National Lab's Mobile Microgrid Adds Grid Smarts by Coupling with Hydro, Nuclear and DERs

The Department of Energy’s (DOE) national laboratories are hard at work developing ways to ensure microgrids work their magic.

For example, two national laboratories — the Pacific Northwest National Laboratory and Sandia National Laboratories — independently developed tools to determine how to best optimize microgrids for resilience, a critical goal as climate change sparks more and more outages.

Microgrid in a box is like a portable test bed

Now comes a microgrid in a box, a portable microgrid from Idaho National Laboratory (INL). It’s like a microgrid test bed packed in a shipping container that can be moved from place to place. Coupled with hydroelectricity, small nuclear reactors and other distributed energy resources (DERs), it can add smarts – and clean energy — to the grid.

Right now, inverters don’t provide the control functions needed for the future grid that integrates DERs, said Kurt Myers, INL’s energy and grid systems integration group lead.

“We haven’t found one inverter that can do all the things that the future grid needs: frequency and voltage regulation, time-of-use programs and peak shaving at the same time,” he said. “We have to get these assets with better controls in them.”

Developed by INL along with the federal Department of Defense, the microgrid in a box can help solve this problem. It can be moved from place to place and hooked up to various DERs, including hydropower, solar, wind, diesel generators or small nuclear reactors to provide resilience in remote or off-grid locations or during emergency situations or power outages. It can also provide some of the advanced controls needed for the future grid.

Using a portable microgrid for grid services

The goal is to use the microgrid in a box, which includes batteries with smart inverters, to provide resilience along with fast-response grid services when needed.

A recent test of the microgrid in a box at a hydro facility in rural Idaho owned by the Fall River Electric Cooperative, a rural electric cooperative, demonstrated that hydropower, coupled with the microgrid and advanced controls developed by INL, can provide resilience after a blackout.

This is especially important to hundreds of small, mostly rural communities that rely on hydroelectricity. With this technology, they can retain electric service after blackouts, said Myers.

Testing hydropower and microgrids

During the demonstration earlier in July, the INL team showed that Fall River Electric Cooperative’s hydropower plants – which provide 4.5 MW – could be utilized, along with the portable microgrid, to restart the grid after a simulated grid blackout.

This effort began in 2016 when Idaho Falls Power and INL began studying the benefits of hydropower microgrids.

The study was launched in response to a three-hour blackout in December 2013 that left approximately 3,500 people in the city of Idaho Falls without access to electricity during extreme winter temperatures.

In 2021, INL and Idaho Falls Power successfully tested a hydropowered microgrid to improve the resilience and reliability of municipal power.

One goal is to stabilize frequency

But the Idaho Falls Power demonstration didn’t accomplish all of INL’s goals, said Myers. That project used capacitors to provide energy storage, but the system experienced too much frequency oscillation – veering away from the ideal 60 hertz, said Myers. Oscillation can lead to blackouts.

INL decided to work with a different run-of-the- river hydropower turbine – owned by Fall River Electric Cooperative – and add controls and upgrades, along with the microgrid in a box and battery storage, to provide more frequency stabilization than was accomplished with the Idaho Falls Power project.

During the recent demonstration at Fall River Electric Cooperative, the hydropower plant, along with the microgrid in a box, were used to restore the grid in a process called blackstart, which involves restarting generation units, transmission lines and distribution systems after a blackout.

With the microgrid in a box, INL wants to provide ancillary services to the grid, in addition to the blackstart and frequency regulation capabilities demonstrated by the project. That will allow utilities to handle more of the two-way flows and variable generation associated with distributed solar and electric vehicles, said Myers.

“We’re figuring out the best way to add more smarts to the distribution grid,” said Myers. “We need the microgrid in a box and batteries with smart inverters to be able to do fast response.”

INL also wants to study ways to stack together multiple portable microgrids to increase the size of the systems.

Testing portable microgrid with small nuclear reactors

One of INL’s next steps will be to pair the microgrid in a box with small nuclear reactors.

The DOE is studying small nuclear reactors as a carbon-free, resilient and potentially affordable component of microgrids, but some microgrid industry members say it’s unlikely their nonmilitary customers will soon embrace the technology because of safety concerns.

When INL is ready to test the microgrid in a box with a nuclear reactor, it will take the portable microgrid to a desert site at its Materials and Fuels Complex, said Myers. At the site, nuclear powers a 100-kW linear generator.

“We’re running the generator with a small nuclear reactor; it’s meant to be a small demonstration,” he said.

Meanwhile, the recent demonstration at Fall River Electric Cooperative has shown how portable microgrids paired with hydropower can provide resilience to small, rural communities. The microgrid in a box would be located at one site most of the time but could be moved to lend a helping hand when needed.

“We can get a lot of use out of the system; it doesn’t need to be stuck in one location,” said Myers.