Many homeowners invested in a photovoltaic system over 20 years ago - a forward-looking step that paid off financially thanks to the guaranteed EEG subsidy. But now the subsidy is coming to an end. What does this mean for the continued operation of the system? And why is so-called "repowering" - i.e. replacing or modernising the existing solar technology - worthwhile right now?

Repowering is a technically and economically sensible decision: it offers clear advantages in the context of the EEG - even without feed-in tariffs.

When the Renewable Energy Sources Act (EEG) was introduced in 2000, it was an important driver for the expansion of solar energy. One of the key support measures: Operators of photovoltaic systems received a guaranteed feed-in tariff - for a period of 20 years. This meant planning security and a reliable source of income, regardless of how electricity prices or demand developed. For many homeowners, this was the decisive reason for investing in a PV system in the first place.

However, this guarantee is now coming to an end for more and more systems. Many of the so-called "Ü20 systems" are reaching the end of their EEG subsidisation and are therefore losing their entitlement to the fixed remuneration.

In concrete terms, this means

• The electricity fed into the grid is now only sold at market prices - e.g. via direct marketing or the grid operator
• The income per kilowatt hour fed into the grid will fall significantly compared to the previous tariff
• At the same time, electricity prices for households are rising steadily - so buying electricity from the grid is becoming more expensive

In short, anyone who does nothing in this situation is giving away money. In many cases, it is no longer worth continuing to operate an old system under the new conditions - at least not without adjustments or modernisation.

This is exactly where repowering comes in: With new technology, optimised self-consumption and, if necessary, a battery storage system, the profitability of your system can be secured - and often even improved - even without EEG remuneration. This not only preserves your investment, but also makes it fit for the future.

You rely on modern technology with higher efficiency, a longer service life and more functions. This allows you to increase the yield of your roof area and integrate additional components such as battery storage, a wallbox or a smart home energy management system.

Whilst it is possible to continue operating old systems, in many cases this leads to reduced economic efficiency. Switching to self-consumption is already worthwhile for many operators today - and repowering is usually the most effective and future-proof solution. With a modern system, you can permanently reduce your electricity costs, increase your independence from the energy supplier and at the same time optimise the use of your existing roof area.

Many photovoltaic systems that were installed 10, 15 or even 20 years ago are still working reliably - but a lot has happened since then in terms of technology and efficiency. Modern components are more powerful, can be used more flexibly and offer functions that older systems do not have. Repowering means utilising these advantages for existing systems - by partially or completely replacing important system components.

This can be, for example

• Replacing old solar modules with more powerful, more efficient versions
• Replacing the inverter with a modern, hybrid model with storage option
• Integration of a battery storage system for more self-consumption
• Expansion with a wallbox or heat pump
• Connection to an energy management system (HEMS) for automatic control

The advantages are obvious:

• More power on the same surface area - new modules produce more electricity per square metre
• Future-proof - current systems are prepared for upcoming standards and requirements such as §14a EnWG
• Smart energy - intelligent networking of PV system, storage system, wallbox and consumers
• Independence from the electricity price - every kilowatt hour you generate yourself saves money and makes you less dependent on rising electricity costs

Repowering is far more than just "replacing defective parts" - it is a step towards a new generation of energy supply. Anyone who modernises their existing system not only increases the yield, but also creates the basis for an intelligent, networked and future-proof energy system in their own home.

State and federal programmes support investments in battery storage systems, wallboxes or self-consumption systems. In addition, tax depreciation can be used to reduce investment costs.

The rules of the game have changed: While the feed-in tariff used to be the most important incentive, the focus today is clearly on self-consumption, storage integration and intelligent control. Those who utilise these options can significantly reduce their electricity costs and at the same time make their energy supply fit for the future.

Old systems are often still technically functional - but no longer economical or standardised. Typical problems:

• Decreasing efficiency of the modules
• Inverters that no longer comply with standards (e.g. communication, grid behaviour)
• Spare parts or service no longer available
• No storage system can be integrated

Repowering brings your system up to date - with warranty, service and connection to modern energy management solutions.

In the past, photovoltaic systems focussed primarily on feeding the electricity generated into the public grid - thanks to high remuneration under the German Renewable Energy Sources Act (EEG). Today, the situation has changed fundamentally: Self-consumption is much more lucrative than feeding electricity into the grid.

The reason is obvious: electricity from the energy supplier now often costs over 30 to 40 cents per kilowatt hour. Self-generated solar power, on the other hand, is only around 8 to 12 cents per kilowatt hour. So every kilowatt hour that you use directly in your own household saves you money.

With a battery storage system, you can also use the electricity produced during the day in the evening or at night. If you also have a wallbox, you can charge your electric car with your own solar power at particularly favourable conditions. This allows you to increase your own consumption and significantly reduce the amount of electricity you draw from the grid.

With a modern hybrid inverter in combination with a battery storage system, you can achieve a degree of self-sufficiency of over 70 % - and make yourself largely independent of rising electricity prices.