Battery Backup for Texas Outages and Winter Storms

Texas homeowners often ask whether rooftop solar will keep the lights on if the grid goes down. The short, honest answer is: not by itself, not on a standard grid-tied system. A home battery, designed and installed for backup, is what allows selected circuits — or a larger share of the home, depending on capacity — to stay on during an outage.

Why solar usually shuts off when the grid does

A typical grid-tied solar system is required to stop sending power to the utility lines when the grid is down. That “anti-islanding” behavior is a safety rule, not a defect. It protects utility line workers who may be repairing downed or de-energized equipment, and it is reflected in standard interconnection policies. New Braunfels Utilities’ solar FAQ, for example, states that a standard grid-connected solar system must switch off during an outage or blackout so that energy is not sent onto the power line, and that a battery is necessary if the goal is to operate the solar panels during an outage. GVEC’s interconnection materials likewise focus on safe parallel operation with the cooperative’s system.

If your only equipment is grid-tied panels and an inverter without a backup-capable battery (or a similar backup device), you should plan on the system sitting idle until utility power returns.

What a home battery can do

A battery storage system can store electricity produced by your panels — or, depending on design and utility rules, electricity from the grid — and discharge it later. In backup mode, after the inverter detects a grid outage, the system can power the circuits included in your backup plan. Those often include lighting, refrigeration, communications, and maybe a well pump or medical equipment. Whole-home backup is possible on some systems, but only if the battery capacity, inverter power, and electrical design support it. We size storage around your priorities rather than promising that every load will run for days.

Runtime depends on battery capacity (kilowatt-hours), how many watts you are drawing, whether the sun is still producing on a backed-up solar array, and how the system is configured. A small battery will not run a large air conditioner for many hours. We will walk through that tradeoff in a consultation rather than invent a runtime number here.

Texas weather is the reason many people ask

Texas has seen multi-day winter outages and summer interruptions during periods of high demand. Winter Storm Uri in February 2021 is the event most people remember: extreme cold, record electric demand, and widespread outages on the ERCOT grid. The Federal Energy Regulatory Commission and NERC’s joint inquiry into the event documented the scale of the storm and the grid emergency. Summer heat can also strain the grid. A battery is not a substitute for a resilient grid, and it is not a generator with an unlimited fuel tank. It is a way to keep critical loads on for a period of time, and, day to day, to use more of the solar energy your roof produces in the evening.

Utility interconnection still applies

Adding a battery usually means additional interconnection paperwork, and sometimes additional metering. GVEC’s solar and/or battery interconnection agreement covers systems under 50 kW. NBU’s connection policy allows backup battery systems and describes a possible one-meter arrangement when a backup battery is installed with a smart switch, for as long as that switch is in operation. Your city may also require a permit and inspection. We handle that paperwork as part of the project.

What we will not claim

We will not guarantee that you will have power through every storm, or invent a number of outage hours a battery will cover in your house. Certified with most major solar and battery manufacturers. During your consultation we will review your loads and recommend equipment that fits your goals and your utility’s rules.

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