Air travel - May 6
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How do you solve a problem like jet fuel?
David Strahan, Petroleum Review via Strahan blog
Say what you like about Sir Richard Branson, but you cannot fault his willingness to suffer in the cause of a photo-opportunity. At the launch of a recent Virgin Atlantic test flight to demonstrate a jet fuel made from coconut and babassu oil, the Virgin boss took a swig of the new biofuel from a coconut shell to drive home his message that aviation could be “truly sustainable” and endured the consequences, burping biofuel, for the rest of the event.
But then desperate times require desperate measures, and aviation is in a fix. First, the airline industry is rightly seen as the cuckoo in the nest of carbon reduction. Britain is now legally bound to cut CO2 emissions 60% to 65MtC by 2050, but under the government’s “best case” projection UK aviation alone will emit 15.7MtC in that year, almost a quarter of the economy’s entire carbon ration. According to the Tyndall Centre for Climate Change, if the additional “radiative forcing” impacts of aviation are taken into account, that figure could rise to over 100%. Either forecast is of course entirely unsustainable.
Second, aviation is uniquely exposed to peak oil. Whereas ground transport could in theory be completely electrified and run on renewable power, for jet engines there is no alternative to energy dense liquid fuels. And while soaring crude prices are already hammering airline finances at $110 per barrel, analysts Goldman Sachs now forecast potential spikes of $150-$200, a risk Sir Richard acknowledged during his biofuel launch...
(6 May 2008)
More at original.
If there is a God, he's not green. Otherwise airships would take off
George Monbiot, The Guardian
Many will cite the Hindenburg, but flying without harming the planet is possible. These craft are worth developing
... There are two reasons why we [environmentalists] make such a fuss about flying. The first is that, even as governments promise to cut emissions, everywhere airports are expanding. In the UK, the government expects the number of airline passengers to rise from 228 million in 2005 to 480 million in 2030. Before long, there will scarcely be a patch of sky without a jet in it. The other is that there are no alternative means of propelling people through the air which are not more destructive than burning ordinary aviation fuel. Or so we think.
The airline companies prescribe two cures that are even worse than the disease. Even before they are deployed commercially in jets, biofuels are spreading hunger and deforestation. At first sight, hydrogen seems more promising. If it is produced by electrolysis using renewable electricity, it's almost carbon free. The prohibitive issue is storage.
... Hydrogen's great advantage - that it produces only water when it burns - turns into a major liability: in the stratosphere, water vapour is a powerful greenhouse gas. The commission estimates that hydrogen planes would exert a climate-changing effect "some 13 times larger than for a standard kerosene-fuelled subsonic aircraft".
But there is another use for this gas, though I am aware that it will go down like a lead balloon with most of my readers. The word airship elicits a fixed reaction in almost everyone who hears it: "What about the Hindenburg?"
... Though the designs have changed, their disadvantages have not disappeared. While a large commercial airliner cruises at about 900 kilometres per hour, the maximum speed of an airship is roughly 150kph. At an average speed of 130kph, the journey from London to New York would take 43 hours. Airships are more sensitive to wind than aeroplanes, which means that flights are more likely to be delayed. But they have one major advantage: the environmental cost could be reduced almost to zero.
Even when burning fossil fuels, the total climate-changing impact of an airship, according to researchers at the Tyndall Centre for Climate Change Research, is 80% to 90% smaller than that of ordinary aircraft.
(6 May 2008)
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