U.S. scientists are finding an enormous amount of the lithium needed to green up the economy.

I'm David Brancaccio in New York.

There may be enough lithium to supply the world's demand for car batteries and much more sitting

under southwestern Arkansas.

The U.S. Geological Survey announced that finding yesterday, Marketplace's Henry Epp reports.

Lithium deposits under Arkansas could meet projected demand for electric vehicle batteries nine times over, the USGS says.

Lithium ion batteries are in lots of devices, but they're especially important

for EVs and hybrids.

As more companies rushed into the EV market a few years ago, prices for the metal shot up.

They've since dropped as more supplies came online and

EV demand growth slowed down, but lithium is expected to be an important

commodity for years to come and right now the US imports about a quarter of its lithium.

The vast reserves under Arkansas could change that and already companies like the fossil

fuel giant ExxonMobil have set up operations to get at these deposits.

That could be a challenge.

The lithium under Arkansas is in brines, meaning it's mixed with water.

Right now, lithium brines are usually brought to the surface then put in large pools where the liquid

evaporates. But Exxon and others hope to extract the lithium directly from the ground.

Whether that can be done cheaply enough for them to turn a profit remains to be seen.

I'm Henry Epp for Marketplace.

Last year, the Energy Department confirmed a separate vast source of lithium

in the geothermal region near California's salt and sea southeast of

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