Next Generation Energy is managed and written entirely by Seed editors and expert guest bloggers. Read more about them The idea of stabilsation wedges is in favour; Joe Romm shows a nice picture in his last post. This shows up some interesting facts: Biofuels are only ever going to be a small part of a solution to CO2 abatement, even if you make very optimistic assumptions about how much land you can possibly use. Moreover, there's an interesting bit that Romm quotes that doesn't get highlighted enough. I've bolded it:
An ethanol wedge would require 250 million hectares committed to high-yield (15 dry tons/hectare) plantations by 2054, an area equal to about one-sixth of the world's cropland. An even larger area would be required to the extent that the biofuels require fossil-carbon inputs
What that is saying is that the standard measure is only considering the production of the biofuels; not the more sensible measure of (output-input). The same difference exists for fossil fuels, of course, but the output to input ratio is much larger in thier case. From what I've seen, the US ethanol-from-corn program is barely energy-positive: Energy yield from corn ethanol equals approximately 125 percent of the fossil energy used to produce it which would mean the wedge referred to above would require virtually all the worlds croplands, if done with corn ethanol (its better if you use sugar cane, though). But corn ethanol isn't an alternative fuel; its a boondoggle for farmers. James Hrynyshyn points out that "we're currently spending somewhere between 960 and 1700 US dollars for each tonne of CO2 not emitted". I'll point out that this is mad: the current price of emitting a tonne of carbon on the european exchange is about 25 dollars. Thats not even close. Even the rather wild-eyed direct capture of CO2 from air has a cost of about 200 dollars a tonne; anything that costs more than that is utterly pointless.
I'd be inclined to abandon the whole fiddly stabilisation wedges idea, and the entire biofuels programme, in favour of something that could actually work: very large scale photovoltaics. Forget putting these things on peoples roofs, which is just yet more small-scale fiddling. I don't have a coal-fired plant in my back garden and I don't particularly want a solar plant there either. Put very large arrays into desert areas. The US has the advantage of having such areas available. Europe doesn't, we'd have to be nice to the folk in the Sahara instead.
This idea has the advantage that it could actually supply all the energy we need, unlike biofuels which demonstrably can't. At todays prices they aren't competetive, but more research and mass production have the possibility to change that (even if Shell seem to have given up on them).I recommend David Mackays draft of his book Sustainable Energy - without the hot air for some thought-provoking and very numbers-orientated discussion of various possibilities.
Comments
Sounds like a great plan. I have a few quick questions. Even though you say that solar panel power plants at a large scale could not compete in the market place today, are you taking into account potentially large government subsidies? I guess I am wondering whether we could build such a massive solar grid right now if there was the political will and money? Would it cost more than the Iraq war has to make us energy independent through solar? If not, it sounds like a bargain to me.
Posted by: tuatara | July 22, 2008 7:46 AM
Coal-fired plants just don't scale down to back yard jobs (and you'd have to ship in coal etc; it's plainly silly), but photovoltaics work pretty much the same at any scale. You get the same power per square metre from 4 panels as you would from 4000. And it all goes straight into your home supply, so 500W from your roof is 500W you're not pulling off the grid.
Home solar isn't going to achieve a great deal all by itself, but it's a straightforward and measurable addition to the energy problem; why would you want to actively discourage it?
[To some extent I agree with you, and I was only over-pushing a point for emphasis. Solar scales a lot better than coal. However, industrially maintained panels are likely to be better cleaned, set at a better angle, and placed in places with more sunshine - William]
Posted by: Kagato | July 22, 2008 9:42 AM
Posted by: llewelly | July 22, 2008 10:34 AM
I can see the point about not discouraging local small solar generation, but based on my experience with solar hot water heating using a three square meter roof panel at 45 north latitude, the energy contribution is very small - it only was effective 3 months of the year. You need to generate locally on a large scale where the energy resource is abundant - deserts for solar, gorges for wind, forests and fields for bioenergy.
Posted by: tom quick | July 22, 2008 10:38 AM
The big question about large-scale photovoltaics is: how quickly can they be manufactured? (And then there are a lot of related questions about how quickly the upstream supply chain can be expanded, and what that does to prices...)
Posted by: Dunc | July 22, 2008 11:45 AM
Biofuels are not intended as a general purpose energy solution problem -- they're intended as a problem to the specific issue of transportation fuel, because with current technology transportation can't run off electricity.
Solve that problem, and biofuel becomes irrelevant.
Posted by: Anthony | July 22, 2008 1:20 PM
On solar power stations: Mali had one on the national grid sometime in the 1980s, but am not sure it is still operational.
