Introduction
The development of renewable energy is accelerating at an unprecedented rate in Europe and worldwide. According to the International Energy Agency (IEA), more than 500 GW of renewable capacity was added globally in 2023, with solar photovoltaics alone accounting for the majority of new installations. In Europe, REPowerEU envisages a significant increase in solar and wind capacity to strengthen energy independence and meet climate targets by 2030.
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In France, the transmission system operator RTE anticipates a steady increase in photovoltaic and wind power installations in its energy transition scenario, with a rise in onshore wind farms, agrivoltaic projects and storage infrastructure.
These projects have one thing in common: they are predominantly located outdoors, in environments that can be harsh, such as coastal areas, exposed terrain, agricultural land, brownfield sites and remote locations. The electrical equipment in these locations is subject to prolonged exposure to UV radiation, temperature fluctuations, humidity and, in some cases, corrosive atmospheres.
In this context, the choice of electrical enclosure can no longer be treated as a secondary consideration. It affects the durability of the installation, the frequency of maintenance operations and the overall operating costs over a period of 15 to 25 years, which is the typical lifespan of a renewable energy project.
For technical departments and procurement managers, this has become a strategic question: should they opt for a metal cabinet (galvanised, painted or stainless steel) or a glass-fibre-reinforced polyester cabinet?
The specific challenges of renewable energy environments
Permanent outdoor exhibition and weather conditions
Renewable energy installations are, by their very nature, located outdoors and often in open areas: farmland, brownfield sites, coastal areas, mountainous terrain or remote locations.
These environments expose electrical cabinets to:
- Continuous UV radiation;
- Significant daily temperature fluctuations;
- Marked seasonal variations;
- Episodes of heavy rain or splashing water;
- Internal condensation.
Protection against the ingress of solid and liquid objects is governed by standard EN 60529 (IP ratings). However, a high IP rating is not sufficient to guarantee long-term reliability if the enclosure material deteriorates due to UV exposure or corrosion.
The performance of an enclosure in a renewable energy environment is therefore not measured solely by its initial IP rating, but by its structural and chemical stability over several years of exposure.
Corrosive environments and aggressive atmospheres
Many renewable energy installations are located in areas classified as being at risk of corrosion according to the categories defined by ISO 12944 (C1 to C5).
Typical examples:
- Offshore or onshore wind power: a salty atmosphere.
- Anaerobic digestion plants: atmospheres containing high levels of chemical compounds.
- Water treatment plants: a damp and corrosive environment.
- Urban industrial areas: air pollution combined with humidity.
In these contexts, corrosion is not a minor issue but a key factor in the premature ageing of metal enclosures. Damage to a coating can become a point of entry for structural oxidation, ultimately affecting the mechanical integrity of the enclosure.
Limited maintenance and logistical constraints
Renewable energy projects are often located in areas far from urban centres. Each technical intervention involves:
- A logistical move;
- Labour costs;
- Occasionally, a partial halt to production.
The operational strategy is therefore based on reducing unplanned maintenance work. The choice of cladding must take this into account: a material that requires regular anti-corrosion maintenance inevitably results in higher operating costs over time.
Metal cabinet: technical analysis and limitations in renewable energy environments
The benefits of metal cabinets
Metal cabinets (galvanised, painted or stainless steel) have historically been the most widely used solution in industry. They offer several advantages:
- High mechanical rigidity;
- A well-established industrial culture;
- Compatibility with a wide range of integration standards.
In indoor or mildly corrosive environments, they effectively meet technical and regulatory requirements.
Limitations in harsh outdoor environments
reliance on anti-corrosion coatings
The protection of a metal cabinet depends on its coating: galvanisation, paint, powder coating or special stainless steel. However, its corrosion resistance is directly linked to the integrity of this coating.
A scratch, a knock or localised damage can act as a starting point for corrosion. In a C4 or C5 environment (ISO 12944), this process can be accelerated.
For a technical department, this means:
- regular visual checks;
- repainting work;
- a risk of gradual deterioration.
Electrical conductivity and earthing
As metal is conductive, it requires proper earthing in accordance with the safety principles set out in, among others, the IEC 61140 standard.
In the event of a fault in the internal insulation, the continuity of the earth connection becomes critical. This requirement is not problematic in itself, but it does require an extra level of vigilance during design and operation.
Weight and structural constraints
Large metal cabinets are very heavy. In multi-site projects or installations on reinforced concrete foundations, this can result in:
- Higher transport costs;
- Handling constraints;
- Une adaptation des fondations.
In renewable energy projects where the aim is to optimise infrastructure costs, this aspect should be taken into account in the analysis.
