The changing economics of solar power generation are creating cost pre-ssures within the PV sector and, while it began with robust specifications, these have been trimmed as competition has increased, says Hot Dip Galvanisers Association of Southern Africa (HDGASA) executive director Robin Clarke.

“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 has not received sufficient attention,” he warns.

Having encountered several instances where companies use generic system specifications in environments in which those specifications are insufficient for the environmental conditions, Clarke says that HDGASA is working with PV industry installers to improve quality standards, particularly in relation to the 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 after ten or 20 years. It should outlive the electrical plant, so that upgrades can be done without disturbing what has already been mounted or planted,” he notes.

On the basis that upgrades should be completed without disturbing already-mounted components, companies should employ hot dip galvanising technology, since the corrosion control that it produces can exceed 40 years in most environments.

However, specifications must be carefully considered: “Mount systems for ground installation were originally thicker steel. However, once sectional thickness was trimmed down, hot-dip galvanised coating pick-ups decreased. This sufficed when systems were installed in fairly 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.”

He adds that, while the organisation has engaged with many suppliers, designers and engineers who recognise that these assessments will aid system longevity, cost concerns often lead to companies selecting “less-than-optimal materials”.

Another challenge, owed to the recent popularity of rooftop solar systems, is installations being completed with inadequate consideration of the roof sheeting condition. However, this has been addressed to a degree.

“Nowadays, roof sheet assessments ensure that installations are not fitted to roofs requiring extensive maintenance or replacement within the timeframe required for the solar plant to deliver return on investment,” Clarke says.

Localisation

The HDGASA notes its disappointment at the ongoing importation of solar plant steelworks, as steel manufacturing and fabrication capacity exists in South Africa.

“We encountered one plant where material imported from Europe – which [did not meet] the specification required for the installation – suffered damage during storage and should not have been installed.”

However, he notes the operation’s attempts to engage with the European supplier for a solution or a compromise proved unsuccessful, not least because it was located 15 000 km away.

Clarke says he has seen a similar scenario play out with imports and components from the Far East. “In South Africa, we have capacity, quality and accountability on our doorstep. This would circumvent some of the problems we encounter in field.”

He believes that many companies in the solar sector wish to operate sound, sustainable businesses and have benefitted from HDGASA training and advice, however they are competing with solar operators that undercut on price, either compromising on standards knowingly or through lack of knowledge of appropriate specifications.

“This is a growth curve. Com-panies 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, multiple standards are required to cater for numerous applications, environmental conditions, equipment and systems – one standard is insufficient.

“Design criteria must be specific to [the area where] a plant is built. There has been a lack of design understanding about regional requirements. 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,” he concludes.