Groups Seek to Create a Microgrid Serving a Multi-Family Project in Northern California, But PG&E’s Cooperation Is Needed
It’s not easy to deploy a microgrid for multi-family housing projects in California because existing state laws don’t allow for master metering–using one meter to provide electricity to all the units in a housing complex.
That’s a challenge, given that 45% of Californians are renters who don’t have access to renewable energy, according to Clean Coalition, a non-profit advocacy group which aims to advance the use of sustainable energy technologies.
Clean Coalition, PAE Engineers and others have teamed up to implement an innovative workaround to the challenge in the South Berkeley project that is being slowed by a perceived lack of engagement by the region’s utility, Pacific Gas & Electric (PG&E).
Craig Collins, senior associate at PAE Engineers, has proposed a solution for the Berkeley Efficient Resilient and Mixed Use Showcase (BERMUS) project, a net-zero multifamily housing project in the South Berkeley neighborhood that would include 65 affordable condominiums and cooperative units and nonprofit commercial spaces.
Creating a solar microgrid behind and front of meter
The plan involves creating a hybrid behind-the-meter/front-of-meter solar microgrid with standard utility revenue meters for each individual unit.
“Clean Coalition strongly believes it is far more effective to treat a site as having a single connection to the distribution grid and avoid the difficulty associated with deploying a community microgrid,” said Ben Schwartz, policy manager at Clean Coalition. “With a 'master meter,' a multi-meter facility would have a single point of interconnection with the utility, enabling the streamlined deployment of a behind-the-meter solar microgrid rather than a community microgrid.”
The project received a $1 million predevelopment grant from the California Energy Commission (CEC) and a $1 million predevelopment loan approved by the Berkeley City Council, and more recently, received an additional $8 million in funding from the CEC, allocated to project partner Northern California Land Trust.
If SB 1148–a bill to authorize master metering for behind-the-meter microgrids– hadn’t died in the state legislature, completing this project would be easier.
The problems of separate electric meters in multi-family developments
“The challenge is that the multi-family housing developments have in the recent past been required to have separate electric metering for each tenant. The expectation is a seperate meter for every apartment system,” Collins said. If the building has 50 units, there must be 50 electrical meters. This makes it difficult to integrate PV, batteries and microgrids and realize the benefits of the technologies for each individual meter.
For example, serving individual units with solar and batteries would require hundreds of square feet of wall space that’s not available in apartment complexes.
The project participants hope to be accepted into PG&E’s Community Microgrid Enablement Tariff (CMET), which allows for construction of community microgrids in partnership with the utility. If accepted into the program, PG&E would evaluate the microgrid system to make sure it doesn’t negatively impact power and reliability for other PG&E customers.
The BERMUS project has made it through four of the 11 steps required, said Ben Schwartz, policy manager, Clean Coalition.
Delays from PG&E present a challenge
“Now we have new funding from the CEC, but we can’t do anything until PG&E makes a decision,” Schwartz said. “We’ve been waiting for over a year. The CMET is the best available pathway, but not an ideal one, because there is no experience navigating the process and other hurdles remain in place.”
PG&E did not respond to a request for a comment by deadline.
To make the solar microgrid workable for all tenants, Collins created a workaround that would require the partnership and permission of PG&E, Collins said.
The BERMUS microgrid would include solar available from a solar canopy covering the entire roof of the building. Half of the solar would be connected behind the house meter, which serves common loads such as heating, ventilating and air conditioning equipment. The other half would be interconnected via a separate production meter to enable participation in PG&E’s virtual net metering program, said Craig Lewis, executive director at Clean Coalition.
How an engineer’s workaround allows for islanding
All onsite solar would be available for island operation during outages through a front-of-meter microgrid isolation device and microgrid controls managing PV, energy storage and building load, Collins explained.
“The only way this would work for front-of-meter solar would be if a grid isolation switch is there, otherwise solar would be turned off,” added Lewis.
Under the plan, about 50% of the load would be moved to the house meter, Lewis said. Solar and storage would be added behind the house meter.
There would be a common heating, ventilating and air conditioning system along with common water heating and WiFi behind the house meter.
A PV system would cover energy use, and a battery system would offset peak demand and providence resilience during outages, Collins said.
“Because the community exists behind a single electric service as opposed to a collection of other services on a city block, it makes the engineering pathway much simpler,” Collins said. There would be a single electric service into the multi-family housing community located on one plot of land.
“This is a great way to deploy resiliency in a streamlined fashion in urban environments,” Collins said.
Ensuring tenants can run medical equipment run on electricity
Two circuits would serve every unit from the house meter, Lewis said. Critical loads would be served by an outlet when the grid goes down. That means tenants could use medical equipment that requires electricity. “You can plug the equipment into an outlet that will only be available during an outage,” he explained.
A group of tenants or the landlord could establish ways to make shared energy expenses equitable, Collins said. It’s possible to hire a subcontractor to install sub meters in the tenants’ units, for example.
If the project is accepted into PG&E’s CMET and is built as proposed, it will yield numerous benefits, Lewis said.
"This is a 100% electric, net-zero project that doesn’t pull energy during peak hours,” he said. “It provides social, economic, environmental and resilience benefits. It will create affordable condos, with ownership from day one. That will create a pathway to wealth for low-income folks.”
