I suspect (but have no definitive proof) that the energy saving from geothermal pre-heat would be negated by the cost in extracting it. Unless we used the famous hot water springs etc. it'd be cheaper to burn the extra ton of coal. Obviously worth investigating further though.
Aluminium oxide? Why not reaction bonded silicon nitride or zirconia, or a silica/aluminium borosilicate fibre composite? Good luck making pressure vessels out of that lot! Size of Canada and the cost of a space program.
I agree about infrastructure. CHP needs including in the planning stage (which is why we don't just cobble it on, of course). I reckon we could move away from the few, giant power stations to smaller, local units thus allowing infrastructure to be upgraded gradually.
Hydrogen is all very well providing you can get enough of it and, more importantly, extract it without expending more energy than the subsequent combustion will release. Doing both at once is the tricky part.
Feel free to write up those proofs as a word.doc and email them to me, I'd be very interested. As they say in poker, I'll see you.
