Savings potential with photovoltaics and energy storage

Combining a photovoltaic (PV) system with an energy storage system is becoming increasingly popular, as it allows homeowners to harness their own solar power, reduce their dependence on rising electricity prices, and actively contribute to the energy transition. But how much can actually be saved, and how quickly does such an investment pay for itself? In this article, we use a sample calculation to demonstrate the savings potential of a PV system with storage and the associated financial benefits.

Energy saving potential of a PV system with energy storage

A PV system converts solar energy directly into electricity that you can use for your household. This self-consumption reduces your electricity bill because less electricity needs to be drawn from the grid. An energy storage system ensures that excess electricity is stored and can be used later—for example, at night or on cloudy days. This maximizes the use of self-generated electricity and increases independence from the grid.

The main advantages:

• Lower electricity costs : Self-generated electricity is cheaper than grid electricity.
• Independence from electricity price fluctuations : Those who use self-generated electricity remain more stable against fluctuations in grid electricity prices.
• High self-consumption : A storage system enables a high self-consumption rate, which increases the profitability of the system.
• Feed-in tariff : Excess electricity that is not stored can be fed into the grid and generates additional revenue.

Let's take an average four-person household with an annual electricity consumption of approximately 4,500 kWh as an example. The household opts for a 5 kWp photovoltaic system with an energy storage capacity of 5 kWh . The current average electricity price in Germany is around 35 cents per kWh .

Assumptions:

• Acquisition costs for PV system (5 kWp) : approx. 10,000 euros
• Acquisition costs for energy storage (5 kWh) : approx. 6,000 euros
• Total cost : 16,000 euros
• Self-consumption rate without storage : approx. 30%
• Self-consumption rate with storage : approx. 70%
• Annual electricity price increase : 3%

1. Savings through self-consumption

Without storage, the household could directly consume approximately 30% of the solar power generated, equivalent to 1,350 kWh. With storage, this self-consumption rate increases to approximately 70%, equivalent to 3,150 kWh.

• Without storage : 1,350 kWh x 0.35 € = 472.50 € annual savings
• With storage : 3,150 kWh x 0.35 € = 1,102.50 € annual savings

2. Revenue from feed-in tariffs

The remaining solar energy not consumed can be fed into the grid. The current feed-in tariff is approximately 8 cents per kWh .

• Without storage (70% feed-in) : 3,150 kWh x 0.08 € = 252 € annual revenue
• With storage (30% feed-in) : 1,350 kWh x 0.08 € = 108 € annual revenue

3. Total annual savings

Self-consumption and feed-in result in the following total annual savings:

• Without storage : 472,50 € + 252 € = 724,50 € per year
• With storage : 1,102.50 € + 108 € = 1,210.50 € per year

Calculating the payback period

With total costs of 16,000 euros and annual savings of 1,210.50 euros, the following payback period results for the investment in the PV system and storage:

• Payback period with storage : 16,000 € / 1,210.50 € ≈ 13.2 years

The system will pay for itself after approximately 13 years. Since the lifespan of a PV system and a storage system is typically 20 to 25 years, the remaining years can be used to generate significant financial savings.

Long-term financial savings

Assuming electricity prices rise by 3% annually, self-consumption through the PV system and storage will result in significant savings over a 20-year lifetime. After the 13-year payback period, the household will benefit from free electricity costs for another seven to twelve years, which could result in total savings of over €25,000.

High savings potential with PV system and storage

A photovoltaic system with energy storage offers enormous savings potential and is a future-proof investment. By maximizing self-consumption, electricity costs can be significantly reduced, and annual savings continue to grow as electricity prices rise. Thus, the investment can pay off not only through financial benefits, but also through sustainable independence from the power grid and lower CO₂ emissions.

If you'd like to invest in solar energy and energy storage, we'd be happy to provide you with personalized advice. We'll calculate the optimal system for you and show you how you can save money in the long term while protecting the environment.