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Payback time of PV and other micro gen technologies

I have heard some vastly different estimates of the payback time for various micro generation technologies. I am currently reading Heat by George Monbiot and he claims the financial payback time for domestic PV is 35 years. This in the UK where the government subsidies are different and the average solar radiation is less than Australia. The source for this claim is an article in Energy Policy (RMIT access only). This same paper claims a 14 year payback for micro cogeneration systems.

Monbiot is extremely critical of micro wind turbines, claiming that they will cause more problems than they solve and would only be capable of generating 5% of a household’s electricity requirements.

Last night we heard from Bill Proudfoot who claimed a payback time for PV’s of 15 years. I don’t remember if he mentioned a payback time for micro cogen systems.

In terms of energy payback I have heard figures of 2.5 years for PV. But i have also heard people claim that they never payback the energy they consume in production.

Does anyone have some more reliable figures relating to energy and financial payback times?

Comments 6

  1. adam wrote:

    hey Iain,

    Check out this generally favorable summary of the research from the (first published in excellent but sadly now finished CSIRO Sustainability Newsletter):
    http://www.energybulletin.net/17219.html

    There are questions to be raised about any energy accounting system, there are *so many* hidden fossil fuel subsidies, and so methodology or setting different system boundaries can produce very different results. Jeff Vail introduces these issues in an essay at The Oil Drum, you might be interested in:
    http://www.theoildrum.com/node/2892

    Best, Adam

    Posted 20 Sep 2007 at 10:24 am
  2. iain wrote:

    The CSIRO report presents an excellent summary of the energy payback times. Have you seen any similar information on economic payback in Australia?

    Posted 20 Sep 2007 at 11:20 am
  3. iain wrote:

    I should add that the CSIRO newsletter that Adam refers to gives an average energy payback for roof mounted PV of 4 years.

    Posted 20 Sep 2007 at 11:23 am
  4. Christian wrote:

    Hi Iain,

    I found this NASA paper that claims an energy payback time of as little as 3.8 years (abstract only)

    http://adsabs.harvard.edu/abs/1977STIN…7724581L

    Posted 20 Sep 2007 at 12:47 pm
  5. Christian wrote:

    Can I also suggest adding The Oil Drum, Robert Rapier and Energy Bulletin to the links

    Posted 20 Sep 2007 at 12:48 pm
  6. iain wrote:

    Hi Christian,

    I’ve already added energy bulletin. In fact adam (see above comments) is the guy who started up energy bulletin. I’ve now added The Oil Drum and Robert Rapier to our list of other blogs.

    cheers, Iain.

    Posted 20 Sep 2007 at 3:55 pm