Using Sunlight to power all our energy consumption

reposted from Edge.org Chris Street highlights in bold

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ALUN ANDERSON Senior Consultant (and Former Editor-In-Chief and Publishing Director), New Scientist The Sunlight-Powered Future I'm optimistic about…a pair of very big numbers. The first is 4.5 x 10ˆ20. That is the current world annual energy use, measured in joules. It is a truly huge number and not usually a cause for optimism as 70 per cent of that energy comes from burning fossil fuels. Thankfully, the second number is even bigger: 3,000,000 x 10ˆ20 joules. That is the amount of clean, green energy that pours down on the Earth totally free of charge every year. The Sun is providing 7,000 times as much energy as we are using, which leaves plenty for developing China, India and everyone else. How can we not be optimistic? We don't have a long-term energy problem. Our only worries are whether we can find smart ways to use that sunlight efficiently and whether we can move quickly enough from the energy systems we are entrenched in now to the ones we should be using. Given the perils of climate change and dependence on foreign energy, the motivation is there. Can it be done? I'm lucky that as a writer I get to meet some of the world's brightest scientists each year, and I know that out there are plenty of radical new ideas for a future in which sunlight is turned straight into the forms of energy we need. Here are just three of my favourites out of scores of great ideas. First, reprogramming the genetic make-up of simple organisms so that they directly produce useable fuels (hydrogen, for example). That will be much more efficient than today's fashionable new bioethanol programs because they will cut out all the energy wasted in growing a crop, then harvesting it and then converting its sugars into fuel. Second, self-organizing polymer solar cells. Silicon solar cells may be robust and efficient but they are inevitably small and need a lot of energy to make. Self-organizing polymer cells could be ink jetted onto plastics by the hectare, creating dirt cheap solar cells the size of advertising hoardings. Third, there's artificial photosynthesis. Nature uses a different trick from silicon solar cells to capture light energy, whipping away high-energy electrons from photo-pigments into a separate system in a few thousand millionths of a second. We are getting much closer to understanding how it's done, and even how to use the same principles in totally different nano-materials. But what of the pessimist's view that we can are just too entrenched in our current energy systems to change? There is a world-wide boom in investment in green technology already under way. And there are many transition technologies coming into operation that enable practice runs for more radical genome reprogramming and creation of new nano-structures. Although the consensus view is that the sunlight-powered future won't be taking over until 2050, I'd place an optimistic bet that one of the many smart ideas being researched now will turn out to be an unforeseen winner much earlier.