Scientists shortlist chemical solutions for sustainable power
With the world’s hunger for energy expected to rise by 60 per cent in the next 25 years, consumers should be crying out for alternative sources that cut carbon emissions. But, as chemists heard at a recent RSC conference, scientists still face huge hurdles in marketing cleaner energy to the public.
’The problem is that cleaner energy alternatives don’t provide new services - they have to compete against fantastic existing technologies,’ explained BP’s chief scientist Steve Koonin at the conference, ’Future Energy - Chemical Solutions’, held in Nottingham, UK. Koonin - profiled in this issue - predicted that, despite scientists’ best efforts, liquid hydrocarbons, coal and gas will still dominate transport, heat and power, for decades to come, simply because they are such cheap, readily available sources of energy.
Only carbon capture and storage or the nuclear industry can make a large-scale impact on cutting carbon emissions in the next decades, Koonin remarked. And then, only if emitting carbon dioxide was associated with a price tag - something between $30 and $40 a tonne.
Chemists agreed that the challenge isn’t just about developing cleaner energy technologies; they also have to be marketed to a public with very little appetite for expensive energy. ’It’s a sad fact that we pay more for a good display screen than for a fundamental energy-generating device,’ said Sir Richard Friend, of the University of Cambridge, UK. Friend is trying to develop photovoltaic cells made from organic semiconducting molecules. He can only afford to do this because the same kinds of molecules have already proven hot property in LED display screens and in electronic ink (Chemistry World April 2007) - commercial by-products for which Friend is thankful, as their success has driven fundamental research in the field.
The same story has already been seen with lithium batteries, where speedy improvements have been driven by mobile phones. Only after this commercial success could they be touted as one of the top candidates for future electric vehicle transport.
Other energy technologies have not been as lucky. Tony Bridgwater, manager of the UK’s Supergen biomass and bioenergy consortium, lamented wryly that liquid pyrolysis - the rapid high temperature conversion of biomass or coal into a black oil-like liquid - has had only one minor commercial success: not in providing pricey bio-energy, but in producing the ’liquid smoke’ used to give meat a barbecue flavour.
Friend recommended that chemists should actively seek out commercial products from which they might leapfrog into energy research. For example, he noted, printing his semiconductor molecules on plastic, bendable substrates might produce lightweight power sources for portable electronic games. Ultimately, the improved performance generated by this demand might then reduce the cost of making solar cells.
Delegates agreed that chemists shouldn’t have to struggle alone to promote cleaner energy - regulatory policy needs to force the change. Just as car pollution was reduced by mandatory regulation on catalytic converters, governments could quickly open up markets for hybrid cars by demanding reductions in exhaust emissions, pointed out David Carslaw of the Institute for Transport Studies, University of Leeds. But forcing consumers to be more efficient by policy measures doesn’t always save on energy use, warned Matthew Leach, of Imperial College London. Historically, making cars more efficient has just allowed manufacturers to waste the saved energy by providing bigger, more luxurious vehicles for the same cost.
Getting off the bench
The conference attendees, from around twenty institutions, picked over a dazzling array of chemical solutions for cleaner energy: whether from microbial fuel cells which can generate power from wastewater; actinide separation technology to improve nuclear waste recycling; new nanocatalysts for speeding up hydrogen-generating reactions; or carbon capture and storage studies.
The quest for a safe, efficient hydrogen storage material remained a central theme, with researchers concentrating on new lithium nitride/borohydride complexes, but still keeping an eye out for the possibilities of porous metal-organic frameworks (MOFs). Martin Schroder, of the University of Nottingham, claimed a new record for stuffing the greatest concentration of hydrogen into a MOF, at 7.8 percent by weight (though only at a chilly 77K). ’Up to two years ago, I’d have said 77K was too low for practical use. But the advice we are getting is that cryogenic cooling might be possible,’ he said.
But while chemists work on innovative energy research, cautioned David Vincent of the Carbon Trust, they should be aware that this is only a small part in the development of a consumer product. ’It’s no good getting the right answer at the bench - you have to push that through,’ he said. And Koonin stressed that chemists should focus all their efforts on the most promising energy solutions. As he put it: ’There are no silver bullets, so we have to pick the bullets with launch calibre.’
Richard Van Noorden