Time-of-Use Battery Storage: Stop Paying Peak Electricity Rates
Store energy when it’s cheap, use it when it’s expensive, automatically.
In many states, utilities charge different rates depending on when you use electricity. These time-of-use (TOU) pricing plans can lead to high bills, especially during peak hours in the late afternoon and evening. With a Fortress Power battery system, you can store energy when it’s cheap and use it when rates spike, saving money without sacrificing comfort.
How It Works
Fortress Power batteries charge during off-peak hours — typically when solar production is high or utility rates are low. When peak pricing kicks in, your system automatically discharges stored energy to power your home, reducing or even eliminating expensive grid usage during those high-cost windows.
It’s a smart, automatic way to control your costs and get the most from your solar setup.
Where Time-of-Use (TOU) Pricing Applies
Time-of-use pricing is increasingly common in states like California, Arizona, Massachusetts, and New York, where utilities are shifting toward demand-based billing. If your utility charges TOU rate, you may be paying 2-3 times more for the electricity that you consume during the peak hours.
Even if you don’t have TOU yet, many utilities are expected to adopt it as the grid evolves.
Battery storage gives you a long-term hedge against rising and variable electricity rates.
Benefits of Fortress Power for TOU Savings
Automatically shift usage from high-rate to low-rate periods
Pair with solar for full self-generation during peak hours
Lower your monthly bill without changing your energy habits
Add resilience with backup power during outages
Compatible with utility incentive and VPP programs in select areas
Extend the value of your solar system by using stored energy after sunset
When paired with smart system design and utility program participation, Fortress Power batteries give you the flexibility to not just survive TOU billing — but turn it into a financial advantage.
Not Sure Where to Start? Design Your System First.
Before you buy a single component, use the Fortress Power System Recommendation Tool to map out your build. Enter your loads, application type, panel information and your backup goals — and the tool will size your battery and inverter configuration based on what you actually need. It takes the guesswork out of system sizing and helps you avoid the two most common DIY mistakes: undersizing storage or overbuying hardware you don’t need. Free to use, no account required.
Common Questions About Time-of-Use Battery Storage
Time-of-use pricing is a billing structure where your utility charges different rates depending on when you use electricity. Rates are typically lowest overnight and during midday when grid demand is low, and highest during late afternoon and evening peak hours when demand spikes. In states like California, peak rates can be 1.5 to 3 times higher than off-peak rates. TOU pricing is already common across California, Arizona, Massachusetts, and New York, and is expanding to more states as utilities modernize their grids.
A Fortress Power battery system charges during off-peak hours, when rates are lowest or when your solar panels are producing more than you need. When peak pricing kicks in, your system automatically switches to stored energy, reducing or eliminating your reliance on grid power during the most expensive hours. The whole process is automatic, no scheduling, no manual switching, and no change to how you live.
Fortress Power systems are programmed with your utility's specific TOU schedule during installation. Utility companies are required to publish their peak and off-peak windows, and your installer or Fortress Power's team programs that schedule directly into your system's software. Once configured, your battery operates automatically around those windows without any input from you. If the TOU schedule ever changes, Fortress Power can update your system in minutes, ensuring you are always protected.
Yes. Fortress Power battery systems are designed to work with solar panels — your panels generate energy during the day, which your battery stores and dispatches during peak rate hours in the evening. If you don't have solar yet, adding panels alongside a Fortress Power battery system is the most effective way to maximize your TOU savings. Contact our team to get a recommendation for both solar and storage sizing based on your home and utility rate schedule.
In many cases, yes, or close to it. The extent depends on your home's energy consumption during peak hours and the size of your battery system. A properly sized Fortress Power system can cover the majority of your peak-hour usage, significantly reducing what you owe the utility during those high-rate windows. Contact us for a system recommendation based on your actual usage and utility rate schedule.
Yes. Fortress Power battery systems handle TOU optimization and backup power simultaneously. Your installer configures a minimum reserve — a portion of capacity held back specifically for outage protection — while the rest of the battery operates in TOU mode. You get bill savings during normal operation and reliable backup power when you need it, from the same system.
Savings vary based on your utility's TOU rate structure, your home's energy consumption patterns, your system size, and your location. States with steep peak rate premiums, like California, generally see the highest savings. Contact our team for an estimate based on your specific utility and usage or use the Fortress Power System Recommendation Tool to get a starting point.
Yes. Time-of-use pricing is part of a broader shift in how utilities manage grid demand, and regulators in many states are actively pushing utilities toward demand-based billing structures. Installing a battery system now protects you against future rate changes — your system is already configured to respond to TOU schedules and can be reprogrammed as your utility's pricing structure evolves.
How Fortress Power Compares to Other Backup Solutions
Not all backup power is created equal. While traditional generators and older battery technologies offer some protection during outages, they come with limitations — from noise and maintenance to short lifespans and safety concerns. Fortress Power’s lithium iron phosphate (LFP) systems deliver clean, reliable, and long-lasting energy you can count on — with fewer compromises and more control.
Features | Fortress Power Solution | Other Lithium-ion Solutions
| Lead Acid | Generator |
|---|---|---|---|---|
| Applications | Backup Power, time of use, self-consumption, and off-grid | Backup Power, time of use, self-consumption, and off-grid | Backup Power | Backup Power |
| Depth of Discharge | 100% | 100% | 50% | N/A |
| Battery Chemistry | Safe Technology | Potential thermal runway or firing | Risk of harmful gasses | Environmental Pollution |
| Life Cycles | 8,000+ (15+ years) | 3,000 | 500-1,000 | N/A |
| Warranty | 10 years | 10 years | 6 months | 2 years |
| Fuel cost | $0 | $0 | $0 | $70-$130 per day |
| Maintenance | No | No | Every 6 months | Yes |
| Energy Cost ($/kWh) | 0.14 | 0.30 | 0.65 | 0.50 |
Want to Save More with Smart Energy Storage?
Get a free consultation and see how Fortress Power can help you manage your energy use, reduce your bills, and take control of when and how you use power.
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