This post is the last (for now at least) in a three part series looking at some of the things that can go wrong during the construction of a solar PV facility. Part 1 of this topic looked at design, programme, labour and environmental conditions that could impact construction. Part 2 focused on the importance of effective onsite management, including quality control, equipment management, housekeeping and safety.
“The best laid plans of mice and men often go awry.” No matter how carefully planned out a project is, progress will always be at the mercy of external events, outside the control of project teams. Some events are possible to predict, and contingency plans, or mitigating plans can be created. Other events come out of the blue, are totally unforeseen.
The contractor should be responsible for completing the project to the extent that they are able to control, or perhaps even influence, what is taking place. But contracts will have ‘force majeure’ clauses included, to address what happens if something happens which is totally outside of the contractor’s control.
Regardless of who is responsible, works need to get back on track, and repair works or accelerated catch-up works may be required.
Weather conditions, like floods, heavy winds, lightning and hail, can lead to facility and equipment damage. Material or equipment supply chain hold ups or shortages may occur (by way of example, a project that I worked on had their steel supplier’s factory burn down). Permission to connect to the electrical grid can be delayed, through no fault of the contractor or employer. Third party works may need to take place (for instance transmission lines, substations or access roads). Third party inspections and/or approvals may be required.
Storm water management/drainage
This is closely linked to external events – as heavy rain is clearly a weather event. And it is linked to the appropriateness of the design (which is discussed in Part 1. But it’s important enough to merit its own mention. Solar facilities are covered with impermeable, smooth, titled panels. They act like a roof, without a gutter. Rain runs off them easily, and, over time, this leaves little grooves in the ground beneath the bottom edge. This water accumulates and then runs downhill. Depending on the ground type (permeability), the facility slope and the amount of rain received, stormwater management can become an issue. Moving water can erode away at ground, roads and earth surrounding the mounting structure base. This is clearly an issue over the life of the plant, but the management of stormwater can also be a problem during construction if water rushes into trenches, washes away civil works, or affects other aspects of work.
It’s therefore important that the contractor is aware of rainfall patterns, and considers how stormwater will behave onsite. Plans should be in place to manage the water, and drainage designs should consider protecting the facility both during construction, and over its operational life.
Access road degradation
For any equipment, people or materials to reach the site, it is naturally important that the facility can be accessed. There is typically a portion of road, of varying length, linking public roads to the facility’s boundary. It’s important that the responsibility for building and maintaining this road is clearly defined. But regardless of who is responsible, this road will take quite a beating over the course of construction. Trucks carrying modules, mounting structures, inverters, switchgear, concrete, and other components and materials will be travelling backwards and forwards for months.
If the road isn’t built properly, it will end up being heavily corrugated and can turn into a swamp with heavy rains. This then affects the delivery of components and materials, and the accessibility of the site for people working there. Because it’s outside of the site boundary, it can be overlooked, but can result in a logistical nightmare if it’s not built properly.
A problem for a number of projects in South Africa was in the power quality at the point of export. Different countries have different connection requirements, which will be set out in the relevant codes, regulations and standards. Equipment may be brought in from other countries, and designs carried out by foreign engineering professionals. This can result in the facility not complying with the specified requirements. Design adjustments, equipment tweaking or reprogramming and/or possible additional equipment may be required, and these may end up delaying the project.
It’s therefore clearly important that the designers are aware of local conditions and requirements, and design the facility appropriately. Sufficient time for testing is also required, in case there are hiccups along the way.
The contract should define whether or not the contractor is liable for any sneaky surprises that may be lurking underground. They will be develop their design according to the conditions that they have observed onsite. The mounting structures, electrical equipment housing units and cable routing designs will all have been selected and developed accordingly. If the actual conditions are different from than what was expected it can have an impact on the suitability of the design. It’s therefore incredibly important that a thorough geotechnical assessment is carried out.