefore an Electric car is 3 times more efficient than a Hydrogen car, half the price to buy, at least 5 times cheaper in fuel costs to the consumer.
How about a comparison with a
How about a comparison with a prius, tesla, diesel and petrol cars, fill them all from empty and drive til they stop, compare the ranges pence per mile and tailpipe emissions.