The Santa Barbara Unified School District has issued a request for proposals for at least six school microgrids as part of a solar and resiliency project that encompasses 15 locations.
The solicitation comes as schools and other California institutions and businesses seek ways to ensure electric reliability following last year’s power outages enacted by utilities to prevent wildfires.
In addition to adding energy resiliency, the project is expected to lower the district’s electricity costs, reduce its carbon footprint, and add shade to campuses.
The school district seeks one firm to finance, design, permit, build, commission, own and operate, and maintain the energy infrastructure under a 25-year power purchase agreement.
The design calls for microgrids with battery storage at six or more sites, as well as solar photovoltaics at 15 sites and PV-paired with battery energy. The project is expected to include about 4.5 MW of solar capacity and 3 MW/6 MWH of battery energy storage (if all of the sites install storage).
The sites include three high schools, four junior high schools, six elementary schools, a district office and a warehouse. The school microgrids, which would offer variable two to six hour islanding mode, are proposed for the high schools, one junior high and the warehouse.
The Clean Coalition, a California non-profit, partnered with Sage Energy Consulting on the RFP. The partners conducted the project feasibility analyses and design and solicitation execution and will work together on the selection of a developer to build, own, and operate the school microgrids.
A model for solar microgrids
In an interview with Microgrid Knowledge, Craig Lewis, executive director of the Clean Coalition, described the RFP as a possible model for others undertaking solar microgrids.
“I think it’s going to be a game changer for the industry in terms of general understanding of how solar microgrids need to be configured in order to provide the type of resilience that we need them to provide…and in terms of how to convey that to the marketplace,” Lewis said.
Among the innovations that the Clean Coalition is attempting to bring to the market within the RFP is what it calls VOR123. The system establishes a value of resilience (VOR) — what power outages cost a facility — by way of load ranking. It’s meant to address a frequent lament within the industry that valuing resilience must be done project-by-project, in a customized way — which adds time and cost.
“Every time you went into a new facility, it was like giving birth or putting a man on the moon,” Lewis said.
Pioneered by the Clean Coalition, VOR123 brings standardization to the process.
The approach ranks load, based on its importance. (See graphic below.) The most critical load — life sustaining and mission critical functions — go into Tier 1, which generally represents 10% of load. The building cannot lose these capabilities.
Tier 2, which usually accounts for 15% of the load, contains appliances, equipment and operations that are a priority, but not critical.
“You’ll keep them on as long as you can without limiting the ability to keep your Tier 1 on,” Lewis said. “And then the Tier 3 loads are everything else.”
So freezers and refrigerators might be within a school’s Tier 1, communications equipment within Tier 2, and lights in Tier 3.
Each of the three tiers has a monetary value assigned.
“Nobody is going to pay more to keep the Tier 3 loads on than they would normally pay for electricity. But they are willing to pay a premium for Tier 1. They’re willing to pay a premium for Tier 2 as well,” he said.
State of Charge for Resilience
The Clean Coalition also included an approach to operating energy storage, called State of Charge for Resilience or SOCr, that it says brings efficiency to battery capacity management.
SOCr sets aside a fluctuating portion of the battery to guarantee resiliency for the facility. The non-SOCr elements of the battery capacity can then be used for price arbitrage, demand charge management or other approaches to economic optimization. SOCr represents the minimum state of charge needed, based on solar availability and load data, in 15-minute intervals. If there is more SOCr at any given time, then there is less battery available for arbitrage and other forms of economic optimization. If there is less SOCr, there is more battery available for economic optimization.
“Some people would just say, ‘Why don’t you just use that whole battery capacity as your SOCr, just have it available 100% of the time for resilience?’” he said. “Well because then you’re not getting the economic benefits of the battery. It’s just a massive expensive asset sitting there to provide backup for you.
Lewis said he hopes the RFP will offer a model for other solar microgrid projects. “We want to facilitate this everywhere. Any facility should really have a solar microgrid in today’s world in my opinion, and in the Clean Coalition’s opinion.”
To qualify to bid, a microgrid provider must have installed and received permission to operate — or be actively engaged in project construction — for at least one microgrid project.
The RFP also puts forward threshold requirements for experience with solar, batteries and power purchase agreements.
Sage Energy Consulting is releasing the RFP only to registered and qualified companies. Those interested can email email@example.com.A mandatory pre-proposal conference will be held at 9 am PT, Tuesday, May 26.
Proposals are due June 25, with July 10 as the tentative date for notification of top-ranked firms and August 25 as the target date for contract awards.