Sunshine to Petrol, while conceptually interesting, seems to me is flat out a waste of effort.
the concept is that it focuses light onto a box of CO2 and water and eventually produces something useful, theoretically a liquid fuel. the mechanics, chemistry, and physics behind it is probably very interesting. but, in the end, what are we left with? an ugly, expensive, and inefficient tree replacement.
except that trees also produce fresh water (by causing rain), reduce climate variability (by increasing humidity, shade, and reflecting a lot of sunlight energy), improve the beauty of an area, efficiently recycle themselves, can act as long term or permanent CO2 traps, can provide a wide range of other useful products, can support wildlife, filter the air, reduce erosion, and can be virtually free to produce.
so, what i want to know is who is doing research on reforestation? what it would take to reclaim the Sahara? how much new forest would it take to absorb the total amount of CO2 that we put in the atmosphere each year? as a form of carbon sequester, how much is an acre of rain forest worth?
these sorts of efforts are the definition of growing the pie because they actually increase our resource base.