Received wisdom has it that when the price of oil goes high enough, the shift to alternative energy will be unstoppable. I now have my doubts about this. All higher oil prices really show in a very broad sense, is demand outstripping supply for energy. It does not necessarily show the demand for clean energy, especially as most of the scaleable off-the-shelf clean technologies are in the business of electricity, not transportation.

That's why I was very taken with a piece in the Financial Times a couple of days ago about the price of uranium. Unlike oil, I would suggest the price curve of uranium has shown more accurately the demand for clean energy (at least, not including the waste). And encouragingly, uranium price performance has easily outstripped that of oil.

Back in June 2003, uranium cost $10.90 a pound and in the last few weeks it has reached $136 a pound. A staggering ten-bagger commodity and I suspect, second to no other in the same time period. Presumably, there is a point when uranium becomes so expensive, the cost of the fuel is prohibitive to nuclear power. Unlike many people involved in alternative energy, I don't mind nuclear power, but this one scenario worth pondering. Just as we may surmise that oil which costs more than $200 per barrel will never come out of the ground.

With 74 nuclear reactors under construction and another 182 planned, it's hard not to see a lot of pent-up demand online for uranium. So if - and if it's a big if - the price of uranium makes some nuclear plants financially unviable, what then?

Arguably, for less wealthy countries like India thorium, which is at least 3 times more abundant than uranium and of course - the main reason I made this post - renewables. Renewables, because the fuel is free, wind, water, sun, tide, wave etc. offer greater price stability further into the future. And that zero fuel cost, although only a part of all the other costs, seems set to grow in importance as part of the alternative energy investors financial calculation.