California PSPS Events and Wildfire Shutoff History: Why Backup Power Is No Longer Optional
California utilities began implementing Public Safety Power Shutoffs (PSPS) in 2018 as a direct response to catastrophic wildfire events linked to electrical infrastructure failures. The deadliest was the 2018 Camp Fire, which destroyed Paradise and killed 85 people. Investigators traced the ignition to PG&E power lines in high-wind conditions.
SCE, which serves most of Riverside County including Temecula, Murrieta, and Menifee, has since conducted dozens of PSPS events. In October 2019, a single PSPS event affected over 179,000 SCE customers across Los Angeles, Orange, Riverside, San Bernardino, San Diego, Kern, and Ventura counties. Customers in some areas were without power for 3-5 days.
The pattern is not improving. As California temperatures rise and dry seasons extend, utility companies are using PSPS as a permanent risk management tool. SCE has published High Fire Threat District maps showing which areas face the greatest PSPS risk, and large portions of the western Santa Rosa Mountains, the hills east of Temecula, and areas near Anza all fall within Tier 2 and Tier 3 classifications.
Beyond PSPS, California's grid faces pressure from heat events. July 2022 and September 2022 saw grid emergencies with rolling blackout warnings across Southern California. SCE asked customers to reduce usage between 4pm and 9pm during multiple heat waves. Battery systems that charged during the day and discharged during those critical hours were among the few residential systems that avoided buying expensive peak power, and owners who had backup capability were unaffected by rolling events.
Why Solar Panels Alone Do Not Work During a Power Outage
This is the single most common misunderstanding among California solar owners. If the grid goes down, your solar panels shut off too, even if the sun is shining at full intensity.
The reason is a required safety mechanism called anti-islanding protection. When utility workers go out to repair downed lines, they need those lines to be dead. If grid-tied solar systems kept generating power and pushing it onto a supposedly dead line, workers could be electrocuted. To prevent this, every grid-tied inverter in the country is required by law to detect a grid outage and immediately stop generating power.
Your inverter is checking the grid signal hundreds of times per second. The moment it detects the grid has dropped, it disconnects and shuts down. This happens within milliseconds. You will not even notice the brief flicker before your home goes dark.
What This Means in Practice
- xSolar panels at full output: system shuts down during a blackout
- xNo grid = no power from your solar panels, period
- xThis applies to every standard string inverter and most microinverter systems
- +A battery with a transfer switch creates an isolated microgrid your panels can safely power
The only exceptions are off-grid systems (designed from scratch to operate without a grid connection) and battery-backed systems that include a transfer switch or a hybrid inverter with islanding capability. When you add a battery, the system detects the outage, disconnects from the grid, and forms its own isolated circuit. Your solar panels see a stable signal and continue generating. Your battery absorbs the solar output and powers your home. This is the only path to using solar power during an outage.
Battery and Solar Together: How True Backup Power Works
A properly designed solar-plus-battery backup system works in three stages during an outage.
Stage 1: Outage Detection and Island Formation (milliseconds)
The battery inverter detects grid loss and opens the transfer switch. Your home disconnects from the utility and becomes an isolated microgrid. The battery immediately begins powering your home from stored energy.
Stage 2: Solar Recharge (daytime)
Once your isolated microgrid is stable, your solar panels see the battery as their grid reference and begin generating. Solar output flows directly to your loads and charges the battery simultaneously. A good system running 5 hours of full sun can add 30-50 kWh back into a large battery bank each day.
Stage 3: Battery Discharge (nights and cloudy periods)
After sunset or during cloud cover, the battery discharges to cover your essential loads. The system manages power delivery automatically, prioritizing critical circuits if total load approaches battery limits.
The key engineering requirement is that your battery must have enough capacity and power output to carry your load through the night before the sun can recharge it. This is where sizing becomes critical, covered in detail below.
