"Solar Maintenance, the solar setup productivity bears the profit over time when the system is periodically well maintained".
Proper maintenance not only provides longevity on the parts but also reduces cost over time thus improving the profits or savings over a period of time.
The investors especially in the PPA or lease model will be more interested in periodic maintenance and checking the vital parameters of the system more frequently to ensure the cost of ownership in maintaining to provide the service is within budget and profits.
Most investors will be interested in
Performance parameters of the solar setup
Service agreement adherence between the customer and provider
Keeping the cost estimates a predictable match
Individual upright solar power setup owners can perform the periodic maintenance by adhering to the checklist of items they should check at different intervals leaving the cost of ownership regulations.
Following are some of the best practice benchmarks outlined in the National Energy Laboratory in their publication.
The Solar power plant operations include the following areas of focus usually investors would be keen
Ensures effective implementation and control of O&M services including
Plan of as-built drawings,
Ownership and manuals, and warranties.
Plan involves not only keeping an archive but selecting what to keep, pursuing missing documents, preserving documents, keeping them up to date, and finally, archiving documents.
Keeping records of performance and O&M measures, preparing scopes of work and selection criteria for service providers, contracting with suppliers and service providers, paying invoices, preparing budget, and securing funding and contingency plans for O&M services.
Administration includes compliance with regulations by the government or authorities having jurisdiction, as well as mandatory guidelines issued by utilities.
Ensures efficient, safe, and reliable process operations including making decisions about maintenance actions based on cost/benefit analysis.
Point of contact for personnel regarding
operation of the PV system
coordinating with others regarding system operation
power and energy forecasts
scheduling maintenance operations
spare parts inventory (either in-stock on-site or in suppliers’ consignment stock)
Inspecting work and approving invoices.
Meanwhile, operations include any day-to-day operation of the system to maximize power delivery; performance assessment and trends; operation of grid interface; manage curtailments; or adjust settings such as power factor or other ancillary services
Build Delivery Performance
Specify the rules and provisions to ensure that maintenance is performed safely and efficiently, including the formalization and enforcement of:
safety policy (including training for DC and AC safety,
minimum staffing requirements, arc flash, and lock-out tag-out);
work hours; site access, laydown areas, and parking; and
Other stipulations under which work is performed.
Confirm and enforce qualifications of service providers, as well as compliance with any environmental or facility-level policies regarding the handling of controlled materials (e.g., solvents, weed killer, insecticide).
Monitor and Track Performance
Maintain monitoring system and analysis of resulting data to remain informed on system status
Metering for revenue; alarms; diagnostics; and security monitoring.
Includes comparing results of system monitoring to benchmark expectation and providing reports to facility stakeholders.
This includes periodically preparing reports as required by O&M contract or as required by the system owner including reports of plant performance;
Key performance indicators; problems and alarms, and maintenance services performed. Site security is performed both locally and with remote monitoring (cameras, intruder alarms) to protect against theft and vandalism
Knowledge Management, Document maintenance
Ensure that operator knowledge, training, and performance will support safe and reliable plant operation.
Information such as electrical drawings, part specifications, manuals, performance information, and records must be deliberately maintained and properly filed/catalogued.
The Solar power plant maintenance should mostly include the following methods for a PPA or Lease model.
Strategize with plan
Ensure effective implementation, control, and documentation of maintenance services and results.
Establishing budgets and securing funds for preventive maintenance
Establishing reserves or lines of credit for corrective maintenance
Planning services to avoid conflict with system operation or operations at the customer site
Correspondence with customers, selection and contracting with service suppliers and equipment manufacturers; record keeping, enforcement of warranties
Providing feedback to designers of new systems
Reporting on system performance and the efficacy of the O&M program.
Schedule and frequency of preventive maintenance is set by the operations function and is influenced by a number of factors, such as
Equipment type, environmental conditions at the site (e.g., marine, snow, pollen, humidity, dust, wildlife), and warranty terms.
Schedule maintenance is often carried out at intervals to conform to the manufacturer's’ recommendations as required by the equipment warranties.
Reactive (break-fix) Maintenance
Repair damage or replace failed components.
It is possible to perform some corrective maintenance such as inverter resets or communications resets remotely.
Less urgent corrective maintenance tasks can be combined with scheduled, preventive maintenance tasks.
Special Scenario Maintenance
Condition-based maintenance is the practice of using real-time information from data loggers to schedule preventive measures such as cleaning, or to head off corrective maintenance problems by anticipating failures or catching them early.
The measures triggered by condition are the same as preventive and corrective measures, they are not listed separately.
Condition-based maintenance affects when these measures occur, with the promise of lowering the frequency of preventive measures and reducing the impacts and costs of corrective measures.
