They're big and dirty - and quite unnecessary for many who buy them. John Simmie on what we must do about SUVs
News that sales of sports utility vehicles (SUVs) increased by 34 per cent last year and that over one third of all sold in 2004 were registered in Dublin should sound alarm bells.
SUVs are not inherently evil - "Satan's chariots" - as some protestors claim. But there are at least two good reasons why we should prevent their uncontrolled proliferation on our city streets.
In common with other vehicles with large displacement engines, SUVs suffer from poor-fuel efficiency and emit a disproportionate amount of the greenhouse gas, carbon dioxide, per kilometre travelled.
The argument that these behemoths are usually diesel powered and therefore somehow environmentally friendly just doesn't wash. Although diesels perform better than petrol equivalents on fuel economy, the fact that we can make petrol engines with a smaller capacity than diesels largely nullifies the diesel advantage.
For example, the 10 best petrol cars can achieve 53-60mpg against 62-69mpg for the 10 best diesel-powered. But in terms of grams of CO2 emitted per kilometre, there's very little difference - petrol scores 113-127 against 108-119 for diesel. So, ordinary diesel is slightly better, not hugely different.
We must also consider that burning diesel gives off more oxides of nitrogen, leading to smog, acid rain and more particulates - specks of carbon which are bad for asthmatics.
Significant gains result from the use of a hybrid car such as the Toyota Prius whose petrol consumption of 65.7mpg and 104g/km achieved with a 1.5-litre engine matches that of the most fuel efficient diesel on the market, the 1.4-litre Citroën C2 with figures of 68.9mpg and 108g/km. The Prius comfortably outperforms the otherwise excellent Yaris whose 1.5-litre petrol engine can get 41.4mpg and 162g/km.
Even more improvement results from switching to liquid petroleum gas (LPG) or compressed natural gas (CNG). For a 2.4-litre Volvo S60 for example, switching from petrol to CNG reduces CO2 emissions by 24 per cent and this is accompanied, of course, by reductions in other pollutants such as carbon monoxide, unburnt hydrocarbons, oxides of nitrogen and particulates.
A problem with LPG is that it's no longer on offer in many areas of the country. This is a pity. San Antonio, Texas - remember the Alamo - runs most of its buses and trams on LPG and has for the past 50 years and, when air quality goes below acceptable levels, the city shuts down the diesel/petrol buses and trams but keeps the LPG ones running.
Switching from fossil fuels to renewable fuels such as ethanol or biodiesel produces another quantum improvement. Since the production of sugar beet is becoming increasingly less viable in Ireland, perhaps growing crops of false flax (camelina sativa) might be a better prospect for the near future.
It's doubtful, however, at our present consumption levels that agriculture could provide all our transport fuel needs, but it could certainly contribute.
In the longer term the best option for the planet is to produce hydrogen gas from electricity generated from renewable sources, such as wind or wave and "burn" it in internal combustion engines or fuel cells.
Some key research issues are still outstanding, such as safe, compact on-board storage of hydrogen and the efficiency of fuel cells. These should be addressed by the Government and its agencies, yet they don't seem to be that interested.
A recent report recommends that we should be spending much more of our national R&D budget on low-carbon technologies. To be fair some car and oil companies, such as General Motors and Shell, are working on the in-car hydrogen storage problem but most car-makers are content to sit it out. Older readers will recall that they weren't that keen on fitting indicators, seat belts, airbags, or exhaust emission controls either.
Until we have a hydrogen economy or a mature biodiesel industry, we should be concerned about the profligate use of fossil fuels. That's why SUVs and their ilk are undesirable. They struggle to better either 40mpg or 200g/km on conventional fuels, yet there are many fine cars which do, such as the C and E class Mercedes, the Subaru Foresters, the Renault Megane, Audi's A4 and A6, etc.
Sensitive souls - aka company managers with exaggerated notions of their importance - can still enjoy pleasurable motoring. Most SUVs are considerably more polluting by virtue of large engines. The Jeep Cherokee, at 20.2mpg and 330g/km is fairly typical, while the ridiculous Hummer doesn't warrant a mention.
We need to change our attitudes that SUVs are trendy or cool and see them as exercises in bad taste. Think shell suits of the 1980s?
What should be done at Government level to reduce greenhouse gas emissions from the transport sector, which is about 15 per cent of our total output and which we must reduce to comply with the Kyoto agreement? Apart from the leader writer in The Irish Times who has returned to this subject time after time, I know of nobody in favour of a flat tax on fuel.
Fortunately, the Minister of Finance, Mr Brian Cowan, listened to submissions from myself and others and scrapped the whole idea. He was aware, I'm sure, that such a tax would unduly penalise rural dwellers and would not achieve its objective anyway.
A recent survey by Amárach Consulting gives clear evidence that Irish drivers would not be discouraged by additional taxation of fuel - two or three said that even doubling the price would not change their mileage. This is not because they are perverse, but simply shows that for the majority no comprehensive public transport is available.
Engine and car makers can easily adapt production processes to improve fuel efficiency if that's what we demand. Indeed great strides have been made in the past 40 years because legislative restrictions have been placed on new vehicles and thereby reduced some exhaust emissions by a staggering 3,000 per cent.
The removal of harmful ingredients from petrol such as the lead alkyls and benzene has been accomplished without serious opposition and is of obvious benefit to health. The next step is to get the EU to set limits on carbon dioxide emissions from road and rail transport.
Curbing aircraft emissions, although highly necessary and desirable, will be a much tougher battle to push through - aviation's transnational dimension demands global agreement. In view of the Bush administration's opposition to the mild restrictions set by Kyoto, this is unlikely to be discussed anytime soon.
But there are reasonable grounds for discouraging use of SUVs for trivial purposes such as school-runs and shopping. Use by farmers, tradespeople and the horsey set is understandable.
SUVs are not just inefficient. They present a clear and present danger to other road users, including especially pedestrians, by reason of their bulk (it costs more to dispose of them at the end of their useful life too) and height (it's so hard to see over or past them).
So, you don't have to be a tree-hugger or a sandal-wearer (how these have come to represent terms of abuse is beyond me) to object to SUVs in cities, especially when they've been bought purely as fashion accessories. We, and planet Earth, deserve better.
Professor John Simmie, an expert in the chemistry of combustion, heads a research group working on ultra-clean diesel fuels in the Environmental Change Institute of NUI Galway. The ECI is a research centre dedicated to understanding and mapping the changes occurring in the Irish environment including biodiversity, climate, marine, the origins of pollutants and the minimisation of waste.