Two decades of research at the Distributed Energy Technologies Lab

Twenty-two years ago, Abbas Akhil and Dave Menicucci recognized a disruption was happening in electric generation. New distributed generation technologies were emerging, and a new microturbine was on the market. Interest in renewable energy was climbing, and concepts such as “premium power” were floating around.

Akhil and Menicucci identified a familiar challenge: how could they integrate these different technologies into a safe, resilient and reliable system?

Looking around at the Photovoltaic Systems Evaluation Laboratory, the pair realized that the lab already had some of the core components they needed to start research on that very question.

“We had the PSEL with that 40-kilowatt array, and there was a lead-acid battery in the back room,” Akhil said. “We already had two pieces of a microgrid. We said, ‘If we can beg, borrow or steal a microturbine, then what are we waiting for?’”

Akhil, who is now retired, acquired not one but two microturbines as well as two fuel cells by honest means. A portion of PSEL was renamed the Distributed Energy Technologies Laboratory in 2002, and Sandia officially had a new lab to evaluate the interplay of distributed energy resources to function as a microgrid.

Microgrids for energy security and energy equity

Some of the earliest work at DETL supported efforts by the U.S. military to develop microgrids at certain bases. In 2012, Sandia became the lead designer for a joint DOD and DOE project known as SPIDERS, the Smart Power Infrastructure Demonstration for Energy Reliability and Security. That led to the development of software known as the Microgrid Design Toolkit, which Sandia then customized for the Marine Corps to support their decisions about energy technology.

DETL researchers have also applied their microgrid knowledge to benefit remote or island communities. Nick Gurule, who has current responsibility for DETL, pointed to Sandia’s work in Puerto Rico and Cordova, Alaska.

“We’re constantly working on these systems and analyzing them, figuring out how we can integrate these technologies into communities to help them,” Nick said. Puerto Rico is pursuing a path to 100% renewable energy with the help of Sandia’s roadmap.

And microgrids aren’t just of interest to the military and communities on Earth. DETL also helped design a microgrid for a future base on the moon.

Leadership in power electronics and standards

In DETL’s early years, researchers looked at improving system components as well as overall system performance. While there had been decades of public and private investment to optimize solar panels, the staff at DETL recognized a research gap for inverters, the devices that convert the direct current power produced by solar panels to alternating current. Inverters of the early 2000s had short lifespans and inconsistent performance.

Charlie Hanley, who managed DETL from 2005 to 2014, recalls the uncertainties of the time. “We were still in the phase of trying to figure out the questions that needed to be answered. Photovoltaic systems were getting bigger and bigger, there were more and more inverters, and folks didn’t really understand the impact this was going to have,” Charlie said. “We were right there with DOE figuring out the technical questions that we needed to ask.”

In 2008, Sandia became the lead lab researching inverters through a DOE initiative known as SEGIS, Solar Energy Grid Integration Systems. “SEGIS was a really effective way to significantly accelerate industry’s ability to enhance the reliability of inverters,” Charlie said.

Of course, one sure way to improve the performance of components is through technical standards. Both Charlie and Nick noted that Sandia staff have more than 20 years of history influencing the development of interconnection standards, such as IEEE 1547, which governs the connection of distributed energy resources to electric power systems.

“Many of the measurements included in the standards came from Sandia,” Charlie said. “The parts that gave those standards teeth and allowed people to assess whether devices were meeting the standards? That came from Sandia working closely with partners in industry and at other national labs.”

Upgrades and expansion to meet the times

DETL still has one microturbine, a diesel generator set and the photovoltaic panels, but the lab has been upgraded and expanded. The lead-acid batteries are gone, replaced by a battery emulator that better approximates the lithium-ion batteries used today for grid storage. Other emulators have been added — for a grid connection, wind energy, larger solar arrays and a “neighborhood” of ten homes to simulate load. DETL staff also installed an electric vehicle charging station recently and are adding a wave-energy emulator.

Nick said automated controls and cybersecurity will be critical areas for DETL in the next five years. DETL researchers can integrate commercially available devices into a system for testing.

Referencing one theoretical scenario, Nick asked, “What if 50 megawatts of solar is hacked and now the reactive power response that was supposed to be helping the system is changed? That can actually drive the system wild.”

Nick also said electric vehicles are drawing attention. He noted some vehicles are being marketed with vehicle-to-grid connectivity or as mobile power stations. “You can plug your truck into your home charger, and it can power your house during a power outage,” Nick said. “Vehicle to grid is a very interesting topic.”

Charlie also sees a strong future for DETL. “I would say cybersecurity, advanced communications and the integration of advanced power electronics are the three areas where DETL is going to be really important,” Charlie said.

Not waiting for the future

Today, DETL is a place where Sandia can conduct interoperability experiments with multiple distributed energy resources, perform cybersecurity research and model advanced grid scenarios. It’s a lab for testing, modeling and asking interesting technical questions, and then finding the answers.

Akhil isn’t surprised that DETL, the lab that he helped cobble together so long ago, is now looking at cybersecurity and advanced controls. “That’s one of the amazing things Sandia can do,” Akhil said, referencing Sandia’s ability to meet new challenges. “The breadth of expertise — there’s just no private company that can do that.”

Take a virtual tour of DETL.