Vehicles


Vehicles02 Apr 2013 10:06 am

Honda Jazz Hybrid Badge

The green has faded only slightly

I have very little respect for motoring journalists. To my mind, their obsession with horsepower, acceleration, maximum speed, torque and displacement encourages automobile manufacturers to build the wrong cars for a warming world. They never fail to test the time it takes to race from 0-100 kms, something no one should be attempting in the real world.

And their impressions of fuel consumption—when mentioned at all—usually consist of a figure calculated from a single half-day of hard driving, a number that is useless for comparing one vehicle to another. It is always much higher than the official consumption figures.

I like to do things differently. I have given myself a year to get to know my Honda Jazz Hybrid. I drive it gently, and have measured fuel consumption tank by tank more than 40 times. (I don’t trust the consumption reading given on the dashboard.) These are my impressions:

I am a big fan of the Honda Jazz line. We own three in my family, and the oldest is still going strong after 9 years and 150,000 kms. I find them to be solidly built, a perfect compromise between the masses of tiny and tinny subcompacts and the larger, more luxurious vehicles that seem to me to be suited neither to modern parking lots nor to the air I would prefer to breathe. The seats fold down like origami, so my bicycle fits in the back.

The Jazz Hybrid is the best appointed of the cars I have owned, and the interplay between the electric and petrol motors is generally seamless. The car’s special engine only announces itself clearly at red lights, or in traffic jams, when the engine shuts off instead of idling. It took my wife a while to get used to this, but more and more non-hybrids are being built with this auto-stop feature, and in the future we will find it a disturbing aberration for the engine of a stopped vehicle to idle. I’m only bothered when the hybrid’s engine occasionally fails to cut out at a traffic light.

The hybrid is only available in automatic, which suits my family’s aversion to clutch pedals. The Continuously Variable Transmission or CVT is an ultra-efficient and very smooth automatic that is used in most hybrid cars worldwide, and in our first Jazz as well. Motoring journalists sometimes complain about CVT response in quick acceleration from a dead stop. After 9 years of driving one, I couldn’t even tell you what they are talking about.

We have been less pleased with this particular car’s handling of hill starts, which require a parking brake on steep slopes. This is routine on manual-transmission cars, of course, but not with automatic transmissions, including our first Jazz. The owner’s manual notes that the Hybrid Jazz sold in Europe comes equipped with Hill Start Assist, to prevent the car from slipping back. South Africans apparently didn’t merit this feature.

The other drawback relative to our other Jazzes is that the boot space—with the seats in their normal position—is compromised slightly to make room for the unseen battery pack. Three medium-sized suitcases will fit, but no more. I used a roof-rack and car-top luggage carrier for one long trip with four passengers.

None of this has mattered as much to me as the chief consideration: Is this car as green as its metallic paint suggests? I keep track of my fuel consumption on a spreadsheet that you can download for yourself here. The calculations tell me that I average 5.8 litres per 100 km driving the hybrid. (In American: 49 miles per gallon.) When my wife, son or daughter are driving, consumption drifts just above 6 l/100 km. You can get a sense of how I drive by reading my 10 Unconventional Tips for Saving Petrol.

It’s all relative, of course. We bought the hybrid when downsizing after two children moved out of the house to attend university. Since our FRV used nearly 10 litres per 100 kms, our fuel bill is way down. Compared to the other Jazz, the hybrid’s improvement is less dramatic. I average 6.9 l/100 kms on that vehicle, about 20 percent more than the hybrid. All of this promises a meaningful reduction in the environmental damage wreaked by our driving, and as I have pointed out in a previous post, hybrid emissions are far lower than mere consumption figures would indicate.

Still, one calculation leaves me puzzled. Compared to the official consumption figures, my average on the old Jazz is 20 percent worse, but actual consumption on the hybrid is 32 percent worse than the official rating of 4.6 litres/100 kms. I’m not the first hybrid driver to notice that real-world driving is different from the testing conditions used for the advertised figures. I suspect that many of those drivers never bothered to pay close attention to their litres/100 kms until they bought a hybrid, however. Their actual fuel efficiency with non-hybrids was undoubtedly also much worse than the official ratings. But I am constantly measuring, and my driving habits are consistent.

