Graph Of The Day: Super-Sizing Rooftop Solar Systems

May 28th, 2013 by Giles Parkinson

This post first appeared on RenewEconomy

It was just a few years ago when a modest 1.5kW rooftop solar system – the equivalent of around six panels – was the norm for Australian households.

How that is changing. As today’s Graph of the Day – courtesy of Warwick Johnston’s Sunwiz Consulting – shows, barely 10 per cent of the rooftop solar systems installed in Australia now are of that size.

Already, the average size of a rooftop solar system around the country is 3kW – and many of the new systems are well above that. According to Johnston’s data, 5kW systems are now the most popular in the progressive “solar” states such as Queensland and South Australia – while 3kW remains the most popular in NSW and W.A. That is probably a reflection of the tariffs paid for exports to the grid.

Of course, Australia still has some way to go to catch up with the US – where according to SunPower, which specializes in solar leasing products, the average size of rooftop solar systems has gone to 8.3kW.

That’s got something to do with the size of the roofs, and also the tariff measures. Most places in the US get a 1:1 tariff, so the incentive is there to put on a larger system.

“That’s a really big system,” Sunpower’s products chief Jack Peurach conceded during an analysts briefing earlier this month. “You are putting as much PV on your roof as you can, but you are putting it there because you want to generate as much electricity as you can. And you do that because it’s cheaper.”

Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.

Tags: Australia, Australian households, Graph, rooftop solar system, Sunwiz Consulting, Warwick Johnston

About the Author

Giles Parkinson is the founding editor of RenewEconomy.com.au, an Australian-based website that provides news and analysis on cleantech, carbon, and climate issues. Giles is based in Sydney and is watching the (slow, but quickening) transformation of Australia's energy grid with great interest.

Ian Arnell

great graph! This will really help illustrate to people just how much solar has changed from their perception of it. No longer is it gigantic bulky systems. They can do so much with sleeker and smaller panels now
- James Wimberley
  
  Oh? The efficiency gains have been slight, so the output per square metre hasn’t changed much. Weight is down by more and the packaging in better.
  - Ronald Brak
    
    Nani? There’s been a significant improvement in average efficiency since 2008. I’d look it up but I slept in and now have to get into a diseased filled tube to get into town instead of walking.
    - James Wimberley
      
      I’m going by the NREL chart of record efficiencies for each cell type. Multicrystalline silicon, the workhorse, has been stuck near 20% for a decade. Production modules are less efficient but you’d expect the gap to lab stuff to be fairly constant. The rapid gains in efficiency have been in high-end multijunction cells, which sell to the Pentagon and NASA for prices out of your or my pocketbook; and at the bottom end, in cheap organic and dye cells, which are catching up from a low base.
      - Bob_Wallace
        
        I’m not sure that’s the data you should use. Best/champion cells can be quite different from what is sold for use.
        
        I wouldn’t be surprised to find that commonly sold panels are much improved over the last decade.
        
        Best I recall my ~13 year old panels are around 12%. There are several on the market now that are 16%+ efficient.
        
        http://sroeco.com/solar/most-efficient-solar-panels
      - Bob_Wallace
        
        Thinking more about it…
        
        The best metric would probably watts per square foot.
        
        Back earlier, when cells were a lot more expensive, cells weren’t trimmed square but a roundish slice was used. That meant that some of the panel space didn’t contain collection material. If you look at pictures of older panels you’ll see diamond-shaped areas between cells.
        
        Going back even earlier, there was a lot of dead space in solar panels, as you can see with this 30 year old panel..
        
        .http://i2.wp.com/cleantechnica.com/files/2012/10/Martin-Halloway-with-his-30-year-old-solar-panel.jpg?resize=275%2C432
        
        And look at how much of the cell face is covered with connector strips. Those have been greatly shrunk over the years.
      - Ronald Brak
        
        That’s a chart of research results, which isn’t the same as what’s going on people’s roofs. It was technically possible to get 20% efficient solar cells 7 years ago, but no one was putting them on their roofs because of the expense. Nowadays it’s not uncommon for high end systems to have efficiencies of or close to 20%.