Unite to Light Blog

Public Safety Power Shutoffs,
Battery Power & You

November 18, 2019

When there are dangerous weather conditions the electric utilities in California, including Pacific Gas & Electric (PG&E), Southern California Edison (SCE) and San Diego Gas & Electric (SDG&E) may decide to shut off power in high fire risk areas in the hopes of minimizing fire risks from utility equipment. This is known as a Public Safety Power Shutoff (PSPS). 

In some circumstances the utilities may be able to target small regions for shutoffs, but when the weather conditions threaten large distribution lines that have no alternatives, people may find themselves without power even though they are far from the fire risk. This scenario occurred in early October 2019 when PG&E shut off power to 738,000 customers, impacting an estimated 1.5 million people

How can you prepare for a PSPS:

Everyone in California should be prepared for an emergency like a fire or earthquake. Luckily, a standard emergency kit is an excellent start to preparing for a PSPS. (See this blog on how to create a DIY emergency kit ). 

Unlike a natural disaster, for a PSPS you should have at least 48 hours to prepare. In addition, during a PSPS you may want to have more power for daily tasks than you would in an emergency where basic survival is the priority. 

What is the best way to get power during a PSPS:

We suggest everyone start with a personal power supply for the basics like a phone and an internet hotspot. You’ll want to make sure the battery is big enough to cover your needs for a few days and/or get a solar-powered battery. For multi-day outages, a solar-powered battery pack is ideal. (Check out our blog post on How to Pick A Solar Charger & Battery Bank.) 

The next step is some type of energy generator. In general we don’t recommend gas or diesel generators. They are significant sources of point-source pollution, rely on expensive fossil fuels, and can be dangerous if installed or used incorrectly (do NOT simply run an extension cord from a generator through a pet door!) For more information on the pollution impacts of back-up power options, see the Air Pollution Control District’s webpage. Therefore, the rest of this post is focused specifically on solar with battery back up. If you need help going solar, see the Community Environmental Council’s Solar FAQ.

If you already have solar and just want batteries in an emergency, you can consider a simple lead acid battery system, which can be readily recycled and may be the lowest cost option. 

If you want to use your batteries to reduce your electricity bills and your dependence on the grid, in addition to providing emergency power supply, consider load shifting batteries. Load shifting means that you charge your battery during the day and after the sun goes down, you use your stored energy instead of buying energy from the grid when it’s most expensive and polluting. Load shifting batteries can be programmed to automatically charge from your solar system when most economical, depending on your Time of Use rates, and net energy metering (NEM) credits. 

Should I back up my whole home? 

There are many factors that a homeowner should weigh when deciding what to back up. Frequently it is not economically viable to back up your entire home and practically, you may not need to power everything in your home in an emergency. Ask yourself what you would really need if you were to be without power for 3-5 days. People with medical conditions may have additional needs but the basics include power for: 

  • Refrigerator

  • Phones and WiFi

  • Minimal lighting 

  • Garage door

What else should I take into account? 

Batteries will degrade over time. Sizing the batteries to ensure that you have adequate capacity in the future is an important analysis that your installer should present. Take into account your daily depth of discharge (DoD) if you’re using your batteries to load shift. A battery that is discharged 80% on a daily basis will degrade faster than a battery that is discharged only 20% per day. 

Depth of Discharge (DoD) Impact on Battery Degredation
Slide was created by Dan Glaser of Panasonic for the Home Energy Workshop hosted by the Community Environmental Council on Nov. 13, 2019. 

Batteries can be expensive but there are federal and state incentives. The federal government is offering a 30% Investment Tax Credit (ITC) through the end of 2019  for batteries that are charged from solar systems. In 2020 it drops to 26%. Talk to your accountant to see if you can take advantage of the ITC. 

In California there is also the Self Generation Incentive Program (SGIP) for load shifting batteries. The current “step” is full and the state has not declared what the next incentive level will be but we assume it will follow a similar pattern to previous steps and come in around $0.20/watt-hour of installed storage capacity. This program has additional “equity” funds for low income and Medical Baseline households. 

Overall, solar and battery storage can make our homes and communities more resilient to emergencies and power shutoffs. If you have further questions, the Community Environmental Council is hosting Home Energy Storage Workshops in Ventura, CA on December 2, 2019 and at Montecito Union School on December 11, 2019. To learn more about the workshops and RSVP, visit the CEC website here. 

This is a joint post by April Price, Community Environmental Council’s Renewable Energy Program Manager and Megan Birney, President of Unite to Light. 

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