Uncategorized01 Dec 2009 04:34 pm

For years, I have tracked my household electricity consumption, sometimes on a daily basis. Knowing my daily kilowatt hours has taught me much about the impact of heaters, oven, clothes drier, and especially my solar hot water system, and how it is affected by usage, weather and seasons. It has helped me set targets for conserving electricity and to monitor my progress. And it has helped me to catch problems quickly. If I see a sudden leap in my kilowatt hours, I know I will find that the pool pump has been left on override, or the geyser is drawing electricity when it shouldn’t.

There are fancy devices out there—not available in South Africa—to bring all of this information into your home. One day I would like to own one. But I do this all with my ordinary municipal meter and a simple, but effective Excel spreadsheet. I have now created a downloadable blank version to make tracking your electricity consumption incredibly easy, even if you know nothing about Microsoft Excel. All you do is fill in the date and your current meter reading. (The final digit on the meter is normally a decimal, which I ignore or round off.) The spreadsheet will calculate the average daily consumption since you last took your reading. To try it out, click here:


Your computer should ask whether you wish to open it directly in Excel or save it. Either option works, but if you choose to open it directly and later save it—using Save As—be very careful to save it in the folder where you keep spreadsheets. It will not automatically opt for the My Documents folder.

I hope it helps you save electricity, or at least gives you some ammunition when fighting the municipality over outlandish readings.

Note: ElectricityMeterReadingsBlank.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. Still, GreenerHouse can take no responsibility for any consequences arising from its use.

Uncategorized03 Nov 2008 09:05 pm

Call me petty, but when I received a gorgeous shirt as a gift recently, I was a little disappointed because two Jeep tags were sewn onto the front of the shirt. (Green tags nogal!)

Chrysler consistently ranks at or near the bottom of fleet fuel economy rankings in the United States, and Jeeps are the thirstist vehicles in the Chrysler stable. Some Jeeps are rated at more than 21 liters per 100 kilometres. (4.7 kms/l or 11 miles/gallon.) They definitely have not earned their green tags.

I’d rather not walk around in a shirt that adds any cachet to the Jeep brand, but I didn’t want to waste a beautiful shirt. So I solved this problem with the help of a stitch-ripper, a handy tool that should be a part of any sewing kit. Without the green tags, my shirt is so much greener.

Recycling &Uncategorized26 May 2008 02:26 pm

Mandla blank

The picture that I meant to take of Mandla

These are sad times in South Africa. And though I mostly feel quite distant from the terrible violence against our African neighbours, I have been touched by the tragedy in one, odd way.

For the past two years, a man name Mandla has rung my bell every Monday morning to see if I have any recyclables for him. I first saw him digging through garbage in my neighbourhood during one of my jogs. He was collecting white office paper, so I told him to stop by my house, since I always separate the good white stuff, which fetches a higher price. Ever since, he has made a weekly stop here. And as prices have risen for other commodities, I have given him cartloads of plastic bottles and cans in addition to paper.

I had just decided that it was time to write about Mandla on GreenerHouse. I liked the topic, because I believe that developing this kind of relationship creates meaning out of recycling, spares the collector the indignity and effort of digging through rubbish, and could save homeowners trips to the recycling depot. I had even decided that I would call the post “Meet Mandla.” I was going to take his picture and place it on the website.

It was going to be a good week for Mandla, because I had worked on the cleanup crew for my daughter’s matric dance and had rescued bins full of PET plastic bottles, aluminium cans and steel (tin) cans. I had them waiting at the gate for him. When Mandla didn’t show up last Monday, I didn’t think much of it. But now he hasn’t rung my bell for two weeks, so I know that last week was not a good week for Mandla. We had never discussed his origin; we mostly talked about the prices of various recyclable commodities. But it now seems clear that he was a Zimbabwean. In my experience, most of the hawkers who collect recyclables on foot are from other African nations.

I hope that Mandla is safe, wherever he is, and that someone is giving him lots of white paper to sell.

Solar &Uncategorized14 May 2008 05:20 pm

The latest issue of Maverick magazine, which is arriving on newsstands this week, includes an article I wrote comparing diesel generators with solar photovoltaic panels. The point is that solar cells are normally considered pricey, with little hope of paying for themselves in the near term and maybe not even in the long run. Load shedding changed all that, however, because many South Africans are now shelling out tens and even hundreds of thousands of dollars for diesel generators to make themselves Eskom-proof. In my article I compare what happens if that money is instead put into generating solar electricity on the roof. I use actual quotes for systems for one house and then run the numbers to see how the two options compare over time.

When this issue of Maverick comes off the newsstand, I will post the article in-full on GreenerHouse. In the meantime, I will share a few insights from my reporting here in the next few days.

Global Warming &Lighting &Uncategorized07 May 2008 09:42 am

frogs on CFL

Those Frogs Still Prefer CFLs

Yesterday in my daughter’s science class, the subject of energy efficiency came up, and another girl in the class mentioned that she had heard that our house was full of energy-saving devices. So my daughter had to explain what we were doing at home to save electricity. One boy asked if manufacturing those compact fluorescent light bulbs doesn’t use more electricity than making a common incandescent globe.

