The changing economics of solar power generation are creating cost pressures within the photovoltaic (PV) sector. While the sector initially established robust specifications, these have been pared back as competition has intensified.
The Hot Dip Galvanisers Association SA is working with various photovoltaic industry installers to improve quality standards by ensuring the correct specification of support-structure materials.
“Although the steelwork supporting solar panels comprises a relatively small fraction of the overall investment, it is the foundation for the success of solar plants, and the selection and quality of steel and corrosion control have not received sufficient attention,” warns Executive Director of the Hot Dip Galvanizers Association of Southern Africa (HDGASA) Robin Clarke.
Having encountered multiple instances where a ‘cut and paste’ of the generic specifications applied when the industry launched in South Africa some 10 years ago does not apply to the environments in which some solar plants operate today, Clarke says that the Galvanizers Association is working alongside various photovoltaic industry installers to improve quality standards through correct specification of support structure materials.
“Corrosion protection ensures that structures achieve service life expectations and meet baseline return-on-investment calculations. The steel structure should remain serviceable for 10 or 20 years to accommodate the next planned electrical upgrades. It should outlive the electrical plant, so that upgrades can be done without disturbing what has already been mounted or planted. On this basis, hot dip galvanized technology is an excellent choice, since corrosion control in most environments can exceed 40 years.”
However, specifications must be carefully considered: “Mount systems for ground installation were originally thicker steel. However, once the sectional thickness was trimmed down, hot-dip galvanised coating pick-ups decreased. This sufficed when systems were installed in benign soil and atmospheric conditions, but not in more hostile environments,” Clarke continues.
“The HDGASA has repeatedly appealed to project owners to perform baseline environmental and geological soil assessments, checking designs for appropriate material specifications. We engage with many suppliers, designers and engineers who recognise this, but pressure remains, driven by cost considerations, to select less-than-optimal materials,” he notes.
Another challenge has emerged with the growing popularity of rooftop solar systems amongst commercial and residential property owners. Initially, installations were done with seemingly scant consideration of the roof sheeting condition. Nowadays, roof sheet assessments ensure that installations are not fitted to roofs that require extensive maintenance or replacement within the time frame required for the solar plant to deliver a return on investment.
Shining a light on localisation
Clarke says the HDGASA is disappointed that solar plant steelworks are still imported when capacity exists in South Africa: “We encountered one plant where material imported from Europe, which was at variance with the specification required for the installation, had suffered damage during storage and should not have been installed. However, the ability to hold a company 15 000 km away accountable is absolutely zero. We had the same problem with components from the Far East, which were utilised in a coastal application.
In South Africa, we have capacity, quality and accountability on our doorstep. This would circumvent some of the problems we encounter in the field.”
Clarke believes that many companies in the solar sector wish to operate sound, sustainable businesses and have benefitted from HDGASA training and advice; however, they face challenges from other solar operators who undercut on price, either to compromise on standards or due to a lack of knowledge of appropriate specifications.
Solar-powered solutions
“This is a growth curve. Companies competing solely on once-off capital investment numbers have little incentive to present robust specifications as an alternative. We are working with suppliers to ensure customers get real value for money,” Clarke explains, adding that there is a greater need for accountability along the entire steel supply chain as demand and volumes grow.
He cautions that in a diverse environment such as South Africa, one standard will never apply to all: “Design criteria must be specific to where a plant is built. There has been a lack of understanding of design requirements for the region. We are encouraging project owners and designers to talk to corrosion control experts, who can provide accurate information about the corrosivity of the soil and the overall environment,” Clarke concludes.