A dark suspicion nags me. The battery charging indicator suggests that the car stops drawing on the batteries when they are still holding a half charge, and begins to charge them from the petrol motor. If so, I’m not deriving the full benefit of the electric motor, especially up long hills. The charging regimen is controlled by software, which can easily be reprogrammed. Is it possible that the cars used for testing fuel consumption were set to maximize the use of the batteries, but the cars sold to customers are programmed to use the batteries more lightly in order to improve their lifespan? I can only wonder.

Still, if I put those suspicions to the side, I am left with the undeniable fact that in 32 years of driving, my Honda Jazz Hybrid is the cleanest, most efficient, even the most enjoyable vehicle I have ever owned. As to those vehicles I have never owned, I couldn’t say. The Toyota Yaris hybrid was introduced in South Africa only a few months after I bought this car, with even more impressive claimed figures for emissions and consumption. Again, I can only wonder . . .

Vehicles19 Jun 2012 11:23 am

Honda Jazz Hybrid Badge

Reduces emissions, increases questions

People notice when you drive a hybrid. And they tend to ask questions—skeptical questions, mostly. A lot of people have heard something from a friend of a friend that has given them doubts about the wisdom or the virtues of owning a hybrid car. Here are the three most common questions, and my responses.

Do you save enough on petrol to pay for the extra expense of a hybrid car?

It all depends on the alternative car, of course. In my case, I was downscaling from a Honda FRV to a Jazz Hybrid. The Jazz cost less than a new equivalent of an FRV—which is no longer available—and consumes about half the petrol. By that standard, it was a win-win purchase. A more realistic comparison would be to the Jazz Executive Automatic, which costs about R18,000 less than the hybrid version. My calculations show that for urban driving, with an average petrol price of R13 a litre, the Hybrid can make up that difference at the pump within two years of driving 20,000 kms per year. (I didn’t take the time value of money into account in this calculation; you wouldn’t charge Mother Earth interest, would you?) Personally, I got such a good deal on a hybrid demo that the hybrid cost less than the Executive Automatic.

Savings on your petrol bill will not overcome a very large price differential, however. If you are choosing between an inexpensive, efficient non-hybrid and a new hybrid, the reduced consumption will probably never compensate for paying an extra R50,000 or more.

Purchasing a hybrid is not purely about saving money at the pump. In fact, if that’s all you hope to get out of a hybrid, you’ve sort of missed the point. Hybrids use a little less fuel and create a lot less pollution. For an example, I took a look at the British government’s wonderful Car Fuel Data website. Comparing a 2013 Honda Jazz 1.4 i-VTECH with the latest Jazz Hybrid, it shows that the hybrid creates less than 1/5th of the carbon monoxide, the gas that gives headaches to drivers stuck in traffic jams and impairs breathing. The hybrid cuts emissions of smog-producing hydrocarbons and nitrogen oxides by a 1/3rd and a 1/6th, respectively. None of these benefits offer any payback, of course, but neither does a sunroof or leather trim. The personal benefits are psychological. I feel a little better knowing that my car is fouling the air less.

That doesn’t mean that I think everyone has to drive a hybrid. Many new technologies are improving the efficiency and emissions of non-hybrid petrol cars. Simply check the carbon dioxide emissions on the windscreen sticker of all new vehicles to compare. The easiest and cheapest way to reduce fuel consumption and emissions is obviously to choose a smaller car or a smaller engine. It costs nothing up front. The savings are instantaneous and ongoing.

Can’t you accomplish the same thing in a diesel?

If you mean making the air safer to breathe, definitely not. Information on the ugly side of diesel in South Africa can be found here and here. Diesel cars are appropriate for rural, open roads, but they are a problem in cities. Just watch the tailpipes of vehicles pulling away when the traffic light turns green and you will know why. Diesels also take longer to warm up, making them less efficient for short hops. In urban driving, a hybrid is far superior in emissions and often better for fuel consumption.

