• Monolith and Modern Hydrogen are using new technologies to create a cleaner hydrogen that's also creating a byproduct that can be used to make cleaner asphalt.
• Using carbon, instead of the usual petroleum, makes the asphalt stronger, cheaper and greener.
• "There is this $100 billion per year market that wants to buy dissolved carbon and put it into asphalt, and that just helps the whole economics of this decarbonization play," said Tony Pan, CEO of Modern Hydrogen.

Companies like Monolith and Seattle-based startup Modern Hydrogen are using new technologies to create a cleaner hydrogen that's also creating a useful byproduct — solid carbon that can be used to make petroleum-free asphalt materials.

"Modern Hydrogen produces clean hydrogen without renewable power. We can do this because we split apart natural gas into clean hydrogen and solid carbon," said Tony Pan, CEO of Modern Hydrogen.

Natural gas is a cleaner fuel than oil, but it still emits harmful carbon dioxide when burned.

Clients put the Modern Hydrogen system, which looks like a large box, where they would normally use their natural gas. The system first separates the gas into solid carbon and clean hydrogen. The client then uses that emission-free hydrogen fuel. A portion of it also powers the system.

Modern Hydrogen has a second business selling the leftover carbon to asphalt makers. Using carbon, instead of the usual petroleum, makes the asphalt stronger, cheaper and greener. Asphalt is traditionally a mix of gravel and petroleum.

"There is this $100 billion per year market that wants to buy dissolved carbon and put it into asphalt, and that just helps the whole economics of this decarbonization play," said Pan.

It's one of the cheaper ways for Modern Hydrogen's industrial clients, pressured by investors and regulators, to decarbonize.

"Decarbonization isn't free, so we're always looking for the least cost, least risk way of doing that. This technology is probably a medium expense to low expense, and that's what we're trying to figure out with the technology," said Chris Kroeker, business development segment manager at NW Natural, formerly Northwest Natural Gas.  

Modern Hydrogen is backed by Gates Frontier, At One Ventures, National Grid Partners, NextEra Energy, Miura Group and Irongrey. It has raised $100 million in funding to date.

Modern Hydrogen now has systems in the U.S. and Canada. Its asphalt is filling potholes in six states as well as Canada. Pan says he is looking to expand into Japan next and plans to go global.

Much of the company's testing has been done in milder climates, but Modern Hydrogen is now working with National Grid at a gas facility on Long Island, New York. It's the first trial in a colder climate. If it holds up, that will open the company up to a broader field of clients. New York produces almost 19 million tons of asphalt per year.

CNBC producer Lisa Rizzolo contributed to this piece.