Schatz Energy Research Center

Solar+ microgrid design

The canopy of the BLR gas station with solar modules

Solar+ (“solar plus”) systems combine onsite solar generation with battery storage, responsive load controls, and microgrid isolation hardware. These systems make businesses more resilient by providing electricity during a power outage — and they are able to integrate high levels of renewable energy on the grid, by storing solar power for nighttime use and managing loads to optimize energy use. Smaller businesses usually can’t afford to build a custom, fully-featured microgrid, which is where the solar+ concept comes in. We are developing hardware and software tools that make solar+ systems easily deployable for many users, extending the reach of microgrid technology to smaller sites. Our focus here is working with a common building type, convenience stores, so we can design with replication in mind.

Diagram of integrated process for solar+ at convenience stores: reactive power support, model-predictive control of building thermal systems, targeting sites based on remote sensing, managing peak loads through EV charging, owner/operator value proposition based on energy upgrade, and optimal sizing and control

There are currently 153,000 convenience stores in the United States, and 12,000 in California alone. Many of these stores share a common building design. They also have similar energy needs, including HVAC and refrigeration, which typically require backup power. And, many of these locations could host rooftop solar. Replicability, a need for onsite power generation, and the capacity to host solar, together make these sites ideal for solar+ design.

Major project elements

Interior of BLR convenience store

For this project, we’re developing components and integration technology that could eventually support “plug and play” packages that make microgrid design much easier and cheaper. This would help store owners and energy planners assess site viability and implement solar+ systems at large scale. Our pilot site is a gas station and convenience store at the Blue Lake Rancheria. In 2018, we coordinated the installation of a 60 kW array of high efficiency SunPower modules on the fueling area canopy. The pilot will be completed in 2019 with installation of the control devices, switchgear, and other microgrid components. Our project partners at Lawrence Berkeley National Lab have been developing the microgrid control software. Building off the open source XBOS (“Extensible Building Operating System”) framework, the LBNL team has been adding model-predictive control and microgrid communications features. The pilot microgrid is scheduled to go online in 2019.

The tools developed by this project will help achieve California’s goals in renewable energy generation, demand response, resilience, and climate stabilization — through reducing costs, improving performance, and catalyzing energy markets to increase distributed generation via solar+ systems.

Publications

Partners

The Schatz Center is the prime contractor and lead technology integrator for the project. Major funding is provided by the California Energy Commission’s Electric Program Investment Charge. Project partners include the Blue Lake Rancheria, Serraga Energy, LLC., and the Building Technology and Urban Systems Division at Lawrence Berkeley National Laboratory.

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