Virtual Power Plant (VPP) services are growing in Texas. Companies such as Base Power, Octopus, and others are offering leased batteries with free installation or installation fees of less than $1,000, which customers can use as backup power in the event of an outage.
The economics of getting one of these batteries depend on the customer. In this article, we are going to focus on understanding how long the battery may last during an outage, the variables that affect battery drain, and some techniques and best practices you can use to maximize its duration.
What variables affect battery duration?
- Size of the battery: This is the most obvious one: the bigger the battery, the better. However, not every household can qualify for the largest battery configuration. Constraints such as available space, zoning, electrical configuration, and other installation requirements can play a big role. The VPP company will normally let you know what battery size is appropriate for your home. In general, the larger the battery, the higher the rental fee, if there is one.
- Battery charge percentage at the moment of the outage: If you have a battery through a VPP, you probably accepted a contract that allows the company to charge and discharge the battery when they consider it convenient. In some programs, they may only guarantee a minimum reserve of around 20%. The reason is mostly economic, and it is part of why they can offer the battery at such a large discount. Their business model is based partly on charging batteries when electricity is cheaper and discharging them when electricity is more expensive. As you can see in our Texas Battery Tracker, the cost of electricity on the Texas grid changes constantly. Long story short, electricity is often cheaper during periods of high solar generation and more expensive around sunset, when demand remains high but solar production falls. So imagine an outage happens at 8:00 p.m. Depending on how the VPP operated your battery that day, its charge could already be significantly lower than 100% when the outage begins.
- Month, day, and hour when the outage happens: This is also affected by the reason above. Battery charge levels can change throughout the day depending on how the VPP operates the system. Another important factor is the time of year and the hour when the outage occurs. Losing power at midnight during the winter is very different from losing power during a heat wave in August at 8:00 p.m. If you have a gas furnace, for example, your house may use very little electricity during a winter night because the A/C is not running. During a hot August evening, however, the A/C may be one of the largest loads in the house. Clear Energy Facts has created a home battery calculator where you can upload your Smart Meter Texas data from the previous year and get an idea of your electricity consumption and how quickly a battery could drain at a particular time or on a particular day.
Recommendations to maximize your battery
- According to the EIA, In 2024, Texas reported 1,614.3 minutes, or approximately 26.9 hours, of annual outage time when major event days were included, compared with 153.4 minutes, or approximately 2.6 hours, when major event days were excluded. These two distinctions are important. During a normal outage, there is a good chance that power will be restored relatively soon. Major events such as hurricanes, severe storms, and winter freezes are different and can result in much longer outages. Always keep an eye on how much electricity you are consuming and plan accordingly. If your priority is to have electricity continuously during a multi-day outage, a generator may be a better option than relying exclusively on a battery, but you should be prepared to spend more than $15,000 for some whole-home generator installations, plus ongoing maintenance. The A/C is usually one of the major appliances driving electricity consumption, so during an outage it is advisable to minimize its use and increase the thermostat setting when possible.
- Extend your backup time by charging the battery during long outages: Some companies offer an optional connection that allows you to connect a generator and recharge the batteries during a major outage. This option can be very valuable if you lose power for many hours or potentially for several days. Instead of running the generator continuously, you may be able to use it periodically to recharge the battery and then continue running the house from the battery.
- Use fans instead of A/C when possible: In line with the first recommendation, use ceiling fans or portable fans when possible instead of relying entirely on the A/C. Fans consume considerably less electricity and can help keep the house more comfortable while extending the battery's remaining runtime.
- Avoid unnecessary high-consumption devices: Electric ovens, washing machines, dryers, pool pumps, EV chargers, and other high-consumption devices can draw a significant amount of electricity. You generally do not need to use these appliances during an emergency, so avoiding them can significantly extend how long your battery lasts.