Uncharted Territory

February 29, 2008

The Icarus Project

Filed under: Aviation, Energy policy, Global warming — Tim Joslin @ 2:08 pm

There was an excellent Cambridge Energy Forum (CEF) meeting on aviation yesterday. As someone said there, it’s astonishing that flying is now a sin. Is this really justified? Do we all have to stop flying? How can we reduce carbon emissions from flying?

It turns out that some work is already taking place to develop (small) aircraft powered by electricity. This could be scaled up, or a development path via hybrids to minimal reliance on liquid fuels.

I drafted the rest of this post in response to an email before the meeting, but nothing was said there that changes my mind – I’m now just somewhat better informed!

I intend to address the thorny issue of aviation in the book I’m (slowly) writing. I don’t agree exactly that the aviation industry should create technologies such as CCS (companies, in my view, should do what they do best), but it should certainly pay for them.

There is a clear economic problem to be overcome if the goal is to reduce carbon emissions from flying. If you just put a price on carbon, or on fossil fuels for that matter, then you introduce disincentives for different activities disproportionately, because, (among other reasons) fuel costs are a different proportion of the total cost of different products and services.

Consumers would still quite happily fly at a carbon cost of $100s per tonne [as was pointed out at a recent CEF talk, if I recollect correctly], but at such levels people would be switching away rapidly from other uses of carbon fuels, e.g. road transport, power generation. Incentives for suppliers to introduce technological changes depend on (inter alia) (a) competition from substitute products – for long-haul flights this will only become significant at a very high price for carbon (for business travellers, the cost would surely have to be $1000s/tonne) and (b) the availability of alternative technologies and the cost to introduce them. It is politically impossible to go straight to a carbon cost of $100s. Therefore, if we simply put a (gradually increasing) price on carbon, the aviation industry will continue to grow for some decades. George Monbiot reaches a similar conclusion, I believe, just by considering possible alternative technologies (an incomplete argument). If the policy agenda is to simply impose a flat cost on carbon emissions, then, by 2050 (say), the global economy will be hugely dependent on an unsustainable mode of transport, making it difficult to achieve further emission reductions.

So we have two distinct reasons for taxing aviation emissions more than other emissions:
(1) the additional Radiative Forcing of aviation emissions (because they take place at altitude);
(2) the need (because of the urgency of the GW problem) to encourage technological innovation in aviation and the development of substitute products (high speed rail, etc.) in parallel with, rather than after, other technological changes (such as the decarbonisation of power-generation and road/rail transport).

It seems to me that it is therefore a no-brainer to impose additional costs on aviation emissions beyond a carbon cost proportional to emissions. It seems logical to use these to pay for CCS, the idea being that once we reach the point where we can afford zero net anthropogenic GHG emissions, the aviation industry will have to pay to capture a multiple (based on the scientific assesssment of the damage of high-altitude aviation emissions) of its GHG emissions (though such an equation would not be climate neutral). Obviously the carbon sequestered shouldn’t come ultimately come from fossil-fuel burning, that would be double-counting, i.e. aviation has to pay for both extracting carbon (and/or other GHGs) from the atmosphere and sequestering or destroying these GHGs.

I wouldn’t completely write off the possibility of decarbonising aviation, though. There are certainly a lot of efficiency savings that could be made (I guess we’ll hear about some of these later today), but, apparently, experimental entirely solar-powered aircraft have been built. My idea (OK, just a thought-experiment to support my argument for the possibility of zero carbon aviation) is to increase the energy available to aircraft by putting up a few (thousand) satellites with computer-controlled solar reflector arrays (any old orbit will do, computers will be able to deal with the problem). Solar-powered aircraft would book slots for satellites to focus light on them (note the word “focus” – nothing below or above the aircraft need get fried). Just an idea, but maybe it could reduce emissions at altitude, which is where you want to get rid of them. (There is also a multiplier effect to be exploited, since, with an external energy source, an aircraft could fly higher for a given onboard fuel to payload weight ratio, reducing air resistance. Also, we should be able to focus a lot of light on solar panels on top of an aircraft, since the surface would be air-cooled). At the airport, an alternative way of using external power would be to accelerate aircraft using electricity (why stop at towing them to a stationary stop at the start of the runway?), e.g. maglev ought to be able to get you to take-off speed. Obtaining power this way during landing could be tricky, though, but maybe after the recent incident at Heathrow, it might be a good idea to develop non-powered landing techniques purely involving drag and braking, anyway! I’m a bit surprised, really, that carbon-fuel free flying isn’t one of the 14 great engineering challenges: http://www.networkworld.com/community/node/25219

Campaigning to prevent runway development is not the way forward, IMHO, since:
(1) It’ll simply displace economic activity that causes flying, i.e by the Displacement Fallacy, the available fuel will simply be used in China, India, Africa… rather than UK.
(2) It may have unintended consequences and reduce opportunities for efficiency savings.
(3) It second-guesses where technological breakthroughs will occur – i.e. what if we manage to decarbonise flying before, say, shipping, and are left without enough airport capacity?
(4) It pisses people off, motivating political opposition (and I’m sure there will always be people who want to do less about GW than others).

My alternative proposal would be to turn airports into more general transport interchanges, adding high-speed rail connections to take advantage of the existing local transport infrastructure that currently only supports air-travellers. This would encourage people to switch transport modes, perhaps initially for part or one leg of a journey. Btw I worked out recently that you could save around 10%, on average, of total journey carbon emissions if you simply got people to take the train rather than drive to Stansted. But I bet you FoE et al would object that improving rail services from, for example, Cambridge to Stansted would “encourage people to fly”. But I’m starting to digress…

It seems to me that a practical first-step would be for (say) the EU and US to get airlines to fund CCS trials, either via a levy/tax or through a voluntary agreement with the industry. We need to know a lot more about the viability and likely costs of CCS, ASAP. There are huge policy implications if the potential of CCS has been overblown (or understated, but that’s never happened before in the whole of human history for a technology at this stage in its development!).



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