Choosing the right kind of O&M dynamics while dealing with Solar Plants is crucial.
Operations and maintenance (O&M) of solar plant assets has always been a critical component of the Industry business. There has been a slow but prominent transition from CAPEX to OPEX model, wherein the need of the hour has been well understood by investors.
The understanding and operation procedures of solar panel management has over time changed from one that consisted of only sprinkling water on the modules to in-depth functional maintenance and with time and innovation this will further keep changing.
The half-handed approach to operations and management of a solar panels left the plant with unskilled and unsupervised labourers who didn’t refrain from adopting non standard practices at site, like that of climbing up on the module glass and mopping the modules similar to that of cleaning a room floor which leads to micro cracks and the cell fingers getting disintegrated and added terrible hotspots.
Often the basic SOPs too were not followed, like that of cleaning the water residues along the aluminum frame with a clean cotton cloth which led to percolation of moisture into the sandwiched silicon cell between the EVA layers. The bus bar rust led to oxide formations which catalyzed an avalanche of electrons facing a major traffic jam to reach it’s designed busbar.
This lackadaisical approach in the maintenance begs the question of ‘How long has it been since we have considered the Snail Trail as a non cosmetic defect which leads to generation loss? Or even How much time did it take the industry to appreciate PID Loss and differentiate it from LID?’ It is safe to assume that it has been a long while.
It has taken us a while to understand that a simple bird vermilion drop generates a destructive hot spot. How many of our Project Installation Teams care to reorient modules to avoid shadow loss from permanent structures – especially in the RoofTop settings. There was also a great deal of negligence shown towards maintaining a minimum table to table gaps so that shadows do not get imposed throughout the diurnal cycle with respect to the apparent migration of the sun with respect to latitude.
There has also been a great deal of negligence towards PV System reports simulated to consider a generic loss percentage and make it a commercially viable document rather than a technical one to fall back upon to gauge actual parameters of loss. Operations faced a major paradigm shift when tracker technology was introduced after the fixed and seasonal tilt feasibility were introspected. Major electromechanical challenges surfaced when tracker cards and gearboxes started failing.
NASA developed an algorithm inscribed in the master tracker cards which was challenged as we saw an opportunity to improve the correction factor between the physical variable incidence angle versus the instantaneous sun migration angle from the east to west with respect to inscribed algorithm tracker angle.
Another big rumor across the industry has been that of more heat and more generation concept. All expect that during peak summers the generation will be the highest. However, it has taken us time to learn that the ambient temperatures above module STC leads to exponential rise in the loss component. Thereafter the process of maintaining close to a feet high mowed grass cover to help in keeping the ambience cool and also bind the soil to minimize loose dust components suspended in the air was started.
Very few respect the safety code of DC overloading of the inverter to be kept not more than an excess of 20%. There has been a refusal towards understanding the ‘Clipping Loss Effect’ of the inversion process as a major loss component over and above the 20% overload band. Overloaded inverters kept warning us of a critical rise in temperatures of especially IGBTs but not much attention was paid to the power derating.
Many also did not refrain from using broken glass modules connected in live strings. Neither of them were divided into sections or sectors with caution saying that module cleaning is prohibited in that section during generating hours. Some even witnessed the magic of fire during rainfall- attributing this dangerous amazement to this phenomenon for sure. Another basic deviation which came to the front was the neglect shown towards aligning the pyranometers with respect to the POA and the lack of cleaning them daily to avoid inaccurate PR measurements.
Quite timely, SCADA came to the rescue and pointed out the importance of recording instantaneous data of WMS and generation, in order to initiate monitoring of data till the string level. This revolutionary approach was critical in defining stepping stones of an effective asset management strategy in solar. The dynamic KPIs were monitored on a real time basis. This also supported the regulatory scheduling and forecasting policies across states in India. The energy demand supply model is managed effectively by the QCA teams appointed by the SLDC.
A war with the ever changing Government Policies continues to be fought. The low and ever falling PPA rates, teach to be endurant and focus limitlessly to all of the above realizations which came in much later.
The above spark in solar operations and maintenance teams will definitely bring back the smiles and interest of investors, in addition to being a befitting reply to all those who once didn’t believe and neglected the importance of ‘An Effective Solar Maintenance’.
Thanks,
Victor Bhattacharya
O&M