Someone found the key for the red semi parked in front of Toyota’s massive Plano campus on Tuesday morning, climbed into the cab and started it up.

It made a sound almost like a big fan — and then the noise stopped. The truck, however, was still running.

The group of Toyota employees standing nearby beamed.

“We can have a normal conversation as it’s running,” proudly noted Scott Friedman, a senior engineer. “If you tried to do this next to a typical diesel truck, we’d be yelling.”

The big rig was Toyota’s second iteration of a Class 8 heavy-duty truck powered by hydrogen. It had stopped on its way from Michigan, where it was assembled, to California, where it’ll join its older sibling, which has been hauling cargo from the ports of Los Angeles and Long Beach, Calif., short distances for roughly the past year.

They’ll be just two of thousands of trucks driving out of the ports each day. But Toyota hopes that number will climb in the not so distant future as the demand for zero-emission cars and haulers grows.

Instead of running on diesel, or on electricity, the trucks have hydrogen fuel cells, which use hydrogen that’s stored in the vehicle’s tank.

The problem is that hydrogen is hard to find at the pump. In Texas, it’s actually impossible because there are no hydrogen fueling stations.

In California, Toyota already sells its hydrogen-powered Mirai sedans — though one will run you close to $60,000. It was the first fuel cell car available to drivers.

But even California's relatively large network of hydrogen fueling stations (about 35 around the Golden State, with another 29 planned) can feel limiting. A Mirai with a full tank can drive around 300 miles, so a driver heading out for the day would have to have a pretty clear idea of where they could stop.

That, Toyota execs said, is why it makes sense to start out using the trucks for what’s known as drayage — or short distance hauling that typically involves trucks to start and end in the same place.

“You could have small, centralized refueling operations, and they’re all serving the port,” said Chris Rovik, executive program manager for fuel cell research and development.

1 / 5Chris Rovik, executive program manager R&D PDO - advanced fuel cell talks about the hydrogen fuel cell semi truck at Toyota Motors North America in Plano, Texas on Tuesday, August 21, 2018. (Vernon Bryant/The Dallas Morning News)(Vernon Bryant / Staff Photographer) 2 / 5Hydrogen tanks can be seen in a hydrogen fuel cell semi truck at Toyota Motors North America in Plano, Texas on Tuesday, August 21, 2018. (Vernon Bryant/The Dallas Morning News)(Vernon Bryant / Staff Photographer) 3 / 5Chris Rovik, executive program manager R&D PDO - advanced fuel cell talks about a hydrogen fuel cell semi truck at Toyota Motors North America in Plano, Texas on Tuesday, August 21, 2018. (Vernon Bryant/The Dallas Morning News)(Vernon Bryant / Staff Photographer) 4 / 5Hydrogen fuel cell semi truck at Toyota Motors North America in Plano, Texas on Tuesday, August 21, 2018. (Vernon Bryant/The Dallas Morning News)(Vernon Bryant / Staff Photographer) 5 / 5Detail of a decal from a hydrogen fuel cell semi truck at Toyota Motors North America in Plano, Texas on Tuesday, August 21, 2018. (Vernon Bryant/The Dallas Morning News)(Vernon Bryant / Staff Photographer)

Michael Lewis, a scientist at the University of Texas at Austin’s Center for Electromechanics who’s studied hydrogen fuel cells, said it’s encouraging that Toyota was eager to show off its new truck — even if it’s not being used here yet.

“I hope what they’re trying to do is generate some excitement in Texas for hydrogen with this,” he said. “We seem to be lagging behind other states — I won’t say the country, but California is leading the way.”

Rovik said that’s exactly the idea.

“It’s hard to produce a lot of trucks if there’s nowhere to fuel them and it’s hard to get someone to put in a station if there aren’t any trucks,” he said. “Unless we make a product like this and put it out there, that kind of stalemate continues.”

Toyota didn’t have a specific time line for when they might be able to use the trucks or sell Mirais in Texas.

Rovik added that bringing the truck to Plano was a good opportunity to let employees see the product of their work.