If Piebalgs gets his wish, then more biofuels will be produced in the world. Since he's against deforestation, that means more artificial nitrogen fertiliser use, which means more natural gas goes into that. So the production of ethanol drives the price of natural gas higher.

N-fertilizer is only about 2% of total natural gas consumption and it's not particularily difficult to produce from numerous other sources(E.g hydrogen from gasification + water gas shift of some corn stover, saw dust, bagasse, waste paper).