Is Sydney’s heat decoupling from demand spikes?

March 7, 2016 by ketanjoshi85 In Uncategorized 6 Comments

If you’re something like me, you don’t do quite so well in the heat. I was born in London; I’m at my happiest pulling up a thick collar, pushing through wind and snow, with a scarf waving in the wind behind my neck.

So, you might be wondering why Sydney’s been through a spell of fairly serious heat the past few weeks. Not extreme heat, mind you – just persistent, unseasonal warmth with no cold breaks, and no rain.

This article in The Conversation explains it quite neatly:

“Over recent weeks, there have been extended periods with a high-pressure ridge over eastern New South Wales and weak low-pressure troughs inland. That is creating mostly stable atmospheric conditions for Sydney (that is, no rain) and funnelling warm air from central Australia over the metropolitan region”

The article explores a range of other factors, but mentions climate change, too:

“If we don’t consider Sydney’s recent weather in isolation, then it is clear that climate change is playing its role here as well. Both land and ocean temperatures have warmed. And those warmer offshore sea surface temperatures keep our nights warmer, particularly in coastal cities.

Warm, hot conditions are becoming more likely, while cool outbreaks are becoming less so. The whole of southeastern Australia has experienced fewer cold outbreaks in recent years (although they do still happen).”

Out of curiosity, I pulled some data from the Bureau of Meteorology’s amazing ‘Climate Data’ tool. Here a fairly simple illustration of just how well above average the last few weeks have been:

February in particular has had a run of hot nights – something which tends to compel the usage of air-conditioners. We know air-conditioners tend to increase power bills, but I feel we we’re not generally cognisant of just how much they push up energy demand – here’s a quick chart I made last year showing the relationship between NSW demand and temperatures – a relationship coupled by the usage of air-conditioners.

This is pretty interesting – there’s a distinct link between hot days in Sydney and broader NSW demand, which makes sense. So has Feb-March 2016 seen an uncommon increase in state-wide demand, to match Sydney’s uncommon run of hot days? Below, I’ve used Global Roam’s NEM Review tool to pull some historical data, and compare it to the past few weeks:

Curiously, demand isn’t much higher or lower than the past five years. Keep in mind this comparison is slightly different – averages from 2000 to 2015, rather than temperature averages from 1859 to 2015 (like-for-like also shows average 2016 temps above the 2010-2015 average, though).

Regardless, there’s a novel disconnect, here. Sydney’s  unusually high temps aren’t driving unusually high demand.

As the article in The Conversation points out, this spell of heat isn’t affecting all of NSW, which would partly explain why there hasn’t been so great an impact on state-wide demand levels. But, I suspect rooftop solar plays a big part here. Here’s the shifting daily profile for January to February, from 2000 to 2016, in a dizzying three dimensional chart gif. Notice how there’s a camel hump in the middle? NSW’ daily demand profile hit a peak in mid 2010, but has been decreasing since then:

To illustrate in a slightly less nauseating way, this is January+February average NSW demand:

This summer’s Sydney heat, and the lacklustre response from state-wide demand, is part of a curious flattening of demand.

This is pretty good news for people like me, who really can’t stand the heat. I rent, but even if I didn’t, I probably couldn’t fit an air-conditioning system (and consequent electricity consumption) into my budget. In the past, price spikes caused by air-conditioning-driven demand were paid for by everyone – regardless of their air-con usage.

Now, demand is lower, and there are fewer price spikes to be covered by consumers, driven partly by solar. It’s still hot, and I’d still prefer to be wafting down an icy street in a scarf, but at least some pressure is being taken off the system to deal with power-hungry air-conditioning systems.