What Appliances You Can Run on Battery Backup: Load Calculation Reference
Every battery backup sizing decision starts with a realistic load calculation. The table below shows typical wattage consumption for common household appliances. Multiply the wattage by hours of use per day to get daily kWh demand.
| Appliance | Typical Watts | Hours/Day | Daily kWh | Notes |
|---|---|---|---|---|
| Refrigerator (modern) | 150W avg | 24 | 3.6 kWh | Cycles on/off; actual draw lower |
| LED lighting (whole house) | 100W total | 6 | 0.6 kWh | Estimate for evening use |
| CPAP (without heat) | 30-60W | 8 | 0.4 kWh | Critical for medical users |
| Home oxygen concentrator | 150-400W | 24 | 3.6-9.6 kWh | Life-critical; size accordingly |
| Phone and device charging | 50-100W | 4 | 0.2-0.4 kWh | Minimal impact on battery |
| Well pump (1 HP) | 750-1,500W | 2-4 | 1.5-6 kWh | High surge draw; requires battery with high peak output |
| Portable window AC (8,000 BTU) | 700-1,000W | 6-8 | 4.2-8 kWh | Consider over central AC during outage |
| Central air conditioner (3-ton) | 3,000-5,000W | 6-10 | 18-50 kWh | Requires multiple batteries; check surge rating |
| EV charger (Level 1) | 1,440W | 2-4 | 2.9-5.8 kWh | Slow trickle charge only during outage |
| EV charger (Level 2, 48A) | 11,500W | - | High | Not practical on battery backup; pause during outages |
Essential Loads Baseline Calculation
Refrigerator + lights + device charging + CPAP = approximately 5-6 kWh per day. A 13.5 kWh battery provides 2+ days of these essentials with no solar recharge. With solar recharging 20-30 kWh per day, you can sustain this load indefinitely.
Adding a well pump and one room of cooling raises daily demand to 12-18 kWh. A two-battery system (27 kWh) covers 1.5-2 days without recharge and is indefinitely sustainable with solar.
Battery Sizing for Backup: 10 kWh vs 20 kWh vs 30 kWh - What You Actually Need
Battery sizing for backup is driven by two independent questions: how long do you need to survive without any solar recharge, and how much power do you need to run simultaneously. Most homeowners focus only on the first question and miss the second.
- - Refrigerator
- - Lighting
- - Phone charging
- - CPAP / small medical device
- - Router/internet
- + Everything above
- + Well pump
- + Window AC unit
- + Electric stove (limited)
- + Garage door opener
- + Everything above
- + Central HVAC
- + Electric dryer
- + Home office equipment
- + Slow EV charging
The second sizing factor, simultaneous power output, is often underestimated. A single Tesla Powerwall 3 delivers 11.5 kW continuous output, which is enough to run most of a home's load except central air. If you try to run central air on a single Powerwall, it may not surge-start the compressor motor. Check your battery's continuous and peak output ratings before assuming it can run your heaviest loads.
For homeowners with electric vehicle chargers, the math changes significantly. A Level 2 EV charger draws 7-11 kW continuously. Running one during an outage on a battery backup system will drain most residential systems within 1-2 hours. The practical solution is to pause EV charging during outages and rely on the EV's existing charge as a transportation reserve.
Whole-Home Backup vs Essential Loads Panel: Which Installation Is Right for You
When you install a battery backup system, you have two wiring options. The choice determines both your installation cost and your outage experience.
Essential Loads Panel
A separate subpanel is installed alongside your main panel. You select 8-12 circuits to back up: typically refrigerator, lighting, select outlets, medical equipment, and HVAC controls. During an outage, only those circuits receive power.
Whole-Home Backup
A whole-home transfer switch is installed at your main panel. Every circuit in the home backs up automatically. You need a larger battery bank to sustain whole-home load for any meaningful duration.
For most Riverside County homeowners, an essential loads panel paired with a single 13.5 kWh battery is the most cost-effective starting point. It covers the critical 24-48 hour window that most PSPS events fall within, and it can be expanded later by adding a second battery without rewiring.
SGIP Equity Resiliency Adder: The Rebate That Covers Most of Your Battery Cost
California's Self-Generation Incentive Program (SGIP) offers a standard battery rebate for all qualifying homeowners, but there is an enhanced tier specifically for backup protection called the Equity Resiliency Adder. If you qualify, this rebate can cover the majority of your battery installation cost.
