Best Practices to Reduce Downtime and Optimize Energy Production
Handling of faults and general incidents in the solar PV business is one of the most critical operations for an operations and maintenance (O&M) contractor. Incidents have an immediate effect on electricity production of solar PV Plants and due to their frequency they can be an important obstacle towards operation optimization of PV assets.
One of the most important duties of an O&M contractor is to respond and most importantly, to resolve issues that affect operations of a PV plant in the shortest time possible. Of course owners always request a minimum response time for contractor performance, but every serious and professional O&M contractor should aim to further improve and provide their client with the best possible service.
Resolution time depends mainly on three factors:
- Time until a fault is detected
- Intervention time and responsiveness of field technicians
- Actual resolution/remedy time on site
With proper management and optimum structure, the overall timeframe from the moment a fault is detected up to the moment normal operation is restored can be reduced by up to 65%. Assuming one incident every two weeks this immediately translates to an increased uptime of the PV plant of up to 5.4%. These representative numbers are based on a simplistic approach assuming each incident results in a 100% downtime of the plant. In most circumstances this is not the case. Normally an incident may affect only part of the plant or just cause a degraded performance of the plant instead of a complete downtime. According to our experience, taking into consideration an average scenario, an increased uptime and/or performance of the plant may be increased by 2-3%; still a very significant number.
Based on these numbers any solar plant owner immediately understands the financial impact to the model if such numbers are achieved. Additionally, the data points to the importance of the reliability of the O&M contractor and the opportunity to turn operations and maintenance from a cost to a revenue center. This line of thinking provides a new perspective on how O&M services are perceived.
Overview
In the early years of the PV boom in Europe most people felt confident once plants are connected to the grid, maintenance needs would be minimal and their assets would produce to their maximum without significant efforts. Taking that for granted was the most common misperception of O&M by solar plant owners and operators.
Unfortunately today it is very well known that proper operations and maintenance is essential to keep the plants running and producing to their maximum of their capacity. Solar PV plant incidents are not as scarce as it was hoped for; on the contrary they do happen very frequently for various reasons:
- Bad design and/or implementation without taking into consideration the expected lifetime of the asset which is more than 20 years
- Cheap and/or not suitable material
- Grid problems and instability
- Security incidents (thefts, vandalism, etc.)
- Material aging and normal wear and tear
- Force majeure events, e.g. adverse weather conditions
Incident handling, due to its frequency and, in many occasions its severity, is one of the key factors of maximizing performance and hence revenue.
The chain of actions involved in incident handling consists of several steps, as explained in detail below and optimizing each step is a big challenge. The basic cornerstones of such optimization are the following three:
- Proper IT infrastructure
- Knowledge building and dissemination across the organization
- Training of personnel, mainly field technicians
In many occasions these parameters are largely neglected by contractors focusing only on minimizing intervention time, which, although very important, is only a part of the whole chain of actions.
Cornerstones of Optimization
IT Infrastructure
The importance of a monitoring system cannot be enough emphasized for the O&M business. Such system is the eyes of the contractor in the PV plant. Without such system is like being blind and in the dark.
In relation to incident handling, a well-designed monitoring solution should be capable of:
- Instantly recognizing and logging malfunctions and creating the respective notifications
- Recognizing medium and long term deviation in the data
- Capture a lot more operational parameters than just the typical data; inverter and meter energy, irradiation and temperatures
“After all, what is an alert system good for if hundreds of false alerts are generated?”
The positive impact of recognizing malfunctions quickly on the plant performance is immediately evident. This is though easier said than done. During the plant operation, especially during high irradiation hours, massive data is generated. The key to a sophisticated alerting system lies in the capturing of all this data and evaluating it with specialized algorithms so that false positives and false negatives are minimized. This has the negative effect of distracting control room personnel from real issues and thus prolonging, the least to say, the actual detection time of a real fault.
“Even with a perfect monitoring system and an extensive knowledge database the job is still done by humans.”
