Do you have photovoltaic panels and still pay a high energy bill? Understand what may be happening

Installing photovoltaic panels is one of the best ways to reduce energy costs. However, many people are surprised to find that even after the investment, the energy bill remains higher than expected. The good news is that there is an explanation — and a solution.

Several factors can compromise the performance of a photovoltaic system, and most of them go unnoticed until a detailed technical assessment is carried out.

1. Poor installation: one of the most common causes

A photovoltaic installation only performs well when it is properly sized and correctly connected. If there are errors in wiring, strings poorly matched to the inverter, or inadequate protections, performance drops significantly.

Common issues include:

• Panels incorrectly connected
• Strings with power different from what the inverter supports
• Inadequate or poorly connected cables
• Incomplete or poorly configured protections

When this happens, the system may still operate, but it produces far less energy than it should.

2. Lack of registration or regularisation with DGEG

Another factor that may affect results is the lack of legalisation of the installation with DGEG. For grid-connected self-consumption, registration is mandatory and ensures that:

• the system complies with regulations,
• the connection is safe,
• the inverter is authorised to inject energy,
• production is correctly registered.

Without proper regularisation, the user may not fully benefit from self-consumption, even if the panels are producing energy.

3. Night-time consumption without a storage battery

Even with an efficient system, night-time consumption still depends on the electrical grid. If much of the energy usage occurs in the evening or at night — such as:

• charging electric vehicles,
• using high-power appliances,
• heating systems — the bill may remain high because solar energy is no longer available.

In these situations, integrating a storage battery allows you to use daytime production during the night.

4. Undersized panels or inverter

In some installations, the number of panels does not match the real needs of the household or business, or the inverter is not suitable for the installed capacity.

This often happens when the initial project:

• was carried out without a consumption study,
• did not consider usage peaks,
• did not foresee future expansion,
• did not assess shading, inclination or roof orientation.

An undersized system produces less energy than necessary to offset consumption.

5. Lack of maintenance or monitoring

Over time, dirt accumulation, communication failures, unexpected shading or even small equipment defects can reduce solar production. Monitoring the system makes it possible to identify performance drops before they cause financial loss.

How to identify and solve the problem

The most effective way to understand why the bill remains high is to carry out a complete diagnosis of the photovoltaic installation. This process includes:

• analysis of wiring and string sizing,
• verification of protections,
• evaluation of real consumption,
• confirmation of DGEG legalisation,
• review of production history,
• assessment of the need for batteries or optimisation.

With the right technical corrections, performance usually improves immediately, and the bill decreases within the first days.

Conclusion

Having photovoltaic panels does not automatically guarantee a reduction in energy bills. The system must be correctly sized, properly connected, regularised, monitored and, when necessary, complemented with a battery.

When everything is correctly aligned, solar self-consumption becomes efficient and delivers the expected savings.

Geoclima provides complete diagnostics, system optimisation and technical and legal regularisation, ensuring that each installation operates with maximum performance and safety.