SGIP Equity Resiliency Adder Qualification Requirements
You must meet at least one condition from each column:
- - Located in HFTD Tier 2 or Tier 3
- - Experienced 2+ PSPS events in prior calendar year
- - Enrolled in Medical Baseline program
- - Enrolled in CARE or FERA low-income program
- - Seriously ill, dependent on life support equipment
- - Income at or below 80% Area Median Income
SGIP Rebate Amounts (2026)
SGIP funding is distributed in budget steps. Each step has a fixed pool. When a step exhausts its funding, no new applications are accepted until the next step opens. Reservation windows can close within days of opening during high-demand periods. The practical implication: file your SGIP application as soon as your permit is submitted, not after installation.
Your installer handles the SGIP application in most cases. Verify this before signing any contract and confirm that the installer uses the correct Equity Resiliency category on your application if you qualify. Incorrect categorization means you receive the standard rate instead of the adder.
Battery Brands Compared for Backup Performance: Powerwall 3, Enphase IQ, Franklin WH15, and Generac PWRcell
Not all home batteries are created equal when it comes to outage backup. The four most commonly installed systems in Southern California each have distinct strengths, weaknesses, and price points.
Tesla Powerwall 3
Top Pick for BackupThe Powerwall 3 combines the inverter and battery in a single unit, simplifying installation and reducing cost. Its 11.5 kW continuous output is the highest in its class, meaning it can handle well pumps, large appliances, and even some HVAC loads simultaneously. The integrated inverter handles both solar input and battery charging, eliminating the need for a separate string inverter.
Enphase IQ Battery 5P
Enphase's modular approach lets you add capacity in 5 kWh increments. A three-unit stack gives 15 kWh at 11.5 kW total output. The Enphase ecosystem integrates deeply with IQ8 microinverters, enabling whole-home backup with sunlight during an outage even without battery storage via the IQ8's Sunlight Backup feature. This makes it uniquely valuable for homes with existing Enphase microinverter systems.
Franklin Electric WH15
The Franklin WH15 is a newer entrant with competitive pricing and a strong backup story. Its 15 kWh capacity per unit gives more usable energy than the Powerwall 3 at a comparable price point. Units stack to 30 kWh for whole-home backup. The WH15 uses a 25-year warranty on its battery cells, the longest in the residential market. Franklin's installer network is smaller than Tesla or Enphase but growing rapidly in California.
Generac PWRcell XC
Generac's PWRcell positions itself for whole-home backup with the highest capacity options in the residential segment. The modular battery cabinet system scales from 9 to 36 kWh. Generac has significant brand recognition from its generator business, and many homeowners choosing PWRcell are specifically moving away from generators. The trade-off is higher cost per kWh compared to Powerwall or Franklin alternatives.
How Fast Does Your Battery Recharge From Solar During an Outage
The recharge rate during an outage determines whether your system can sustain indefinitely or whether you will eventually run out of stored energy. The math is straightforward once you understand the variables.
Outage Recharge Calculation
Find your solar system size in kW (example: 8 kW system)
Temecula averages 5.5 peak sun hours per day. Multiply: 8 kW x 5.5 hours = 44 kWh generated per day under ideal conditions
During an outage, battery inverter efficiency reduces effective generation by 5-8%. Net generation: approximately 40-42 kWh per clear day
Your loads run during daylight. Subtract daytime consumption from solar output to get net recharge. Example: 40 kWh generated minus 10 kWh daytime consumption = 30 kWh available to refill batteries
A fully depleted 13.5 kWh Powerwall 3 recharges from empty in under one clear afternoon with an 8 kW solar system
The critical caveat is inverter capacity during outage mode. Some hybrid inverters limit their solar input rate during backup operation to protect the battery from overcharging. Check your battery's maximum solar input specification, which is separate from its output rating.
Cloudy day performance drops solar generation to 20-30% of peak. Temecula averages fewer than 40 overcast days per year, and severe overcast that reduces generation below 15% is rare. For planning purposes, assume full recharge capability on the majority of outage days.
