In the previous article regarding wind resilience, three issues have been discussed:

What is the wind resilience problem of PV trackers?
How has the wind resilience problem come into existence?
How does the lack of codes for PV trackers affect the PV industry?

This article will focus more on the solutions to the previously discussed issues.

A Structural Code Is Vital for Improving the PV Tracker’s Wind Resilience

Independent engineering reviews are usually carried out in the last stages of the project.

However, according to pv magazine’s interview with David Banks, head of solar services for wind engineering laboratory CPP, very few stakeholders would accept the bad news without some form of resistance, should the review contain information that may sink the whole project.

Product inspectors are reluctant to criticize the imperfections of their clients’ products
Some say it does not pay to be nice. However, it is not the case for product inspectors.

When a manufacturer calls an inspector for a review, the latter is less inclined to point out the defects or inadequacy in the product designs of the manufacturer, who is also the inspector’s client.

The more critical the inspectors are, the more likely their critique may harm the manufacturers’ business, which makes the manufacturers less willing to call the inspectors in the future. This, in turn, hurts the inspectors’ business.

The long-term solution: A code for building and installation
Due to all these conflicting interests mentioned above and the previous installment of this series, a building code is absolutely crucial.

When a code is in place, non-compliance will hurt the business of the solar farm. Therefore their stakeholders will have more incentives to comply.

The upside is that a whole chapter about solar energy is set to be included in the next round of updates of the American Society of Civil Engineers code, according to pv magazine.

The downside is that the update is not due until 2022. Therefore, until 2022, the PV industry remains unregulated in terms of structure and installations.

What is a stakeholder to do in the meantime?

The short-term solution: Set your own standards
According to Simon Hughes, a partner at Everoze, a European technical and commercial energy consultancy, given that the codes the manufacturers adopted may be lacking or even absent at the moment, the stakeholders need to set their own standards and check the designs.

It would also pay to closely study the wind tunnel report. Stakeholders should pay attention to

What the wind tunnel report is telling them
What the wind tunnel report is NOT telling them

If the two tasks listed above prove to be improbable, stakeholders may need to get assistance from independent engineering labs to review the report.

The Design of PV Trackers Needs Modifications

Hughes also pointed out that for the PV trackers to withstand different levels of wind speed, there are many factors to be considered and adjusted:

Length
Module arrangement
Stiffness
Damping
Stow strategy

Take module arrangement for example. When modules are in portrait, aerodynamic loads are hard to predict. Serious tweaking is needed to make them work and ensure their stability.

Hughes noted that there are more and more manufacturers keen to demonstrate their commitment to ensuring the stability of their trackers.

Therefore more changes to the design of the PV trackers may be introduced in the near future.

In the meantime, the manufacturers may choose to downgrade their claims regarding the design wind speed.

Wind Measurements and Simulations Could Help Reduce Capex

In most cases, national standards are a good indicator in terms of severe wind speeds. However, when it comes to the multifaceted environment, the said standards are no longer sufficient.

Therefore some manufacturers have performed wind measurements and wind simulations to minimize the wind damage.

Moreover, it makes good economic sense to conduct a thorough examination of the site where the solar farm will be built.

Hughes explained that, if the site in question is unlikely to be exposed to strong wind, the buyer would have more options and more bargaining power, which could achieve huge savings in costs.

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