The cost of solar energy has changed dramatically over the years, with module prices plummeting from $4 per watt in 2008 to $0.34 per watt in October 2017. Similarly, solar operations and maintenance (O&M) practices are also changing rapidly in response to the continuing efforts to further reduce costs. The majority of O&M costs comprise labour costs (for maintenance) and infrastructure costs (data centre and control room for ongoing supervision, operations, software, etc.).
However, unlike modules, inverters and other products, O&M cannot be commoditised. Different power plants require unique and sometimes contrasting O&M programmes. Accordingly, some solar photovoltaic (PV) companies choose to perform asset management and O&M of their PV plants/portfolios internally, others prefer to outsource these activities to service providers, and many opt for intermediate scenarios that combine insourcing and outsourcing.
Choice between outsourcing and in-house O&M
The past decade has witnessed the emergence of a variety of solar power developers ranging from small-scale operators to large diversified players. In the initial years of development, most of these companies were outsourcing O&M services as they lacked expertise in this space. However, with the portfolios of some of these companies growing beyond 1 GW each, there is an emerging debate about whether asset owners with large portfolios should perform O&M in-house or outsource it. At the commercial and industrial level, it seems that more asset owners are outsourcing O&M.
Financial asset owners such as investment funds usually do not perform O&M activities in-house because they consider it to be too far beyond the domain of their core competencies. But as portfolio sizes grow beyond 100 MW, some investors are revisiting the in-sourcing option with the increasing need to reduce operational expenses.
Independent power producers often perform O&M activities in-house, especially if they already operate and maintain other generation assets such as wind power plants. Some decide to outsource these functions until they grow a significant portfolio that justifies investment in PV-specific expertise. Others consider solar PV maintenance activity to be too minor to justify the investment (in comparison with the large number of existing coal and gas plants that require much more maintenance).
Even when these players choose to bring O&M within the company’s services, it is not always truly in-house or done at the same consistent, high standard. Very few companies have direct hire employees all over the country that are capable of carrying out O&M activities. Moreover, in-house O&M requires being updated with latest innovations and technologies in this space to remain as efficient as one’s competitors. In this context, outsourcing O&M seems to be an optimum solution as besides other things, it also allows the asset owner to focus on diversification, returns and scale. However, outsourcing solar O&M is not just about technology and techniques, it is more about partnering with a company having knowledge of the best practices in plant inspection procedures, quality assessment plans and checklists for maintenance.
The outsource partner must provide O&M services that include periodic and preventive maintenance checks with IV curve analysis and thermographic imaging. Physical O&M tasks such as module cleaning, housekeeping and security could be carried out through third parties under the supervision of the outsourcee, making it an integrated O&M service contract that includes real-time monitoring, service and asset management.
Warranty management is another key aspect that must not be ignored by developers outsourcing O&M. Data capture from RFID tags and module flash reports permits online warranty management of the most expensive assets in an integrated manner in any case. To have the outsourcee examine and report on every other component would facilitate a double check on the equipment and make for a better operating performance.
As is obvious, O&M involves expenditure for the longest phase in a project life cycle. Solar project owners should therefore decide on performance monitoring systems as management tools for the 25-year project lifetime, and such decisions can be made in conjunction with engineering, procurement and construction (EPC) contractors (that may exit after two or five years), but not left to them alone.
Finally, the terms for outsourcing to an O&M partner must ideally be decided alongside the terms of project finance. Engaging early with the right O&M experience can keep costs well below the power purchase agreement throughout the project life cycle. For instance, if the O&M contract is for five more years, the cost of hardware and software can be negotiated in the O&M cost itself because it would form a part of the performance guarantee and build a financial stake for the outsource partner as well. On the other hand, the EPC contractor would be greatly facilitated should the developer outsource O&M since it adds value for the installation, the developer, the cost of operation and the payback for all concerned.
Using computing technologies for effective O&M
When it comes to solar O&M, site inspection is a key component. Whether through ground- or roof-level inspections or aerial assistance, understanding how a system is performing helps ensure its successful lifespan. For large farms, using manned aircraft has been a common norm for providing precise information. However, of late, latest computing technologies like drones, robots, software, sensors and networks are being increasing used for inspecting solar farms globally.
In 2013, US-based SunPower bought a start-up called Greenbotics, which developed a robot that lowers the cost of cleaning solar panels while using less water than human washers. The Greenbotics team now works on engineering projects at SunPower and manages SunPower’s fleet of 40 solar-panel cleaning robots. Since then, a large number of companies have come up with robotic cleaning solutions across the world. Another solar developer in the US, Strata Solar uses drones with infrared cameras to survey the more than 1 GW of solar projects after they become operational. The images can highlight solar panels that are not producing electricity.
While drones are playing an increasing role in the solar industry globally, in India, their penetration has been limited. First, it is a relatively new technology and most solar plants in the country have only come up in the past decade. Second, there is no specific government policy on the usage of drones so this camera-based equipment has been operating only in grey areas, and hence on a smaller scale.
The solar power industry is awaiting final guidelines from the Ministry of Civil Aviation for operating drones, the usage of which by civilians was restricted by the Directorate General of Civil Aviation (DGCA) in 2014 owing to security reasons. In November 2017, the DGCA came out with draft guidelines for unmanned aircraft systems and sought public comments. According to these guidelines, drones are to be classified into five categories depending on their weight; used only during the day and below 200 feet; and operated within 50 km from the international border. The finalisation of these guidelines will allow the usage of drones for solar plants, which will then help reduce O&M costs and increase the productivity of large solar plants in a significant way.
An example of the impact of drones is their use for site surveys to assess vegetation around panels and improve clearing cycles from monthly grass cutting site-wide to localised bimonthly frequency, and reducing clearing costs by 15-20 per cent. These can also be used for soiling/hotspot detection, which, if detected early, can improve generation by 2-5 per cent.
According to Gensol Consultants, “Using drones cuts the cost of thermographic inspection by half and reduces the time taken by a fifth. It also helps in capturing more details than is possible with a handheld instrument. Lastly, the analysis software behind a drone is able to crunch a larger volume of data at a faster rate.”
Another important development on the technology advancement front is related to module-level monitoring. To this end, module-level power electronics (MLPE) technology is being deployed to remotely monitor and troubleshoot at the module level, thereby enabling both preventive and corrective maintenance. Preventive maintenance is conducted before any issue is detected to ensure that the system is operating at its highest level of performance and limiting downtime. Corrective maintenance is conducted after an issue has been discovered and includes repair.
MLPEs help in shifting some corrective maintenance tasks to preventive maintenance, and to even eliminate some maintenance altogether. For example, one part of preventive maintenance is an annual site visit to check the system health. With string and central inverter systems, each module needs to be individually inspected to ensure proper functioning. This is a costly and a time-consuming procedure, and it can pose safety concerns such as working at heights and with high voltages. But MLPE systems allow service providers to inspect and maintain systems without visiting the site. Through module-level monitoring, MLPEs send pinpointed alerts and help in fault detection and allow remote troubleshooting to reduce trips to and the time spent at sites. For example, if a module has a failed diode, then an automatic alert will notify the O&M provider.
MLPEs are even more advantageous for ageing systems requiring more maintenance, or systems that are geographically spread out and difficult to reach in a timely manner.
To sum up, new technologies are driving changes in solar O&M. India is currently focused more on project development. But as plants become older and the scale of installed solar capacity increases, it will become essential for developers to adopt new O&M practices to derive best results. And for being able to adopt these technologies, the market will have to make way for large-scale specialised O&M players capable of offering the most cost-effective solutions.