The commercial PV industry has continued to grow and shows every indication that it will continue to supplement and even surpass conventional energy production methods in the future. The requirement for professional and experienced operations and maintenance service providers has grown right along with it. Commercial PV owners and managers have seen the value of consistent availability and rapid return to service times, and this has allowed asset managers to forecast energy production with greater reliability and quality. Without question, the value of solar O&M has been established in the last ten years and is now understood to be an integral part of any PV systems operational requirements. With energy output guarantees and power purchase agreements, the requirement to maintain and optimize is in every contract and is on every PV system manager’s mind. What we are now starting to see is that due to system aging and new technology, the requirement to remove and replace part or all an existing system is being considered and becoming more common.
Risk
PV systems that do not have scheduled maintenance programs to support the products individual components and systems do not typically have the best ROI for the customer. These systems sometimes underperform unless a maintenance plan is in place and operational. Often, the owners or financial stakeholders do not know if the system is not meeting production estimates. What is becoming more obvious is that these systems are also “aging prematurely” due to deferred maintenance and neglect. It’s difficult to understand how a system could be left without a maintenance plan or needed repairs but it happens regularly and at different degrees and times in the energy production lifecycle. The reasons for this deferred maintenance or even abandonment is varied but runs the gamut from poor budgetary planning to company or asset management turnover. This can cause a much bigger problem than underperformance.
Hidden Costs
The largest hidden cost is failed power production expectations and the potential of having to remove and replace some or even all the systems costly components. Customer’s plan, forecast and budget based on the expected power that is estimated during design and construction. A PV developer’s future financing and business model can be seriously affected by an underperforming project or the missed opportunity to accurately forecast long term system replacement costs. Expensive repair costs, extensive downtime, and additional resources to manage and repair the asset can add up quickly. Damage to the builder’s and the solar industry's reputation to provide a cost-efficient energy alternative is also very costly.
The Problems
Any component of the system has the potential for failure, and every component left uncared for will deteriorate and fail over time. The aging of the system will also bring other issues into consideration. Such as structural problems with the facility where the system is installed on defective roofing. When an aging system is installed on a roof that needs replacement, a larger decision should be made. Some immediate and important questions come to mind. Does the existing system need to be removed and replaced as it was originally built? Does a redesigned system with new components need to be installed to provide long term production reliability and warranty coverage? Does the cost of this pencil out? Finding and contracting with a reputable and experienced PV EPC and O&M provider can be time-consuming and challenging. Knowing how much service to contract for and at what price can be a difficult process to work through unless you find an experienced and qualified service partner. Many O&M service providers offer a standard menu of services that can be customized to address your specific site's scope and schedule. O&M service providers are now seeing the need to retrofit aging systems with new components or rebuild them entirely. Ask your service provider to explain and propose their full offerings in detail and inquire if they have the experience and capability to remove and replace an older existing system. Developing a relationship with a qualified full-service provider is more essential now than ever in assuring expected energy production.
Inverters
The inverter is the core of any PV system. Although designed to handle the elements, water, dirt, and debris intrusion is an issue. Moisture can be drawn in by the cooling fans or introduced by sprayed irrigation. Dirt and other debris can be absorbed by the cooling fans’ vacuum. Filters are in place to reduce the amount of intrusion; however, they are not foolproof, and the filters do require regular cleaning. In the last five years, the commercial PV industry has seen a move to string inverters from central units and many older PV systems can and will need to benefit from this industry change. Some central inverter manufacturers have reduced or curtailed production and service offerings. This development is placing owners, managers, and warranty holders in more jeopardy. String inverters can require much less maintenance and minimize production loss in the event an inverter goes offline.
Ground faults
Failed grounding lugs, conductor insulation failure, and pinched or lose conductors can cause system faults, underperformance, or damage. Over time, grounding measures can begin to fail due to several causes. Sometimes an entirely new and upgraded system will need to be installed to eliminate costly service calls and downtime.
Racking
Loose or missing fasteners, improperly installed hardware and corrosion can lead to module, system, and or property damage. New developments and simplification in racking design can mitigate current structural, production, and safety issues.
Modules
Underperforming and failed PV modules can cause many issues that affect system performance. If undetected during system commissioning and operations and subsequently left in a string of otherwise healthy modules, string and subsequently array production can and will be reduced. As modules age, the installed module may become unavailable and obsolete. The opportunity to remove and replace with higher output modules where spares can be purchased for future needs can be an important consideration to make.
