User login
Contact
- anz at theoildrum dot com
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
Archives
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
GAIA Host Collective
Here's a reference to an excellent article suggesting that the energy payback time on PV production is surprisingly long (decades under some scenarios).
http://www.peakoil.org.au/news/energy_profit.htm
Lots of debate about how true this is (and I suspect it is much less true with the new thin film solar that is now appearing) :
http://www.bml.csiro.au/susnetnl/netwl58E.pdf
http://www.jeffvail.net/2006/05/valuing-elegance-annoyances-and.html#com...
http://www.jeffvail.net/2006/11/energy-payback-from-photovoltaics.html
http://www.teslamotors.com/blog2/index.php?p=29&
(Tesla also have a good graph of EROEI for various forms of solar power in one of their presentations, but I can't find it right now)
The US DOE says that the payback period for PV is between 2 and 4 years.
http://www1.eere.energy.gov/solar/myths.html
Thanks for the links.
I am picking my way through them. In doing so I came across Jeff Vail's concept of "the Price-estimated EROEI of PV" in which the energy invested is estimated by the cost of the PV and the energy return by the market selling price of the electricity produced.
I did the sums for my house and the payback time was 27 years.
PS. How do you manage to keep up with all this?
You can't use price to estimate EROEI. Price is not energy. Many things which use a lot of energy are quite cheap (eg Big Mac burgers), other things which use little or no energy are expensive (eg ocean views).
If you look at solar in terms of how long it takes to earn back the money you put into it, then solar looks very bad - but then, so does any other power source. Solar cells are just the worst of a very bad lot.
If you look at solar in terms of how long it takes to earn back the energy that was put into it, it looks pretty good.
Jeff Vail in one of the links above suggests that EROEI is a difficult number to measure and use of price is a simple approximation to the truth.
You only have to look at the wildly varying claims for the EROEI for PV (from 1 to 30+) to see how controversial the measure is. It is not easy to know who is correct
Measuring EROEI is notoriously tricky - Jeff did a few posts on the subject here at TOD too.
Cost based estimates have a lot of distorting factors, so they can be an interesting data point, but aren't the final word on the subject.
Here is another link I was searching for - see the table at the end for a comparison of different forms of PV (solar thermal - CSP - is another matter altogether - one with a much high energy payback).
http://www1.eere.energy.gov/solar/pv_basics.html
The glib answer is I don't watch TV.
In reality some of this does / has coincided with my day job (not much in my current job though) so I've got to do a lot of study on the various subjects over the years.
Running a couple of blogs on these topics helps to grind the stuff into my brain too - being told you are an idiot after publically saying something stupid from a position of pseudo-expertise does concentrate your mind somewhat.
Lastly, I get far less sleep than I need to - hence the occasional dips into incoherence...