November 2007


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

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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.

Global Warming &Uncategorized &Vehicles16 Nov 2007 08:32 am

Even the complete version of my article on diesel fuel leaves some open questions. Before you ask, here are my answers:


So which car should I buy?

If the answer were simple, I would have fit it into the article. The conundrum is this:

Diesel cars emit somewhat less carbon dioxide. (Not as much less as you thought, but less nonetheless.) But diesel cars emit more local pollutants. But the newest, clean, Euro 4 diesels driving on ultra-low-sulphur fuel emit acceptable levels of local pollutants. But half of all the ultra-low-sulphur diesel in South Africa is made in a way that emits huge amounts of carbon dioxide.

You can’t win.

You also can’t use diesel as an excuse to buy a bigger, more powerful vehicle than you need. That’s exactly what the car companies are trying to get you to do. (See question below: “Why are SUVs cleanest?”) I think that most city dwellers, especially those on the Highveld, should buy the most fuel-efficient petrol car they can find that suits their needs. If you can afford it, the Toyota Prius is ultra-clean for both local pollutants and greenhouse gases.

If you live in a rural area in the Highveld, where local air pollution from traffic is not as much of an issue, you might consider buying a diesel vehicle and running it on normal, 500 ppm sulphur diesel. You are most likely to avoid coal-based fuel that way and will reduce your contribution to global warming. (Note that if your manufacturer says you must use ultra-low-sulphur fuel, it could damage your vehicle to use 500 ppm sulphur diesel.)

If you live in KwaZulu-Natal, most of your fuel comes from petroleum. With the coal issue set aside, diesel makes more sense. Look for the vehicle—petrol or diesel—with the lowest CO2 emissions that suits your needs. In KZN cities, you should only buy a diesel if it meets Euro 3 or Euro 4 specifications and fill it with ultra-low-sulphur diesel.

Cape Town is even more complicated. Fuel retailers generally buy from the nearest refinery, but Sasol transports ultra-low-sulphur diesel all the way from Secunda to its filling stations in Cape Town. I wouldn’t buy it. BP stations get their ultra-low-sulphur diesel from the Durban refinery that BP owns with Shell. I don’t know about the others.

Does a diesel make economic sense?

The Diesel Dilemma, a report by the Union of Concerned Scientists, concludes that:

Gasoline vehicles are more cost-effective than diesel for reducing oil use and lowering global warming pollution.

By that, they mean that if the extra expense it takes to make a clean diesel engine were put toward greater efficiency in petrol vehicles, the petrol vehicles would save more oil and greenhouse gases than diesel cars. Unfortunately, other than hybrids like the Prius, few petrol cars have benefited from that kind of attention toward fuel economy.

Looking at clean diesels available in South Africa, the BMW X5 sd costs an astounding R68,000 more than its petrol equivalent the X5 si. Even after 150,000 kms, you would be R47,000 poorer, at October’s fuel prices. The diesel Honda CRV, which has perhaps the most advanced diesel engine on earth, emits 10 percent less carbon dioxide than a similar petrol CRV and costs R20,000 more. After 150,000 kms, you would be only halfway toward recouping that differential.

I’m not a great believer that every expenditure for the sake of the environment must pay for itself. If someone in Durban really needs a 4×4 soft-roader and is willing to pay the extra money for the sake of the earth, they should buy a diesel CRV. I’m just not sure how many people out there really need a 4×4 soft-roader.

Smaller diesel cars may have a smaller price differential, but few if any small diesels in South Africa today are clean enough to meet Euro 4 emissions standards. In 2008, some will be available, and perhaps they will pay for themselves over time. They certainly will make more sense for the environment than a 3-litre diesel powerhouse with a lot of emissions controls on it.

Why are diesel SUVs cleanest?

The cleanest diesel engine BMW has brought to South Africa is in its giant X5. Honda’s cleanest diesel is on the 4×4 CRV. VW’s only Euro 4 vehicle in South Africa so far is the Touareg SUV. Volvo has put its best diesel emissions controls on the 4×4 XC. What’s going on here?

