The Demon Diesel

I’ve been hiding. Not behind the sofa whilst watching Doctor Who (a base under attack and lots of running down corridors – Oh yeah! But more on that next week) but because I drive a VW Golf and am now labelled as an environmental vandal even though I am one of those rare people who drive a petrol engined variety. At the moment it is not entirely clear what VW are going to do to fix the problem of their dodgy diesels but it is suspected that they will have a major recall of affected models so that the owners can have a paper bag fitted over their heads to re-establish the boring car anonymity that they believed they had bought into.

In fact what VW appear to have done is actually so ingenious, in an evil Bond-villain kind of way, that I almost have a certain amount of admiration that they have been able to pull  it off for so long. The vehicles have been fitted with a piece of software that ensures that they conform to the toxic emissions regulations whilst being tested and only whilst being tested. Once out on the open road they happily spew whatever they feel like into the atmosphere. Now real Bond villains usually have a plan to steal a gazillion dollars, irradiate the US gold reserve, spark off World War Three or benefit from televising the affair. Spewing crap from motor vehicles into the atmosphere seems a bit low key although it was once the plot to an episode of Doctor Who (The Poison Sky).

Whatever VW’s nefarious motives it does reinforce one particular prejudice that I have had for quite a while: that is that diesel engines have no place on passenger cars. Diesel cars actually have many fans who would willingly pay out extra for them but from my experience I can only assume that they are deaf, daft or stupid. In fact much of my abhorrence of the technology comes from the fact they fail abysmally to do what their fans claim that they capable of: i.e. that they are cheaper, more reliable, cleaner, more powerful and more efficient than their petrol counterparts. It is a technology that promises much and delivers very little.

The first point is fairly self-evident: check out any range of passenger cars and the diesel variant costs more to buy. It doesn’t stop there. Years ago I wrote a short piece for an early version of the Top Gear website in which I compared the cost of servicing and fuel for the diesel variant of the car I had at the time and proved that it would never actually break even over the lifetime of the vehicle. Admittedly, fuel was much cheaper back then but even at today’s prices it wouldn’t make economic sense once the extra cost of servicing was taken into account. In terms of reliability, it was probably once the case that a well maintained diesel car would be less trouble than its petrol equivalent but whilst the petrols lost carburettors, points and electro-mechanical distributors (i.e. the things that caused problems) diesels gained such delights as dual mass flywheels and DPF filters (i.e. the things that will empty the bank account when they go wrong). The idea that they offer more power comes down to turbo chargers – remove that and the performance is miserable (and two can play at the turbo game).

The last point, and one I would still grant to diesel overall is that they use less fuel – at least in terms of litres consumed. In part, this has been down to fundamental differences in the design of the engines but it is also down to the fact that diesel fuel is more energy dense than petrol. The fuel economy is why I went for a diesel variant of the Mazda Premacy which on paper looked like a sensible economic choice (45mpg for the diesel compared to 31mpg for the petrol). At least it made sense until I took into account the astronomical servicing costs, the sheer embarrassment at the mushroom clouds of black soot that were emitted from the back of it and the fact that the dismal reliability of the diesel unit cost me far more than the supposed savings in fuel. However, it was genuinely efficient when using it on long motorway journeys. That was the one thing it seemed good at but if I compare the real world fuel consumption of my petrol Golf (around 50mpg) to a colleagues similar diesel engined model (55mpg) it doesn’t make a clear case for itself and, considering that diesel produces 15% more CO2 per litre burnt, it would appear that the petrol wins even on the level of greenhouse gasses – supposedly the diesel car’s forte.

So why am I bothered? Aside from my miserable experience with the Mazda I’ve avoided this abomination of a technology but our (and most of Europe’s) government have been doing their best to encourage diesel car ownership. In part this has involved subsidising diesel through preferential duty rates. Even in this country, where petrol and diesel duty is the same per volume, diesel has benefitted from not having to pay for its additional 15% CO2 emissions and, more importantly, it has benefitted from preferential rates of Vehicle Excise Duty and company car taxation based on its largely fictitious emissions ratings. The problem with this is that it causes a great glut of diesel vehicles to hit the second hand market. When I was looking for a petrol Golf, the local dealership didn’t have a single petrol variant on the forecourt. Whilst VW may have been wrong in gaming the system they were actually responding to the rules that our governments set out for them to play with.

In terms of rebalancing the public policy I would like to see the taxation move away from standardised tests that merely encourage the manufacturers to fix the game. Toxic emissions are difficult for the average consumer to spot but it would not be beyond the wisdom of legislatures to design regulations that would monitor emissions in real usage. As for the CO2 figures it would make far more sense to tax the fuels for their carbon content and tax the vehicles according to their weight and size which have a far greater bearing in real life motoring and would be very difficult to fiddle.

Fixing broken regulation is one answer but what is the real solution? Petrol engines still burn copious amounts of fossil fuel and they still produce significant levels of toxic pollution. There has been a slow but steady move towards electric and hybrid solutions. Our local taxi firm now uses almost exclusively Toyota hybrid vehicles and for their work, which largely involves driving around urban areas, they are ideal with a vastly reduced fuel consumption and far superior reliability compared to either of their exclusively dinosaur juice competitors. I’ve also seen quite a few all-electric cars being used locally and these have the advantage of being both emission free at the point of use and being capable of being powered by energy produced by the large local windfarms.

Diesel does still have its uses – at least in the medium term. It is still by far the most versatile way of powering large, heavy vehicles such as HGVs and public service vehicles and, considering I am still expecting goods and services to be delivered to me, diesel would seem to be the best way to do this until such time that a viable alternative can be found. But as far as the passenger car is concerned, could we just accept that diesel has had its day?