Tuesday, 13 December 2016

Is that factoid true?

I came across this comment as I was preparing a lesson on cooling: 

"US uses more electricity on cooling than Africa does on everything."

As often happens, the factoid gets divorced from its source, and just stays there, overly confident in its truth. But is it true? And how do I find out? As Churchill said, "A lie gets halfway around the world before the truth has a chance to get its pants on." He said this long before the internet was invented and the term "social media" was coined, but some things do not change. Or perhaps, and somewhat more scarily the world today is similar to the 1920s, and we are heading towards a repeat of the 1930s. 

According to this article in Mother Jones (July, 2015), the US spends 11 billion dollars on air conditioning, and in the process emits 100 million tons of CO2.

According to the Carbon Dioxide Information Analysis Centre (2008) Africa's carbon emissions 311 metric tonnes. But that's all emissions, not just electricity. 

Wait a minute, was the Mother Jones statistic metric tonnes, long tons or short tons? The latter are 10% more or less the former. Also, the factoid said "electricity" and Africa presumably has other carbon emissions than electricity. So it may be true.

According to accountants KPMG, Africa's electric generation capacity was 680 billion kWh in 2012. The US average 12 cents per kWh. So, I can work back from the 11 billion dollars to get 90 billion kWh. Now we're even further out and Africa is using over seven times more energy for everything than the US does for cooling.

US Energy Information Administration's website gives around 2 pounds CO2 per kWh of electricity. If a short (US) ton is 2000 pounds, that's 1000 kWh per ton of CO2. So 100 billion kWh on air conditioning in the US.

Interestingly, if the above emission figures are correct, Africa's energy generation is at least twice as clean as the US. This is possible if Africa has a higher proportion of hydroelectricity, and a lot of the plant is newer and more efficient. 

Or perhaps this factoid was just talking about domestic air conditioning, rather than commercial or industrial.

This is neither US nor Africa, but may have some air conditioning
Or maybe the article was just wrong. This US Department of Energy site claims $29 billion were spent by homeowners on air conditioning, emitting 117 million metric tonnes of CO2. 

But where did I actually get that factoid from in the first place? It probably came from this July 2012 article on Yale Environment 360 by Stan Cox. It was probably true at some point, since the US has a long history of air conditioning, and Africa is still rapidly developing as an electricity consumer. 

Oh for that world of long ago, when all good things were true...