Former Vice President Joe Biden repeatedly lied about his family’s ties to coal mining throughout his more than 40-year political career, but now wants to ban the energy source outright.

Biden, who has been known to exaggerate his own history for political reasons, told union mine workers in Castlewood, Virginia during the 2008 presidential campaign he was one of them.

“I hope you won’t hold it against me, but I am a hard-coal miner, anthracite coal, Scranton, Pennsylvania,” he said. “It’s nice to be back in coal country. It’s a different accent [in Southwest Virginia], but it’s the same deal.”

Biden, at the time a U.S. senator and the Democrat nominee for vice president, had traveled to the region to court union miners with the promise of “clean coal.” In order to sell himself and the Democrat ticket, Biden claimed a personal connection to the miners and their cause.

As Biden told it, his great-grandfather had been a mining engineer before his election to the Pennsylvania legislature. More interesting, however, the ancestor was also rumored to be the member of a secret organization working to unionize coal miners in the 19th century.

“He went out of his way to prove that he wasn’t, and we were all praying that he was,” Biden said.

The story, although touching to some, quickly failed to hold up to scrutiny, especially in light of an admission Biden had made during a 2004 interview with Jon Stewart. Speaking about the plagiarism scandal that destroyed his first presidential run in 1988, Biden had told Stewart he did not have any coal miners in his family.

“Hell, I might be president now if it weren’t for the fact I said I had an uncle who was a coal miner,” Biden told Stewart. “Turns out I didn’t have anybody in the coal mines, you know what I mean? I tried that crap — it didn’t work.”

The reference was to a speech Biden had plagiarized from Neil Kinnock, the former leader of the British Labour Party, during his 1988 race. In particular, Biden had lifted a line from Kinnock about how his ancestors worked in the coal mines, “and would come up after 12 hours and play football for four hours.”

After the lie came to light in 2008, Biden’s campaign attempted to dismiss his comment as simply a “joke.”

Underscoring the problem was that until being tapped as Barack Obama’s running mate, Biden had mixed record the issue of coal. In 2007, shortly after announcing his second presidenital campaign, Biden was asked during an interview with Bill Maher to rate coal, terrorism, and high fructose corn syrup in terms of which was more likely to kill “your average American.”

Biden, who often touts the fact that he authored the very first climate change bill in the U.S. Senate, responded by ranking coal a higher threat than terrorism.

“Air that has too much coal in it, corn syrup next, then a terrorist attack,” he said. “But that is not in any way to diminish the fact that a terrorist attack is real. … But hundreds of thousands of people die and their lives are shortened because of coal plants, coal-fired plants and because of corn syrup.”

Biden echoed a similarly tough line in August 2007, telling Grist he did not envision a role for “clean coal” — a phrase used to describe technological advancements that limit the pollution emitted through the excavation and burning of coal — if the country became energy independent, as his campaign pledged.

“I don’t think there’s much of a role for clean coal in energy independence, but I do think there’s a significant role for clean coal in the bigger picture of climate change,” he said. “Clean-coal technology is not the route to go in the United States, because we have other, cleaner alternatives.”

At the time, Biden elaborated he was willing to invest in the development of “clean coal” provided it was only “for export.”

His position, however quickly shifted when he joined the Democrat ticket. Obama had openly embraced “clean coal” while campaigning through Appalachia, Biden quickly adopted his position.

The transition, however, turned out to be only one of political convenience. At the second Democrat presidential debate last month, Biden implied he was in favor of banning coal and fracking outright if elected in 2020.

“We would make sure it’s eliminated, and no more subsidies for either one of those, any fossil fuel,” Biden said when asked if there would be any place for fracking and coal in his administration.

The former vice president followed up on that promise earlier this month when the told voters in Iowa he supported the “total elimination of fossil fuels” by 2050.