I put this question to Jan Lotter, the product planning manager for BMW South Africa. He laughed, and said that I had made a good observation. Then he said:

There’s a growing awareness of SUV consumption; people are talking about carbon footprints, environmental impact. This is a little more of an investment to make them more acceptable.

I think he’s right. It’s a last-ditch effort to keep people who are starting to feel that it’s environmentally unacceptable to drive a 4×4 to Sandton City from buying a smaller, less expensive car.

Lotter made another salient comment:

The unfortunate thing about diesel is that it is still expensive. With the invention of common rail diesel technology, and going to higher and higher pressures [to make diesel engines cleaner] it becomes difficult to introduce entry-level diesels.

BMW has a small, Euro 4 diesel car that can even beat Toyota’s Prius in fuel efficiency, the 118d. But it isn’t sold in South Africa.

Does it really make a difference whether I buy coal-based fuel?

One could argue that avoiding coal-based ultra-low-sulphur diesel from Sasol’s Secunda plant does nothing for the environment. Fuel is in short supply in this country and Sasol will keep producing to capacity. The company may end up selling the fuel as regular diesel and it may end up selling the diesel somewhere else, but Secunda’s emissions are not going to decline just because fewer people buy ultra-low-sulphur diesel in the interior.

This argument has some validity, but I would make three counter-arguments:

  1. Sasol makes more profit selling their diesel as ultra-low-sulphur diesel. The more profit they make on diesel, the more likely they are to go ahead with the second coal-to-liquids plant, which is now in the feasibility-study stage. Such a plant would be a disaster for South Africa’s greenhouse gas emissions.
  2. If ultra-low-sulphur diesel becomes in short supply, the government may be more favourably inclined toward another coal-to-liquids plant.
  3. It might just bother your conscience to think that the source of all those greenhouse gas emissions killing polar bears and ruining the crops of African farmers is sloshing around in your fuel tank.

Don’t you have anything nice to say about Sasol?

Sasol does an impressive job of reporting emissions data and was willing to let some of its experts talk to me openly for this story. The refinery owned by BP and Shell, by contrast, would only answer questions by email and mostly didn’t answer questions at all. Sasol’s greenhouse gas emissions are edging down relative to their total production, partly because they are using more gas from Mozambique, which is less polluting than coal. There, I managed to say something nice about Sasol. (But if you haven’t read the M&G article yet, their Secunda plant has roughly the same greenhouse-gas emissions as Israel.)

Don’t you have anything nice to say about BMW?

I’m afraid that BMW’s marketers set themselves up for criticism by portraying a big SUV as a solution to global warming. That said, the company is working on some very interesting technologies for improving the fuel consumption of both petrol and diesel vehicles. In 2008 we may see the first BMWs that cut the engine instead of idling at a stop light and use the energy from braking to recharge the battery.

Appliances &Uncategorized &Water Use/Greywater15 Nov 2007 06:18 pm

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The 35 degree solution

For years I’ve had to avoid my wife, for fear that she would again ask me how long she must wait before I will replace our leaky, ineffective dishwasher. This Indesit was so old that the last few repairs have required salvaging used spares. I had been procrastinating that decision even though I knew that it would reduce wasted water and electricity. My procrastination had nothing to do with a fondness for mopping the floor or scraping crud off the bottoms of teacups. I simply feared the amount of research that would go into finding an energy-efficient, water-conserving dishwasher that gets dishes clean. I am happy to report that my new Bosch SGS44E12EU (also called the SGS43E02EU) arrived today, and the investigation was not quite as painful as I had anticipated.

Not that I got everything that I wanted. My first goal was to find a dishwasher that could make use of the spare hot water my solar panels produce for nine months of the year. Alas, a Bosch technical representative explained to me that no domestic washer has hot and cold intakes, and the intake valve on a Bosch dishwasher could not tolerate a temperature above 40 degrees. This would require me fitting an expensive mixer valve to cool the water before it entered the machine. Besides, he explained that the way modern dishwashers work is to start with cold water and gradually raise the temperature. Use hot water in the first cycle, he warned, and you will bake the food onto the plates. I gave up on that track.

