Due O&M Services is a must for the growth of Solar Rooftop sector

We have seen some  Rooftop Solar (RTS) projects in apparently inaccessible locations such as Metro Rail & factory sheds. Again, there will be a lot of similar potential sites to tap the vast rooftop solar energy potential in the country. But, the access to all such sites is a must to undertake the needed O&M services; cannot be overlooked to get the desired benefits of such projects throughout its lifecycle of 20-25 years. This is also must to create the desired market for RTS growth.

RTS has been the fastest growing renewable energy sub-sector in India. Still it will not be able to meet the 40 GW target by March 2022 as set by the Government of India. As per estimates rooftop solar installations will grow at a CAGR of 50% in next 03 years suggesting a cumulative 13 GW of installed capacity by FY2021-22.

Besides this target, the country has a vast growth potential of RTS energy generation as it is said that 70% of the building stock in India is yet to be constructed. There are other favorable reasons as well. But the potential cannot be met if the due considerations are not given on quality of execution and thereafter O&M services; extend life of solar plant equipment, improves generation and in turn gives the best possible return on investment (RoI).

All O&M activities can be divided into two (02) categories (Preventive & Corrective Maintenance).

1. Preventive Maintenance Activities– this helps to minimize the downtime; Scheduled maintenance (cleaning of solar panels, inspection of solar panels for defects, shading, structures and cable connections, cleaning of inverters/ junction boxes, earthing effectiveness, output checks vs expected output,etc.). Of these activities, Solar panel cleaning is done on regular basis depending on location of plant, dust, leaves, bird droppings,etc. This is called Soiling of solar panels which can reduce the output by up to 80%.

Case Study : The importance of the panels cleaning. Effect of dust on PV modules-Dust can substantially affect the electrical output from the system. The table below shows the impact of dust in month of ‘December’ on a 10 kW system located at the GERMI building in Gandhinagar, Gujarat. Units generated by uncleaned panels- 1143 units Units generated by cleaned panels- 1443 units Units gained in a particular Month = 300 units.

Module shading is another important aspect to be checked on regular basis. Photo Voltaic (PV) systems generate electricity based on the amount of sunlight they receive, therefore when a shadow is cast on panels either from clouds, trees, building, vegetation, wires or any object that blocks the pathway of sunlight falling on PV modules, the power output decreases substantially and it may harm the panel in long run creating hotspot (areas of elevated temperature which results in lower power output and  materials degradation in the affected area).

Condition Based Maintenance (CBM) is also prominent to take actions based on the conditions. The conditions of the plant and the individual equipment are known through remote monitoring and thereafter alarm based systems . CBM is also called Predictive Maintenance.

2. Corrective Maintenance Activities- are reactive in nature and the maintenance involves diagnosis of problem, sourcing of spare parts and thereafter necessary repair. In this context the response time is critical to avoid any generation loss. General problems that bring the plant down are Blown fuses, damaged fans or control cards in inverter. In rare occasions, damage to panels or structures may occur. The best way is keeping spare parts recommended by EPC available at site.

O&M cost for on-grid RTS plants are low as there are no variable costs such as fuel. Major cost of O&M is for cleaning of solar panels.

In the case of off-grid plants, maintenance costs are high as they have batteries. Depending on the battery technology, the maintenance requirements would be different such as water topping, tightening of connections etc. Also, batteries need to be replaced every 4-5 years.

References :-

1. GERMI O&M Handbook for RTPV Systems
2. Vast Potential of Rooftop Solar in India – IEEFA