Sandbar Solar & Electric Microgrid

Invinity and partners deliver pioneering microgrid storage project in Santa Cruz, California.

(Originally published on, 2019)

In late 2018, Sandbar Solar, one of the leading solar installers for distributed generation commercial, industrial, and residential solar PV systems in Northern California, moved into its new headquarters. This 11,500 square foot facility will allow Sandbar to increase its ability to provide best-in-class service to its growing customer base.

Back in the planning stages of the project, the final design of the facility had been far from clear. Sandbar’s new headquarters would be built on un-improved land within city limits, without any existing utilities to the site. That meant that Sandbar President Scott Laskey was struck with a choice: Pay the high cost and plan for the multi-year process of bringing PG&E electric utility power to the building, or explore an innovative stand-alone micro-grid solution. 

The choice was easy – despite the facility being located less than 50 feet from a power pole, Sandbar’s facility was going to operate independent of the electric grid.

Microgrid storage batteries onsite at Sandbar Solar.

Having served Northern California’s solar PV needs since 2004, Sandbar knew that solar power was up to the task. And with solar-coupled storage batteries emerging as an important new market segment, Scott felt that a solution was possible. However, there were several challenges: Battery systems were typically rated only for a limited number of charge / discharge cycles; the kinds of software that would combine solar, storage and backup generation together were cost-prohibitive for a system of this size; and the batteries needed to run totally on solar power were very expensive. Scott’s not one to give up, though, and felt confident he could find more advanced solutions that would get his facility off grid, on time and on budget.

Lithium batteries have become a common addition to many residences and businesses in recent years, where they can be used to capture self-generated solar power and redeploy that power when it is most useful. Sandbar had experience with these installs on a commercial and residential scale, but knew that lithium ion batteries’ limited cycling capabilities wouldn’t work for a facility that runs 24/7/365 on battery and solar power. Further, Sandbar felt that the limited commercial track record of many of the emerging companies in the lithium space added additional risk to that storage technology. When Scott discovered the vanadium flow battery (VFB) from Invinity (then Avalon), he knew he had a solution. The VFB employs vanadium flow battery technology, proven to deliver limitless cycling over decades of use.

Sandbar had implemented a number of solar monitoring systems and controllers for his clients, but none of those devices had the capabilities needed for a complete system integration. Enter Ageto Energy, a Colorado-based microgrid controls solutions provider whose mission is to accelerate the adoption of renewable energy by simplifying the integration and control of off-grid and behind-the-meter power systems. Ageto Energy and Invinity had previously worked together to deliver small demonstration microgrid systems; with the Ageto Renewable Controller’s ability to easily incorporate batteries, solar PV and backup generation into a cohesive, high-performance local power system, the company was an ideal fit.

Finally, Sandbar needed to get the job done on a budget. That’s when a unique characteristic of the Invinity VFB came into play. The “flow” in Flow Battery means that energy is stored in a liquid “electrolyte”; and in this case, the vanadium dissolved in that electrolyte is the element that actually stores the energy. The reason the VFB is able to deliver stable performance over decades of use is that vanadium never gets lost or degrades. This means that the vanadium retains 100% of its value at the end of life. Not only does that greatly improve recyclability, but from a financial perspective, it means the electrolyte can be rented at very low cost, not sold as part of the battery.

This option was a slam dunk from Scott’s perspective; not only did renting the VFB electrolyte decrease his costs, but he saw it as a great tool for growing Sandbar’s storage business. He commented that “One of the biggest hesitations our customers have about adding batteries to new or existing solar arrays is that they don’t understand their value, and they are legitimately concerned about the technology and commercial risk from what can be a significant up-front investment. By deferring a large portion of the battery cost we not only help our customers afford storage, it also gives them comfort that the battery is going to work, as expected, over its design life.”

Ageto Energy’s energy resource-agnostic Ageto Renewable Controller (ARC) is able to seamlessly integrate both renewable and conventional power sources, providing Sandbar with a complete turnkey microgrid control solution. This platform was delivered the ability to model the performance of the microgrid, develop and optimize real-time controls, and monitor performance once the system was operational.

Invinity, for its part, is thrilled to have delivered the world’s first flow battery project where the vanadium electrolyte is rented, not sold as part of the battery. This type of model has been discussed since I joined the vanadium flow battery industry back in 2005; only with real commercial applications like Sandbar’s becoming a reality is the model ready to be implemented. Of course, getting the volume of vanadium electrolyte that will be required to fill future market needs will require the collaboration of a great team of vanadium battery producers, suppliers and financiers; I’ll leave that discussion for a future blog post.

And how has this groundbreaking solution worked to date? Since November 2018, Sandbar’s facility has been up and running totally independent of the grid. While winter weather in Santa Cruz isn’t always sunny enough for the full facility load to be delivered from the solar panels, in the first three months of operation the on-site natural gas generator has had to run only infrequently to top off the batteries when solar gain is insufficient. With its new facility up and running, Sandbar is looking to grow its business faster than ever – with a new, potent offering of grid-independent solar, durable batteries and integrated controls to give its customers the same advantages the new facility enjoys.

Do you operate a commercial or industrial facility where becoming more – or totally – grid independent will help you save money? Contact us to learn more!

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