“There are a lot of big problems out there that humanity has,” says Chad Miller, president and CTO of Burlington-based Verde Technologies. “There’s economic inequality, social injustice. But those seemed daunting to me, because I didn’t know how to approach them… What drives me and the company and everyone involved, is climate change. So the question, then, is what is the best way to combat climate change?”
The various renewable energy sources, Miller says, have their strengths, but only solar can scale and make a big enough difference.
“There's enough sunlight hitting the earth every day,” Miller says, “to power the earth 20 times over. It's huge. And you can scale it.” To prove his point, he shares a map of the world researchers have created, showing that we only need to cover a total land area the size of Spain with solar (operating at 20 percent efficiency) to power the entire world’s energy needs. And it could be done by strategic placement of solar installations around the globe.
But for all that, Miller says, solar has a problem. And it is silicon. While it has been the basis for getting solar energy efficiency up to 24-25%, it must be created at very high pressure, in a slow, highly energy-intensive process. “It doesn't scale without a lot of money,” Miller says.
And so Miller and Verde are developing what could be a game changer. It is a thin solar film based on perovskite (a mineral structure found in Russia back in the 50s, but not used for solar applications until 2009; it had an efficiency of ~3% then, but is now greater than that of silicon) that can “just be printed like a newspaper,” Miller says. “And it is also super thin, lightweight... it's great because it's cheap to make. It doesn't require [such] expensive equipment… and it's just as efficient as silicon.” It also doesn’t involve any rare earth metals or huge expenditures of energy. It just requires some basic chemistry and technology.
“Don't get me wrong, I think silicon's a good technology,” Miller says. “I just think this is better and it's better for the environment, better to make, easier to make.”
He hands over a sheet of lightweight solar film. It's flexible and a bit thinner than a cellphone’s screen protector, but it is embedded with solar cells.
Miller got his PhD from the University of Utah in 2017, and returned to Vermont (he was born and raised near Burlington). He had been teaching for a few years at Norwich when Randall Headrick, the head of UVM’s Physics Department, sent him an email, saying “Hey, I have this project, I want to put your name on it, if you want to come back and be a postdoc.” Miller says he was missing being in the lab, so he agreed.
The fact that Verde is housed at UVM, Miller says, has allowed the company to make “incredibly fast technical progress, which is really interesting. Normally in science it's so painstakingly slow, but everything we've done so far has worked out pretty well.”
He says their ability “to translate lab-scale results to full-scale production lines pretty quickly” is unique. And this will help them address the main weakness that perovskite film technology faces: longevity.
But, given the cost differential, that problem is eminently solvable.
“Last year,” Miller says, the cost of producing silicon “was like 24 cents a watt.” And, perovskite sheets, if you do the math and have scaled-up production, “come in between 13 and 17 cents a watt.”
Add to that the fact that, for solar installations with silicon, only about a quarter of the cost is down to the panels themselves. The rest of it is the balance of systems, permitting, steel racking, etc. And so, if you go from heavy silicon panels to lightweight sheets (“just peel and stick right to the roof”), he says, “you can reduce labor and you can really reduce the cost on both ends. You can have a cheaper panel and cheaper installation… and the form factor is another beautiful thing about it. You're not restrained to have this four-by-four, six-by-six, or whatever-sized cell. You can have it be whatever size you want, whatever the size of the roof is.”
And that has some interesting implications for situations like emergency relief, Miller says. “If the power goes out somewhere and you need to ship a bunch of stuff. How much easier is it to just send out a bunch of rolls and tubes?”
That this breakthrough solar work is being done in Vermont, about as far from the US sunbelt as one can get in the lower-48, is an irony not lost on Miller, who said that “if Vermont wanted to harness solar, it'd be smarter for us to put up a field in Arizona and ship the power back here.”
And yet, perovskite solar also has interesting implications for Vermont, because reputedly 30 percent of our roofs aren’t strong enough to hold the heavy load of solar panels, including many commercial flat roofs. When the product is far cheaper, easier to install, and does not add any weight to the roof, it changes the equation.
“What excites me right now,” Miller says, “is the ways that this can be used and the cost is right at scale. It is cheaper and you can implement it in many different ways.” That includes stacking the film in layers, which could potentially increase perovskite sheets’ efficiency by another 50 percent.
Miller says that what he loves most about being a maker is “the potential to have a significant change” – to impact climate change.
If the promise of Verde’s technology can be harnessed as anticipated, the changes could be significant indeed.
