Hi Guys

SM I suspect you are right but notice my references to the vagaries of weather, especially in places like Oz. Bio-mass would provide all power needs if we say used ethanol powered fuel cells or could derive hydrogen from biomass easily [as other energy research is hinting] but it is a land-intensive and water-intensive way of deriving power. In Oz we could build EnviroMission's huge solar towers...

http://www.enviromission.com.au/

...setting up thousands of them to supply Oz's power needs, plus a bit for export. Low water costs and suited to dry hot conditions with zero fertiliser needs. Also has about the same power production efficiency as biomass. Start-up cost is heaps higher but in Oz we really need to start accounting for water costs properly - salination of farmland is becoming near catastrophic thanks to ground-water wastage via irrigation inefficiencies.

Adam

PS

Actually I am not too sure on those figures for biomass for energy production. I had read about 30 t/hectare, with about 30 Gigajoules per ton, which is only 0.3 % efficiency. A solar tower produces about 40 W/m^2, which is an efficiency of ~ 4%, and thanks to its thermal capacity it can put this out all night too.

In Oz we use about 10kW per person, which is 250 m^2 of solar tower, some 5000 sq km total for ALL energy needs. All Earth's population needs just (!) 1.5 M sq km to be given current Oz power supplies. 5 times current global average. Via Power Relay Satellites, Oz could become a global solar power farm to the world. Or Nevada. Or the Sahara... etc...