Unquestionably they lead to fuel switching, that's the entire point to price carbon. So for sure, if you're pushing it for ideological reasons only and don't grasp the economics behind it you certainly run the risk that the fuel switched to is worse if there aren't any options there. I saw an interesting expose on Bloom fuel cells and the founder, who grew up in an undeveloped part of India so knows better, claiming that although they're effectively not viable in the U.S. at least because solar and wind fell down the price curve so much faster then expected, they are perfect for the developing world where electricity is so much more expensive. They run on natural gas....