Don’t the batteries wear out, costing you a fortune?

This is a very reasonable question, given the experience we all have with failing car and cellphone batteries. But current hybrids use nickel-metal hydride (NiMH) batteries, which have far greater longevity than the lead-acid starter batteries in cars or the lithium-ion batteries in cellphones and laptops. A good article on the durability of hybrid batteries comes to the following conclusion: “Even with the first round of hybrids reaching their tenth birthday, those big batteries are still hanging in there.”

My hybrid is brand new, so I have no personal experience on this subject, but if you want to read the appraisals of those who have driven their Toyota Priuses for more than 160,000 kms, you can check out the 100,000-Mile Club on PriusChat.com. It’s difficult to find complaints about battery longevity on that forum.

Regarding the cost: yes, a full set of new batteries is very expensive. For that reason Toyota offers long-term warranties to ease the concerns of buyers. The hybrid Toyota Yaris, for example, comes with an eight-year/195,000 km warranty on the batteries. In other countries, Honda has also been very generous with hybrid battery warranties, even retroactively extending the guarantee on some previously purchased vehicles to an astounding 11 years or 220,000 kms, after some bad press over battery failures in the 2009 Hybrid Civic. Disappointingly, Honda South Africa does not offer its hybrid customers anything more than the standard three-year/100,000 km warranty, unless they purchase an extended warranty.

Vehicles10 Mar 2012 04:47 pm

Honda Jazz Hybrid Badge

Unmistakably green

How much extra do you have to pay to buy a hybrid car? A lot less than I expected.

Looking at sticker prices in South Africa, the difference is rather scary. Honda’s new Hybrid Jazz lists for R245,000, a full R20,000 more than the top-of-the line non-hybrid equivalent, the Executive Automatic Jazz. But for the moment, at least, the real difference is far smaller. I just purchased a bright green 2011 Jazz Hybrid demo for R181,000, considerably less than the Executive and approximately the same price as the basic Jazz Comfort automatic. (The Executive and the Hybrid are not exactly comparable—the Executive has a glass roof, for example—but they have many similar features.) Yes, my Hybrid has 6,000 kms on the odometer, but I hardly consider that used; it’s barely broken in.

I know I made a good deal, but you can get the same bargain right now, especially if you live in Durban. The Umhlanga Honda dealership has three demo Hybrid Jazz cars on the showroom floor, left over from the COP 17 conference. None of them has been driven more than 15,000 kms, and one of them was offered to me for the same price I paid in Gauteng.

And why look only at new hybrids? It’s almost always greener to buy a used product than a new one, especially a car, since manufacturing a new vehicle accounts vast quantities of energy and emissions. Manufacturing the average new car creates about three tonnes of carbon emissions according to Chris Goodall’s excellent book, How to Live a Low-Carbon Life. A quick look at www.automark.co.za shows that a low-mileage, used Toyota Prius can be had for about R150,000. Hybrids are only expensive if you lack imagination.

Global Warming &Vehicles01 Nov 2010 01:23 pm

95 right? More likely wrong.

The conversation after Sunday lunch somehow migrated to the topic of octane in petrol. A woman was complaining that her husband makes her buy premium 95 petrol even though it costs more. The husband, who drives a Prius, was defending the extra expense on the grounds that the extra octane makes the engine run more efficiently, reducing carbon dioxide emissions.

I had never heard this before, and any idea that might reduce C02 emissions catches my ear. Was I unwittingly damaging the atmosphere by my frugal habit of buying the cheaper petrol? I had to look into this.

One of the best sources of information available was an Engen FAQ on octane, which confirmed, as I had suspected, that we cheapskates are right. “The great majority of vehicles inland . . .  are satisfied by 93 octane,” the website explains. “The use of octane grades higher than your vehicle actually requires will cost you more, cost the country more and have a negative environmental impact.”

The FAQ explains that this is because:

“There will be no additional benefit to driveability or performance of your vehicle if you use a higher grade than it requires. Petrol with a higher octane requires more severe refining and greater energy use in the production process. If not offset by greater fuel efficiency of the vehicle using the fuel, this extra energy use is wasted energy. This wastage results in higher emissions of greenhouse gas (carbon dioxide), which harm our environment.”

