Keeping a commercial array performing after handover

A solar system is a twenty five year asset whose business case assumes it keeps producing. The model allows for a small amount of annual degradation, which is the panels ageing gracefully, not an allowance for faults left unattended.

The losses that hurt are the avoidable ones: a failed inverter, a tripped string, soiling on a low pitch array, or a monitoring platform nobody logs into. Each is easy to fix and expensive to ignore.

Maintenance is also the difference between a warranty that pays out and one that does not, since most manufacturers require evidence of proper upkeep.

Remote monitoring with defined alerting, so faults are detected rather than discovered. Periodic inspection of modules, mounting, fixings, cabling and connections. Electrical testing to the appropriate standard, with results recorded and compared over time.

Inverter servicing, including firmware, cooling and filters where applicable, plus checks on the roof interface: penetrations, ballast position, drainage paths and any signs of movement.

Cleaning where it is justified. UK rain deals with much of it on steeper pitches, but shallow tilt arrays, dusty industrial settings and sites near agriculture or heavy traffic accumulate soiling that measurably reduces output.

An agreement that promises support without defining a response time is not offering much. Ask for the time to remote diagnosis, the time to attend site and the typical time to a parts fix, in writing.

For a large array, days of downtime carry a real cost, and it is easy to work out from your generation figures. That number is the basis for deciding how much service level to buy.

Spares matter too. Ask what is held, what has a long lead time and whether a temporary replacement is available while a unit is repaired.

Rooftop work needs a safe access strategy, fall protection and an isolation procedure, and your own contractor management obligations apply to whoever attends the roof.

Keep the documentation: design drawings, string layouts, test certificates, the G99 connection agreement, warranty documents and the maintenance log. It is needed for warranty claims, for insurance and for any future sale of the building.

Where a battery is present, the fire strategy and the insurer's conditions form part of the maintenance obligations rather than being one off items completed at handover.

The installer that built the system is usually best placed to maintain it, because they know the design and hold the workmanship warranty. Independent providers are an option, particularly where a site has multiple systems from different contractors.

Agree the maintenance arrangement at the same time as the installation contract. It is far easier to negotiate before the work is won than afterwards.

NRG Solar matches you with vetted installers and makes sure the proposals you compare include maintenance on a like for like basis. The contract itself is between you and the installer.