Not just anyone can develop networked microgrids.
The problem? It requires ownership of the land on which all of the networked microgrids will be located, according to Tim McDuffie, senior business development engineer for Smarter Grid Solutions.
His company has proposed networked microgrids for the Hoopa Valley Tribe, located in Hoopa, California, a remote area of northern California where the tribe is subject to outages because of public safety power shutoffs (PSPS) from Pacific Gas & Electric (PG&E)
The project would network, behind the meter, a number of small microgrids located in critical buildings on tribal property, including the fire station, police station, medical center, a community center and a tribe owned grocery store. They are located within an area that has a two- or three-mile radius, he said.
Attempting networked microgrids in a town or other nontribal community can be difficult, he said. What’s different for the Hoopa project is that one entity owns all the different pieces. “It comes down to broad ownership of resources and existing buildings,” McDuffie said.
In California, microgrids that attempt to connect buildings to more than two contiguous parcels, or across a street, run afoul of what’s known as the over-the-fence rule. Such microgrids are deemed to be utilities, meaning they become subject to a level of regulation impossible for a small entity to manage. Microgrids in other states often face similar restrictions.
As a result, networked, or “clustered,” microgrids remain rare, although some believe they represent the future of the electric grid.
In this case, each microgrid would include between 60 kW and .5 MW of PV and about 2 MWh of storage.
The Hoopa Valley Tribe paid Smarter Grid Solutions for a feasibility study, and it is now talking to Shell New Energies and others about developing the project. A tribal vote on working with Shell is expected later in January. A few ownership options are on the table, including the tribe signing a power purchase agreement with Shell or having Shell own the system outright, McDuffie said.
Some funding could come from California’s Self-Generation Incentive Program (SGIP), said McDuffie. The tribe is located in a state equity resiliency zone, which applies to lower-income, medically vulnerable and communities at risk for fire. These zones are first in line to receive higher incentives for battery storage, according to the California Public Utilities Commission (CPUC).
The equity resiliency SGIP rebates can bring the cost of energy storage to nearly zero, according to the CPUC.
With such rebates, the tribe will come a step closer to its goal of achieving resilience as soon as possible.
The Hoopa Valley Tribe’s microgrid effort differs in important ways from Blue Lake Rancheria’s well-known tribal microgrid, which is also located in California.
“Blue Lake has primary service that comes in, and all electrical infrastructure is served off that. They put all their energy assets and PV assets together in that one spot,” McDuffie explained. “The primary service is what connects Blue Lake to the utility.” The tribe owns the lines, poles and switchgear.
In the Hoopa Valley project, the assets are spread out, and there is no infrastructure on the tribal land that’s available for the tribe to use.
In its efforts to move forward quickly, the Hoopa Valley Tribe had asked if it could use PG&E infrastructure. “People always ask us, ‘Why can’t we buy the PG&E infrastructure?’” said McDuffie. The answer: The utility won’t sell it.
The tribe isn’t the only client that has made this request.
Who owns the infrastructure
“People think utility infrastructure is like roads or public works, paid for by tax dollars. But they are private companies with different regulations. You can’t just use their lines. Helping people understand that is a big challenge,” McDuffie explained.
If a community or tribe doesn’t own the infrastructure, another option is to network small pockets of energy, as his company has proposed. That involves networking the distributed energy resources (DER) together and managing the five buildings from a centralized point.
“Someone in the tribe, not necessarily an engineer, can manage their DERs and all five buildings,” he said.
McDuffie’s company will provide the controller, which is key to networking the microgrids. The controller, called Strata Resilience, identifies the status of different assets. It will allow the tribe to manage the transitions between being on grid and off-grid. It also will allow the tribe to optimize the assets when the microgrids are not in island mode, providing the greatest value when the microgrids are connected to the grid.
“When trying to coordinate services during an outage, that’s when communication is critical. You have an emergency operations center that tells where you do and don’t have power,” McDuffie said. The controller provides the status of different assets and gives operators the ability to make informed decisions.
The controller can be integrated with a building’s energy management system and implement automated load shedding to prioritize which loads get power during a PSPS.
“It’s all about centralizing all the data, knowing where you have power. Also, human interfaces are important so people can make the best possible decisions with the power they have,” he added.
Critical services in a power outage
If someone needs a breathing machine — as may be required because the tribe has a large elder population — and the power goes off, the person can be moved to a fire station that provides power via an islanded microgrid.
“You can move Grandma to the fire station where you know you have power so she can hook up there and ride out the PSPS and go back home when she’s done,” McDuffie said.
The networked microgrids will be capable of sending power to the grid when they’re connected to the grid. But the main goal of the networked microgrids is to provide resilience.
“The tribe thought they could put solar on their property to keep the local substation energized during PSPS,” said McDuffie. “Technically, we can do that, but we aren’t legally allowed to do that without PG&E’s permission.”
Programs like a proposed Community Microgrid Enablement Program (CMEP) — which aims to provide technical and financial support for community microgrids in areas prone to public safety power shutoffs — would allow the tribe to use solar to keep the substation energized, said McDuffie.
“Programs like CMEP may allow you to do that down the road, years and years off.”
But given the tribe’s desire to move as quickly as possible, the networked microgrids are the best option, he said.
“We’re trying to focus on helping them understand what is possible now and targeting the tribe’s greatest needs,” said McDuffie.
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