What is a microgrid and how does it work? New portable units allow you to “island” home energy for off-the-grid security.
No, we’re not talking about miniature cooking pans for making tiny pancakes! Rather, new “micro-microgrid” technologies are allowing individuals to adopt homestead-sized versions of a microgrid for their own energy security. These systems serve the same purpose of keeping the lights on when utility-supplied power goes down, but at a fraction of the cost of more expensive solar-plus-battery-storage systems. They’re owned by a homeowner, rather than a utility, and are sited on the owner’s property, located on the owner’s side of the meter – plus, they’re portable.
Today’s micro-microgrids can be small enough to resemble a carry-on suitcase complete with fold-out solar panels and batteries, or they can come as larger units built into modified shipping containers that can power whole properties (provided you have a big budget to match). Prefabricated in a factory with all the components pre-wired, each type of system plugs-and-plays in minutes, and because the smallest among them are housed in protective cases equipped with rollers and handles, you can load them into the back of an off-road vehicle and take them to remote locations.
What is a Microgrid and How Does it Work?
For these reasons, I figure the term “microgrid” should’ve been referring to home-scale systems all along, and let me tell you why. The technology (really a whole grouping of technologies) traditionally referred to as a microgrid is actually a relatively large-scale system intended to operate independent of the “macrogrid” – the plain ol’ grid – in the event said grid goes down. A defining feature for microgrids is that they “island,” or fully disconnect from the larger grid, and keep running during an outage. To serve a single neighborhood, a microgrid can require a huge bank of batteries capable of storing megawatts of energy fed by 10 or more acres of solar panels (and a common misconception is that all microgrids run on renewables; any fuel type, including coal and fossil gas, can power them).
Size aside, micro-microgrids provide all the benefits of their jumbo forebears with a few more perks. But before I continue extolling their virtues, let me explain how microgrids of all shapes and sizes came about.
Microgrids, Then and Now
We hear a lot of talk about “energy security” these days. It makes sense: Our electrical grid is mostly aboveground and vulnerable. When electricity came to rural America in 1936 under the Rural Electrification Act (the same year the Hoover Dam came online), the distribution lines flanking gravel roads weren’t more elaborate than a couple of copper wires tacked to short poles barely higher than the fences below them (the fences would pick up stray electrical current that gave cows and farmers a healthy jolt). Things have evolved a bit over the past nine decades, but our national grid is still fundamentally powered by the same technology: huge turbines spun by water, nuclear- or fossil-heated steam, wind, and solar. Electricity travels over a network of high-voltage transmission lines to substations and, ultimately, to your home’s meter. The combination of these many intricate components forms the modern-day grid.
Microgrids, on the other hand, are much smaller and more local, serving specific geographic areas, such as towns, neighborhoods, military installations, farms, and homes. One way we could secure the national grid is by building a cross-country system of microgrids that’ll continue to operate if central power plants or lines are lost. This isn’t a new idea, and the general concept behind microgrids was developed in the 1960s. Known as the Advanced Research Projects Agency Network (ARPANET), the project developed a special communications network intended to protect missile sites, such as the Titan II ICBM site (where I served), command centers, and other military locations, from losing communications should any of the lines be knocked out of service. ARPANET was commercialized in the 1980s and became what we know today as the “internet.”
Microgrid technology has made little leaps ever since. A good example from more recent times is a microgrid I designed for a retirement community in Texas that suffered millions of dollars in property damage during the 2021 ice storm. To avoid a future crisis, I proposed a microgrid to interconnect with the utility grid during normal times but that could island if (or when) the power failed again. An even more innovative example comes from Ann Arbor, Michigan, where the city’s government is seeking to construct a series of community-owned microgrids as a way to reduce its reliance on non-local energy sources. The Sustainable Energy Unit, as the conglomeration is called, would bundle all the locally produced solar and battery storage (even linking those installed at homes and businesses) to form what’s essentially a community utility.
But developing in tandem with these projects are the ultra-small ones, made possible by a new generation of technology available at scales much smaller than whole neighborhoods.
Small and Smaller: Micro-Microgrid Technology
When I was growing up in the Ozarks of rural Arkansas, I wished we had a way to power our dairy’s milking machines when the power went out (which it did a lot!). Some of the larger farms had backup generators, but we couldn’t afford a $100,000 system for our small herd. A small, inexpensive micro-microgrid sized solely for the energy-hogging milking machine would’ve made a lot of sense – had they existed. Today’s portable micro-microgrids are available in sizes suitable for barns all the way down to towing along for a camping trip or for emergency-response crews to take into the wilderness. Capacity starts at about 1 kilowatt. I’ve had great experiences using the 22-inch-tall Big Genny made by Briggs & Stratton to run several critical devices for more than a day.
A typical homestead would need a 10-kilowatt system or larger, and that’s not something you’d wheel around. However, full-home microgrids can fit into a shed or repurposed shipping container, such as those the company Brightbox is making. Running on batteries alone, you might get enough backup power for about four hours (more with solar hooked into it). My company, TeraVolt Energy, developed a portable microgrid series called Modular Expandable Portable Energy Systems, or MEPES. The components fully integrate into hard poly cases with coasters and retractable handles and come in sizes ranging between 1,000 and 3,500 watts. The smallest unit will power a refrigerator for a day, and the largest will power a home (or a small dairy-cow-milking operation) for several hours.
The Right Tech for You
With typical solar-plus-storage systems, a homeowner needs an expensive assemblage of rooftop or ground-mounted solar panels combined with batteries to achieve off-grid security. They need to carefully monitor to ensure batteries aren’t depleted, and that their solar panels aren’t exposed to high winds and hail. Microgrids solve for all of this, plus units can expand by adding more plug-and-play solar-battery combos, as need dictates and budget allows. They can be used with portable generators to recharge batteries or connect to the utility grid if one is accessible. Because you’re not feeding power back to the grid, using the system properly may not require permitting.
I acknowledge a few disadvantages to using a portable system: Some jurisdictions still may restrict these systems from linking to the grid, so always check with your utility and local laws first. If you’re allowed to draw from the grid, you may need an adapter kit and a higher-amperage electrical outlet that might require hiring an electrician (smaller units have receptacles built in, so all that’s needed is high-quality extension cords). Finally, these aren’t inexpensive systems, even at tiny scales. That doesn’t mean they’re not worth their cost, especially when you consider they require no professional labor to install permanently on a structure. For emergency power, they can often be the least expensive option.
Every year, we see what happens when large areas are devastated by severe weather or wildfires and those living in remote areas become isolated without electricity for weeks. Micro-microgrids provide a way to bring in power that doesn’t require a continual supply of fuel and can stow away when the coast is clear.
Hoss Boyd is founder, president, and CEO of TeraVolt Energy and a recognized solar and energy-storage expert. Learn more about TeraVolt Energy at www.TVNRG.com.
Originally published in the April/May 2025 issue of MOTHER EARTH NEWS and regularly vetted for accuracy.
