MACHINE TO TAKE CO2 OUT OF AIR?

This article in ScienceDaily and this link describe 'a simple machine' being developed at university that could, if multiplied across the planet, remove billions of tonnes of carbon-dioxide from the atmosphere.

Richard Branson, head of the Virgin Group, has offered a $25 million prize to anyone who can devise a system to remove a billion tonnes of CO2 per year from the atmosphere for at least ten years.

The Calgary device consumes 100kWh for every tonne of carbon-dioxide it removes. The prototype removes 20 tonnes a year. So 50,000 devices of the same capacity would be needed to win the Virgin prize, and would consume 5GWh/year of electricity.