Grid-Tied Battery Backup
Keep Your Home Running When the Grid Goes Down
Whether you need to protect a few critical circuits or your entire home, a battery backup system gives you automatic, seamless power during outages. Add solar to offset your electric bill year-round.
Two Approaches to Backup Power
Every grid-tied home is different. Some need to keep just the essentials running. Others want the whole house covered. Here is how both options work.
Critical Load Backup
A dedicated subpanel protects the circuits that matter most: refrigerator, well pump, lighting, internet and communications, and medical equipment. During an outage the battery feeds only these loads, stretching runtime significantly.
Best for:
- Homes where long outages are rare but disruptive
- Budget-conscious projects that still need protection
- Properties with a well pump or medical equipment
- Starting small with room to expand later
Whole Home Backup
The battery system backs up every circuit in the house. When the grid drops, the transfer switch isolates the home and the batteries (plus solar, if installed) power everything: HVAC, kitchen, laundry, EV charger, and more.
Best for:
- All-electric homes that cannot afford any downtime
- Homes with electric heat, hot water, and cooking
- Families who want a seamless outage experience
- Properties that also want solar self-consumption and peak shaving
How It Works
A grid-tied battery backup sits between the utility meter and your home electrical panel. During normal operation it charges from the grid (or solar). During an outage it takes over automatically.
1. Grid Is Up
Batteries charge from the grid or solar panels. Your home runs normally. If you have solar, excess production can feed the grid and earn credits on your bill.
2. Outage Detected
The transfer switch isolates your home from the grid in milliseconds. Batteries take over seamlessly. Lights stay on, appliances keep running.
3. Solar Extends Runtime
If solar panels are installed, they continue producing during the outage and recharge the batteries during daylight. A solar-plus-storage system can ride out multi-day outages.
Solar: Offset Your Power Bill Year-Round
Backup is just one piece of the picture. Solar panels paired with batteries give you daily financial benefits on top of outage protection.
How Solar Offsets Your Bill
Grid-tied solar panels produce electricity whenever the sun is shining. That production directly reduces what you draw from the utility. Under net metering, any excess production you export to the grid earns credits that offset future usage, often bringing your monthly bill close to zero during high-production months.
Over a full year, a properly sized solar array can offset 80-120% of a typical home’s electricity consumption. The batteries add a second layer of value by storing that solar energy for use after sunset instead of exporting everything to the grid.
Solar + Battery Benefits
- Lower monthly bills — solar production offsets grid consumption during daylight hours
- Net metering credits — excess solar exported to the grid reduces future bills
- Self-consumption — batteries store daytime solar for evening use instead of buying from the grid
- Outage protection — solar recharges batteries during extended outages
- Federal tax credit — the 30% ITC applies to both solar panels and battery storage
Peak Shaving: Another Way Batteries Pay for Themselves
If your utility charges demand fees based on your highest usage spikes, the same battery that protects you during outages can also shave those peaks and reduce your bill every month.
What Is Peak Shaving?
Peak shaving uses your battery to cap the amount of power your home draws from the grid during high-demand windows. The battery discharges to cover the difference, so the utility meter never sees the spike. This directly reduces demand charges on your bill.
For KEC customers in North Idaho, this is especially valuable. KEC’s Peak Use Charge bills you based on your single highest hour of grid draw during peak windows (6-10 AM and 5-9 PM). A battery system can hold your visible grid usage at or below 5 kW, eliminating the demand penalty entirely.
One Battery, Multiple Benefits
The same hardware that protects your home during outages can shave demand peaks every day. Battery systems are programmable: they charge during off-peak hours (or from solar), then discharge during peak windows to keep your grid draw flat. That means you get backup protection and monthly bill savings from a single investment.
Critical Load vs. Whole Home: Side by Side
Frequently Asked Questions
Do I need solar to have battery backup?
No. A battery backup system works with grid power alone. The batteries charge from the grid during normal operation and discharge during outages. Solar is an excellent addition because it extends outage runtime and offsets your electric bill, but it is not required.
How long will my home run on battery during an outage?
Runtime depends on battery capacity and what loads are drawing power. A critical-load system with 10-15 kWh of storage can run essentials for 12-24+ hours. A whole-home system with 20-40 kWh can power the full house for 8-16 hours. Adding solar panels extends runtime indefinitely during daylight.
Can I start with critical-load backup and expand to whole-home later?
Yes. This is one of the most common paths. We install the inverter and transfer switch sized for future expansion, then start with enough battery capacity to cover your critical loads. When you are ready, we add more battery modules and move additional circuits onto the backup panel, or upgrade to whole-home coverage.
What is the difference between backup and peak shaving?
Backup protects your home during grid outages. Peak shaving is a daily financial strategy where the battery discharges during high-demand periods to reduce demand charges on your utility bill. The same battery system can do both. For details on how peak shaving works with KEC’s rate structure, visit our KEC Peak Shaving page.
How does solar offset my electric bill?
Solar panels produce electricity during daylight hours, reducing what you draw from the grid. Under net metering, any excess solar production is exported to the grid and earns credits on your account. Over a full year, a properly sized system can offset most or all of your electricity consumption. Batteries add another layer by storing daytime solar for evening use rather than exporting it all.
Is the federal tax credit available for batteries?
Yes. The 30% federal Investment Tax Credit (ITC) applies to battery energy storage systems, whether they are paired with solar or installed standalone. This can significantly reduce the upfront cost of a backup system.
Will the battery switch over automatically during an outage?
Yes. The transfer switch detects a grid outage within milliseconds and automatically isolates your home and activates battery power. You may not even notice the switchover. When grid power returns, the system reconnects to the grid and begins recharging the batteries automatically.
Ready to Protect Your Home?
Whether you want to start with critical loads or cover the whole house, we will design a system that fits your home and your budget. Free consultation, no pressure.
Serving grid-tied homeowners in North Idaho and Eastern Washington