'Solar' breakthrough reveals green ambitions

A reader points me at an energy story that comes larded about with exciting predictions. MIT Energy Storage Discovery Could Lead To "Unlimited" Solar Power!

A reader points me at an energy story that comes larded about with exciting predictions. MIT Energy Storage Discovery Could Lead To "Unlimited" Solar Power! Illustrated with a large picture of a solar cell array, it has a familiar, breathless style:

"The process, loosely based on plant photosynthesis, uses solar energy to split water into hydrogen and oxygen gases. When needed, the gases can then be re-combined in a fuel cell, creating carbon-free electricity whether the sun is shining or not. According to project leader Prof. Daniel Nocera, “This is the nirvana of what we’ve been talking about for years. Solar power has always been a limited, far-off solution. Now, we can seriously think about solar power as unlimited and soon.”"

Is this as exciting as made out, wonders my writer.

No. It is, however, curiously misleading.

What has been discovered, as far as I can tell. is a more efficient form of electrolysis using catalytic electrodes, using electricity to turn water into hydrogen and oxygen. This could lead – as with the headline, there's an awful lot wrapped up in 'could' – to a more efficient form of power storage. Which in turn could make domestic solar power more attractive, but that's as far as the solar angle goes. The photosynthesis aspect, implying as it does direct conversion of solar energy to electricity, is a bit of misdirection; the discovery would work just as well – or badly – with any form of generation, from hamster wheels to windmill generators on the chimney.

Whild the rather elderly original press release does mention other original sources of electricity, it doesn't talk about is the efficiency of the new process. There are no details either of how the new process is related to photosynthesis, which is a stupendously complex business (the curious should read Eating the Sun by Oliver Morton for an engaging look at the cogs) that in any case doesn't produce atomic hydrogen but oxygen – it locks the energy recovered from the sun into carbohydrates, which the plant uses for metabolism and we sprinkle on our cornflakes or burn in our cars.

Hydrogen is a much more problematic intermediate storage medium. The paper talks about using a fuel cell to turn stored hydrogen back to electricity, but this glosses over many interesting engineering challenges. And the fuel cell itself remain a technology still heavily laden with "could" in its own right: we are not invited to ponder how far the whole system has to go to compete with existing battery technologies. And "soon" apparently means 'in ten years', which in futurology code means "we have no real idea". At least they avoided invoking nanotechnology.

That there's some interesting science here, I don't doubt. That it may be useful is also true, but only for certain very badly defined values of 'may'. And that the key mechanism for splitting water is in some way related to some aspect of photosynthesis – well, yes, why not. Photosynthesis is extremely clever and does things we'd love to emulate.

None of this leads particularly to making solar power "unlimited and soon", at least not on the evidence in the press release. Perhaps the real energy source that MIT hopes to exploit by the production of such an optimistic story may be best detected in the final paragraph of that press release. See if you can spot it!

"The success of the Nocera lab shows the impact of a mixture of funding sources - governments, philanthropy, and industry. This project was funded by the National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make the large scale deployment of solar energy within 10 years."


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