FRP vs Galvanised Steel on an Agrivoltaic Farm. There Is Only One Correct Answer.

When a solar farm is also a working farm, the choice between FRP and galvanised steel mounting frames stops being a procurement decision and becomes an agronomic one. The two materials perform very differently in active agricultural environments, and only one of them leaves the soil in the same condition it was in before the panels arrived.

Published by Reinforce Technology  |  June 2026

The case for agrivoltaics rests on a single proposition: that the same land can produce food and electricity simultaneously without either activity compromising the other. It is a compelling proposition, supported by growing evidence. Land use efficiency of up to 186%. Net farm income increases of up to 142%. Soil organic carbon building under the array over time. Water evaporation falling by up to 30% (GreenMatch, 2025).

But that proposition has a condition. The solar infrastructure on the farm must not compromise the farming. It must not contaminate the soil. It must not require maintenance access across active growing land at intervals that disrupt the crop cycle. It must not introduce materials into the farm environment that work against the agricultural outcome the system is designed to deliver.

Galvanised steel mounting frames fail that condition. Not dramatically, not immediately, but progressively and cumulatively across the 30-year operational life of the installation. FRP mounting frames meet it entirely, from day one to year thirty, without exception.

In an agrivoltaic system, the mounting frame is in direct physical contact with the farm environment for 30 years. What it is made from determines whether it supports or gradually undermines the agricultural operation beneath it.

What Galvanised Steel Does in an Agricultural Environment

Galvanised steel corrodes through a well-understood mechanism. The zinc coating provides protection by corroding preferentially, sacrificing itself to protect the steel beneath. In active agricultural environments, this process begins from the first growing season. Fertilisers and pesticides accelerate it. Organic soil acids accelerate it further. In the most productive agricultural soils, intensive arable and horticultural land, precisely the land where agrivoltaics is most financially compelling, zinc coating depletion at ground contact can be measurable within three to five years.

The zinc released into the soil is not neutral. Zinc at elevated concentrations is toxic to the microbial communities that underpin organic soil fertility. It disrupts nitrogen cycling, suppresses beneficial fungal networks, and accumulates in the soil without breaking down. Every season the frames remain in contact with the soil, the zinc load in the root zone around each frame base increases. On certified organic land, this is a direct certification risk. On conventional land, it is a slow degradation of the biological quality of the soil that makes the farm productive.

As the zinc layer depletes and base steel is exposed, iron oxide, rust, begins to form. Iron oxide at high concentrations also affects soil chemistry, altering pH and interfering with plant nutrient availability. By the time a galvanised mounting frame has been in service on active agricultural land for fifteen years, the soil chemistry in the immediate vicinity is measurably different from what it was at installation, and the direction of change is not agronomically neutral.

What FRP Does in the Same Environment

Nothing. FRP has no corrosion mechanism. There is no sacrificial coating to deplete, no zinc to release, no iron oxide to form. The composite matrix of glass fibre and polymer resin does not react electrochemically with soil moisture, organic acids, or agricultural chemicals. The soil beneath an FRP mounting frame at year twenty-nine is chemically identical to the soil at installation day in terms of infrastructure-derived contamination (IntechOpen, 2022).

This is not a marginal advantage. In an agrivoltaic system designed to demonstrate that energy generation and food production can coexist on the same land across 30 years, the mounting frame specification that introduces no chemical contamination into the farming environment across that period is the specification that makes the coexistence genuine rather than theoretical.

Lower Manufacturing Emissions on the Same Land That Grows Food

The agrivoltaic case is partly about carbon. Solar electricity generated on farmland displaces fossil fuels. The soil beneath the panels, improving in organic carbon over time, draws carbon from the atmosphere. The crop rotation continues to sequester carbon in the biomass it produces. The farm is participating in the carbon cycle rather than simply consuming from it.

The mounting infrastructure should be consistent with that logic. Primary steel production requires temperatures above 1,500°C and emits approximately 1.85 tonnes of CO₂ per tonne at the blast furnace. Pultruded GFRP manufacturing emits approximately 60 to 70% less CO₂ per tonne on a cradle-to-gate basis, based on lifecycle assessment data from the European Composites Industry Association (ScienceDirect, 2025). For an agrivoltaic installation where the entire purpose is to produce clean energy and healthy food from the same land, mounting frames that carry a substantially lower manufacturing carbon footprint are the specification that aligns the infrastructure with the values of the project it supports.

The Head-to-Head Comparison

The agrivoltaic proposition only holds if the solar infrastructure does not compromise the farming beneath it. Galvanised steel frames introduce zinc contamination into the farm environment and require maintenance access across growing land. FRP frames do none of these things.

Reinforce Technology FRP Products for Agrivoltaic Installations

Reinforce Technology supplies FRP pultruded structural profiles and cable management systems for agrivoltaic solar farm applications across the UK. I-beams, H-sections, C-channels, box sections, and angle profiles for agrivoltaic mounting frame applications, independently tested by SGS and TÜV Rheinland. Available in polyester and vinyl ester resin systems with UV-stable formulations for the full 30-year operational life of the installation.

Contact us to discuss your agrivoltaic project and the correct FRP specification for your farm environment, crop rotation, and financing model.

Final confirmation of structural suitability for any specific agrivoltaic application remains the responsibility of the appointed project engineer. Reinforce Technology provides material guidance based on information supplied to us. We are happy to provide full technical data sheets and application-specific support to assist with that process.

References

GreenMatch (2025) Agrovoltaics: Solar Energy for Sustainable Farming. Available at: https://www.greenmatch.co.uk/blog/agrovoltaics-solar-energy-for-sustainable-farming [Accessed: June 2026]. [Land use efficiency up to 186%; net farm income increase up to 142%; water evaporation reduction up to 30%].

IntechOpen (2022) 'Fibre-Reinforced Polymer (FRP) in Civil Engineering', in IntechOpen Engineering Series. Available at: https://www.intechopen.com/chapters/84203 [Accessed: June 2026]. [GFRP no corrosion mechanism; 75% lighter than steel; non-conductive].

NACE International (2016) International Measures of Prevention, Application and Economics of Corrosion Technology (IMPACT). Houston, TX: NACE International. Available at: http://impact.nace.org/economic-impact.aspx [Accessed: June 2026].

Younis, A., Ebead, U. and Judd, S. (2018) 'Life cycle cost analysis of structural concrete using seawater, recycled concrete aggregate, and GFRP reinforcement', Construction and Building Materials, 175, pp. 135-144. doi: 10.1016/j.conbuildmat.2018.04.183. [Approximately 50% lifecycle cost saving for GFRP versus steel over 100-year study period].