Conduit failure
Exposed conductors from damaged, failing, or broken conduit can lead to some very expensive and time-consuming repairs. Troubleshooting faults, pulling new conductors, splicing testing, and terminating wiring is a road no system owner or manager wants to travel. This problem can lead to other future failures and safety issues when undetected and not repaired.
Monitoring
Recently our industry has seen a number or DAS providers merge and sometimes fail and the need to reevaluate the service providers offering is constant. Many new DAS offerings are positive as well and a good look at what is now on the market is extremely valuable. Performance monitoring is a solar array’s lifeline to its service provider. Email notifications alert a monitoring specialist to irregularities on site, such as low production or a down inverter, issues that could otherwise go days or weeks without being noticed. Data collected from monitoring also allows easy performance reporting to stakeholders and rebate programs. Tracking the system’s performance regularly to identify trends in production or anomalies is vital to optimizing system output.
Corrosion
Stuck and or failed fasteners on the system can disable mechanical functions, affecting structural integrity, and aesthetic quality. Preventative maintenance that addresses corrosion is not always included in most O&M service offerings but is an important aspect of system longevity and value. Often corrosion is addressed in the original EPC contract but not followed up in the O&M proposal. Corrosion can be especially problematic in high-humidity environments and without mitigation can lead to complete structural failure in some cases.
Landscaping
Landscaping also plays a role in the effectiveness of a PV system. Untended grounds can generate shading on panels, lowering production values. It is also not uncommon for weed abatement procedures to use large mechanical equipment to throw up dirt and rocks, damaging panels at the cost of the owner. Erosion can cause damage to conduit and conductors, as well as racking and inverter pads, and must be mitigated.
The Plan: Maintenance and Remediation
It’s important to remember that not all sites are designed or constructed the same nor are they located in common environments. A well-scoped and scheduled maintenance plan is essential to the customer’s ROI. This maintenance plan should be customized to the system that it is being used to maintain and not a generic form that is good for every system in the “fleet”. Preventative maintenance should be performed at least once a year. However, each site’s characteristics will vary. An agricultural packaging facility may need service multiple services a year, whereas a college campus may only require an annual visit, and a utility site may require continuous service. It is important to seek a provider who can develop a maintenance package that suits each individual system’s needs. Data Acquisition Systems (DAS) can provide a suite of useful information that show the service provider what and when essential maintenance services are needed. The optimum time to clean solar modules or set a tracker program can be determined through a DAS, as well as the replacement of system fuses and modules. Visual inspections including drone fly-by and thermography play an important part in scheduling maintenance tasks and photographs of the site are always an important resource.
The Documentation
Reputable service providers will always provide reports upon completion of any maintenance service. This documentation is vital to the effective maintenance of the system. It details the scope, schedule, and service history that is unique to the system. It can and will save the manager or owner time and money in the short and long run of the power systems service life. Maintenance documentation can be an essential requirement when addressing warranty coverage and many warranty holders will not provide service without it. Though documentation may require more involvement on the owner or manager's side, it allows greater scrutiny and protection of your investment. Regular maintenance could mean the difference between a short-term year high production lifespan, or an extended years-plus, decreased production lifespan, and ultimately a corresponding ROI. Reactionary services on a PV system tend to be costly, and full unit replacements may be necessary to return the system to operation. Systems that operate at 99% availability for the production year typically earn a high ROI and increased customer and industry confidence.
Remediation
There comes a time in the life of every facility, system, or component that a decision needs to be made to repair or replace some or all of it. The alternative is to lose the asset and its expected value. An active and long-term maintenance plan is essential in maintaining and assuring production but even then, time may take its toll and a system will need to be remediated. When considering this tough decision, make sure to reach out to those companies that have experience in the full spectrum of services required for the work. It’s very important that you select a company that can provide the critical EPC and service provisions that will assure your project is completed with the expected value and reliability and that the most current design and components are utilized in the project.
About Day Electric
Day Electric is a full-service solar O&M service provider with complete project design, procurement, commissioning, repowering, and construction management capabilities. The company also provides professional operations and maintenance services for solar power plants as well as small businesses and residences. With completed projects spanning government, education, commercial, and municipal customers. The Day Electric portfolio of projects makes the company one of the top solar PV service firms. For more information contact Day Electric by phone at (434) 333-0355 or info@dayeletricusa.com.