What the Engen website did not explain is the relationship between octane and altitude. Octane is purely a measure of how petrol reacts to pressure. Higher octane fuels will not ignite prematurely under higher pressure, which could cause engine knocking. But the Highveld altitude has a low ambient air pressure, which reduces the pressure inside most engines and thus reduces the need for octane. I spoke to John Fitton, an independent petroleum industry consultant, who said that most engines requiring 95 octane at the coast—as is recommended in the manual for my Honda Jazz—only need 91 octane in the Highveld.

South African regulations allow for three grades: 91, 93 and 95. At low altitude, 95 is the only grade available. Highveld petrol stations offer 93 and 95, but 91 isn’t sold at all in South Africa. Fitton told me that this is only because the petrol retailers are trying to satsify ill-informed customers. “Consumers think octane is power,” he said.

Fitton pointed out that the lower octane requirements at higher altitude do not apply to turbocharged engines and a minority of newer engines with gasoline direct injection. (These engines are sold under a variety of brand names such as Mercedes-Benz’s Charged Gasoline Injection, VW’s FSI and Ford’s EcoBoost.) Owners of these cars should obey the instructions in the car manual whether they are in Lesotho or Lambert’s Bay. For the rest, Fitton said, “There’s no advantage to using the higher octane; you’re just going to spend more money and emit more C02.”

Global Warming &Vehicles18 Aug 2010 12:29 pm

Since this blog is dedicated to finding everyday solutions for environmentally-concerned South Africans, I don’t usually stray into political issues. But my comments on the new carbon tax on automobiles, which appear in the latest issue of The Star Motoring, are relevant to the decisions car buyers make. Starting in September, the government will be adding a tax to any car that emits more that 120 grams of carbon dioxide per kilometre.

At 75 rand per gram above 120 g/km, the tax can add up. So check the website of the National Association of Automobile Manufacturers of South Africa for the carbon emission of the vehicles on your list before you head to the showroom. Despite the howls of protestation from the auto industry, I found a surprising number of cars that will attract no tax. Here’s the list:

Audi A4 2.0 TDi 100kW, Citroen C1 1.0i and C3 1.6 HDi, Daihatsu Charade 1.0, Fiat 500 1.2, Ford Fiesta 1.6 DV6, Honda CR-Z  Hybrid, (as well as the anticipated hybrid Jazz), Peugeot 107 and 207 1.6 HDi, Smart fortwo, Toyota Prius (the cleanest of the lot) and the VW Golf 6 1.6 TDi, Polo 1.6 TDi, and CrossPolo 1.6 TDi. BMW’s 320d Dsl comes so close to the mark that the tax will have no noticeable impact on the sticker price.

And in case you missed the latest Star Motoring, here are my thoughts on the tax:

The “debate” over the carbon tax on new cars is hardly a debate at all. The Retail Motor Industry’s opposition to a tax based on vehicle carbon dioxide emissions receives plenty of publicity, and the government fails to rise to the defense of the new tax, due to be implemented in September.

But there are plenty of good arguments for taxing CO2 in the car showroom that are not being heard. The decision made at the point of sale is a fateful one, and not just for the new owner of the car. Should the buyer naively choose a thirsty vehicle without calculating the lifetime fuel costs in advance—a common occurrence—the environment will lose regardless of what happens after he drives away from the dealer.

We do not live in Japan. Cars do not head for the scrapheap after 100,000 kms. They are passed down the economic ladder to poorer and poorer drivers until they literally fall apart. So if the new owner of this vehicle suddenly turns green or tires of paying dearly at the pump, he will sell it on to someone else to do the polluting for him.

Similarly, if he decides to drive less to compensate for his fuelish vehicle—the alternative suggested by the motor industry—the car will last longer. He may be delaying its ultimate output of CO2, but if the car will last 300,000 kms and emits 200 grams of CO2 per kilometre, it will eventually send 60 tons of carbon dioxide into the atmosphere.