Generator vs Battery Backup: A Practical Comparison for California Homeowners
Generators and batteries both provide backup power, but they serve different use cases and come with fundamentally different trade-offs. The right choice depends on your outage frequency, duration, and household circumstances.
| Factor | Standby Generator | Solar Battery System |
|---|---|---|
| Installed Cost | $8,000-$20,000 | $9,000-$18,000 before incentives |
| After incentives (SGIP + ITC) | Not eligible | $4,000-$10,000 net cost |
| Fuel source | Natural gas or propane (supply dependent) | Solar (infinite during daylight) |
| Noise level | 65-80 dB (lawnmower level) | Silent |
| HOA restrictions | Often prohibited or restricted | Protected under California law |
| Outdoor air quality days | Cannot run during Red Flag conditions | Always operable |
| Maintenance | Annual service, oil changes, fuel stabilizer | Minimal; software updates only |
| Carbon monoxide risk | Real risk; kills dozens annually in California | Zero |
| Wildfire evacuation scenarios | Cannot take it with you; fuel storage is a hazard | Battery can charge EV before evacuation |
| Ongoing electricity bill savings | None | $800-$2,000+/year via TOU arbitrage |
The case for generators weakens in California specifically because PSPS events are often triggered by the same Red Flag fire weather conditions that make running a gas generator outdoors dangerous or restricted. A battery system does not care whether the air quality index is 300 or a wildfire is 2 miles away. It runs silently, indoors, and without any fuel logistics.
Storm Watch, Storm Guard, and Pre-Storm Charge Features: How They Work
One of the most underappreciated features of modern home battery systems is their ability to predict grid outages and pre-charge before the event occurs. Each major brand has implemented this differently.
Tesla Storm Watch
Storm Watch activates automatically when the National Weather Service issues a Severe Weather Alert, Tornado Watch, Tropical Storm Watch, Hurricane Watch, or High Wind Warning for your zip code. The Powerwall switches to charge-priority mode and targets 100% charge before the event. If you have a Time-Based Control policy that normally lets the battery discharge during off-peak windows, Storm Watch overrides it and keeps charging. You receive an app notification when Storm Watch activates. No action required.
Enphase Storm Guard
Enphase Storm Guard monitors weather forecasts and activates when a severe weather event is predicted within 48 hours of your location. The IQ Battery holds its charge in reserve rather than performing normal self-consumption cycling. Storm Guard disables automatic grid export to preserve stored energy for backup use. The feature works with the Enphase app and can be toggled manually if you want to pre-charge before an event that has not triggered an official NWS alert.
Franklin and Generac
Franklin WH15 and Generac PWRcell both offer manual backup reserve settings that you can configure via their apps. Both allow you to set a minimum state of charge that the battery will not discharge below under normal conditions. Generac's PWRview app also integrates weather data and can alert you to upcoming events. Neither currently offers the fully automated NWS-triggered charge mode that Tesla and Enphase have implemented.
How Long Do Outages Last in Riverside County: SCE Historical Data
Sizing your battery correctly requires honest data about outage patterns in your specific area. Riverside County has two distinct types of outages: equipment failures and storms (typically 2-8 hours) and PSPS events (12-72+ hours).
SCE Riverside County Outage Patterns
The 2019 PSPS event is the benchmark worst case for SCE Riverside County customers. Some areas near Anza and the mountain communities east of Temecula lost power for over 72 hours. For these households, a single 13.5 kWh battery with solar recharge is the minimum viable setup. Without solar recharge, even 30 kWh of storage would exhaust in 2-3 days running essential loads.
SCE's PSPS notification system sends alerts 48 hours, 24 hours, and 2 hours before planned shutoffs. This advance notice is what makes pre-charging so valuable. A battery with Storm Watch or a high backup reserve can reach 100% charge before the shutoff occurs, maximizing your covered duration before you need solar to recharge.
PSPS Notification and Preparation Checklist for Temecula Homeowners
SCE provides 48-72 hours of advance notice before PSPS events when possible. Use this window to maximize your battery performance and reduce household consumption during the outage.
