What Is Public Safety Power Shutoff (PSPS) And Can Solar and Battery Help?
What’s worse than facing a heat wave and imminent wildfire threat? How about facing a heat wave and imminent wildfire threat without power.
As extreme heat and wildfire events increase in frequency and intensity, power utilities are using Public Safety Power Shutoffs (PSPS) to reduce the risk of power lines sparking potentially devastating wildfires.
PSPS is basically the lesser of two evils. Being without power is disruptive and uncomfortable, but it’s far less destructive than a major wildfire.
But there is a third option. By pairing solar with battery storage, homeowners supply their own power during Public Safety Power Shutoffs.
What is Public Safety Power Shutoff (PSPS)?
Public Safety Power Shutoff is, well, exactly what it sounds like. It’s a planned power outage that utilities use to keep customers safe by reducing the risk of power lines sparking wildfires.
Although it’s not a preferred option for anyone, PSPS is one of several tools utilities use to prevent electricity infrastructure from sparking wildfires. From 2011-2015, electrical power was the third most common cause of wildfire in California, including some of the largest and most devastating events.
According to the California Public Utilities Commission (CPUC):
“Electric utility infrastructure has historically been responsible for less than 10% of reported wildfires. However, fires attributed to power lines consist of roughly half of California history’s most destructive fires.”
Also known as rolling blackouts or de-energization, PSPS events occur most frequently during peak wildfire season (September and October in California). But with wildfire season extending nearly year-round, they may occur throughout the year.
For example, California investor-owned utility PG&E performed five PSPS events in 2021, including one in January.
- January 19
- August 17-19
- September 20-21
- October 11-12
- October 14-16
PSPS events can be short, but typically last for 24-48 hours until weather conditions improve and the electric infrastructure has been inspected and deemed safe to re-energize.
Where Do Planned Safety Power Shutoff Events Occur?
PSPS events are most common in California. Between 2013 and 2019, the state averaged 8,000 wildfires per year and the three largest utilities performed 33 PSPS de-energization events (5.5 per year, on average).
To minimize disturbance to their customers, utilities target the highest-risk areas of the grid to shut down. Even so, a single PSPS event can leave tens of thousands of customers and hundreds of critical facilities without power for days.
The higher the wildfire risk, the greater the chance of utilities shutting down the grid to prevent starting a fire. Below is a map of the Tier 2 and Tier 3 high-fire threat zones in California. Use this map to zoom in for more detail.
Example PSPS event timeline
Utilities monitor weather conditions weeks ahead to try to plan for potential PSPS. Conditions such as low humidity, strong winds, and dry vegetation elevate the risk of fire danger, which can trigger a PSPS event. When possible, utilities send notifications days before a possible planned outage.
Here’s a typical PSPS timeline, according to Southern California Edison (SCE):
Planning and monitoring:
- 4-7 days ahead: Extreme weather conditions forecasted, PSPS planning begins
- 3 days ahead: Notifications of possible PSPS event sent to community leaders (government officials, first responders, hospitals, etc)
- 2 days ahead: Initial notifications sent to customers
- 1 day ahead: Updates with timing information sent to customers and community leaders
- 1-4 hours before: Notifications that power will be shut off sent
Outage and re-energization:
- Power shutoff: Notifications sent to costumers and community leaders
- Preparing for re-energization: Field crews inspect infrastructure to determine if re-energization is safe. Notifications are sent out before restoring power
- Power restoration: Notifications are sent when power is restored
- PSPS All Clear: Final notification that PSPS is no longer being considered
Of course, extreme weather can be unpredictable and PSPS can occur more suddenly based on conditions. It’s best to prepare for PSPS events ahead of time, especially if you rely on medical equipment that requires electricity.
Can You Use Solar Power During a Planned Safety Power Shutoff?
The short answer is maybe. Whether you can use solar panels to power your home during a Planned Safety Power Shutoff – or any power outage, for that matter – depends on a few things.
Most solar systems are designed to automatically shut down during any power outage. This prevents the flow of electricity onto the grid, ensuring the safety of utility workers and emergency responders.
However, there are two ways to keep your keep your solar panels producing during a power outage:
- Use a special inverter system that automatically disconnects from the grid during outages
- Use solar battery storage to store and use your own energy
According to CPUC, both can be viable options during Planned Safety Power Shutoffs. However, there are pros and cons to both options.
Inverters for opportunity power
One way to continue producing solar power during an outage is to use special inverter systems that produce opportunity power by forming a “grid-agnostic” system. Most notably, the SMA Sunny Boy and Enphase Ensemble systems can be used to produce opportunity power when the grid is down.
However, there are limits to how much opportunity power your solar system can produce.
For example, the SMA Sunny Boy system is designed to produce a maximum of 2,000 watts of power. That’s enough to power essential appliances like a fridge, along with phones, a fan and maybe a TV. But that’s not enough to keep the air conditioning going.
And, of course, off-grid solar without battery storage will only provide power while the sun is shining.
Opportunity power may be enough for some homeowners during Planned Safety Power Shutoff events. However, solar paired with battery storage is a much more robust solution.
Solar with battery storage during power outages
By pairing solar with battery storage, which now qualifies for a 30% federal tax credit, you essentially create your own mini-utility to power your home during Planned Safety Power Shutoff events.
Exactly how much power solar and battery can provide depends on the size of the system, your energy usage, and the sun exposure. A typical solar battery can store 10kWh of electricity, which is usually enough to power priority appliances (fridge, lighting, phone charging) for 24-48 hours.
If the sun is shining and your solar panels are producing enough electricity to power your home and charge your battery, you may be able to run your entire house – including air conditioning – during the PSPS.
Talk about energy independence!
Should You Use A Gas Generator During PSPS?
Gas and diesel generators can provide backup power during planned and unplanned power outages, but they are not as clean, quiet, and seamless as solar backup.
According to the CPUC, “(Generators) can also be noisy and pose safety hazards, including fire and carbon monoxide poisoning… If you don’t understand how to use your generator, you risk damaging your property, endangering your life, and endangering the lives of repair crews and first responders working in your community.”
Not only are they loud and polluting, fuel for generators can be expensive, cumbersome to handle, and dangerous to store (especially during wildfire season). Gas generators may also violate community noise ordinances.
The Bottom Line
In many areas of California, Planned Safety Power Shutoff events are a part of life that can leave tens of thousands of people without power for a few hours to several days. It’s expected that PSPS events will become more common as wildfires increase in frequency and intensity.
Pairing solar with battery storage is the best option for keeping your power on during PSPS events or any power outage.
PSPS Frequently Asked Questions
What is PSPS?
PSPS stands for Planned Safety Power Shutoff – which is exactly what it sounds like. When wildfire conditions intensify, electricity utilities will shut off certain parts of the grid to reduce the risk of power lines sparking a wildfire. Also known as de-energizations, this is a common practice in California and other Western states during peak wildfire season in September and October.
Can I use solar during a power outage?
Unless connected to battery storage, most home solar systems are automatically shut down during planned and unplanned power outages. This prevents them from putting energy onto the grid and ensures the safety of repair workers and emergency responders.
If the solar system is connected to battery storage, it can be used to power a home during grid outages, such as Planned Safety Power Shutoffs. There are also special inverters that automatically detach from the grid during outages, enabling the solar system to directly power the house to an extent.
Why are they turning off the power in California?
Utilities in California perform Planned Safety Power Shutoff events to reduce the risk of electrical infrastructure starting a wildfire. On average, there are five to six PSPS events per year that typically last 24-48 hours. Your electricity provider should notify you before, during, and after PSPS events.