She didn’t know the answer. And neither did I. But I was glad that the younger generation thinks about the carbon footprint of the products we buy, and I thought it deserved a little research. After much digging, I came up with some information from Osram about the electricity that goes into making their bulbs.

Osram says that they need 3.36 kilowatt hours to produce each 15 watt CFL. This is about two-and-a-half times the amount of electricity required to make the equivalent 75 watt incandescent globe, 1.29 kilowatt hours. An incandescent bulb is a simpler product, after all. So the advantage goes to the incandescent on day one.

It loses the advantage quickly, however. If you use the two bulbs for four hours a day, by the 9th day, the incandescent has used so much more electricity that it has lost its advantage. By the end of a year, my very rudimentary life-cycle analysis shows the CFL winning the race by 25.26 kWh to a whopping 110.79 kWh for the incandescent.

Even if you were burning these bulbs in Iceland, using carbon-dioxide-free geothermal and hydroelectric power, the CFL would be more environmentally friendly because it lasts longer and so one CFL is the equivalent of several incandescents.

If, like Noah, you know that the world is going to be swallowed up in a flood in a few days, an incandescent bulb is the green choice. If you think the flood might take a few more years as the Greenland ice cap melts, you should buy CFLs.

Lighting &Uncategorized09 Apr 2008 11:19 am

I just received a comment to a year-old post about compact fluorescent lamps. The reader raises concerns about mercury in CFLs. I replied to him at length with my own comment, but the information is too important to leave it buried there.

The issue of mercury in CFLs keeps rearing its head. I once read a long article in the Star that left the reader with the impression that CFLs’ negatives may outweigh their positives.

This is simply not true. If you read what the independent experts have to say, it is clear that compact fluorescents reduce the amount of mercury in the environment in the long run. One thorough article on the subject notes that:

CFLs represent between 0.006 and 0.04 percent of U.S. anthropogenic [mercury] emissions

It concludes:

CFLs prevent the emissions of substantial quantities of mercury, greenhouse gases and other pollutants; they reduce consumer energy bills; and they last far longer than incandescent alternatives. They are currently the environmentally preferable product despite their mercury content – whether they are recycled or not.

Two other web pages worth reading on the subject can be found at the Natural Resources Defense Council and Popular Mechanics.

The reason CFLs can contribute to mercury emission reductions despite containing mercury is that coal-burning power plants are the world’s largest contributor to mercury emissions. In the U.S., they are responsible for about a third of the mercury released. Since coal accounts for less than half of U.S. electricity generation and about 90 percent of South Africa’s electricity generation, it’s safe to say that more than half of all mercury released in South Africa comes from Eskom. Cut your electricity consumption and you reduce mercury pollution.

Aside from the broader environmental issue, some people are concerned about exposing their families to a source of dangerous mercury in their homes. John Balbus, M.D., the Chief Health Officer at Environmental Defense, writes

The exposure from breaking a compact fluorescent bulb is in about the same range as the exposure from eating a can or two of tuna fish.

Still, if a bulb breaks in your home, it’s worth following a few precautions such as using disposable paper towels to wipe up—not a vacuum cleaner—and washing your hands when you are finished. For more details, you can read the instructions suggested by the U.S. Environmental Protection Agency.

I don’t want to go too far in minimizing the dangers of mercury. It is a serious poison, and we should all try to reduce our contribution to mercury pollution in any way we can. Batteries are a very large source of mercury, so you should only buy watch batteries and alkaline batteries that are mercury free. (Recyclable batteries are even better, of course.)

In buying CFLs, the best recommendation is to stick with major international brands such as Osram, GE and Philips. They have to comply with EU standards that allow no more than 5 mg of mercury in a globe. Osram CFLs have 3.5 mg according to their technical marketing manager in South Africa, Wally Wilmans. Cheaper brands may have more.

There is no way to recycle CFLs in South Africa currently, but Eskom has a working group tasked with this issue. CFLs last so long that before the bulb you buy today burns out, even Eskom may have come up with a plan.

Appliances &Global Warming &Uncategorized25 Mar 2008 12:32 pm

A warm, green towel, served medium-well

A friend of mine stopped by yesterday on his way home from shopping for a heated towel rail. He had been fretting for years at his wife’s extravagant use of the tumble dryer simply to warm and dry a single towel before bathing. He worries that tumble dryers use vast amounts of electricity. I used to have a similar affliction, until my tumble dryer broke down last year. I simply didn’t bother to repair it, and I have been a happy man ever since.

The towel rail my friend wants to buy, he told me, uses about as much electricity as a single light bulb, or 100 watts. Though my friend is a former maths teacher, I wasn’t convinced that he had done his calculations.

