A battery in a home without solar — can it actually pay off?

A battery in a home without solar panels can make sense — but the calculation is different from a solar owner’s. Without your own production, the battery has two earning legs left: it can charge when power is cheap and cover the house’s consumption when it is expensive — and it can sell its response capability to Energinet as ancillary services. That second leg is independent of the sun, which is exactly why the question “does a home battery require solar panels?” has a clear answer: no.

What can a battery do without solar panels?

Most home batteries are sold as accessories to solar installations, but technically a battery is just storage with a fast inverter. Without solar it works with two things:

1. Spot arbitrage: charge cheap, use expensive. The electricity price is set on Nord Pool and swings across the day — typically low at night and high at the evening peak. The battery charges in the cheap hours and covers the house’s consumption in the expensive ones. You can see today’s swings hour by hour on the electricity prices page.
2. Ancillary services for Energinet. The grid must be kept at 50 Hz at all times, and Energinet buys reserves such as FCR-D in daily auctions — one for every hour. Batteries are the fastest reserve on the grid, and the reserve sells whether it is sunny, cloudy or the middle of winter. The background is explained in the article on grid balancing.

Note the difference: arbitrage is a saving on your electricity bill, while ancillary services are actual income paid out to you.

How does the battery participate without solar?

A single household’s battery is too small to bid into Energinet’s auctions on its own. Instead it joins a virtual power plant run by an aggregator, which pools many households and bids the combined capacity. NM1 has been live since June 2025.

Without solar, the battery’s state of charge is more predictable, and the control system bids accordingly: when the battery is full, it is bid in the “deliver to the grid” direction; when it is empty, in the “absorb” direction; in between, it can respond both ways. We only bid in when doing so is worth more than not doing so — you never risk the battery buying power at an inconvenient time.

Activations are short — seconds to minutes — and come in bursts: some days 5–6 of them, then perhaps ten days without any. On average a few per week. The rest of the time the battery simply stands ready, and that readiness is what Energinet pays for.

Can it pay off?

That depends on three things:

• The battery’s price and size. Without solar, the battery must earn back its entire price through arbitrage and ancillary services — there is no self-consumption leg to help. The price factors are covered in the article on home battery price and earnings.
• Your consumption and your electricity contract. Arbitrage requires an hourly-priced contract — otherwise power costs the same all day and that leg disappears.
• Market prices. Both spot-price swings and FCR-D auction prices vary. Past earnings are no guarantee of future earnings — calculate conservatively, and don’t base the purchase on a single year of high prices.

For some households the answer is yes, for others no — but the calculation must count all the legs, and ancillary services are the leg most often forgotten. See how earnings are calculated on the earnings page.

How to get started

If you already own a compatible battery, signing up is free — there is no hardware cost to NM1. The battery needs stable wifi (typically 2.4 GHz), and integration happens through the inverter manufacturers, including Solplanet. See which batteries and inverters we can connect, or start directly on the get started page. As a customer you follow the battery’s activations and your payouts in the web app.

If you are considering solar panels later, the battery only becomes more valuable: you add the self-consumption leg on top — read more in the article on a battery for solar panels.