What Is a Dynamic Tariff?

In the past, most households were on a “Fixed Tariff,” paying a set price per kilowatt-hour (kWh) regardless of when the electricity was used. A dynamic tariff changes this by linking your electricity price directly to the wholesale market (such as EPEX SPOT), where the price per kWh fluctuates over time based on supply and demand on the power grid.

Under dynamic electricity pricing in Europe, price fluctuations can be significant:

• Peak prices: During high-demand periods, especially winter evenings (17:00–20:00), electricity prices can reach €0.60–€1.00 per kWh, and occasionally even higher
• Off-peak prices: When renewable generation is high (overnight or during sunny/windy midday hours), prices may drop close to €0.00 per kWh, or even become negative (–€0.05 to –€0.20 per kWh), meaning consumers are effectively paid to use electricity.

The table above highlights the key differences between Dynamic Tariffs and Fixed Tariffs across several important dimensions.

How to benefit from dynamic tariff with the exsiting PVs?

Therefore, for homeowners who already have solar panels installed, adding a battery is a smart and affordable way to save more money and use your own energy better. Solar panels make most of their electricity during the day. But many families use more power in the evening, after the sun goes down. At the same time, electricity prices are usually low when the sun is shining and higher at night. This means some solar energy is wasted, and you miss chances to save money with dynamic tariffs. By adding a battery system, extra solar power can be stored. The battery can also charge when electricity is cheap or even free, and use that energy later when prices are high. This helps homeowners lower the bill and use energy in a smarter way. The easiest way to add a battery to an existing solar system is with AC coupling. You do not need to change your inverter, installation is fast, and it works well with most solar systems.

Solution

The Sunpura S2400AC and S4800AC home battery systems are specially designed for retrofitting existing PV systems in Europe.

From a hardware point of view,

• Real plug and play: Installation is simple and takes about 15 minutes — just unpack the system, stack the inverter and battery, plug it into a standard socket, and connect it according to the manual, like using a normal household appliance.
• Ideal to retrofit the existed system: Non-invasive upgrade with no changes to the current solar system or home electrical structure, so PV system stability and its existing warranties are not affected.
• Flexible expansion：The system has a modular and stackable design, allowing flexible expansion from 2.4 kWh up to 43.2 kWh whenever needed.

From the perspective of HEMS Software,

Sunpura’s integrated Home Energy Management System (HEMS) can be upgraded, so it can become smarter over time, with better control, new features, and stronger cost-saving performance, without changing the hardware.

• It also provides:
  • Compatibility with 700+ European electricity providers (including Tibber, Octopus Energy, and more) and support in 20 European countries. Just open the APP and then choose the providers you have already subscribed to or the available provider in your region.
• Provides day-ahead electricity price forecasts andreal-time price updates every 15 minutes. With dynamic electricity pricing, you can see electricity prices in advance, avoid peak-price periods, and automatically optimize energy consumption to reduce electricity bills.
• Real-time monitoring of grid connection power and energy data is displayed in the Sunpura App.
• The HEMS automatically uses solar power for your home first and stores excess energy in the battery to be used when electricity prices are higher.

• Smart functions for dynamic tariff savings
  • Zero feed-in: In many parts of Europe, feeding excess electricity into the grid is restricted. The Sunpura EMS monitors grid connection power in real time and directs surplus solar energy into the battery. With just one button, you can activate the zero feed-in function to ensure full regulatory compliance.
  • Self-consumption mode: By combining Weather forecasts, Dynamic electricity prices and Household consumption patterns, Sunpura EMS automatically plans energy usage one day in advance—maximizing self-consumption, minimizing costs, and enhancing grid interaction.

Important Note: Smart Meter Required

To use dynamic electricity tariffs, a smart meter is essential. Dynamic pricing requires time-based consumption data, which can be provided by a smart meter. It records real-time electricity usage, distinguishes consumption by time periods, automatically transmits data to the electricity provider, and supports API integration with the Energy Management System (EMS). Sunpura battery systems are compatible with many leading smart meter brands, including Shelly, Everhome Ecotracker, HomeWizard P1, Powerfox, Tibber, and IOMeter. If a compatible smart meter is already installed, no changes to the existing setup are required. Users can directly connect it to the Sunpura energy storage system and immediately benefit from dynamic tariff optimization.

ROI and Payback Time

For detailed battery recommendations based on different PV system sizes, see our article: 👉 https://sunpuraenergy.com/ac-coupled-battery-storage-roi-europe-existing-pv/

• Typical payback period: 3–4 years
• With dynamic tariffs, the return on investment can be even faster.

Conclusion

With the implementation of the Energy Act 2025, the gradual phase-out of net metering, and increasing electricity price volatility, Europe is entering a new era of energy consumption. For households with existing solar PV systems, combining AC-coupled home battery storage, intelligent Home Energy Management System (HEMS) software, and 15-minute dynamic electricity pricing is one of the most effective ways to reduce electricity bills, avoid peak-price exposure, and achieve true energy flexibility. Designed for this evolving energy landscape, the Sunpura S2400AC and S4800AC enable solar systems to perform at their best in dynamic electricity markets, helping homeowners future-proof their energy investments against ongoing policy and market changes.