The next step was to compare water and electricity usage of various dishwashers. In Europe, Australia and many other markets, this is a simple task. Each appliance is labeled with a large sticker showing energy consumption, water consumption and an overall A-G rating. Dishwashers in Europe get three ratings: one for energy consumption, one for washing efficiency and one for drying efficiency. The Department of Minerals and Energy has long been promising South Africans a similar system, starting with refrigerators in May of 2005. Two and a half years later, the only appliances with an energy labels are a few imports with their European label intact.

Still, through the Internet, brochures and the Which? website, it was possible to get information from overseas efficiency ratings. Bosch’s South African website, for example, clearly displays the European ratings and consumption data for all of its dishwashers. (Curiously, they don’t display that information for their tumble driers, which, like the vast majority of these energy hogs, get Cs.) All of Bosch’s dishwashers get European As for energy consumption, which means that they use less than 1.06 kilowatt hour for a standard 50 degree wash. Not coincidentally then, many dishwashers, including all of the Bosch dishwashers sold in SA use exactly 1.05 kWh. The one I chose also uses a modest 17 litres of water for a standard wash. The top-of-the-line SGS 46 E 28 GB uses a mere 12 litres. But it costs R6399, a full R3000 more than mine, which is a lot of money to pay to save the equivalent of less than a flush of the toilet.

More important, the upper-range dishwashers have 45 degrees as their coolest setting. The economical dishwasher I chose goes down to 35 degrees. My sister-in-law uses a Bosch similar to mine and says that she never moves it from that coolest setting. She doesn’t rinse anything before putting it into the dishwasher, and even sticky porridge bowls come out clean. I haven’t succeeded in getting the data from Bosch on the electricity consumption of a 35 degree wash, but I did my own calculations. Since it uses 1,05 kWh for a 50 degree wash, and since heating 17 litres of water by 15 degrees should theoretically require 0,28 kWh, the 35 degree wash should use approximately 0,77 of a kWh.

A while ago, I checked the consumption of my old dishwasher at home, using the same, moderately precise methods I used to check electricity lost to chargers, transformers, appliances on standby and other vampires. It used 1.35 kWh on its lowest setting and guzzled 35 litres of water. Worse yet, because it cleaned so poorly, we used many more litres rinsing dishes. This is a purchase my gardener will appreciate. (Why? See here.)

My dishwasher only gets a C for drying efficiency, but that’s because it doesn’t have the electricity-wasting drying feature. It should get an A+ for leaving that off.

If you want to read a good overview of dishwashing written with a sense of humour, check out the Appliance Advisor’s guide to green dishwashing. By the time you are finished reading it, you will be convinced never to rinse your dishes again before putting them in the machine.

But do you even need a dishwashing machine? Advertisements for dishwashers often claim that they use far less water and energy than hand washing. I’m not so sure. Washing carefully, with 5 liters of solar-heated rinse water in one sink and 10 litres of solar-heated soapy water in another, I could beat any dishwasher on energy consumption. But my new dishwasher is a big step in the right direction. And it’s a lot better for my marriage.

Garden &Uncategorized &Water Use/Greywater13 Nov 2007 10:44 am

For many of us in South Africa who are fortunate enough to be able to employ people to work in our homes and gardens, saving electricity and water must be a cooperative effort. I have installed the dual-flush toilets, the low-flow shower head and the indigenous garden. But when the garden water taps and kitchen appliances are largely in the hands of people who don’t pay the utility bill, how can we fully control consumption?

Six months ago, I launched an experiment to address this conundrum, and I am happy to declare it a success.

First an anecdote to illustrate how far apart my gardener’s mindset was from mine. Last summer, when we went away for two weeks, I took a chance that good rains would continue and shut off the sprinkler system. (I always shut it off in the summer whenever we have had 25 mm of rain in the past week.) When I returned to Johannesburg, I was delighted to see the city looking lush and green; I knew that my gamble had paid off. As I arrived at my house, however, I was appalled to find my sprinklers spraying full-blast. The next time I saw my gardener, he cheerfully reported that the day I left he had discovered that I had left the sprinklers off “by mistake” and that he had “fixed it” for me.

