With the rapidly increasing size and scale of solar projects, there is a greater focus on optimising performance and reducing operational costs. As a result, efficient operations and maintenance (O&M) has taken centre stage in the Indian solar industry. At a recent Renewable Watch conference on “O&M for Solar Plants”, key industry representatives discussed the new and emerging O&M technologies, key trends in the solar O&M space, the challenges faced and best practices to ensure optimal performance. Excerpts…
Fourth Partner Energy lays emphasis on asset management, which depends on long-term risk and return management. This often contradicts the objectives of the engineering, procurement and construction (EPC) vertical, which focuses on the short term. Fourth Partner has an in-house O&M team, although we do opt for third-party O&M if it seems to be a more efficient alternative. For instance, when our assets are located in an area where our project density is low, we prefer to have a third party carrying out O&M. In addition, whenever we do not have in-house expertise for a particular technology, we involve a third party.
As a developer, our key concern is long-term risk and return management in order to sustain the useful life of the asset. Challenges emerge when initial assumptions are not validated. Some of the key issues that we have been facing recently are changing weather patterns, water shortage, uneconomical plant sizes, unavailability of manpower, and the degradation of plants. Overall, irradiation is lower than assumed, especially in north India owing to issues of smog and soiling. Water shortage is becoming a growing problem, which has led to more experimentation with dry cleaning solutions. However, they do not always work out.
When a new contract is initiated, it often involves an agglomeration of various sites. As a whole, the contract would entail a large capacity, which may be distributed across various sites. Thus, an individual site often becomes uneconomical to manage. Further, the availability of semi-skilled manpower is becoming increasingly erratic. The cleaning of modules gets delayed if manpower is not available.
Measuring the exact degradation of each plant is difficult. Scanning is one way to go about it though it is not feasible to scan hundreds of plants on a monthly basis. We are currently working on mathematical ways to estimate the extent of degradation. In the case of third-party plants, it has been found that there has been more degradation than initially projected. Another issue is of health and safety. Currently, there is very little consideration for health and safety measures in India. As the tilt angle of roofs is increasing, the O&M of rooftop solar systems is becoming more dangerous. Thus, there is a need to focus on safe practices.
Dilip Kumar, Executive Director, Inspire Clean Energy
Inspire Clean Energy is a focused asset management company. Asset management has two verticals – financial asset management and technical asset management. The company focuses on technical asset management. Under this, one of our functions is to help developers plan their finance for the future by providing them with output and performance predictions. Accurately predicting the output from a system is a challenge. Irradiation data taken from satellites is also not very accurate. Alternatively, we work on numerical weather-based model predictions for our assets. This involves taking historical data and running it through a pattern recognition system to make a prediction for rooftop players. We provide predictions for small-size systems of around 550 kW, based on grid availability for the past three to four months and data of the past one year.
Cleaning is a major task in the rooftop solar space, especially with the hub-and- spoke model. To this end, we have deployed GPS-enabled technology with geo-tracking to monitor cleaning. Further, we have put in place a QR code system, which scans the code to verify the physical presence of a worker. To address the issue of water scarcity, we have worked with the Central Institute for Plastic Engineering and Technology to come up with a brush, which uses only 300 ml of water on an average. Dry cleaning is also emerging as an option. However, cementation costs, on account of fumes that contain oils and paraffin, reduce its feasibility. We only take up assets that comply with the relevant safety requirements. In some cases, we have even helped the customer put up safety systems. Further, there needs to be enough space for a person to walk in order to carry out maintenance for a rooftop system. Often, in order to compete in terms of output or capacity, the space on a rooftop is not properly allocated. Shading due to exhaust shadows also affects output. In order to assess asset quality, we must look at the generation instead of the installed capacity.
The smallest size that we manage is an 8 kW plant in Delhi. Working with a hub-and-spoke model, we have built a hub that can manage 3-5 MW. It is not an uneconomical size, since we have now come up with a support partner model. Many small instrumentation and control contractors that have a small team of two to three people join in as support partners. In turn, we allow them to use our brushes and technology.
Gensol started off as a consultant in the design and engineering space, and then moved to EPC and O&M. Currently, Gensol has a portfolio of about 3 GW under O&M, which includes both ground-mounted and rooftop projects. We are trying to optimise the cost, capture losses while figuring out the reasons behind it, and improve the overall output of projects.
One of the issues that can be seen in the initial stage is that many plants have been built, although the quality of those plants is quite poor. In order to achieve the projected capacity, the quality is often compromised. Another challenge is the lack of supervisory control and data acquisition (SCADA) systems to monitor plant performance. These result in a lack of data required to monitor the performance and functioning of the plant. In cases where SCADA and other control systems are already in place, regular and proper calibration of parameters must be undertaken to ensure the quality of data.
Most of the rooftop sites either do not have a pyranometer or have it just for the sake of it. Safety is also a major issue for most projects. Basic safety measures must be in place not only for safety, but also to improve the quality of output. We have developed an application for the safety of engineers who carry out routine maintenance. If an engineer is unable to complete an activity in a given time and is unresponsive to the buzzer, a team immediately rushes to help. There is also an application that screens the people entering the campus to ensure that only authorised entries are allowed. All visitors entering the campus and the plant premises are screened properly. Security is also a major issue for rooftop systems as restricting access to roofs is difficult.
Further, to keep up with the structural and technological changes in the O&M space, there is a need to develop effective strategies. Plant sizes have been increasing, along with capacities of inverter blocks and transformer sizes. In view of this, we are now trying to move from a site-based model to a central model to develop more cost-efficient solutions.