The growth of photovoltaic energy and the rise of self consumption are leading more and more homeowners, businesses and local authorities across the Var and Alpes Maritimes regions to question which solar energy storage solution best meets their needs. Should you choose a physical battery installed on site, or opt for a virtual battery offered by certain energy suppliers such as EDF, TotalEnergies or Engie? The choice between these two solutions has a direct impact on profitability, energy management and long term energy independence. Edmond Solutions, a certified solar installer with more than 15 years of experience in the Var region, explains the key points to help you make the right decision.
What is a physical battery?
A physical battery provides a practical and tangible approach to solar energy storage. Installed close to the photovoltaic system, it stores excess electricity generated during the day for later use. Whenever solar production exceeds immediate consumption, the surplus is stored in the battery instead of being exported to the grid.
Most residential batteries rely on lithium ion technologies such as LFP and NMC. Depending on the model, storage capacities generally range from 3 to 15 kWh for residential applications. This allows users to increase their independence from the public electricity network by using stored energy whenever solar production is insufficient, such as during the evening, overnight or in periods of poor weather.
How does a virtual battery work?
Unlike a physical battery, a virtual battery does not require any hardware. It is a digital solution offered by certain energy suppliers. The concept is simple: electricity exported to the grid is not immediately sold. Instead, it is credited to a personal energy account as a virtual energy balance.
This balance can later be used when solar production is insufficient. Energy consumption is deducted from the virtual account. If the balance reaches zero, electricity is supplied and billed at the standard retail rate. Unlike a physical battery, a virtual battery does not provide protection against grid outages.
What are the advantages and disadvantages of each solution?
Advantages and limitations of a physical battery
The main advantage of a physical battery is genuine energy independence. The electricity remains within your own installation, limiting transmission losses. Modern lithium ion batteries generally have a lifespan of 8 to 15 years depending on usage and technology, with LFP batteries often offering the longest service life.
The main drawback is the initial investment. Purchase, installation, maintenance and eventual replacement costs must all be taken into account. In addition, a dedicated, secure and properly ventilated installation space is required.
Benefits and constraints of a virtual battery
A virtual battery is attractive because of its simplicity. There is no equipment to purchase, no storage space required and very limited upfront costs. Most solutions operate through a monthly subscription or a one time activation fee.
However, the entire system depends on the supplier’s infrastructure and contractual conditions. Storage is purely contractual and subject to commercial terms that may change over time. Since the implementation of the S21 framework in June 2026, surplus electricity buyback rates have fallen to approximately €0.011 per kWh, further reducing the economic appeal of virtual storage when exported energy is valued only at this rate.
What criteria should you consider when choosing a solar energy storage solution?
Analyse your needs and solar production
Before making any decision, the first step is to evaluate your ideal storage requirements. This involves analysing the size of your photovoltaic installation, your consumption profile and the relationship between production and demand.
For households that consume most of their electricity during the evening or at night, a properly sized physical battery maximises self consumption. For offices and businesses that consume most of their energy during daylight hours, the need for large storage capacity is generally lower.
Evaluate the total cost of ownership
For a physical battery, the total cost includes purchase, installation, maintenance and potential replacement at the end of its lifespan. Residential systems with capacities between 5 and 10 kWh typically cost between €3,000 and €8,000.
For a virtual battery, costs are generally limited to subscription fees or activation charges. However, these costs should be monitored over time, as some suppliers impose limits on virtual storage volumes or charge additional fees for certain services.
- Key factors to consider include:
- Acquisition costs
- Subscription or activation fees
- Maintenance requirements
- Storage capacity adapted to real production and consumption levels
- Available installation space
- Desired level of independence from the grid
What impact do these solutions have on profitability and energy independence?
The profitability of a physical battery is highest when solar production aligns well with deferred consumption. Over time, greater energy independence and lower electricity bills help offset the initial investment. The strong solar irradiation available in the Var and Alpes Maritimes regions further improves the economic case for battery storage.
For a virtual battery, energy independence remains largely theoretical. The stored energy does not physically belong to the user and exists only through a contractual arrangement. This solution does not provide protection against power outages and remains dependent on supplier pricing policies.
Criteria | Physical Battery | Virtual Battery |
|---|---|---|
Initial Investment | Physical Battery: High (€3,000 to €8,000 including installation) | Virtual Battery: Low to moderate (subscription or activation fee) |
Maintenance | Physical Battery: Required | Virtual Battery: None |
Lifespan | Physical Battery: 8 to 15 years on average | Virtual Battery: Dependent on supplier contract |
Grid Dependence | Physical Battery: Low | Virtual Battery: Total |
Space Requirements | Physical Battery: Yes | Virtual Battery: No |
Profitability | Physical Battery: Excellent when correctly sized | Virtual Battery: Variable depending on supplier offer and consumption profile |
For personalised support in the Var or Alpes Maritimes regions, Edmond Solutions offers a free assessment of your project and can help you select the most suitable storage solution for your needs.
Frequently Asked Questions
What Storage Capacity Should I Plan for My Photovoltaic Installation?
For an average household, a storage capacity between 5 and 10 kWh is generally sufficient. Homes with high evening consumption often benefit from larger physical batteries, while households that consume electricity mainly during the day may require less storage capacity or a virtual battery solution.
What Costs Are Associated with a Virtual Battery Compared with a Physical Battery?
A physical battery requires an initial investment ranging from €3,000 to €8,000 including installation, as well as maintenance costs. A virtual battery generally involves a monthly subscription or activation fee and does not require equipment purchase or maintenance.
How Does Energy Management Work with a Virtual Battery?
Every kilowatt hour exported to the grid is credited to a virtual energy account. When solar production is insufficient, electricity consumption is deducted from this balance. Once the balance is exhausted, electricity is supplied through the grid at the standard tariff.
Which Users Benefit Most from a Physical Battery or a Virtual Battery?
Physical batteries are generally best suited for homeowners with available installation space, high evening consumption or a strong desire for energy independence.
Virtual batteries are often attractive for tenants, urban users, first time solar adopters and households that consume most of their electricity during the day and wish to minimise upfront investment.