End-of-Performance Period Handover
Should include the options for the parties in an signoff contract (such as a PPA) at the end of the performance period, or
The end of the projected life of a host-owned system,
The alternatives to include are the following
to continue the performance contract for an extended term
Continued O&M service
Purchase of the system by the site or others (often at “fair market value”), involving a new O&M provider
Removal of the system and restoration of the site.
Guarantees related to O&M include: response time guarantee; availability guarantee; performance ratio guarantee; and energy production guarantee.
Plant Technical Maintenance best practices
If micro-inverters are not used, the PV system will have both alternating current (AC) and direct current (DC) components.
The DC system determines system power capacity and energy production, whereas the inverter and the AC system has the greatest impact on system reliability.
There can be several single points of failure in the AC system—for example, the central inverter, or the generator step-up (GSU) transformer.
Maintenance measures and cost depend on the wire management system employed, will be minimal for conductors in conduit or lay-in trays, which are designed as an integral part of the rack and wiring system.
Wires and plastic components require frequent checks as UV exposure will degrade the life over period of time. Frequent replacements are recommended.
Expansion due to thermal effects or tracking power point which requires an allowance of space there by modules do not touch other components.
Insulation of wires at all joins and stress concentrated zones where they are prone to exposure and short circuit.
Direct burry of wires as appropriate should be performed. Not all plants would require such design, however if applicable enough measures for ease of access to wiring etc should be considered.
For large scale Solar Power setup appropriate use of Transformers must be selected during system design
The O&M is unique in how the solar circuit is connected with the inverter:
Independent micro-inverters per module
string inverters connected in series
Optimized DC inverters with micro and string modules
Inverters Centralized for larger capacity.
Micro inverters run on higher cost than string and central inverters.
A service based inverter maintenance should be signed with the manufacturers. Most providers have a 20 year replacement plan on inverters.
Roof Maintenance includes
Identifying the roof leaks and fix them
Fixing the effects of blast
AMC service should include check on roof system components as well.
Always better to avoid complex roof top system to mount the solar panels.
An ideal slope angle for Solar panel mounting must be adhered to depending on the local geographic azimuth on sun’s light to achieve maximum optimal tracking point.
The roof top system condition should be periodically monitored for any cracks, rusts, leaks or stagnant water points.
Rack Attached Areas
A roof deck mount or a structure can be used to hold the PV. In few locations Ballasted mount is done, which means held in place by added weight.
Low-slope or flat surface enable Ballasted systems but not more than 5 degrees; 1:12 pitch.
To reduce wind loads, ballasted systems can only be used if solar collectors are at a low tilt angle—usually a 10-degree tilt and limited to no more than 20 degrees (one dual-orientation ballasted system has a south-facing panel tilt angle of 25 degrees, and north-facing of 15 degrees).
Such a low tilt angle is a minor penalty on annual energy delivery depending on latitude, but allows more kW per square foot of roof area and delivers more in summer, when utility rates are higher.
Some of the factors to be looked upon during Racking are as follows
Wear on Roof Membrane
Extreme Snow Loads and Ballasted Racks
Maintenance of Proper Roof Drainage
Migration of Connections on Roof
Ground Mount Maintenance
Ground mount helps to avoid the roof maintenance, however they have issues of their own such as
Vegetation growth on the ground
Disruption due to Snow
Airborne dirt and pollen add to ground mount cleaning efforts.
Tracking (if any) maintenance
The complexity of tracking systems requires much more maintenance, not only on the load-bearing moving parts of the array, but also, for the associated system for actuators and controls. Additional considerations for tracking systems include
Electrical connections, controllers and enclosures
Controls: checking all control devices to perform desired output
Rack and Actuator: All moving parts must be frequently checked for mechanical parameters.
Many environmental conditions outside human control affect performance of solar setup.
Soiling is solved through cleaning
Other environmental conditions can affect O&M, but are outside human control.
Humidity (this may be addressed by installing dehumidifiers in shelters that contain sensitive equipment)
Soiling reduces the energy output of the PV array, and can lead to localized hot-spot failures if the soiling is uneven.
Design of array can increase or decrease snow accumulation.
Clearance between the bottom of the array and the ground or roof avoids wind-driven drifts and allows snow to slide off.
Snow generally slides off steep arrays (for example, 30 degree tilt), but does not slide off low-sloped arrays (<20 degree tilt).
Snow removal is generally not recommended because it damages the modules, but it is sometimes required to reduce snow weight on a roof or to remove ice dams.
Snow removal is by powerful turbo-fan, not shovel or other mechanical means. Snow removal to provide access (roads, walkways) is generally required.
Access to Site
The Solar setup site must be easily accessible. The utilities must be easily be able to move around the construction area etc.
Solar plant site usually will be many acres. It’s advisable to provide drive access to these areas, such as ambulances, fire trucks, cranes.
Roads must be well maintained to help ease of access.
Physical site security is must to prevent any untoward events to humans as well as animals that would lead to damage of site equipment. Deployment of security guards or CCTV cameras will do the needful.