So when he later borrowed a couple thousand rand to buy materials to build his mother a house, I knew how I could help him pay it back. I showed him my water bills from 2006, and told him that we would follow the 2007 water bills and compare them. As long as the garden remained reasonably green, we would share 50/50 any money we saved on water.

The first change I noticed was that he was using a broom to sweep a brick walkway that he used to hose down. When he washed the car, he used a big bucket, instead of a running hosepipe. And where I had often found him watering parts of the garden that didn’t need it, he now asks first.

My water bills for the last six months have come down by an average of 38 percent, and my gardener’s debt has been cut by R670. I know that some of this is because the garden is more established now and needs less water. The good rains in October also helped. But I am convinced that a major reason is that we both share the same mindset now when it comes to water conservation.

I still have control over the sprinkler system, so the garden won’t go brown, and I know that he is too proud to let plants wither. But I have a hunch that the next time I shut off the sprinklers for a holiday, he won’t be fixing my mistake.

Appliances &Global Warming &Uncategorized12 Nov 2007 12:05 pm

Three aging appliances in my kitchen have been declared beyond repair, which has led me to undertake a lot of research on appliances. A good starting point I have found is Which?, the British non-profit magazine and website that thoroughly tests and reviews consumer products. I will report on my research on dishwashers, etc., when I have completed it. In the meantime, I stumbled upon this page in on the Which? website that has interesting, straightforward, and surprising information on television electricity consumption.

I had always assumed that LCD televisions use far less power than standard CRT (Cathode Ray Tube) televisions, since this is the case with computer monitors, as I reported here in my post on saving electricity in the office.

Which?, however reports that after testing dozens of TVs, it found that a 32-inch CRT TVs use 50-100 watts, similar sized LCDs use 100-200 watts, and 42-inch Plasma TVs (they aren’t made in the 32-inch size) consume 200-300 watts. That’s up to 6 times more than a CRT only 10 inches smaller.

Though I believe the Which? does very thorough and unbiased research, I do think that the full story is slightly more complicated. A revealing chart produced by the Australian government when researching electricity consumption by TVs shows that in the smaller sizes (below 40 cm) , LCD TVs are more efficient on average. This would explain why they are the greener choice for a PC monitor. But CRT TVs don’t experience as great a leap in consumption as they get larger. LCD and Plasma TVs use a lot more electricity with each step up in size. Beyond 60 cm, most CRTs are somewhat more economical, though there is enough variation between models that it is possible to find a large LCD that outperforms a same-size CRT at the plug.

As for Plasma TVs, they are simply energy hogs. The larger ones can draw 500 watts or more. Some guides to televisions will divide the consumption by the size of the TV, which makes plasma televisions look a little better. But I think this is beside the point. One of the most important decisions a television buyer must make is the size, and it is important to know that making do with a smaller television is much better for the environment. If you already own a plasma TV, you can reduce its power usage by turning down the brightness. (Dim the room lights at the same time and you’ll save again.)

And, as I explained in this post, when you’re finished watching, take the consumption all the way down to zero. Don’t put it into standby with the remote; turn it off at the television itself.

Global Warming &Uncategorized10 Nov 2007 02:25 pm

I spent the morning meeting with the creator of South Africa’s first Internet carbon-footprint calculator, which will premiere on Greener House in the near future. He is a brilliant young engineer who has just been named the best Certified Energy Manager in South Africa for the year, so you can trust that the calculator will be backed by solid data. Measuring the amount of greenhouse gases produced by a person is a tricky and inherently imprecise task. But he is committed to making the calculator as accurate and as useful as possible.

There are plenty of carbon calculators in the Internet, so why do we need another one? Because the others make assumptions that you live in America, the U.K., or somewhere else that has conditions different to South Africa’s. For instance, if you use a calculator from a country that uses a lot of nuclear power for electricity, the carbon contribution from your electricity consumption will be misleadingly low. And no other country produces significant quantities of petrol and diesel from coal; our calculator will take that into account as well.

We will be glad to consider refinements to the calculator once it is up on Greener House. But we don’t want to just throw up a rough draft, hence the long meeting today. Our aim is to have it up and running by the end of the year. It’s tough, I know, but try to be patient.