Last week, Wired magazine published its Top Ten Green Technology Ideas for 2008. Wired’s picks (in reverse order) are:

• 10 Floating solar power islands
• 9 New materials that capture and hold carbon for permanent sequestration
• 8 New anti-CO2 legislation
• 7 A new catalyst that combined with solar panels cheaply separates water into hydrogen and oxygen
• 6 T Boone Picken’s plans for a nationwide wind power grid
• 5 Resurgence of desert locations for large scale solar power
• 4 Obama appointing a green tech specialist to head the US Dept of Energy
• 3 New solar panel technology that enables gigawatt scale plants
• 2 The start of new distribution networks to support green transport technologies (battery sap stations recharging stations etc.)

Ideas 8, 6 and 4 are debateable as new ideas to my mind (and US-centric). While the solar technology and carbon sequestration stuff sound promising, the distribution network sounds premature.  I expect the existing transport support infrastructure (petrol stations and parking building will actually move quickly once one or two technologies start to dominate, and standards are agreed (such as plug/socket, gas fitting, etc).

Biofuel’s absence from the list shows that it’s not PC at the moment, which is a pity.  Biofuel from non-food crops such as coppiced willow, grown on marginal land, will increase forestation, stabilise landscapes, is carbon-neutral, and utilises existing technologies, distribution and infrastructure.

Ah, but what about the No 1 idea?  Believe it or not, it’s cement.

Cement? With all the whiz bang technologies in green technology, cement seems like an odd pick for our top clean technology of the year. But here’s the reason: making cement — and many other materials — takes a lot of heat and that heat comes from fossil fuels.

Calera’s technology, like that of many green chemistry companies, works more like Jell-O setting. By employing catalysis instead of heat, it reduces the energy cost per ton of cement. And in this process, CO2 is an input, not an output. So, instead of producing a ton of carbon dioxide per ton of cement made — as is the case with old-school Portland cement — half a ton of carbon dioxide can be sequestered.

With more than 2.3 billion tons of cement produced each year, reversing the carbon-balance of the world’s cement would be a solution that’s the scale of the world’s climate change problem.

Now I really like that one.  The world is embarking on a huge infrastructure build over the next ten years, and the BRIC economies will continue building like crazy for at least the next 25 years.  As roads are renewed, bitumen can be replaced with concrete.  I agree with Wired - in their list, this is definitely the No 1 idea. Let’s hope it can be quickly proven and rolled out.