Many consumers breathed a sigh of relief, but a fact that received little attention at the time was the indication by NERSA that the 25% p.a. increases allowed for 2010, 2011 and 2012 would now likely continue after 2012.

The article later adds:

Irrespective of which scenario is considered, the projected electricity prices in the draft IRP 2010 show annual increases well above inflation up to 2021, and it would appear that the golden era of Eskom price increases at or below inflation will only arrive thereafter.

And concludes:

. . . take heart! Electricity prices should level off in about ten years time. Highlight 2021 in your diary as the dawn of a new era of Eskom price increases in line with inflation. Maybe…

I ran some of these numbers through a spreadsheet to see what they might mean to my electricity bill. For Eskom to reach the prices it originally envisioned before NERSA put a lid on annual increases, 25 percent price hikes will have to continue to at least 2014. Assuming that City Power of Johannesburg passes these increases on to residential users, this means that the 68 cents per kilowatt hour we pay today could leap to R1.66 in the next 3 years.

I don’t raise this issue to increase anyone’s blood pressure. What interests me is that this information completely changes any cost-benefit analysis of investments in energy efficiency at home. Back at my spreadsheets I find that  a solar hot water system that would pay for itself in 5 years at 68 cents a kilowatt hours, recoups the outlay in just 2 years at R1.66 a kilowatt hour. An efficient, variable-speed pool pump that makes sense as an investment over 7 years, suddenly makes much more sense by turning profitable in just 3 years.  LED lights that were expected to cover their costs in 6 years achieve that mark in 2 1/2 years.

I don’t think that every effort to make a greener house has to pay for itself. A little bit of financial analysis does help point out the changes that can make the greatest impact for the least expense, however. Eskom may not be doing our budgets any favours, but it sure is turning the cost-benefit analysis for eco-friendly investments green.

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.”