Oil companies that are slow to shift toward cleaner energy source risk of being left behind as the world reduces carbon emissions, US energy secretary Jennifer Granholm said.

Her remarks today are the latest from cabinet members serving under President Joe Biden who are urging the industry to decarbonize. Granholm said diversifying would help the oil sector remain competitive over the long term, as the US steps up efforts to reach new commitments under the Paris climate accord.

"The bottom line is you have got to move," Granholm said today during an event hosted by news outlet Politico. "You cannot hang on and be the Kodak or the Blockbuster Video of the energy world. You have got to diversify."

Blockbuster and Kodak were household names in video rental and film but lost business as their industries went digital. The companies sought bankruptcy protection in 2010 and 2012, respectively.

The US over time will shift to clean electricity as it reduces carbon emissions, Granholm said, with a likely continued role for biofuels in hard-to-decarbonize industries such as air travel. Granholm said companies like ExxonMobil are offering proposals like a hub for carbon capture in Houston because they see where the world is headed.

"Some of the oil companies have decided that they are going to diversify and become diversified energy companies," she said. "The proof will be in the pudding. You do not want to just assume that somebody is greenwashing."

ExxonMobil, Chevron, BP and other major oil companies have urged the US to put a price on carbon emissions to achieve its climate goals. Biden has sought to increase an existing tax credit for carbon sequestration as part of a $2 trillion infrastructure plan named the "American Jobs Plan," but he has yet to embrace an economy-wide price on carbon.

"A lot of economists believe this is the most efficient thing to do, but this administration is not there yet," Granholm said. "They want to use the American Jobs Plan using the carrots that they have to incentivize and move away from carbon polluting industries."

Despite the lack of an existing price on carbon, Biden is "particularly interested" in evaluating whether to deploy a US border adjustment mechanism that would reflect carbon emissions, White House climate envoy John Kerry said last week during an interview with Bloomberg TV. The EU is considering its own carbon adjustment on trade, which could offset the economic incentive to shift carbon-intensive businesses outside of the trading bloc to avoid carbon pricing.