An Inventor Retires as His Solar Technology Takes Flight

June 9, 2022 | By Molly Rettig | Contact media relations

Photo of a man, wearing a mask, in a lab with wires and metal casings.
Greg Glatzmaier tests the high-temperature thermal and mechanical stability of sealants that are being used in process equipment that is installed at the 70 MW Nevada Solar One power plant. Photo by Dennis Schroeder, NREL

When Greg Glatzmaier left the National Renewable Energy Laboratory (NREL) for the last time after a career that spanned four decades, he was already planning trips to Nevada and Spain. But not to play poker or hang out on the beach. Instead, he will spend the next year working with solar power plant operators to implement a technology he created to make the plants run more efficiently.

"I still have a lot of work to do," Glatzmaier said, speaking from his office on his last day.

When Greg started at the laboratory in 1987, it was still called the Solar Energy Research Institute (SERI), a group of passionate solar researchers who wanted to change the world. Since then, he has watched NREL become a national laboratory and has seen solar balloon from a niche technology to a dominant one, comprising nearly half of all new electric generating capacity in the United States this year.[1] His innovations in concentrating solar power helped drive this change, collecting two R&D 100 awards and four patents along the way. While many research projects never make it out of the lab, Glatzmaier is retiring on a high note: He invented a product and took it all the way to the market.

"I have not met anyone else at NREL who can do the breadth of research that Greg has done," said Mark Mehos, who previously managed thermal systems research at NREL and has worked with Glatzmaier since the very beginning.

History at NREL

In 1987, when Glatzmaier was finishing his Ph.D. in chemical engineering at the University of Colorado–Boulder, the job market did not look good. The U.S. economy was in bad shape after a major stock market crash. He considered taking a job in the oil sector, but then he saw an ad in the engineering building on campus. SERI was hiring a solar engineer. Glatzmaier had been interested in solar since going to college in Minnesota, appreciating the fact that it produced no pollutants or byproducts.

"I thought, I need to get this job," Glatzmaier said.

He headed straight to the office of a professor who had worked with researchers at SERI and asked for a recommendation. Glatzmaier landed an interview, then the job. He joined Mehos and a larger team working on concentrating solar power, a new technology that was just taking off in the United States.

Concentrating solar power (or CSP) plants use mirrors to capture heat from the sun then convert it to electricity through traditional steam turbines. This process produces a tremendous amount of heat, usually collected at temperatures above 300°C, which researchers are always looking for new ways to exploit. In the early 1990s, Glatzmaier came up with a way to use this heat to create silicon carbide, a hard ceramic powder that can be used to make bearings, gaskets, and seals, and won an R&D 100 award for it.

But in the mid-'90s, renewables hit a lull. The sense of urgency created by the Gulf War a few years earlier had faded, and funding for clean energy had dropped off. While Glatzmaier and his fellow researchers were still making strides in the lab, they were not seeing a huge uptake in the marketplace. So, Greg decided to take a break from solar and left NREL to perform contract work for NASA and the U.S. Air Force.

In the early 2000s, growing concern about climate change revived public interest in clean energy. Renewables were on the rise, including CSP, and Mehos asked Glatzmaier if he would come back to NREL.

"When I came back in 2007, there was so much more interest and investment in solar. The technology was coming into its own," Glatzmaier said.

Since then, solar has seen meteoric growth. Over the past decade, generating capacity increased more than tenfold. Costs have plummeted by 70%, making solar the cheapest form of power globally. While today's market is dominated by solar photovoltaics, CSP still makes up a significant chunk, with 130 plants around the world. CSP plants produce approximately 6 GW of electricity in the United States, and they are big—as large as 250 MW, which is on par with a conventional coal-fired power plant.

Around 2014, plant operators started noticing a problem: They were producing less power. Solar power producers make money by selling a set amount of electricity at a set price over a span of 25 years or so. There are no fuel costs, since the sun is free, but you need to keep production at a certain level to pay off the initial investment. If the plant starts generating less electricity in year 5 or 10, it cuts into profits and scares investors away.

When plant operators voiced their concerns to NREL, Glatzmaier and his team went out to investigate, cruising up and down rows of CSP collectors taking infrared images. They confirmed that hydrogen was building up inside the glass tubes, causing them to lose heat and reducing their efficiency by as much 15%. For a large plant, this equated to millions of dollars of lost revenue each year.

"These plants had been dealing with this inefficiency issue for years," Glatzmaier said. "I thought, 'There's got to be a remedy for this.'"

In 2015, Glatzmaier tackled the problem with modeling and design work, and then he built a proof-of-concept module in the lab. He developed a hydrogen sensor and separator that measured and extracted hydrogen from the CSP plant components, including the receivers (the glass and metal tubes that trap the sunlight), and cleaned them out, restoring their efficiency. In 2018, plant staff from Acciona's Nevada Solar One power plant came to NREL to check out the invention. Nearing 10 years old, their CSP plant was struggling with this exact problem. Before the meeting was over, they wanted to install Glatzmaier's technology at their plant.

"They made their decision right during our meeting, which was a little bit disconcerting. And I thought, 'Did I oversell this?'" Glatzmaier said.

He spent the past four years getting the technology installed and operating at the Nevada Solar One plant. After more than a year of pandemic delays, installation was finally completed last summer at the solar plant south of Las Vegas. Glatzmaier does not want to celebrate too soon, but so far it is doing its job. In fact, based on calculations, it should pay for itself in a matter of months.

Glatzmaier is one of the few researchers who could pull this off, Mehos said. While he had help from colleagues along the way, he spearheaded the entire process: from diagnosing and modeling the problem to engineering and prototyping the solution, and ultimately scaling it to the real world.

NREL research engineer Koenraad Beckers said he has learned a lot from Glatzmaier over the past five years, since Glatzmaier pulled him from the geothermal program to help develop his CSP technology.

“When you work with people like Greg, you’ll automatically love the type of research they do. He has had a whole career in solar and just knows everything about it. I’ll miss him as a researcher but also as a friend.”

"He was practically a one-man show," Mehos said.

Now CSP plants all over the world are interested. That is why Glatzmaier cannot fully retire yet. After his trip to Nevada, he will travel to Spain, where the technology is being licensed to another power plant. Another in North Africa is interested too. In the future, it could be used in every CSP plant in the world based on parabolic trough design—because at some point, they will all run into the same problem.

Glatzmaier looks forward to seeing where CSP goes, especially because it can provide energy storage even cheaper than batteries. By the end of this year, he has promised himself to be done working full time. He will spend more time hiking and camping in the Colorado mountains with his wife, Mary. He will still see colleagues like Mehos, but on the ski slopes rather than in the lab. Many adventures await that have nothing to do with solar power.

But first, he has a trip to Spain.


Tags: Concentrating Solar Power