Fifty years from now, the entire economy may run on hydrogen.

The proof of concept sits tucked away in the corner of a lab at the University of Louisville’s Conn Center for Renewable Energy Research — decorated with a Cardinals basketball sticker.

It’s a box the size of a footstool outfitted with solar panels. Those panels collect energy to power electrolyzers, which use electricity to break water molecules into hydrogen and oxygen. Vent off the oxygen, capture the hydrogen and you’ve got fuel.

Hydrogen fuel has the potential to be entirely carbon free — an enticing prospect in the face of a global climate crisis caused by our dependence on carbon emitting fossil fuels.

The problem is that process is still too expensive, said U of L’s theme leader for solar research Joshua Spurgeon. This month Spurgeon received $500,000 from the National Science Foundation to scale solar hydrogen technology to make it cost-competitive with hydrogen derived from natural gas.

“Our goal is to, through science and engineering, figure out how to take the critical elements of each of these different systems and integrate it into a single system that can take in light, split water and make hydrogen,” Spurgeon said.

And he’s got a good idea of how to do it.

Scaling Down, Way Down

Spurgeon is using silicon-based particles, smaller than the width of a human hair. These “micro-wire particles” are the foundation:

Because silicon is one of the most abundant materials on the planet. Because it makes a good semiconductor (which is why it’s used in solar panels).

But the silicon on its own can’t create enough voltage to split water molecules, so he needs a second semiconductor. That second material is still up in the air, but right now Spurgeon and his team are working with titanium dioxide, which is commonly used in white paint pigment.

That plus a catalyst to help accelerate the electrochemical reaction, and bang, you’re splitting water.

“So you have a whole bunch of floating particles in water, you shine light on it. And then you collection the hydrogen over a large area, so you are harvesting sunlight as fuel,” Spurgeon said.

Low-Cost ‘Plastic Baggie’ Reactors

Imagine a pool filled with a slurry of Spurgeon’s particles and water. Sunlight hits the pond, the water molecules break apart, large plastic bags over the top of that slurry collect the hydrogen, and it’s piped into a facility where it’s concentrated and stored.

The best part is that it’s a closed system. When the reactor combusts the hydrogen to turn the turbines to make energy, water is the only by-product. WATER! That water could then be piped back into the pools where the process can begin all over again.

“Hydrogen is kind of that holy grail type molecule where if we get it from water, the planet is two-thirds water, so there is tons and tons and tons of it,” Spurgeon said. “And then you get hydrogen, when you burn it, you just get water, so it’s a perfect closed loop system.”

A World Without Fossil Fuels

Right now, researchers all over the world are trying to figure out how to store the energy made from wind, solar and other renewables so that it can be used 24 hours a day. Hydrogen fuel solves that last major hurdle.

Ultimately, if it becomes cost-competitive, large utilities might use solar-derived hydrogen coupled with other renewable technologies to have a 100 percent carbon-free energy portfolio.

But hydrogen could not only solve that problem, it could also provide a carbon-free fuel to power the world’s transportation, including cars and airplanes — one of the largest culprits of greenhouse gas emissions.

“There are a lot of fuel cell cars under development right now, Toyota has a big program in that space,” Spurgeon said.

Looking Into The Crystal Ball

As scientists regularly remind us, humans are still hurtling us toward a warmer world. And the longer we wait to reduce our carbon emissions, the worse that world will be. So please allow this speculative reprieve to serve as a moment of hope amid what can at times be a bleak outlook.

I floated the idea of Hydrogen fuels and Spurgeon’s research to Chris Heimgartner, a municipal utility manager in western Kentucky who has spent decades working in the energy industry.

“That’s the future,” Heimgartner said. “My prediction, 50 years from now hydrogen will be the single largest load on the electric grid. Period.”

He predicts that carbon-based energy sources will fall by the wayside as wind, solar, nuclear, and other renewable technologies are bolstered by hydrogen. He imagines existing natural gas pipelines retrofitted to carry hydrogen.

And as for transportation, Heimgartner foresees batteries as a bridge technology until scientists figure out how to efficiently scale compressed or liquefied hydrogen running through fuel cells to power electric motors.

“Fifty years from now, there will be no stationary carbon sources in America,” Heimgartner said.