When You Receive the 48-Hour Alert
- 1Check your battery app - confirm Storm Watch has activated or manually set backup reserve to 100%
- 2Run dishwasher, laundry, and other high-draw appliances while the grid is available
- 3Fully charge all EVs - your charged EV is also a backup transportation resource
- 4Pre-cool your home to 70-72 F; thermal mass keeps it comfortable longer once HVAC stops
- 5Fill water containers if you have a well pump - store a 72-hour supply before shutoff
During the Outage
- 1Reduce loads to essentials: pause EV charging, raise AC set point by 4-6 degrees
- 2Monitor battery state of charge via app; plan load reductions before reaching 20%
- 3Maximize solar hours: open curtains, avoid large loads between 10am and 3pm when recharge is fastest
- 4Unplug phantom loads: televisions, gaming consoles, and office equipment draw 5-50W even in standby
- 5Use SCE's outage map to monitor restoration progress in your specific area
Medical Baseline Allowance and SCE Backup Tariff Programs for Life-Support Customers
California customers who depend on electrically powered medical equipment have access to specific programs that both reduce their electricity costs and trigger enhanced PSPS protections.
SCE Medical Baseline Program
Customers with life-sustaining medical equipment (dialysis machines, ventilators, oxygen concentrators, CPAP, infusion pumps) qualify for additional baseline electricity allocation at the lowest rate tier. This adds approximately 16.5 kWh per day to your baseline allowance, reducing the amount of energy billed at higher rates. Qualification requires a physician statement.
Medical Baseline customers are also on SCE's Life Support Equipment (LSE) registry, which means you receive priority PSPS notification and SCE will attempt to contact you 24 hours before any planned shutoff.
SCE's PSPS Medical Baseline Portable Generator Program
SCE has operated a portable generator lending program for medical baseline customers during PSPS events in high fire risk areas. Eligibility and availability vary by event and customer status. Register with SCE's Life Support Equipment program well in advance of fire season to be included in outreach when the program activates. A home battery system eliminates reliance on this program entirely while providing continuous daily bill savings.
CARE and FERA Program Interaction with SGIP
Customers enrolled in CARE (income at or below 200% of Federal Poverty Level) or FERA (income between 200-250% FPL) already receive 30-35% discounts on their SCE bills. These same income qualifications make you eligible for SGIP's enhanced equity adder. The combination of SGIP rebate plus 30% federal ITC can result in a battery system installed at near-zero net cost for qualifying Medical Baseline CARE customers in HFTD zones.
Installing Battery Storage Without Solar Panels: Grid-Tied Battery for Arbitrage or Backup-Only
A common question from Temecula and Murrieta homeowners who rent, have shaded roofs, or simply are not ready to install solar: can I get battery backup without solar panels?
Yes. A battery can be installed as a standalone grid-tied system and charged directly from the SCE grid. Without solar, the financial case shifts to pure TOU arbitrage: charge during off-peak hours at 12-18 cents per kWh and discharge during on-peak hours when you would otherwise import power at 47-55 cents per kWh on SCE's TOU-D-PRIME rate.
Grid-Only Battery: What You Get and What You Give Up
- + Backup power for 24-36 hours on essentials
- + Bill savings from TOU arbitrage
- + 30% federal tax credit on battery
- + SGIP rebate eligibility if you meet criteria
- + Option to add solar later (battery is solar-ready)
- - No recharge during extended outages (battery is finite without solar)
- - Lower total bill savings vs solar + battery combination
- - Extended multi-day PSPS events will exhaust the battery
For short PSPS events of 12-24 hours, a standalone battery covers the critical window. For Riverside County households in areas with a history of 48-72 hour events, pairing the battery with even a modest 4-6 kW solar array dramatically changes the math. The solar recharge eliminates the finite-storage limitation.
Temecula-Specific Wildfire Risk Zones and Outage History
Temecula sits in a geographic transition zone between the coastal climate of San Diego County and the desert climate of the Inland Empire. This position creates specific wildfire risk patterns that directly affect PSPS probability.
Temecula Area HFTD Classifications
The Santa Ana winds, which blow from the northeast through Riverside County in fall and early winter, are the primary PSPS trigger in Temecula. When the National Weather Service issues a Red Flag Warning for winds over 25 mph with gusts above 40 mph and relative humidity below 15%, SCE evaluates circuit-by-circuit PSPS implementation based on their High Fire Threat assessments.
