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Generate electricity yourself: Time for an electricity storage
Generate electricity yourself: Time for an electricity storage
Video: Generate electricity yourself: Time for an electricity storage
Video: Energy 101: Electricity Generation 2023, February

It has never been so cheap to generate your own electricity. Technical advances and significantly lower costs for photovoltaic modules and electricity storage make it possible. Still, there are a few questions that are relevant to homeowners. Information from

In the landscape, the blue-glowing photovoltaic systems are a matter of course today. More than 1.5 million such systems convert sunlight into electricity across Germany. A little more in summer, a little less in winter. Most PV systems are in private hands on the roofs of single or multi-family houses.

Is a photovoltaic system still worthwhile?

In the past, solar power generated a decent return. The calculation was very simple: the homeowner buys a photovoltaic system and gets the money back step by step via the state feed-in tariff. After 10 to 12 years, the acquisition costs have paid for themselves and the PV system earns money.

That has changed. The feed-in tariff has dropped so much that this model no longer works today. But it is worth taking a closer look because it has changed even more. Due to mass production, photovoltaic systems now only cost a fraction of what they were five or six years ago. At the same time, the price of electricity has risen significantly. In Germany it is around 29 cents / kWh. In Europe you only pay more for it in Denmark.

For homeowners, this means that they can now use a photovoltaic system to produce electricity at a cost that is far below the electricity price. You don't have to be an arithmetic artist to find out that you can save a lot of money by using this electricity yourself. A photovoltaic system is now more worthwhile than ever, but only for those who also use the electricity they generate themselves. Self-consumption is the new keyword.

Why electricity storage?

Anyone who uses a photovoltaic system for their own consumption will quickly reach its limits. At noon, the system delivers a lot of solar power, only then there is nobody at home who can use it. In the evening again, a lot of electricity is needed, but then the sun is no longer shining. In this situation, an electricity storage is almost inevitable. This means that the unused electricity is available from day in the evening and at night. Self-generated electricity is available around the clock regardless of the weather. This is also proven by the figures: while a household with a photovoltaic system can only supply around 30 percent of its own electricity a year, together with a storage system it is around 75 percent. In summer it can even be 100 percent. As a result, the electricity bill drops enormously. With a family home with an annual consumption of 3, 500 kWh, you can save an average of around 750 euros per year.

Produktions- und Verbrauchskurve für mit Photovoltaik erzeugten Strom
Produktions- und Verbrauchskurve für mit Photovoltaik erzeugten Strom

This is what 98% electricity self-sufficiency looks like in the web portal of the solar battery. Yellow shows the production of the PV system and gray shows the electricity consumption in the household. The green curve shows when the solar battery has charged and violet when the battery has powered the household.


Aren't electricity storage systems still immature and far too expensive?

Many people still consider electricity storage for private use to be a dream of the future, which is also priceless. What many do not know is that such energy storage devices have given an enormous boost to development. Both technically and economically. The German manufacturers are world leaders. Electricity storage systems are no longer a niche application that only a few idealists treat themselves to, but have become interesting for the general public. The number of electricity storage systems installed in Germany more than doubled from 10, 000 to 25, 000 today. Providing your own, ecologically generated electricity in the long term hardly costs more than a small car today. A complete storage system such as the solar battery is available from € 5, 475 including VAT. It is significantly smaller than a refrigerator and can be attached to a wall. There is a lot of intelligence in the storage system that can trim the household for maximum self-consumption by weather forecast and self-learning algorithm. With a lifespan of 10, 000 charging cycles or 20 years, the solar battery has reached a technical maturity that is more than sufficient. In addition, there is a 10-year guarantee on all parts.


With this box you get a piece of independence from the public networks in the house. It adapts to any environment and does not even attract attention in living areas.

Photo: Sonnenbatterie / Fotolia / 3darcastudio

How do electricity storage systems differ?

Where there is a large market, there are also many different manufacturers. When it comes to energy storage, almost every manufacturer also uses a different technology. It is therefore very difficult for homeowners to keep an overview here. While lead storage dominated in the past due to low prices, it is now long-lasting and efficient lithium-ion storage that is driving growth. The reason is that the prices for it have dropped significantly. An essential difference between electricity storage systems lies in the question of what actually belongs. There are complete systems and single component systems. All components such as inverters, battery modules or controls are already included in the complete system and coordinated with one another. Something similar to that of TVs, computers or washing machines. With the single component system, on the other hand, the individual components are installed separately in the house and connected to each other. If you buy a power storage device, you should pay attention to what system you actually have in front of you.

For your orientation, the table shows some key parameters, using the example of the solar battery, against which electricity storage devices can be compared quickly.

Parameter Solar battery

Complete system (battery module, Inverters, energy managers, Measuring technology)

lifespan 10, 000 charge cycles
capacity 2 - 16 kWh
Depth of discharge 100%
power 1.5 - 3.3kW
Can be expanded later Anytime in 2 kWh steps
quality Li-ion house storage safety guide

Type certification, 10 year guarantee on all parts

Online portal Yes
Flexible interfaces Micro CHP, wind turbine, fuel cell
Price from 5475 euros (incl.VAT)

Is there government funding?

Electricity storage facilities are currently subsidized by the state KfW with around 30 percent of their net purchase price. This remarkable funding, which quickly amounts to a few thousand euros, will expire at the end of this year. If you still want to use them, you should hurry up. In order to take advantage of the funding, an offer from an installer is required, which everyone can submit to their bank. Installers who have experience in dealing with electricity storage are familiar with the processes and are happy to help.

Is it worth waiting?

With every new technology, prices are high at the beginning and then fall fairly quickly. Of course, this is also the case with electricity storage systems. So should you wait a while to make them cheaper? In the past year, the costs have already gone down significantly. The solar battery, for example, reduced its prices by 50 percent last year. An intelligent storage system now only costs half as before. Added to this is the current storage subsidy of 30 percent of the acquisition costs, which currently makes a purchase very lucrative. Since this funding expires at the end of the year, potential price cuts will be compensated for in the foreseeable future by the discontinuation of storage funding. So in the medium term it is not worth waiting for cheaper prices. In the long term, it should be borne in mind that self-generated electricity is (!) Still free of taxes for the majority of homeowners. In 2014, the federal government already showed what it could look like in the future instead. At that time, she introduced a levy known as "sun tax" on self-generated electricity, which has since applied to PV systems with an output greater than 10 kWp. However, a normal household usually only needs between 4 and 7 kWp and is therefore not affected by the levy. However, it is possible that such levies will later affect smaller facilities and therefore all homeowners. So if you wait a few more years, you may have to pay taxes on your own electricity in the future, which could cancel out the lower investment costs. Last but not least, every homeowner saves electricity costs from the very first day with a PV system and storage. So if you wait 1 year, for example, you lose the money that you still pay to the electricity supplier, which could amount to around 750 euros for a single-family house. In this respect, there are many arguments in favor of getting into self-consumption now.

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