Flood Risk Assessment Essential for Longevity of Solar Assets

Damages to modules, cables, and electrical equipment may not be covered under warranty


Preliminary flood risk analysis, development of efficient drainage, and systems for channelizing excess water outside project boundaries are essential in preventing large-scale damage to solar installations during a flood, consultancy firm Sgurr Energy indicated in a recent white paper.

According to the firm, river flood, flash flood, ground waterflood, sewer flood, and coastal flood could cause heavy damage to solar projects.  Destruction of components largely depends on the intensity, duration, and level of waterlogging during a flood. Floods may completely submerge projects and damage equipment. Ground grips of module mounting structures could be affected due to soil erosion.

Corrosion could accelerate, resulting in damage to modules mounting structures. Floods could submerge underground cables, cables connecting control and inverter stations resulting in generation downtime, the firm warned.

“To avoid all such situations, it may be essential to conduct an in-depth hydrology study during the project planning stage. The study considers flood occurrence, distribution, and water movement,” Sgurr Energy said in the paper.

Damages to components like PV modules, DC cables, and electrical equipment may not be covered under warranty; the study pointed out.

Although floods cannot be predicted with precision or controlled, it is necessary to put in place systems to minimize damages to solar plants during such events, the firm suggested.

It necessitates the need to put in place an efficient drainage system. In the case of faults in natural drainage, artificial drainage systems could be used for water management. Cleaning or widening natural drainage could enhance the drainage rate of water. Low land, large water bodies, shallow groundwater table, impermeable soil, steep land slope are likely to worsen situations.

In case the existing drainage system is ineffective, an alternative way of channelizing excess water from outside the plant boundary could be a solution. However, if the site topography does not permit such solutions, one could restrict water from entering the site through an effective retaining structure. Draining off the water using water pumps could be one of the answers.

However, restricting water outside plant premises may lead to social issues. Besides, channelizing water or construction of retaining structures may require large capital expenditure.

According to the firm, it is essential to choose between water channelization and diversion and plant design by keeping in mind the flood impact.

A report by McKinsey Global Institute on ‘Climate Risk and Response’ suggests that climate change will have substantial physical implications at a local level in regions across the world. Weather volatility will continue to wreak havoc on physical assets like buildings. Extreme precipitation, tidal flooding, forest fires, and other havocs can wipe out significant parts of towns and cities. Rural and remote settlements are at higher risk due to this.

Last year, the onslaught of monsoon and severe weather caused significant damage to a 250 MW solar PV project in Madhya Pradesh. Heavy rainfall and lightning accompanied by storm with wind speed nearing 10.44 m/sec and 20.26m/sec was recorded on the night of July 5, 2019. According to a damage assessment report reviewed by Mercom, there was extensive damage to the inverter that tripped on the ground, modules, along with damages to cable tray and module mounting structures.