After a first search, I think you mis-remember what you heard. I find Gabriel argued with higher CO2 emissions in the debate over Steinkohle vs. Braunkohle in the distribution of 2008-2012 emission certificates -- correctly saying that sub-bitumenous coal has higher CO2 emissions per electricity generated.

But I search further, maybe he did say it about nuclear, too.

_{*Lunatic*, n.
One whose delusions are out of fashion.}