SCADA systems can only generate alerts based on the data measured on-line. They are not able to evaluate medium or long term trends. This is especially important when there is no immediate acute fault, but rather trends of slow degradation of performance that are not identifiable with the comparison of parameters over a short period of time (e.g. 15 minutes). A simplified example for that is soiling on the panels. The plant would not show any immediately evident fault, but comparing performance over a period of days or weeks would immediately show the loss of performance over time.
Another important parameter of a monitoring solution is the collection of the event log entries of the devices used in the PV plant along with a series of other measurements not related to the inverters. Most monitoring software in the market capture only the basic measured data (inverter energy, meter energy, temperatures, irradiation and probably some others). ACTIS, Alectris’ proprietary monitoring system is able to capture dozens of parameters including the log entries of devices providing valuable information to the control center personnel on each fault.
The Alectris ACTIS, Asset Control Telemetry Information System, solar O&M platform provides:
- A platform to deliver all solar O&M activities correlated to the outcome
- A holistic view on the plant operation through the storage of all relevant information in one structured database
- Full activity history to understand the possible root causes of failures
- Optimization opportunities are readily identified and quantified leading to informed decisions
- Transparency and trust between solar PV plant owner and O&M provider
Knowledge Building and Dissemination
Whatever the location, PV plants all over the world operate exactly on the same principles and using similar equipment and setup. The good thing about PV plants is that their technical complexity is rather low. Consequently a big part of the faults show a lot of similarities across geographically distributed plants. Building a knowledge base of the resolution of various faults and distributing this knowledge across the organization provides great help to technical personnel. In such cases, people do not have to re-invent the wheel in each occasion, but merely refer to solutions to problems of the past. This dramatically minimizes the time needed to actually resolve problems since research time is minimized.
Training
Even with a perfect monitoring system and an extensive knowledge database the job is still done by humans. Training is a critical part of providing high quality services. The better technicians are trained the quicker they can understand instructions, provide reliable information and act quickly on site.
We have seen lately a strong trend of companies from other O&M sectors (e.g. telecommunications or facility management) entering the PV O&M market. Although at first glance this may sound a logical step, one should consider what efficiency a technical crew, not trained specifically on the PV technology, can have when asked to resolve complex technical issues on PV plants.
Training should not be just a one-off task. There is a clearly a need and a benefit of closely monitoring performance of technical crews and reviewing it on a regular basis. The ultimate goal should be to understand the deficiencies of a team and organize specialized training sessions to address such deficiencies.
Summary
Incident handling is one of the most common tasks an O&M contractor has to undertake. Incidents can occur due to various reasons. Some of them relate to external factors (e.g. adverse weather conditions, power outage etc.) and some of them are caused by mechanical breakdown or normal wear and tear of equipment. Unfortunately it is not uncommon that PV plants have been designed or constructed with low quality, without taking into consideration the lifespan of a PV plant being more than 20 years. Design and/or construction flaws cannot be corrected after commissioning of a plant, or such correction would not justify their investment.
Hence, responsiveness and quick resolution of fault is of major importance in order to maximize performance of plants bringing their output to the maximum of the PV plant’s abilities.
Solar PV plant incident resolution time can be shortened by:
- Proper IT infrastructure
- Knowledge building and dissemination across the organization
- Training of personnel, mainly field technicians
Part 2 will demonstrate this approach in action can indeed increase dramatically the overall performance and revenues generated by a plant. Such improvements in performance can be up to 5.4% in extreme cases, whereas our experience has shown that an average availability and performance ratio (PR) increase is in the range 2-3%.
The ultimate goal is of course to avoid any sort of failures. This is in theory to a certain extent possible using failure prognosis methods. Such methods are widely used in other industries, where a failure is critical (e.g. in aerospace failure could lead to loss of lives), but can also be implemented in the solar PV sector. Alectris is working in such a direction for over a year now, expecting first commercial results in 2014.
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