Solar panel energy payback: What’s the truth?

a loop One of the myths that gets bandied about a lot is the idea that it takes more energy to create a solar panel:  through mining, transport, manufacturing and distribution, than will ever be generated by that solar panel over its lifetime.

20 years ago that was a valid argument against solar power. However in 2012 that myth is pure BS. Hopefully this post can set the record straight.

How much Energy is required to make a solar power system?

The process of creating solar panels, like any manufacturing process, requires a number of inputs.  The fundamental ingredients that make up a solar cell include the minerals silicon, aluminium and gallium. These must be mined, smelted and transported to the factory where they are assembled into a complete solar panel.  After assembly the solar panel must be transported to a local, Australian distributor, then onto the installers and finally your roof.

And don’t forget that there is more to a solar system than just the panel. More energy is consumed in the manufacture of the wiring and the inverter.

Andrew Moore from PE International, in a 2010 Australian study found that the production of the solar panels account for 85% of the manufacturing energy that goes into a solar system. The solar inverter amounted for 7% of the energy and the framing and wiring 4%. The remaining 4% came from transport.

Feeling guilty about shipping your premium solar panels over from Germany?

Don’t! To ship a panel from Germany to Australia only adds 2% to the energy required to make a complete solar system compared with getting a locally made panel!

What is the energy payback period?

All this talk of mining, smelting and transportation has probably got you wondering how those panels on your roof could possibly pay back the energy made to produce them. Well, get this: our pal Moore found that PV systems installed in Australian cities paid back their energy debt accrued in production in 1.7 to 2.3 years depending on which city they were installed in.  A solar panel installed in sunny Perth would pay back in 1.7 years. In not-so-sunny Hobart it would take 2.3 years. I reckon those are pretty good numbers.

How much Greenhouse Gas is emitted per kWh of solar electricity produced?

Moore also calculated that, taking into account the energy used in manufacture,  electricity from solar panels emitted 96% less greenhouse gas than grid electricity that is generated from coal.

So there you have it – solar power really does make sense from a whole-of-lifecycle perspective. And your average solar panel system produces less CO2 averaged over its lifetime than your farting cat (probably).

And as technology improves and the efficiencies of the solar cells increases, the energy paybacks are only going to get better.

If you going solar now you really are contributing to a virtuous circle. Buying solar supports the ongoing development of the technology – which increases the performance and reduces the cost of future solar panels. Someone should tell Clive Palmer and his pals…

References:

Bourzac, K. (2009). Mining Fool’s Gold for Solar. Technology Review, 112(6), 80-82.

Moore, A. (2010). The solar lifecycle test. ReNew. 109, 46-48.

About Finn Peacock

I'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and founder of SolarQuotes.com.au. My last "real job" was working for the CSIRO in their renewable energy division.

Comments

  1. Interesting article, thanks for debunking this myth!

  2. weterpebb says:

    Two references are given for this calculation. One is not available on-line at all, the other requires me to pay money to look at the issue containing the article.

    Is there nowhere on the internet that does this calculation which doesn’t require me to pay money upfront to find potential errors?

    Because unless we can see the assumptions made in the studies we can have no way of determining if they are correct. So its just your word. Again.

    • weterpebb,

      In the million to one chance you really care about backing up your arguments with the truth you can 1) get off your chair and go to the library 2) pay a handful of dollars to see proper peer-reviewed literature.

      • weterpebb says:

        So there is no public site anywhere on the internet that shows that PVs produce more power than is consumed in their production? That you know of?

        But that still doesn’t explain the absence of the “ReNew” article which you claimed as justification. I searched the site for the article, but couldn’t find it anywhere. Do you have a direct link we could look at? (I did wonder why you linked to the organisation, not to the article you cited as a reference.)

        All very odd. There must be a bazillion internet sites dealing with solar and renewable energy, but not one of them that you know of manages to show that PVs actually produce more energy than is consumed in production. Except for a “ReNew” article, and that has mysteriously vanished.

        To see this claim of yours justified, apparently I have to go to a library. Which book should I ask for, to see this calculation?

        And this is very important. If PVs consume more energy in production than they produce in operation, they are a very terrible idea. Perhaps you should put the record straight by actually supplying the calculations which show PVs produce more energy than they consume, as this calculation currently doesn’t exist on the public internet at all?

        • “To see this claim of yours justified, apparently I have to go to a library. Which book should I ask for, to see this calculation?”

          As per the citations above ask for:

          Technology Review (Published by MIT press) issue 112(6), page 80-82.

          ReNew Magazine. (Published by the ATA) issue 109, page 46-48. Also available for sale from ATA.org.au

          • weterpebb says:

            Neither would be carried by my local library.

            You claim that PVs produce more energy than they consume, but provide no data to substantiate the claim. To see if what you say is correct, we have to pay money to buy articles which may or may not support your position.

            This is because according to you, you know of no website which doesn’t cost money to access which shows that PVs produce more energy than they consume. As you provide no publicly available sites at all, it is very unlikely that anyone will bother checking what you say. Bit like where you claimed that PVs were already cheaper than grid, but the link you gave was not to the calculation but to the organisation which made this claim, with the actual calculations nowhere to be seen. You did almost exactly the same with your claim that domestic solar costs $0.12 per kWh; again your reference was to an organisation’s website, with the actual article nowhere to be found.

            It is a recurring pattern. You make some dodgy claim, put a link in as reference, but the link doesn’t actually reference the claim, it is just a link to an organisation’s website. And the actual article and claim is nowhere to be found on the website.

            But something I still don’t understand. As this is a critical question affecting the whole feasibility of PV as a replacement for grid power, why does Mr Moore make people pay to read his article? Why hasn’t one of the millions of PV supporters actually put the calculation up on a website? Why don’t you?

            As I said, most odd. I can find public internet sites which detail the construction of nuclear weapons, I can find public internet sites which show how cats can fit into different size jars, I can find internet sites which claim that aliens live amongst us, I can find internet sites which prove the earth is flat and 9/11 was done by the CIA, but according to you there are no public internet sites which show that PVs actually produce more energy than they consume. If only websites which show PVs produce more energy than they consume in manufacture were as common as those claiming that the earth is only 6,000 years old, it would be easy to verify (or otherwise) your claims. But no …

          • “The eye sees only what the mind is prepared to comprehend.”
            ― Robertson Davies, Tempest-Tost

            If you invest 3 seconds in a Google search you would find:

            http://spectrum.ieee.org/green-tech/solar/how-free-is-solar-energy (more commie engineers!)

            http://greenenergyoptions.com.au/wp-content/uploads/2013/02/renew-article.pdf (I saved you $5!)

            Amongst another 65,000 pages – most of which explain how quickly a modern solar panel will repay its energy debt.

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