On biofuels: ICRISAT has some interesting perspectives on non-corn biofuel here. Basically, they are favouring producing bioethanol from sorghum, which can be more efficient than from sugar cane, and biodiesel from Jatropha and Pongamia. Jatropha in particular grows well in semi-arid lands with rainfall below 500 mm/a (where corn cannot be produced). More details here.
Posted by: Babakathy | July 22, 2008 9:59 PM
"Forget putting these things on peoples roofs, which is just yet more small-scale fiddling. I don't have a coal-fired plant in my back garden and I don't particularly want a solar plant there either."
(I put in a more detailed post, but it seems to have hung up).
William: before you making sweeping statements like that, you need to talk to actual electric utility people in places like CA that have sun & rational PUC rules.... Some of this doesn't work anywhere, but here:
They *like* solar roofs.
They like anything that saves energy.
They like enough local generation and distribution to help knock the peak energy use down, and to lessen the costs of long-distance transmission. [Ignoring the powerplant and grid effects is like ignoring the cost of networks in a computer cluster.]
They subsidize CFLs.
They come and out do energy audits.
They support better building standards.
Their CEO Peter Darbee is very sharp and articulate.
Bottom line:
Efficiency
PHEVs and BEVs - I attended PLugIN 2008 tonite, but see especially GoogleIT. even thought CA isn oil state, we have extra reasons to go as electric as possible, i.e., pollution problems do to the climate and wind patterns.
Windfarms where they work
Big solar CSP farms off in the deserts, with some storage
Energy audit existing buildings, add solar PV where sensible.
Solar hot water (CA AB 1470 has a 10-year program to get 200,000 solar hot water heaters on homes and businesses)
Raise efficiency standards for new homes and businesses, solar materials as part of building construction, not addon. Lower-CO2 materials, smarter windows, etc, etc.
Obviously, we don't care about corn ethanol out here, but I wouldn't begrudge the Iowa folks that, if we could get corn subsidies to stop.
Posted by: John Mashey | July 23, 2008 2:24 AM
I'm sure this has been covered somewhere, but I've never seen a discussion of it - how would a massive PV array in the Sahara (say) be protected from dust and sand damage (both in storms and not)? Deserts are notoriously harsh on electrical equipment in general... Also, you mention the importance of proper cleaning in your answer to Katago, above; how would this be achieved on that scale in an African desert? These don't seem like minor issues to me (and nor does the political/sovereignty issue, tho I don't want to push the debate in that direction now).
[Probably fair points. Cleaning: well, people or machines would be employed to do it on a regulart basis. Storms... at this stage, I'm just the ideas man, don't expect details. Of course if this was a really huge array it would affect the local climate, not to mention covering up all the sand that would otherwise blow around. Politics is yet another matter -W]
Posted by: outeast | July 23, 2008 11:00 AM
Hmm, posts seem to keep getting lost. I'll try again, short.
[Don't know why they're getting lost. This is the first I've seen -W]
1) PV on houses is worth doing, at least in places like California, because:
a) It lessens the need for additional power plants, and probably even more important,
b) it lessens the need to build long-distance transmission, and here, it does so exactly when it is most important, i.e., when usage is heaviest on Summer afternoons, and when transmission lines are hottest... hence it avoids the need to use the least-efficient peak capacity.
[a) agree. Less sure there is any point in the UK. b) yes, but if we do solar-in-the-desert those lines need to be built anyway -W]
The local utilities *care* about this, but of course, they're icnented for efficiency, not just generating megawatts.
2) PV in Sahara: in big deserts, surely one would prefer solar thermal (CSP, fmany reasons. We have some already in the Mojave, and PG&E ha signed a deal with Ausra for more.
[Could be. Whatever works, really -W]
Posted by: John Mashey | July 23, 2008 7:29 PM
With a British (Yorkshire) wife, from experience, I indeed suspect that PV on houses is less relevant in the UK than in CA :-)
If somebody does solar in Sahara, you indeed need some serious HVDC.
Posted by: John Mashey | July 24, 2008 11:02 AM
I think the one thing that could make biofuels a more reasonable solution is going to algal sources, for which the consideration is not surface area but volume, with the depth determined by how deep photosynthetically useful radiation penetrates. Has that been looked at in detail?
Posted by: Lee J Rickard | July 24, 2008 12:32 PM
Lee:
Has it been looked at in detail?
Google: sunlight penetration depth
yes.
Posted by: John Mashey | July 25, 2008 3:13 AM
NEXT GENERATION ENERGY: THE BIGGER PICTURE Commentary on story.
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THE TWELVE BILLION GALLON ETHANOL QUESTION...?
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Posted by: howard stern | August 12, 2008 11:26 PM