As the effects of climate change become more obvious, the promise of nuclear fusion — a virtually unlimited source of carbon-free energy — is getting a new wave of attention. The field has drawn almost $5 billion in funding, with recent interest off the charts.

One of the newest efforts to commercialize fusion comes from startup Focused Energy, founded by a pair of physics professors with expertise in extremely high-powered lasers, Todd Ditmire and Markus Roth. The startup launched last summer and has a strong bench of veterans, including Prav Patel, who spent 23 years at the Lawrence Livermore National Laboratory.

Now the startup has scored $15 million in early-stage funding from the venture capital firm Prime Movers Lab, plus Marc Lore (who sold e-commerce companies Diapers.com and Jet.com to Amazon and Walmart respectively), tech investor Tony Florence, and the former Yankee slugger Alex Rodriguez.

Unlike nuclear fission, which powers all the commercial nuclear reactors in the world today, fusion does not generate long-lasting nuclear waste. But it requires a sustained reaction at extremely high temperatures, and despite decades of effort, nobody has yet figured out how to turn it into a commercially viable energy source.

There are two religions in the race to commercialize fusion: magnetic confinement fusion, which uses ultra strong magnets and a round device called a tokamak, and inertial confinement energy, which typically uses lasers. Prime Movers Lab has invested in Commonwealth Fusion Systems, a Boston-based fusion company spun out of Massachusetts Institute of Technology, as its best bet for magnetic confinement fusion. Focused Energy is its top pick for the “breakout” laser driven approach, according to partner Carly Anderson.

Even so, attempting to contain the same energy source that powers the sun will require a lot of research and effort.

“Focused Energy is capitalizing on over 70 years of government research into fusion,” Matthew Moynihan, a nuclear fusion consultant, told CNBC. “They have a credible team and a good plan, but they have hard challenges ahead.”

Ditmire worked at Livermore for three years, where he worked on the very first ultra-powerful petawatt laser and met Roth. In 2000, Ditmire joined University of Texas in where he built the Texas Petawatt Laser. Its power is hard to conceptualize.

“The U.S. electrical grid produces about a half a trillion watts of power. So that’s a half a terawatt,” Dimitre explained in a conversation in June. “A petawatt is 1,000 trillion watts. So a petawatt laser has the same power as 2,000 times the power output of the United States electrical grid.”

He continued, “You take all the wattage of the sunlight falling on the state of Texas, it’s about 140 terawatts. So I would always say Petawatt is brighter than the Texas sun.”

In 2010, Ditmire started a company in Austin called National Energetics to design and build the kind of high-powered lasers he needed for his own research. “It turns out it in 2010, the only place you could get a customized power laser was from France,” Ditmire told CNBC.

At the company’s peak, it had a staff of about 30. In 2014, National Energetics won a $40 million contract to deliver a 10 petawatt laser system to the Czech Republic, which the company is in the final stages of finishing. After that project is wrapped, so too will the company. Ditmire is transferring all the intellectual property from National Energetics into Focused Energy.

“I decided it was time to go off and slay a bigger dragon,” Ditmire said. “And what what bigger dragon could there be than fusion energy?”

For a six month period, Ditmire worked with Marvel Fusion, another startup working to commercialize fusion with lasers. Roth also worked at Marvel Fusion for a time. Marvel Fusion is using proton boron as the fuel source, which is an “interesting concept,” according to Ditmire, but his “real interest” was in working with laser fusion and using fuel made from hydrogen isotopes deuterium and tritium.

So Roth and Ditmire decided to start their own company.

In 2009, the Lawrence Livermore finished building the National Ignition Facility, where 192 laser beams point to a central chamber, creating the kinds of temperatures and pressures that exist in the center of stars, planets, and an exploding nuclear weapon.

Patel expected the team to get to a key fusion landmark, called ignition, within a few years. “I thought it would be quick. And that was almost that was 10 years ago. Then we spent the next 10 years getting the ignition,” Patel told CNBC.

The lab finally reached ignition on Aug. 8, 2021, meaning it had produced 1.3 megajoules of energy. Omar A. Hurricane, the chief scientist for the Inertial Confinement Fusion Program at the lab told CNBC at the time it was “a Wright Brothers moment” for the fusion industry. 

That validation was an important step for investors in the nascent industry.

“The NIF shot removed a major element of risk for Focused Energy’s approach,” Anderson told CNBC. “For Focused Energy to achieve cost-effective fusion, the team needs to develop cheap lasers and cheap fusion fuel. These are engineering challenges. Significant scientific risk (solving the plasma physics challenges needed for a machine that will produce burning plasma from scratch) has been retired.”

After that milestone achievement, Patel was willing entertain Roth and Ditmire’s offer to join them — an offer he’d previously declined. Focused Energy is going to use both the kind of lasers that Ditmire has been building and the kind that Patel has worked with for decades at Lawrence Livermore.

“We have conventional long pulse lasers like at NIF to compress this fuel. And then we have these Petawatt lasers that Todd was talking about to produce this intense beam of protons,” Patel said. The goal then is to ignite the fuel with a spark. Ideally, that fuel continues to burn on its own — what’s called a “propagating burn” — to fuse the rest of the fuel, Patel said.

“It’s a scheme that potentially with lasers two or three times smaller than NIF, you could potentially get 30 times more energy out.”

One of the advantages of using laser-ignition fusion, as opposed to magnetic confinement fusion, according to Ditmire, is that it uses only tiny pellets of tritium, a mildly radioactive isotope.

The company is in very early stages and faces significant challenges ahead.

“They need to be able to cheaply and reliably make small pellets of fusion fuel and place them inside a chamber for compression. Once fused, they have to covert the resulting fusion energy into safe, economic and reliable electricity,” Moynihan told CNBC. “All of this needs to be done within the legal frameworks for fusion written by the NRC (Nuclear Regulatory Commission) and those rules are still evolving.”

Focused Energy aims to prove out its fusion process with an ignition facility by 2030. That will cost $3 billion to build. The $15 million raised so far will be spent on a laser system at University of Texas at Austin and to build out experimental facilities in Darmstadt, Germany.

Demo power plants in the 2030s is “not inconceivable,” Ditmire said. “And that’s not too late. It’s probably just in time. We probably don’t have time to dally, but it’s just in time.”

A commercial fusion facility will cost Focused Energy about $5 billion to build. But the money is flowing in fusion right now. It took Ditmire four years of going back and forth to Washington D.C., lobbying on the Hill, to get $15 million to build the Texas Petawatt laser. “It took me four years of work. You know, we went out and raised $15 million with 4 Zoom calls,” for Focused Energy, Ditmire said. “The investor interest was just stunning.”

The fusion industry depends on investors’ continued interest in the “holy grail” of energy.

“We stand on the shoulders of giants,” Ditmire said. “But times are changing, which means the rate at which science progress has happened is going to have to accelerate, and the place that’s going to happen is in is in the private sector.”

For Ditmire, it’s personal, too. “It is my raison d’être in my career to make this happen before the end of my career,” he told CNBC. “This is it, baby. This is the dragon in Mordor.”