Building Resilience with Solar+Storage

Fundamentals of Resilient Solar

The frequency of grid outages has increased in recent years, and a growing number of communities, residents, and building owners are seeing the value in ensuring their solar panels can provide them with backup power when the grid is down.

Source: Blackout: Extreme Weather, Climate Change and Power Outages. (Kenward & Raja 2014)

Installing solar energy in a way that allows it to generate power during grid outages is seemingly simple and yet often quite complicated. A typical solar array shuts down when the grid is down. This avoids sending power back to the grid, which could endanger workers who are trying to restore the grid. However, the technology exists to disconnect, or “island,” the PV systems from the grid so they only serve the building or microgrid where they’re located. This then allows the PV systems to provide power even when the grid is down. Before making a decision about resilient solar, it’s important to be familiar with the basics of how it works, its benefits, and the possible challenges. Introductory resources like this fact sheet from the City University of New York and this webinar by the Clean Energy Group are a great place to start.

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Community Plans, Permitting, and Programs

While storage projects ultimately come down to planning for each individual installation, leading cities like New York and San Francisco are exploring solar+storage opportunities across their communities and developing city-wide plans and roadmaps to accelerate deployment, remove barriers, and drive down costs. In 2016, New York became the first city in the U.S. to have an energy storage goal—100 Mwh of energy storage by 2020. The city’s DG Hub Resilient Solar Roadmap introduces strategies for addressing the key hardware, software, economic, and policy barriers to solar+storage in an urban environment. In San Francisco, work to plan storage projects across the city began with the creation of a map identifying critical facilities used during emergencies.

Local and state governments can encourage the deployment of resilient solar by taking actions such as passing tax incentives for energy storage—a step recently taken in Maryland—and clarifying and streamlining the permitting process, which can save costs. Communities can work with building inspectors, fire departments, and other code officials to clarify the process, remove barriers, and create opportunities to learn about storage systems, which are often new to these agencies and officials. Fire departments have expressed concerns about the fire safety of batteries, and a number of resources exist—or are in development—to ensure fire safety concerns are appropriately addressed when permitting these systems.

Many communities are creating microgrids that link multiple buildings and are powered by renewable energy generators, including wind and solar. While these systems are technically more complex, they can provide many benefits in power quality and reliability. The number of microgrids in the U.S. is growing significantly, and examples like this mixed-use community in Prince George County, Maryland and the campus of Illinois Institute of Technology are proving the benefits of microgrids.

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Financing Resilient Solar

While the costs of solar+storage are both on the decline, they are still significant and financing these systems can be a challenge. In certain energy markets, these systems can pay for themselves based on energy costs alone. However, the value of resilience often determines whether a system makes economical sense. This factsheet developed by the City University of New York helps explain the economics of solar PV projects that include battery storage systems in New York City. Financing mechanisms are emerging to implement projects and can attract private capital to make solar and resilient power installations more affordable.

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