Temecula's most significant PSPS events have occurred in October and November during peak Santa Ana season. The 2019, 2020, and 2021 fire seasons all produced PSPS events affecting portions of the greater Temecula Valley. While central Murrieta and Winchester are less frequently affected, eastern Temecula and Rainbow have experienced repeated shutoffs.
To verify your specific address's HFTD classification, use SCE's public HFTD viewer at sce.com/wildfire. Your HFTD tier is the single most important factor in SGIP Equity Resiliency eligibility and determines the size of the rebate you can access.
Find Out What Backup Coverage Your Home Needs
Every household in Temecula and Riverside County has different load requirements, HFTD exposure, and budget. A 20-minute conversation gives you a specific battery recommendation, a cost estimate after SGIP and federal incentives, and a clear picture of what you can run during the next PSPS event.
Free assessment. No obligation. Serving Temecula, Murrieta, Menifee, Lake Elsinore, and Wildomar.
Frequently Asked Questions About Solar Battery Backup in California
Will my solar panels keep working during a power outage?
No. A standard grid-tied solar system shuts off automatically when the grid goes down. This is a required safety feature called anti-islanding protection. Without a battery, your solar panels cannot power your home during an outage even when the sun is shining. A battery-backed system with a transfer switch or off-grid capable inverter is required to use solar during an outage.
How many kWh of battery storage do I need for outage backup in California?
A household running refrigerator, lighting, phone charging, and a medical device needs roughly 8-12 kWh per day. One Tesla Powerwall 3 (13.5 kWh) covers 24-36 hours of essential loads. Two Powerwalls cover 48-72 hours and add the capacity to run a portable HVAC unit or standard well pump. If you need whole-home backup including central air, plan for 20-30 kWh minimum.
What appliances can a solar battery backup system run during a blackout?
A single 13.5 kWh battery system can typically run a refrigerator (150W), LED lighting (50-100W), phone and device charging (100W), a medical device such as a CPAP (30-60W), and a ceiling fan (50-75W) for approximately 24-36 hours. Running a well pump (750-1,500W) reduces runtime significantly. Central air conditioning (3,000-5,000W) requires multiple batteries or a load-managed system.
What is the SGIP Equity Resiliency Adder and who qualifies?
California's Self-Generation Incentive Program offers an enhanced Equity Resiliency Adder for households in High Fire Threat Districts or areas with two or more PSPS events, and who are enrolled in a medical baseline or CARE/FERA low-income program. The adder can reach $1.00 per watt-hour, making a 10 kWh battery eligible for up to $10,000 in direct rebates, often covering most or all of the installed battery cost.
How long do PSPS events typically last in Riverside County?
Most SCE-initiated PSPS events in Riverside County last between 12 and 48 hours, though some extended events have lasted 72 hours or longer during severe Santa Ana wind conditions. The October 2019 PSPS event affected over 300,000 SCE customers statewide. A battery system sized for 24-36 hours of essential loads covers the majority of Riverside County shutoff events historically.
Can I install a battery for backup without adding solar panels?
Yes. A battery can be installed as a standalone grid-tied system and charged directly from the utility grid. Without solar, the battery charges during off-peak hours at lower rates and discharges during peak hours or outages. However, the battery will not recharge during an extended outage without solar. For true backup resilience during multi-day outages, pairing a battery with solar is strongly recommended.
What is the difference between whole-home backup and an essential loads panel?
An essential loads panel (also called a critical loads panel) is a subpanel that separates selected circuits from the rest of the home. During an outage, the battery only powers those selected circuits, dramatically extending runtime. Whole-home backup uses a larger battery bank and a whole-home transfer switch, powering every circuit in the home. Whole-home backup costs $3,000-8,000 more but is required if you want to run central HVAC, a full-size range, or a well pump during outages.
Does Tesla Storm Watch automatically charge the Powerwall before a storm?
Yes. Tesla Storm Watch is an automatic feature that activates when the National Weather Service issues a weather alert for your area. The Powerwall switches to charge-priority mode and fills to 100% before the storm arrives, ensuring maximum backup capacity. Enphase IQ batteries offer a similar feature called Storm Guard. Both features activate without user intervention and reset to normal operation after the alert expires.