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X-Charge: Improve the profitability of your solar roof with a battery solution

26.01.2024 - Optimizing your electricity independence

Nowadays more and more people have a solar roof installed with the goal to improve their ecological footprint, to increase their independence from the grid and to reduce the costs of their energy bills. Sooner or later the question will come up: would a battery storage solution like X-Charge make sense for me or not? And if yes, how large should the capacity of such a battery be?

Very often there are unclear explanations and vague recommendations when it comes to this topic and people are left alone in figuring out what makes sense and what not. Reading through online guidelines and forums it usually gets quickly cumbersomely complicated and, in the end, it is still not clear what is now advisable.

Hence, we created here an easy-to-understand model, where you can very quickly find out if a storage solution makes sense for you and what battery size would be recommendable.

You simply enter below the yearly amount of kWh of electricity your solar roof generates. Usually if you are a homeowner this will be around 6’000 – 14’000 kWh per year. In a second step you enter the amount of electricity your household needs on a yearly basis in kWh. You can look the number up in your electricity bill. The price you pay for 1 kWh of electricity will depend on which grid operator you use and in which municipality you live. You can look up the current price applicable for you under this link from ElCom.
X-Charge battery storage solution
Alternatively, you can work with estimates and use our proposed numbers as rough guidelines. For example, the median electricity price in 2024 for single family houses in Switzerland is 0.29 CHF. The electricity needs of a 5-room detached house is estimated by ElCom at 7’500 kWh/year. If it includes a 5kW heat pump add another 5’500 kWh. If it includes an electric resistance heating, add 17’500 kWh.

These numbers do not factor in an electric car. As more and more people own an electric car and as this requires a lot of electricity, we added a separate field for the additional yearly electricity requirements your car will have. An electric car uses on average 20 kWh per 100 km. An average person in Switzerland drives around 16’000 km per year. This will require additional electricity of 3’200 kWh if one solely charges the car at home.

Finally, you can choose a battery size to be able to compare its impacts on your level of power self-sufficiency. The pie charts which will get generated below will visualize your grid dependence, according to the chosen battery size.

Electricity deficit:
Elec. deficit with battery:
Grid independence:
Grid indep. with battery:
Total profit in 20 years:
Break-even year:
Internal Rate of Return:
Estimated Inflation:
Average solar energy generation vs. energy consumption needs

The line chart compares the average power generation of your solar roof with the average energy consumption needs of your household across the year. The model calculates the performance based on real time measured reference numbers, applicable to “European” latitudes or countries with similar geographical settings. The energy requirements vary over the year, being higher during cold months due to the increased heating.

The chart visualizes the overall performance capability of a solar roof and to which degree it can cover the overall electricity requirements of the household (under the condition the power supply can always satisfy the demand at any point of time during the day).
Average monthly electric power purchase from grid with and without battery

The before mentioned condition of power supply always satisfying the demand at any point of time will usually not apply since the sun does not always shine when electricity is needed. If we want to run the dishwasher at night, the demand cannot get satisfied. This is where the battery comes into play, bridging the gap between available power supply when the sun shines and electricity demand in the evening, at night or during cloudy days.

The line chart visualizes the power deficit derived from the chart earlier before. The closer the deficit function is to the zero line the less electricity needs to be consumed from the grid.

Any electricity needed outside of time periods where the sun is shining, will require buying electricity from the grid to cover the power demand of your household. Depending on the size of the battery this can be drastically diminished. A solar battery solution is often able to generate full grid independence during the warmer months of the year.
Profitability of X-charge battery over an investment horizon of 20 years

Is it worth investing in a battery storage solution? The model calculates for you the economic profitability of the chosen battery. The initial investment will usually be paid back within a few years (breakeven point), as the yearly cost savings compound quickly, especially with rising electricity prices.

The model assumes an inflation rate of 3% and calculates the internal rate of return (IRR), a financial key performance indicator, essentially reflecting the interest rate at which the discounted return yields the capital investment. In other words, the growth rate where the money spent for this investment equals the amount of profit that same investment generates, essentially paying for itself. The higher the IRR number, the more profitable the investment.
If your solar system is not profitable and you have a low level of grid independence, buy an X-charge battery solution. We are more than happy to provide you with a quote. If you have any questions or believe the model might not cover fully the situation you are in, feel free to contact us. We will be delighted to assist you.
Results and conclusion

Please fill in the form above and hit the evaluate button that we can provide you with some results and a conclusion.

The calculations provided on this page are based on daily and monthly solar power performance estimates and electricity user patterns. They are intended to offer you a general understanding of potential solar power generation and expected profitability indicators of a battery solution. There are multiple variables which can affect solar energy production, including but not limited to geographic location, seasonal variations, and the specific characteristics of your solar installation. Please note that while we strive for accuracy, there will be instances where actual solar power output deviates from our estimates. These discrepancies can arise due to unforeseen changes in weather patterns, shading, or other environmental factors not accounted for in our calculations. As such, we present this information for informational purposes only, aiming to guide your decision-making process. However, we cannot be held responsible for any inaccuracies in the content, or any decisions made based on these estimates. We encourage you to consider this information as part of a broader analysis when planning your solar energy solutions.