I expect he is deliberately attempting to set a high end benchmark for which to strive for and then inevitably fail. At least it might get him a few headlines today (such as this article in the FT).
He should be careful to maintain at least some sense of credibility.
Gore seeks 100% green energy [FT]
The US should aim to generate all of its electricity from zero-carbon energy sources within a decade, Al Gore, the former vice-president, urged on Thursday.
In a speech in Washington he argued that only by making such a commitment could the US solve the pressing problems of the high oil price, the export of jobs abroad and climate change.
Note that US politicians seem the need to mention the dreaded "jobs" word to get attention.
The final quote of the mandatory "critic" that all newspaper articles need to throw in for balance sums is amusing and almost certainly true - which begs the question of "WHY".
“We couldn’t come close to [his] goal of producing all our electricity from solar, wind, and geothermal energy in 10 years without coercive, even authoritarian government.”