Heated towel rails are designed to run constantly; they generally don’t come with timers or thermostats, other than a safety shut-off to prevent overheating. If he runs this towel rail constantly for a year it will consume 876 kilowatt hours of electricity and add nearly a ton of carbon dioxide to the atmosphere. In my house, that would mean a 10 percent jump in total consumption most months. And at the rates just proposed by the Johannesburg municipality for the coming year, the towel rail would increase his annual electricity bill more than R350. If rates triple over the next several years, as predicted by some experts, the annual cost would approach R1000.

Tumble dryers use roughly 2000 to 3000 watts. That’s terrible. But presuming that his wife doesn’t leave the tumble dryer running all day to keep her towel warm and dry, it might use less electricity than the towel rail. Run a 2500 watt tumble drier for a 30 minutes a day and it will use less than half the electricity—and contribute half the carbon dioxide—of  a round-the-clock towel rail.

That’s still not good for the environment, however. The almost-environmentally-friendly solution is to have an electrician install the towel rail with a switch and a timer and then use it a few hours a day in the winter and turn it off entirely in the summer. The hundreds of rand you will save each year will easily pay for the timer. The problem with this solution is that it contributes to load-shedding because it will add to your electricity consumption at the exact morning and evening peak hours when Eskom has no spare capacity.

If you really can’t see a way to keep your spouse happy without warm towels—and I am very conscious that sometimes we must compromise to avoid marital misery—I suggest trying the microwave oven. WARNING: YOU CAN BURN YOUR SKIN OR EVEN START A FIRE IF YOU HEAT A TOWEL IN THE MICROWAVE FOR TOO LONG. I would not even attempt this in a microwave without a digital timer, and children should not be allowed to try this unsupervised. For my 750-watt microwave oven, 30 seconds warms a small towel nicely and 45 seconds heats a large bath-sheet towel to perfection. Thirty seconds at 750 watts is a mere 2 percent of the electricity used by a 100-watt towel rail in 3 hours. If you don’t have a doting lover on hand to run the warm towel from the kitchen, warm two towels for 30 seconds each and wrap one inside the other to keep warm while you bath or shower. Just because I’m opposed to global warming doesn’t mean that I don’t support wet-body warming.

Uncategorized07 Mar 2008 05:11 pm

GreenerHouse has made the short list for the 2008 South African Blog Awards in the category of Green Blogs. If you think this is the best environmental blog in South Africa, and believe that more South Africans should be exposed to the ideas and information found on Greenerhouse, click on the button to the right. A nomination will bring this site to the attention of many people who might not otherwise hear about it. There’s no money in it for me, but the posts I write for Greenerhouse are only worth the time I spend on them if lots of South Africans get to read them.

The voting process is simpler than the rather tricky nominating process, I promise. Voting concludes on the 19th of March.

Global Warming &Uncategorized06 Mar 2008 09:00 pm


One is greener than the other

This week I took delivery of a 48 kg cylinder of liquid propane gas. This may seem odd, because I only use gas for heating in the winter. (I wrote about this here.)

But it was all part of a plan. Because burning LPG purchased in the summer may be about the only way to use a fossil fuel at virtually no cost to the environment. That’s right, no net carbon dioxide emissions, sulfur dioxide or any other nasties will be released into the atmosphere as I stay warm burning this gas in the coming winter.

The logic is this: LPG is a byproduct of the refining process. Wherever petrol is made from oil, gas or coal in South Africa, some LPG is produced. As a friend a Sasol first told me, in the summer, when LPG demand is down, these plants run out of storage capacity for LPG and frequently flare it. So if I work on the assumption that my new bottle of gas would have been flared into the atmosphere anyway, I can burn it with a clean conscience.

I planned ahead for this moment back in August, when one gas bottle was depleted. I always have one spare 48 kg cylinder on hand, and replace an empty as soon as I switch over. But two weeks into August I did some quick calculations and figured there was no way my new bottle would run out before warm weather arrived.

Of course, if South Africa had a rational, competitive market, LPG prices would come down in the summer, everyone would have a financial incentive to plan ahead and buy gas in the summer, and flaring of LPG would come to an end. But anyone who buys bread or has a bank account in this country knows that we do not have a rational, competitive market.

So should I buy more LPG bottles to get me through the winter? I don’t know. I worry that South Africa could run into a gas-cylinder shortage this winter. So many people are switching to gas for cooking because they no longer trust Eskom. I will try to investigate the gas-bottle supply situation before winter arrives. If it looks good, I will buy an extra bottle and let you know.

Appliances &Uncategorized26 Feb 2008 09:06 pm

My article on televisions and electricity consumption is now available on the Mail & Guardian website at this link. The previous post contains all of the practical advice that a television buyer could glean from the article, but the original text does provide more context. It also includes a salient comment by Professor Ernst Uken, head of the Energy Institute at the Cape Peninsula University of Technology.

Uken says households play a larger role in the South African power crisis than their overall consumption would suggest. The morning and evening spikes in power usage are caused by the domestic sector, he says, “and spikes are the reason for the power outages. The tail is wagging the dog.”

Next Page »