On the 12th December, we went along to the Bath Science café, to watch Prof. Chris Rhodes give a talk on What Happens When We Run Out Of Oil? We actually managed to get a seat, these events are always packed out. Perhaps it should be moved to bigger premises? Anyway, this isn't an objective summary of the talk, it's infused with my own strongly held views!

Two things stood out in the talk. Rhodes explained that not all oil is the same. Light oil has low viscosity, and heavy oil has high viscosity (bitumen being the heaviest). On another axis, sweet oil is low in sulphur, and sour oil has high sulphur content. Rhodes reckons we've used about half of the total oil in the earth, but most of the stuff we've used is light and sweet, and most of the oil left is sour and heavy.

The thing is that light and sweet oil is easy to extract and use. Heavy and sour oil is hard to extract and refine. In the worst case (bitumen) it takes 3 barrels to extract 4 barrels.

The other thing that I hadn't properly realized was that wind turbines need rare earth elements (REE) in their manufacture. Rhodes says that China has 97% of the REE in the world, and they need all of that for their own turbines. He opined that scarcity of REE would be the thing stopping the expansion of wind turbines. Is that true?