Photovoltaic repowering: complete guide to renewing your solar system

In recent years, with the exponential growth of photovoltaics in Europe, a new need has emerged: improve the efficiency and yield of existing systems. This is where the concept of repowering comes into play, which refers to the technical and technological update intervention on an already active photovoltaic system, to increase its productivity or adapt it to current standards.

What is repowering and why is it increasingly requested

Evolution of systems and diffusion

In many European countries, most photovoltaic systems were installed between 2009 and 2015, a period of rapid growth driven by national incentive programs. After over a decade of operation, technologies begin to show signs of obsolescence, both in terms of panel efficiency and inverter reliability.

Impact of obsolescence on energy yield

A photovoltaic panel, on average, loses between 0.5% and 1% efficiency each year. After 15 years, the loss can exceed 15%, negatively impacting the self-consumption capacity and the economic balance of the system. Repowering specifically intervenes to correct this degradation.

When is the right time to repower

Age of the system and production decline

If the system is over 10-12 years old, and the annual production is visibly lower than the nameplate data, it is a strong indicator that an upgrade intervention is necessary.

Performance analysis

Monitoring through inverters or IoT systems now allows for easy assessment of the actual production curve. A constant decline not attributable to environmental factors can confirm the need for targeted interventions.

Differences between repowering and revamping

Partial interventions vs complete replacement

Revamping involves partial modifications, often structural, without increasing the installed power. Repowering, on the other hand, may also include an increase in power and complete replacement of panels and inverters.

Technical and economic implications

Repowering requires in-depth design, may involve new authorizations, and has a significant impact on incentives, deductions, and energy balance.

Upgradable components in a photovoltaic system

Next-generation solar panels

The current modules, thanks to high-efficiency monocrystalline cells (PERC, TOPCon, HJT), offer up to 30% higher yield compared to those installed ten years ago.

Inverters and storage systems

Replacing the inverter is often the most urgent choice, especially for those installed before 2015. The new devices support smart monitoring, energy optimization, and connections with batteries.

Tangible benefits of photovoltaic repowering

Increased production and self-consumption

An upgraded system produces more, but above all allows for better use of energy for internal consumption, reducing dependence on the grid.

Reduced maintenance costs

Updated components imply fewer failures, less technical intervention, and greater reliability of the system.

Regulations and Mandatory Communications in Europe

Rules for repowering vary across countries. In general:

• Authorizations: if installed capacity increases or major components are replaced, new grid connection approvals or building/ environmental permits may be required.

• Grid operators: system modifications must often be reported to national or local grid operators.

• Existing incentives: in many European states, incentives are not automatically lost with repowering, but strict compliance with communication requirements set by national energy authorities is essential.

Tax incentives and available concessions

• Residential: many EU countries offer tax deduction schemes for energy efficiency (e.g., Germany through KfW programs, France with MaPrimeRénov’).

• Commercial: businesses may benefit from tax credits, energy leasing, grants, or regional/national funding.

• EU-level support: the Green Deal and REPowerEU also fund improvements on existing installations, especially when combined with storage systems.

Economic aspects and return on investment evaluation

Average intervention costs

The cost of a repowering varies between 700 and 1,200 €/kWp, depending on the quality of the components. This should be added to the cost of design and, in some cases, construction works.

Return on investment

On average, the financial return occurs between 5 and 7 years, even more quickly if combined with batteries or in the presence of tax bonuses.

Technical requirements and project planning for the intervention

Inspection and compatibility

A qualified technician will assess the condition of panels, cables, structure, and inverter, verifying whether the system can support a technical upgrade or needs complete replacement.

Compatibility of repowering with storage systems

When it pays to integrate a battery

The combination of repowering and storage allows to maximize self-consumption and reduces grid dependence.

Available types

Today the market offers modular lithium-ion systems, which can also be integrated into existing systems thanks to hybrid inverters.

Management of material disposal

WEEE and disused panels

Photovoltaic panels fall under the category of WEEE (waste electrical and electronic equipment) and must be disposed of through certified companies.

Recycling and sustainability

The majority of materials (glass, aluminum, silicon) are recyclable up to 90%, thus contributing to a circular economy model.

Risks, errors to avoid, and best practices

Incompatible technologies

Choosing uncertified panels or inverters can compromise the system and render the request for concessions inadmissible.

Omitted communications to GSE

Missing mandatory communications can lead to suspension of incentive payments or, in the worst cases, revocation.

Operational checklist for those who want to repower

1. Verification of the existing system

2. Technical analysis with a qualified professional

3. Economic evaluation and choice of components

4. GSE communications and administrative processes

5. Installation and testing

6. Post-intervention monitoring

Conclusion and next steps

Repowering is today a strategic, sustainable, and cost-effective choice for those who own an outdated system and wish to increase its efficiency. Whether it is a home or a business, this intervention can breathe new life into an already existing system, improving performance and energy autonomy.

To begin, it is essential to contact qualified installers and request a customized technical evaluation. It is also useful to consult the official resources of the GSE and local authorities to stay updated on incentives and regulations.