How does battery storage for solar panels work, and what benefits does it provide?

Battery storage is a gamechanger for solar panel owners, as it allows you to store surplus electricity from your solar panels and use it when you need it – e.g., in the evening or on cloudy days. At EcoRay, an independent advisory solar panel platform, we use advanced technology, artificial intelligence, global data, and data-driven APIs to design solar panel systems with battery storage that are tailored to your consumption. This maximizes both your financial savings and your independence from the grid. Here we explain how battery storage works and what benefits it provides, especially in combination with our optimized solar panels, which deliver 30% higher production than previous estimates.

How does battery storage for solar panels work?

Battery storage for solar panels is a technology that stores the surplus electricity your solar panels produce when the sun is shining, so you can use it later. Here is a simple explanation of how it works: Solar panels produce electricity: When the sun shines, your solar panels generate electricity. For a 10 kWp system, this can be up to 11,700–14,300 kWh annually (with EcoRay's 30% higher yield thanks to UV-coated and light-sensitive panels). Direct consumption: The electricity you use in your home, e.g., for a heat pump, electric car, or household appliances, is taken directly from the solar panels when they are producing. Surplus electricity is stored: If you produce more electricity than you use (especially midday), the surplus is sent to the battery instead of the grid. Use of stored electricity: When the sun is not shining – e.g., in the evening, at night, or on cloudy days – you draw electricity from the battery instead of buying expensive electricity from the grid. Intelligent control and grid balancing: With EcoRay's advanced control systems, the battery can also be programmed to charge when electricity prices are low or sell electricity to the grid when prices are high, optimizing your finances. The batteries, we use, are typically lithium-ion-based, which are safe, efficient, and have a lifespan of 10–15 years. They are integrated with an inverter that converts the solar electricity into usable alternating current and controls the flow of electricity between solar panels, battery, home, and grid.

Benefits of battery storage

Battery storage makes your solar panel system even more valuable, especially in Denmark, where electricity prices can fluctuate, and solar production varies between seasons. Here are the main benefits:

Increased self-sufficiency

Without a battery, a typical household uses 35–45% of the solar panels' production directly. With a battery, you can increase this to 60–75%, meaning you use 7,020–10,725 kWh of a 10 kWp system's annual production of 11,700–14,300 kWh. Result: You buy less electricity from the grid, significantly reducing your electricity bill, especially if you have large electricity consumers like a heat pump or electric car.

Greater savings on the electricity bill

By storing surplus electricity, you avoid buying electricity at high prices in the evening or during winter months. For example, you can save up to 70% on your electricity bill in a household with an annual consumption of 12,000 kWh if you combine solar panels with a battery. EcoRay's intelligent control ensures that the battery is used optimally, e.g., to cover consumption peaks or charge your electric car.

Optimized sale of surplus electricity

With a battery and grid balancing, you can store electricity and sell it to the grid when prices are highest (e.g., DKK 1.00–1.50 per kWh during peak periods). For a 10 kWp system, you can sell 3,575–6,110 kWh annually, generating an income of DKK 3,575–9,165 per year. This makes your investment more profitable compared to sending surplus electricity to the grid at lower prices without control.

Independence from the electricity market

Battery storage makes you less dependent on fluctuating electricity prices and potential price increases. You can use your own electricity when the grid is expensive, thereby protecting your finances from fluctuations. In the winter months, when solar production is lower, the battery can still supply stored electricity or charge from the grid when prices are low.

Flexibility for large electricity consumers

If you have a heat pump (3,500–6,000 kWh/year) or an electric car (2,500–5,000 kWh/year), the battery can store electricity to cover their consumption, e.g., in the evening or at night. This shortens the payback period for your solar panel system to 5–6 years instead of 8–9 years without a battery.

How does EcoRay help you?

At EcoRay.dk, you can get a personal calculation that combines your household consumption, solar panel production, and battery size. Our platform includes detailed financial analyses that also take into account grid balancing and the possibility of selling electricity to the grid. We help you choose the optimal battery size and inverter solution that matches your goals for economy, sustainability, and energy security.

Conclusion

Battery storage for solar panels is an effective way to increase your self-consumption, reduce your electricity expenses, and create economic value through grid balancing. It also provides increased energy independence and contributes to a greener electricity grid. If you want to ensure that your solar panel investment achieves maximum value, you should consider battery storage as an integrated part of your solution. Try EcoRay’s calculator today to get an overview of what battery storage can do for you.