Solargas would be a useful supplement to other carbon dioxide reduction measures, but is not a solution to greenhouse gas emissions on its own. The process of converting solar energy to synthetic fuel is inefficient. It is much simpler and cheaper to replace stationary fossil fuel use, particularly burning coal for generating electricity, with renewable energy, than fuel for transport.

Also with transport, there are easier measures than synthetic fuel, such as more efficient fuel use and use of electric power. As an example, building an inland freight corridor from Melbourne to Brisbane would reduce emissions. Trains are much more efficient than trucks, even when both are using diesel engines. Similarly, more use of public passenger transport (preferably electric powered, but gas is okay), reduces emissions from cars.

@tomw
You are right I should have highlighted that the proposed technology is designed to be used in situations where there are no ready made alternatives - in particular in aviation. The only alternative there is not to fly at all.

BAYGON, rail is an alternative to aviation in some cases. In July I flew into Guangzhou (China) and took the express electric train to Hong Kong. Unfortunately visas and the crowded Guangzhou metro make this less than ideal: http://blog.tomw.net.au/2015/07/hong-hong-to-guangzhou-by-train.html

If globally we invested more in rail especially the superfast rail version then aviation would be reduced to long haul flights. There is no reason why we should continue to build our domestic transport around aviation - it has killed small towns, demanded more expensive roads for the B doubles and made us dependent on fossil fuels.
All that said I still see a role for solargas - if for no other reason that it removes carbon dioxide from the atmosphere.

And here I was thinking K Rudd was the only person I knew stupid enough to think you could build a railway from Oz to China.

Fast trains are a total stupidity when they have to service small widely distributed populations. To build a fast rail system from Townsville to Perth would cost more that the entire aviation industry has cost since the war, & would lose a fortune, just as existing rail does.

Hasbeen, we can't build a railway from Oz to China, but China has already has a high speed network which Australians could use for part of their international trips. The idea would be to fly into southern China and then take the train for several thousand kilometers. As an example, landing in Guangzhou and taking the train to Beijing cuts 1,365 km (15%) off the flight.

As you say, fast trains are not viable for sparsely populated areas, like much of Australia. But Sydney-Canberra-Melbourne is one of the busiest air routes in the world and a reasonable case for high speed rail. Even Canberra-Sydney may be viable, when the political costs of building a second Sydney airport are taken into account.