If, however, the new tax prods him to save R5250 by purchasing a vehicle that emits 130 grams/km instead, the planet will be spared 21 tons of CO2 in that single decision.

The auto retailers do have some reasonable proposals to protect the environment. They are correct that a carbon tax on fuel gives drivers of both new and used vehicles a flexible incentive to save by driving less. They argue convincingly for stricter fuel guidelines that will give South Africans access to the cleanest new engines and improve the emissions of existing cars as well.

But global warming will not be stopped by drivers cutting back on kilometres. It will not go away because our fuel is cleaner. Nor will it be fixed by a carbon tax on inefficient new cars. It will take all of these approaches in combination and many more.

Many eminent scientists believe that to keep the earth from warming into the danger zone of higher than 2 degrees above pre-industrial levels, greenhouse gases will have to cut by 80 or even 90 percent in the developed world. We don’t need to choose the single best solution among many; we need to adopt all reasonable solutions.

The carbon tax on new vehicles is not perfect. It addresses only one facet of the problem, and the tax is calculated into the sticker prices instead of staring consumers in the face. But we consider it entirely acceptable to fund the government with imperfect taxes on such virtues as saving (interest tax), earning wages (income tax) spending (VAT) and running a successful business (corporate profits tax). Compared to these, a tax on the polluting capacity of new vehicles smells like a rose.

Global Warming &Vehicles24 Apr 2010 03:54 pm

Our morning got off to a curious start, to my mind. When my 17-year-old finally awoke, my wife asked if she wanted to come along for a jog.

“No,” she replied, “I have an extra maths lesson in one hour.”

“That’s fine,” I said, to my wife. “You run, and I will walk her to maths.” (1.8 km away)

“Walk?,” exclaimed my wife, “She doesn’t have time for that; she has tons of homework.”

If the humour of this conversation does not immediately occur to you, perhaps you should exercise your mind. Our culture has compartmentalized each aspect of our lives so completely that exercise is a specialized activity done purely for its own sake and worth the time it requires. Traveling to school, work, shops, friends or errands is a separate activity, to be done as quickly as possible, by car. Using a slower mode of transport is a waste of time, even if it involves exercise. But my calculations show that traveling more slowly actually saves me time, in two ways.

I jog for exercise and pleasure and cycle to get around and also for pleasure. It horrifies me to see people who will ride a bicycle all the way to the Magaliesburg on a Saturday morning for fun, get home, shower and hop in the car to get to the post office. I’ve seen this happen.

My longest regular ride is to a weekly voice lesson. It’s a 7.5 km trip by car that takes 15 minutes, or a cycle of anywhere from 25 to 35 minutes. On the morning of my voice lesson, I skip my usual one-hour jog, saving the same time that it will take me to cycle in both directions. Jogging and then driving would together take an hour and a half. Cycling takes one hour. 60 + (15 x 2) – (30 x 2) = 30. I save a half hour.

That’s not all I save. I don’t keep track, but I figure that sometime this year I will have made my hundredth cycle to my lesson. 100 x (7.5 x 2) = 1,500. That’s 1,500 kms of driving I have saved—farther than Johannesburg to Cape Town—and 150 litres of petrol worth well over a thousand rand. The environment has been spared more than 350 kg of carbon dioxide.

Let’s exercise our maths some more. A health study following more than 5,000 people over 40 years concluded that exercise equivalent to walking for 30 minutes a day for five days a week adds 1.3 to 1.5 years to your life.  Do those regular walks for 30 years, and you will spend 234,000 minutes walking, (30 x 5 x 52 x 30 = 234,000) but will have added 735,840 minutes to your life. (1.4 x 60 x 24 x 365 = 735,840.) So the averages tell me that the 20 minute stroll to her maths lesson added perhaps an hour to my daughter’s life. 735,840 ÷ 234,000 x 20 = 62.89. And, she later reported, “It was a pleasant walk.”

1 + 1 = 2.

