Hybrids not necessarily better than diesels, says Emissions Analytics

30/10/2014

The advantage of hybrids over frugal diesels is often illusory, if judged solely on fuel economy, according to testing firm Emissions Analytics.

The company took a sample of 10 vehicles tested since 2013 – two standard hybrids versus 8 diesels – from real-world fuel economy testing. Each has an engine in the 1.5 to 2.2 litre range, power up to 150bhp, two-wheel drive and with hatchback, saloon or estate body style. The table shows the sample, ranked by fuel economy with the best MPG at the top:

Make	Model	Engine Size	Derivative	Fuel	Transmission	True MPG
Honda	Civic	1.6	i-DTEC ES	Diesel	Manual	67.2
Skoda	Octavia	1.6	Greenline III TDi CR	Diesel	Manual	61.9
Peugeot	308	1.6	Allure BlueHDi	Diesel	Manual	60.8
Mazda	3	2.2	SE-L Nav Skyactiv-D	Diesel	Manual	59.4
Toyota	Auris	1.8	Touring Sports Icon VVT-I	Petrol hybrid	Automatic	58.7
Citroen	C4 Cactus	1.6	Flair e-HDI	Diesel	Automatic	57.8
Toyota	Yaris	1.5	Excel VVT-I	Petrol hybrid	Automatic	57.8
Peugeot	2008	1.5	Feline e-HDi	Diesel	Manual	57.7
Volkswagen	Golf	1.6	Bluemotion TDi	Diesel	Manual	56.8
Honda	CR-V	1.6	i-DTEC SR	Diesel	Manual	56.5

While hybrids deliver good fuel economy in real driving, they can be eclipsed by up to 10mpg by some non-hybrid diesels - and that is after having taken into account any net changes in battery charge levels, to ensure that the hybrids are not penalised over the cycle.

Comparing motorway driving to town driving, all types of vehicle show better MPG on the former, but the difference between hybrids and ICE vehicles is dramatic – typically because the downsized engines found in the hybrids are less suited for high speed motorway cruising.

Author: Fleet News Fleet News

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Weave - 30/10/2014 12:17

I'm no supporter of Hybrid technology but there is a fundamental flaw in your survey. Both hybrids are automatic and 7 from 8 of the diesels are manual. In reality whilst autos are so much better than they used to be, where both manual & auto are available in a car the manual remains the more frugal. So com on, compare eggs with eggs

christopher.smith - 30/10/2014 12:33

@Weave - it's a fair point - although a driver opting for a hybrid wouldn't necessarily opt for an automatic if they were choosing a diesel. On the other hand, petrol hybrids would have a fuel cost advantage.

Goob_It - 30/10/2014 13:44

No one manufacturer has claimed that a hybrid offers better fuel consumption over a diesel but they all claim that they are far better for the environment as there is less CO2, near zero NOx and no particulates that a diesel spews out by the exhaust full, I think the point has been completely missed here about the advantages of a hybrid vehicle over diesel!! Also shame on FN for not doing a like for like comparison, knowing full well the results would be majorly skewed by manual over auto...tut tut tut

Darren - 30/10/2014 14:27

@Goob_It - Do't forget that the CO2 values of diesels compared to petrols per CC is in fact much lower. A petrol 1.8 produces higher CO2 than a diesel, even a hybrid if its not running on batteries. The only real advantage of petrol over diesel is the particulates levels

Len - 30/10/2014 17:06

1. The CO2 claims in favour of hybrids are not relevant. Actual CO2 emissions are inversely proportional to actual mpg. Higher mpg means actual emissions are lower. Simple chemistry GCSE stuff. 2. Does any manufacturer produce a manual hybrid? I thought they are all autos. 3. Don't forget the huge environmental damage from the manufacture of lithium ion batteries. They are about the least green product around.

Edward Handley - 31/10/2014 10:25

No real surprises here! Despite the widely published views of Boris Johnson and a few others, modern diesel engines are clean and very efficient. Hybrids do perform well around town because electric motors provide high torque at low revs so are very efficient in stop start traffic where as internal combustion engines need to hit relatively high revs to get adequate power to move off which makes them less efficient. The problem with hybrids is that they are hybrids so they have two propulsion systems which adds a lot of extra weight and makes them far less efficient once travelling at higher speeds. The solution is simple: If you spend most of your time driving in heavy traffic, you buy a hybrid. If the majority of your driving is on motorways you don't. The problem is that the politicians and green campaigners only see it from their own perspective and want one solution for everybody, so instead of "One size fits all" you end up with "One size doesn't actually fit anybody".