Glass-fibre-reinforced polyester enclosure: a solution tailored to the demands of renewable energy
Inherent corrosion resistance
Glass-fibre-reinforced polyester is a chemically stable composite material. Unlike metal, it does not oxidise and does not require a coating to resist corrosion.
In a salty or humid environment, the material’s durability does not depend on a protective surface layer, but on its intrinsic properties.
For environments classified as C4 or C5 under ISO 12944, this feature offers a strategic advantage: corrosion protection is not dependent on the integrity of the coating.
Natural electrical insulation – Class II
In outdoor installations exposed to moisture, this feature enhances the intrinsic safety of the enclosure and simplifies certain approaches to structural earthing.
In outdoor installations exposed to moisture, this feature enhances the intrinsic safety of the enclosure and simplifies certain approaches to structural earthing.
For a technical manager, this represents an additional layer of passive security.
Thermal performance and condensation management
Composite materials have lower thermal conductivity than metals. This characteristic helps to minimise thermal bridging and mitigate rapid changes in internal temperature.
In photovoltaic installations exposed to strong sunlight, or in regions with significant daily temperature variations, this relative stability helps to:
- the protection of sensitive equipment;
- the reduction of condensation.
Certaines conceptions permettent en outre l’intégration de structures sandwich isolées, adaptées aux environnements exigeants.
Mechanical strength and durability
Polyester enclosures can achieve levels of mechanical strength that comply with IK10 requirements (EN 62262), thereby meeting the demands of remote or public-access sites.
Unlike a corroded metal structure, the mechanical strength of a polyester cabinet is not compromised by oxidation over time.
Reduced weight and simplified logistics
For equivalent mechanical strength, polyester is significantly lighter than steel. In renewable energy projects involving multi-site deployments, this can result in:
- simplified logistics;
- a reduction in lifting constraints;
- optimisation of the flower beds.
For procurement departments, this factor can affect the project’s indirect costs.
Summary strategic comparison
| Criterion | Metal cabinet | Polyester cupboard |
|---|---|---|
| Corrosion resistance | Depends on the surface | Intrinsic |
| Electrical conductivity | Conducteur | Insulation (Class II) |
| Weight | Hight | Reduced |
| Anti-corrosion maintenance | Recommended | Low |
| Saline environment | Sensitive | Suitable |
| Long-term stability | Variable | Stable |
In controlled indoor environments, both solutions may be suitable. However, in harsh outdoor renewable energy environments, polyester offers performance stability that is less dependent on maintenance.
TCO approach: actual cost over 15 years
For a procurement department, decision-making cannot be limited to the purchase price.
The total cost of ownership must include:
- anti-corrosion maintenance work;
- technical visits;
- premature replacements;
- the consequences of any unavailability of the facility.
A building envelope that requires regular maintenance or is at risk of gradual deterioration may, over a period of 10 to 15 years, incur cumulative costs that exceed those of a solution that is initially more durable.
In renewable energy projects, where operating contracts are often long-term, the stability of equipment performance is a key factor.
Renewable energy applications where polyester plays a key role
Ground-mounted solar power stations
Installed outdoors in large open spaces, they expose the cabinets to direct, continuous sunlight. Ranges such as Maxi Euro or Euro Medium are particularly well suited to these environments.
Wind farms and coastal areas
The salty atmosphere accelerates metal corrosion. The use of polyester covers reduces the risk of structural deterioration over time.
Energy storage and batteries
Storage cabinets must be able to withstand heavy loads and incorporate spill containment systems. Bespoke polyester solutions meet these specific requirements whilst maintaining high corrosion resistance.
Electric vehicle infrastructure
Installed outdoors and sometimes in harsh urban environments, the terminals and associated cabinets are housed in a sturdy, insulated enclosure.
How do you draw up a set of specifications for a renewable energy project?
For a renewable energy project, the specifications for a switchboard should include:
- Required IP rating (EN 60529);
- Résistance mécanique IK (EN 62262) ;
- Environmental class (ISO 12944);
- Electrical insulation requirements;
- Thermal constraints;
- Target service life.
Incorporating these parameters right from the design stage helps to avoid costly trade-offs later on.
Conclusion
The choice between a polyester cabinet and a metal cabinet is not necessarily a matter of one being better than the other. It depends on the installation context and the environmental requirements.
In indoor or mildly corrosive environments, metal cabinets remain a viable option.
Conversely, in renewable energy environments characterised by prolonged outdoor exposure, corrosive atmospheres and limited maintenance, glass-fibre-reinforced polyester offers structural and chemical stability that ensures long-term performance.
For technical and procurement departments, the issue is not merely technical: it is strategic. The durability of the building envelope determines the overall reliability of the installation.