Vehicles27 Feb 2010 09:58 am

I keep track of my fuel economy with every fill-up. It’s a little obsessive, I know, but I’ve learned quite a lot from seeing the differences in economy between cars, drivers, seasons, tyres, etc. There is good research to show that when people are aware of consumption, they tend to reduce it. It’s also good to know whether the fuel economy gauge in your car is accurate. In my experience, the gauges always make your fuel consumption look better than it really is.

I’ve made the process very simple for myself by creating an Excel spreadsheet that instantly calculates kilometres per litre and litres per 100 kilometres, with a running average for the last ten fill-ups. Now I’m making it simple for you, too, with a downloadable blank spreadsheet that has all of the formulas to make those calculations. All you have to do is reset your trip odometer at each fill-up, record the number of kilometres on the till slip—which already has the litres printed on it—and enter those two numbers on the spreadsheet.

To have your own copy of the spreadsheet, click on this link:

FuelEconomy

You should then be offered the option of opening it directly in Excel or saving it. Either option works, but if you choose to open it directly and then wish to save it—using Save As—you must be very careful to save it in the folder where you keep spreadsheets. It will not automatically opt for the My Documents folder.

After using it, if you’re not pleased with the fuel economy you see, try my 10 Unconventional Tips for Saving Petrol.

Note: FuelEconomy.xls was scanned with a fully updated version of Norton AntiVirus 2009 immediately before it was uploaded to GreenerHouse. No viruses or other security risks were found. That said, GreenerHouse promises not to take credit for your improved fuel economy if you promise not to make GreenerHouse responsible for any troubles with your computer or your spouse arising from the use of this file.

Vehicles02 Jul 2008 09:16 am

With petrol breaking the R10 barrier today, I’m sure the newspapers will be hauling out the AA’s list of fuel-saving tips yet again. We’ve all read them least a dozen times. The list is generally sound: use the correct tyre pressure, don’t accelerate too quickly, etc., etc., etc. Our eyes are glazing over, however. It’s time for a new list. It’s time to push the envelope.

The fuel consumption numbers in the literature for new cars (and now on windshield stickers in South Africa) are useful for comparing between cars. But few people can keep their fuel consumption that low on the streets. The official stats are derived under very controlled conditions that don’t really reflect the habits of typical drivers.

I hate to brag, but I do sometimes match the official fuel consumption figures for the cars I drive. You can, too. Follow me.

[Lawyer's note: Use these tips at your own risk. GreenerHouse is not responsible for your prang. Safety first.]

1. Don’t brake.
2. Hold your right foot in the air
3. Watch your rev counter
4. In town, windows down
5. Ride the roller coaster
6. Drive your spouse’s car
7. Change your clocks
8. Know your numbers
9. Rearrange your “To Do” list
10. Drive farther . . .

1. Don’t brake

Ok, if a ball rolls out into the street with a child running behind it, slam on the brakes, but most braking is an unnecessary waste of energy. You must learn to feel guilty every time you brake, converting all of that good momentum your engine has given you into wasted friction and heat, requiring you to accelerate all over again.

Not braking requires planning ahead, allowing space in front of your vehicle and exercising patience. A typical example is a street with speed bumps. Most drivers accelerate after each bump and brake before each bump. It makes no sense. The bumps are there because the people who live on that street convinced the government that cars should drive slowly for the safety of the neighbourhood’s children and pedestrians. Settle into the speed at which your car can handle the bumps and stay there. Unless you’re heading downhill, you shouldn’t have to brake.

Look way ahead to the traffic lights and let your car slow naturally well in advance of a red light. People are always in a hurry to sit at a red robot, wanting to give the poor smash-and-grabbers a sporting chance. Don’t worry about the guy behind you flashing his headlights. You’re saving him petrol and a smashed window, too. Smile and wave.

If you have to brake at the bottom of a hill or before a curve, it probably means that you were accelerating unnecessarily a few moments before. Slow down in advance—it’s not safe to brake on a curve, anyway—and keep your foot off that darned brake.

(more…)

Global Warming &Uncategorized &Vehicles24 Nov 2007 02:17 pm

The Mail & Guardian has now put the full, uncut version of my diesel article on their website. Click here to read it.

