The San Francisco Department of the Environment has developed a free tool to calculate how much solar PV and how much battery storage is needed for a particular building.
Some notes for use in conjunction with NC CLEAN PATH 2025:
Solar Resilient provides three levels of analysis: quick, standard and detailed.
- Quick: just enter your peak load, location, and percent of load you want covered
- Standard: upload your entire electricity profile for a year (downloadable from your utility)
- Detailed: enter detailed data on specific electrical needs of each room in a building
This tool, as the name suggests, was designed for building owners who want to install enough solar and batteries to ensure continued power during an outage. For implementation of NC CLEAN PATH 2025, we are installing solar+battery systems to provide a portion of a building’s power on an everyday basis. To adapt the tool for this purpose, follow these steps:
- Under target outage duration, select 1 day
- Depending which level of analysis you choose for your energy data:
- Quick or Standard – select 100% emergency load percentage (to find out what it would take to meet all your building’s power needs; you can reduce this later if your roof space or budget will not accommodate that large a system)
- Detailed – put in all of your expected load (not just items that need power under emergency conditions)
- In the advanced options, under Battery System Parameters, under Grid Service: select either “Frequency Regulation” or “Demand Charge Mitigation” (rather than “Resiliency Only” which assumes you using the system only in emergencies).
Solar Resilient doesn’t calculate cost, but you can export a PDF and give it to your installer to help them do a precise assessment and give you pricing. The Solar Resilient output doesn’t substitute for an installer assessment, but it’s a start in that direction.