JediMaster, I agree that you need to look at the dust to dust emissions, and for me it makes a lot of the current debate surreal.

Everyone pretends that we can reduce CO2 emissions immediately when we have locked-in increased CO2 emissions because the industrial effort to replace our current energy sources will itself emit much more CO2. This will continue to be the case until you have sufficient renewable energy sources that they will be the source of the industrial output to replace existing hydro-carbon-fuelled sources.

If you really want to reduce Australia's CO2 emissions then stationary energy is the lowest hanging fruit, and you would replace it with nuclear, not with any of the other technologies.

I don't have a problem with the nuclear option, but if you were to replace our current generating capacity with nuclear you'd generate a lot more CO2 than you'd replace in the early replacement stages.

I understand that some solar panels actually emit more CO2 in construction than they save over their entire life, meaning solar panels may actually be increasing CO2 emissions, unless they are built using non-emitting power sources.

There are more "scams" going on than just in some of the science.

GrahamY: "I understand that some solar panels actually emit more CO2 in construction than they save over their entire life, meaning solar panels may actually be increasing CO2 emissions, unless they are built using non-emitting power sources."

You qualified it with "some", but unless "some" means insignificantly small I don't see how it can be true. There was myth that it costs more energy to manufacture a solar cell than it will produce. It is wrong: http://www1.eere.energy.gov/solar/myths.html (see myth 6).

In fact the energy pay back time for manufacturing is 1 to 2 years. http://en.wikipedia.org/wiki/Solar_cell#Silicon_processing With that sort of pay back, the claim that manufacturing solar cells produces more CO2 than it saves is possibly one of those scams you mention, perpetrated by solar's competitors.

Solar has enough problems with cost and the reliability of the sun without being tarred by that brush. The cost problem might be solved if the cost curve keeps on its current downward trend. It might happen (eg http://www.popularmechanics.com/science/research/4306443.html and http://www.physorg.com/news185093054.html ). That leaves the storage problem. The US seems to be happy to rearrange 5,700 km2 of mountains to to get at coal. 5,700 km2 of pumped-storage would probably solve it.

JediMaster: "I keep referring to my OLO essay of Oct 08 www.onlineopinion.com.au/author.asp?id=5695 where I spell out one possible way of looking at the problem"

What you show is replacing the current infrastructure would cost a lot of carbon. Undeniably, that is true, as replacing the current infrastructure costs energy, and we currently get our energy from carbon. But once replaced, the energy is CO2 free. Thereafter we can build as many solar cells, nuclear plants, wind turbines and what every else we want while only releasing the CO2 required to make the concrete.

So I didn't understand your point. It seemed like you were saying that a CO2 free future cost too much CO2. Obviously that makes no sense. If the climate models fanning AGW are correct, only the total CO2 emitted matters. Emitting more now so less is emitted over the long term is the right thing to do.

rstuart,
The way we are applying solar cells may be aggravating our problems.
I have seen it reported that the feedin tariff in Spain is major factor
in their deficit. This because the government carried the cost of the tariff.
Is the same being done here ?
I have always thought that the high gross feedin tariff was dangerous
and must have a short lifetime.

GrahamY and rstuart

We are now getting closer to the heart of the matter.

I raised the issue of the "front-loading" problem with the Garnaut committee. They didn't seem to understand that a rapid and heavy investment in new energy sources (for this purpose it doesn't matter if it's solar or nuclear) would actually increase the level of carbon emissions- even if the rate of emissions dropped later with emissionless electricity generation. It's analogous to increasing short-term debt levels so that you can increase long term profitability. The lenders may set a threshold for your borrowing for prudential reasons analogous to CO2 atmospheric thresholds. I personally didn't think that this was rocket science.

Thank you for your references rstuart. All of them use the same limited methodology to which I refer in my paper- it is life-cycle "process energy", but not total value-chain energy- it does not take into account the energy cost of the infrastructure,or what energy is consumed in making the things purchased by the wages etc. An analogy would be to say that bank interest should only be a tiny fraction over the Reserve Bank borrowing rate because the marginal cost of my electronic transaction is very tiny. But banks have to also pay for the ATM, the building, the staff, executive perks etc, not just the tiny direct process cost.

As I said, until a comprehensive, global input-output net energy analysis is performed, I would prefer to stick to the dollar-trail. It's looking pretty good for renewables- even without subsidies.

rstuart, only one of those links says anything about the amount of CO2 used in manufacture of solar panels versus the emissions they save over their life time, and then it doesn't offer any evidence.

I admit I can't find a link to my information, which was a Chinese university study, but I'd want to go beyond a bland assertion by a US government body that the payback period is 4 years, but will shortly be 1 year!

And I'm used to reading a lot of these official studies and seeing what information they leave out. There must be some serious academic or industry work around about this, and not just from boosters of the solar products. Any explanation that relies on projections forward to make its point is flawed for a start.

I was doing Young Liberal policy papers back in the 80s about how great solar was and how the costs were coming down. I know better now.

Maybe JM has some papers we can look at. Or I might be able to find my Chinese info, if I can find the time.

GrahamY
"There must be some serious academic or industry work around about this, and not just from boosters of the solar products."

Yes- you'd think, considering the serious and fundamental nature of the problem of net energy analysis, that someone, somewhere, would have sorted it out in a defensibly scientific way.

The University of Bath has been working on the Inventory of Carbon & Energy (ICE) for some time.https://wiki.bath.ac.uk/display/ICE/Home+Page It is a pretty comprehensive document, but again, is only process-chain energy.

I had some discussions with Charles Hall of SUNY last year- check out his extensive articles on "Why EROI Matters" in The Oil Drum http://energyandourfuture.org/node/3786. Hall told me that for a few million dollars they could sort it all out- but grants for this kind of work are very hard to come by.

So- if you read any claims about energy payback periods- which are a close proxy for carbon emissions- ask the claimer how they derived their data. Most of the analyses are incomplete process chain jobs. In principle,it is easy to reduce the (apparent)process chain energy use by exchanging on-site energy consumption for energy embodied in infrastructure or labour.

But Graham- renewable energy prices ARE dropping- without the subsidies. Solarbuzz (http://www.solarbuzz.com) is a very good commercial site which produces detailed stats on the solar industry. The noughties saw prices static because of silicon supply bottlenecks. These problems are now clearing and module prices are declining rapidly http://www.solarbuzz.com/Moduleprices.htm.