A primary objective for any power plant is to ensure it continuously and reliably operates, thereby generating the maximum economic and energy performance, and PV power plants are no certainly exception. The Operation and Maintenance (O&M) of large PV plants requires an integrated management system that should be implemented throughout the entire project lifecycle and generation chain to achieve the maximum benefit.

Our practical experience suggests that many issues emerging during the O&M phase are strongly related to the upstream phases of the project lifecycle (siting, development, design, etc.) and may have very significant effects on the downstream phase (performance, production). In particular, suitable planning, supervision and quality assurance activities are critical at all stages of the PV plant in order to minimize the risk of damages and outages, optimize the use of warranties, avoid dilution of resources and ultimately improve the overall performance of the PV plant.

 The typical O&M issues usually include aspects related to land availability, engineering features of the plant, grid connection procedures, contractors’ selection, extreme weather events, data acquisition and security systems, general housekeeping, and management of Social, Environmental and Health & Safety impacts.

Here are a few examples of solutions that we have identified in our experience to respond to the need for plant efficiency, continuity and performance.

 A typical issue in terms of continuity and convenience of the energy delivery is a reliable and proactive relationship with the transmission system operator. This can help especially when unexpected events or emergencies occur. Interruption prevention measures, as well as clear contingency and communication plans and re-start procedures, are key to minimizing plant downtime. Given the involvement of many stakeholders, including utilities, O&M contractors, substation workers, local authorities and health and safety agencies, preventive maintenance training that includes sharing plans and procedures with them plays a huge role in addressing and resolving unscheduled outages and emergencies in the shortest possible time.

Extreme natural events, particularly those related to climate change, may also cause serious damage and outages. Severe structural and economic losses may be incurred if specific components are damaged such as structural elements, electrical parts and components, control and inverter rooms, and connection lines. Flooding can affect different functions of the plant, both on the electrical generation side and on the balance of plant (BOP) side, including connection lines continuity, accessibility of different parts of the plant, erosion of roads and other infrastructures, fence functionality and interference with electrical, data monitoring and security systems.

In general, these types of events can be prevented by running a comprehensive risk assessment of the possible impacts on the continuity of the plant that will lead to the design of redundant systems for evacuation and connection lines, as well as for monitoring and security systems, and effective run-off and drainage systems.

Data acquisition is another crucial issue to be considered to track and maintain optimal system and plant performance particularly with regard to the O&M contractual obligations such as guaranteed Performance Ratio, i.e. the overall plant production efficiency. The assessment of the contractor’s objectives is essentially based on the measurements of the meteo station, which in order to be representative needs constant calibration and certification. It is also critical that the dust cover conditions of the irradiance sensors are consistent with those on the panels, in order to be comparable, i.e. cleaning should preferably be done at the same time. 

 Security systems are essential for a suitable operation of a solar farm in order to avoid damages and possibly plant downtime from theft and vandalism. In order to minimize the occurrence of such events a suitable balance between a remote control system and on site security personnel should be achieved, depending on the size of the plant, its morphology and extension and the general environmental setting.

Finally, considering the local context, it is always advisable to proactively engage and involve the local community and key stakeholders in order to keep them informed on the plant development and operation at all stages, build positive, trusting relationship with the community and relevant authorities, provide adequate avenues for community feedback and ensure social issues are identified at an early stage, managed and, where feasible, resolved.

Francesco Belfiore is Principal, European Power Sector Leader at Golder Associates S.r.l.

[Editor's Note: Francesco Belfiore will be speaking at Solar Power-Gen during the session: O&M Considerations for Large-scale PV Plants. Register here to attend the show.]