How dynamic tariffs are reflected in the electricity bill

28.10.2025

Source: E & M powernews

A study commissioned by electricity provider Naturstrom quantifies the savings potential for households with a dynamic tariff. Costs can fall even without an electric car or heat pump.

For whom is a dynamic electricity tariff worthwhile? The consulting firm "Neon Neue Energieökonomik" investigated this in a short study commissioned by Naturstrom. The authors calculated the costs of a fixed-price tariff and a dynamic tariff for four model households in the period from September 2024 to August 2025. The basis for the "hourly simulation" was a fixed price tariff of 33.9 cents/kWh, while the dynamic tariff varied between 5 and 133 cents/kWh during the observation period. In addition, time-variable grid charges were included in the calculation. The Westnetz grid area served as a blueprint, "whose grid fees roughly correspond to the national average", as the authors of the study write.

They assumed an annual consumption of 2,800 kWh for two of the modeled households and 4,000 kWh for the other two. One household each had a higher consumption during the day, while the other consumed more in the morning and evening hours.

It was also modeled how much can be saved with a dynamic tariff if the household uses an electric car, a heat pump or a battery storage system. The authors assumed that the electric car requires 5 to 10 kWh of electricity per day and the heat pump more than 15 kWh on average.

Up to 70 euros a year without an electric car

Regardless of the size of the household and the level of electricity consumption, the dynamic electricity tariff would have been worthwhile for all households surveyed over the past twelve months, the authors conclude. "However, the savings for households without an electric car or heat pump are low overall and only amount to a small percentage of the electricity costs," they continue. The bottom line is that they save 20 to 70 euros.

If the household has an electric car and charging at the home wallbox is postponed to hours when electricity prices are low, the charging costs are reduced by 164 euros per year, according to the study. If, on the other hand, the car is always charged as soon as it is connected to the wallbox, the dynamic tariff does not bring any significant financial benefits.

More than 80 percent savings with time-variable grid charges

The savings effect can increase significantly through reductions in grid fees. The grid operator Westnetz grants a discount of 169 euros per year if it is allowed to temporarily limit the charging capacity from 11 to 4.2 kW. If time-variable grid charges were also applied, electricity costs could fall by more than 80 percent, according to the modeling. The annual charging costs would be reduced from 537 to 93 euros.

As the authors point out, operating a heat pump with a dynamic electricity tariff without flexibilization is hardly cheaper than with a fixed price. However, it would not be more expensive either, even though the heat pump tends to run at higher electricity prices, especially on cold days, they say. The situation is different if the pump heats "intelligently". According to the simulation, the electricity costs for its operation are then six percent lower than the costs with a fixed price tariff. The savings can be increased to up to 28 percent through reductions in grid charges.

Home storage saves 50 euros per year

According to the experts, whether a home storage system in combination with a dynamic tariff pays off "depends heavily on the costs and the dimensions of the storage system". The subject of their model was a storage unit with a capacity of 2.4 kW. Taking the purchase costs into account, they calculated an annual saving of 50 euros.

"A dynamic tariff can be extremely attractive financially," says Naturstrom CEO Oliver Hummel. And points out another effect: "A smartly charged electric car uses up to 42 percent of the electricity that would otherwise have been curtailed due to negative exchange electricity prices."

The short study "Savings potential for households through dynamic electricity tariffs" is available to download free of charge.

Author: Manfred Fischer