Battery or no battery? How DC net metering settles the question

What net metering already does

Under net metering, Pepco credits the solar power you send to the grid at the full retail rate, and those credits offset power you use later. In effect, the grid already stores your daytime surplus for you at full value.

A battery that stores the same surplus to use in the evening saves very little more, because the credit was already worth the same as the power. That is the core reason battery payback is weak in the District.

When a battery earns its place

Batteries make sense when keeping power on during an outage matters. Solar alone shuts down when the grid goes down, for the safety of line workers; a battery with a backup gateway keeps chosen circuits running and recharges from the panels the next day.

• Medical equipment that cannot lose power.
• A sump pump in a basement that floods.
• Working from home where an outage costs a day's work.
• Refrigerators and freezers full of food in a long summer outage.

If none of these apply to you, it is reasonable to skip the battery and add one later if your needs change.

What happens in an outage

When the grid goes down, a backup gateway disconnects the house from the utility lines within a moment. The battery then powers the circuits on the backup panel, and the solar keeps running in daylight because it now has a safe, isolated system to feed. Surplus solar recharges the battery.

When the grid returns, the gateway reconnects the house and the system goes back to normal net metering. Most owners notice the outage only because the neighbors' lights are off.

Without a gateway and battery, grid-tied solar shuts down during an outage and stays down until the grid returns, even on a sunny day.

What batteries cost in 2026

The federal 25D credit that once covered batteries charged by solar ended on January 1, 2026 for homeowner-owned systems. For households at or below 80 percent of area median income, DC's Solar Advantage Plus rebate offers up to $10,000 toward solar or solar plus storage.

Sizing for outages

Two numbers matter. Energy capacity, in kilowatt-hours, sets how long the battery lasts. Power, in kilowatts, sets what it can run at once and whether it can start large motors. A battery with plenty of energy but limited power may keep the fridge going all day and still fail to start central air.

Most DC homes choose partial backup: essentials moved to a small backup panel fed by one battery. Whole-home backup is possible, but usually needs two or more batteries and costs far more.

Batteries and electric cars

A home battery is usually too small to charge an electric car meaningfully during an outage, and charging an EV from it would drain the backup meant for essentials. For everyday charging, net metering means daytime solar already covers EV miles at full value whether the car charges by day or by night.

If an EV is part of your plans, the more useful step is making sure the main panel has room for a charger alongside any future battery.

Adding a battery later

If you are not sure, a battery can be added to most systems later. Many retrofits connect on the AC side and leave the panels and inverter untouched; others replace an aging string inverter with a hybrid model. Planning the main panel and space for a gateway at install time makes a later retrofit simpler.

Questions to ask before buying

• Which circuits will stay on, and for how long on a cloudy day?
• Can the battery start the largest motor you want backed up?
• Does the quote include the gateway and the backup panel?
• How much reserve is kept for outages, and can you change it?
• Can a second battery be added later?

If a quote cannot answer these clearly, it is selling a box rather than backup.

Sources

1. EnergySage: DC solar rebates and incentives
2. A1 Solar Store: Solar battery storage cost
3. NuWatt Energy: Battery storage cost 2026
4. City Renewables: Cost of solar per watt in DC, 2026

Figures are as published by the sources above in 2026 and can change. Call (202) 978-0232 to check how they apply to your address.