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.
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
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. We worked through 2019 on specifying and installing 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.
In 2020 the project was brought online and was operated to support resilience at the site and to help learn about the performance of the Solar+ system. Research activities concluded in 2021, and the final project report will be available soon.
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
- Initial project fact sheet (Dec 2017)
- Solar+ Optimizer: A Model Predictive Control Optimization Platform for Grid Responsive Building Microgrids – Energies journal (2020)
- Resilient buildings for fire-adapted landscapes: EE and flexible loads integrated with solar and storage microgrids – ACEEE Summer Study conference paper (2020)
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.
