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The BoxPower microgrid at the Casitas de Esperanza shelter combines two 22-kilowatt solar arrays with 266 kilowatt hours of cumulative battery storage. Each unit is interconnected to a 35-kilowatt prime power propane generator as a system backup.
The significance of the Casitas de Esperanza emergency shelter is symbolized by its name. Translated as “Homes of Hope,” the 25 shelters in San Jose, California, provide stability and dignity to families who are often doubly impacted by the COVID-19 pandemic — losing their jobs in the ensuing economic downturn and unable to safely rely on traditional shelter facilities.
In order to quickly build a temporary facility on property it could eventually repurpose, Santa Clara County’s Office of Supportive Housing turned to Pallet Shelter, which manufactures 100-square-foot shelters equipped with folding beds, storage, windows, heat, and air conditioning.
While each individual shelter is connected to power for personal devices, lighting, heating, and cooling, the facility’s parking lot site lacked access to reliable grid power. Extending power to the site would have cost at least $650,000 and taken at least eight months. Instead, the community turned to a clean, renewable microgrid energy solution from BoxPower that combines solar power, battery storage, and backup propane generators.
Cleaner, more reliable power
The San Jose shelter’s power solution is a microcosm for the microgrid trend playing out across California and the rest of the United States. Due to the increasing prevalence of wildfires across California, the California Public Utilities Commission has required the utilities to harden their lines against wildfire damage. In some cases, microgrids provide a more affordable and feasible solution, says Jenna Herzog, director of marketing for BoxPower, a company that provides containerized microgrids.
“The utilities have found out that in a lot of rural and remote setting, the financial equation for upkeeping and maintaining their lines to meet wildfire standards are just outrageous,” Herzog says. “So when they serve small loads with multiple miles of distribution line, they’re realizing that, financially, it makes more sense to decommission those power lines and replace them with the onsite solar, battery, and backup generator.”
Generators are an optional component in BoxPower’s microgrids, which are generally deployed in modular shipping containers to make them rapidly deployable. But in situations such as the San Jose shelter or with utility clients, generators provide the necessary resilience to keep the microgrids running during prolonged periods without sun.
For projects where emissions, air quality, or decarbonization are a consideration, propane is the fuel of choice for those generators, Herzog says. “There’s no way around it that propane is cleaner-burning than diesel,” she says. “CARB, the California Air Resources Board, has a lot of restrictions around diesel generator run times and how close they are to people. It’s just so much faster and easier to get a propane generator permitted, rather than diesel.”
Air quality was an important consideration at Casitas de Esperanza because the generators were sited near the shelters. “They obviously don’t want those emissions to add that environmental justice issue on top of everything that those folks are already dealing with,” Herzog says.
Resilience in a box
While the California utilities are one of the most high-profile examples of microgrid applications, microgrids can be used anywhere for projects that need power that’s more reliable, affordable, and in most contexts cleaner, Herzog says. A lot of tech companies in California are using microgrids for reliability and cost, while critical facilities such as hospitals, police stations, and military facilities that can’t afford an outage are using microgrids to protect against California’s public safety power shutoffs.
The use of solar power and propane generator backup could become increasingly attractive to organizations and communities looking to decarbonize their operations as renewable propane, made from a mix of waste residues and sustainably sourced materials, becomes more available. Propane generators can easily switch to run on renewable propane, making these systems easy to future-proof.
“It’s enticing to us and something that we’re hoping to pilot,” Herzog says, “hopefully within the next year or two and likely with the utility companies.”
Top photo: After a major fire destroyed the power lines that served Briceburg, California, the utility PG&E worked with BoxPower to install a remote grid with a 36.5-kilowatt solar array, a 69-kilowatt-hour battery bank, and two 35-kilovolt-amp propane prime power generators.
