Well I'm hoping this might be part of that reason?! https://www.google.co.uk/amp/s/www.bloomberg.com/amp/news/articles/2017-02-01/buffett-s-rocky-mountain-to-test-biomass-that-may-cut-coal-use
I have a raft of AEG shares and am very keen on a bbboom if Buffets tests at the end of the year match the labs.