Global Warming &Uncategorized &Vehicles16 Nov 2007 08:33 am

dieselmg.jpg

If you’ve read my article in today’s Mail & Guardian, you already know that diesel is not quite the panacea to South Africa’s environmental problems that the advertisers would have you believe. South African diesel fuel is still much dirtier than the diesel available elsewhere, and so are our diesel cars. So they play a large part in the smog and particulate pollution in South African cities. The last two-fifths of the article were supposed to explain why diesel vehicles are also not quite the solution to global warming that some think they are, either. But that part of the article was lopped off at the last minute before printing, for some reason. Here’s the rest of the story . . .

. . . These problems are all local, however, and some would argue that the far-reaching impact of global warming means that some diesel pollution must be tolerated. But diesel’s potential for reducing greenhouse gas emissions is regularly overstated. BMW’s X5 brochure, for example, notes that their diesel model uses “up to a quarter less fuel than its competitors,” including the equivalent petrol X5. It adds that this “of course, means a reduction in the greenhouse gases responsible for global warming.”

One little-known reason for diesel’s superior efficiency, however, is that the fuel is denser than petrol, with more carbon. As a result, litre-for-litre it gives off more earth-warming carbon dioxide when burned. So in measuring the grams of CO2 per kilometre, Britain’s Vehicle Certification Agency finds that the X5 3.0sd diesel is only 11 percent better for the atmosphere than the petrol version, despite having 25 percent better fuel economy. Fuel consumption “is only really useful in terms of amount of money you’re going to spend on fuel,” notes Frank Schwegler, president of South Africa’s National Association for Clean Air, “but greenhouse-gas emissions is quite a big factor to consider.”

For now, finding a car’s CO2 emissions per kilometre at a dealership requires scrutinizing the fine print of a technical specifications sheet, if the figure is there at all. Starting in mid-2008, however, all new cars in South Africa will have to display this number—as well as litres per 100 kilometres—based on standardized measurements that can be compared between brands.

In the meantime, the Union of Concerned Scientists suggests that car shoppers should adjust a diesel car’s litres-per-100-km figure upward by 18 percent. Comparing the resulting figure with the fuel economy of a petrol vehicle puts the two on an equal footing as far as greenhouse-gas emissions are concerned.

Even after those adjustments, diesel engines remain somewhat more efficient than their petrol counterparts. And with cleaner Euro 3 and Euro 4 compliant vehicles arriving now in showrooms, some environmentally conscious consumers may decide to tolerate diesel’s local pollution—or the high cost of effective emission controls—in exchange for the lower greenhouse gas emissions. As if that decision was not complicated enough, a more vexing quandary faces diesel buyers at the filling station.

Since Sasol’s coal-to-liquids plant in Secunda is the largest source of ultra-low-sulphur diesel in South Africa, opting for 50 ppm sulphur diesel over ordinary 500 ppm actually quadruples the chances that the fuel in the pump is coal-based.

Sasol’s Fischer Tropsch coal-to-liquids process is an incredibly dirty way to make an incredibly clean fuel. Every drop of diesel that the company makes from coal is so low in sulphur—approximately 10 ppm—that it could be sold in virtually any country in the world.

But the Secunda facility emits about 60 million tons of carbon dioxide into the atmosphere each year. That’s barely less than the greenhouse gas emissions for all of Israel and its 7 million people. In making a litre of coal-to-liquids diesel or petrol, Sasol sends well over three kgs of greenhouse gases into the atmosphere, far more than a car will emit while driving on that litre.

Sasol already supplies half of all the ultra-low-sulphur diesel sold in South Africa, and it is the best situated to increase supply as demand rises. Bizarrely, Sasol has to sell most of its clean diesel as regular 500 ppm sulphur diesel for a lower price; demand for 50 ppm is not yet high enough. As sales of “green” diesel cars grow, Sasol can sell that same fuel for more money as ultra-low-sulphur to take a dominant market share in the 50 ppm segment.

It will be a sad irony when most of the millions of tons of greenhouse gases spewed by Sasol to make diesel is paid for by the drivers who bought the most “environmentally friendly” cars.

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