Operations and maintenance

A solar array or battery is not a fit-and-forget purchase. It is generating plant, and plant needs operating. The gap between a well-run system and an ignored one does not announce itself: an ignored system still sits on the roof, still shows a green light, and still generates something. What it stops doing is generating what the business case assumed, and without monitoring nobody finds out until the numbers have quietly slipped for a long time.

This is the operations argument in miniature. Energy assets underdeliver for the same reason energy costs drift: no measurement, no feedback loop, no one whose job it is to notice. The organisations that extract full value from their systems are not luckier; they are the ones in which someone watches the data.

What actually goes wrong

Panels degrade slowly and predictably; that is priced into any honest model. The real losses come from events: inverter faults and outright failures, strings tripping offline, accumulating soiling, new shading from growth or neighbouring development, and monitoring links that silently stop reporting. Batteries add their own list, including degradation from cycling patterns and dispatch settings that were configured once and never revisited when the tariff changed. Each of these is cheap to catch early and expensive to discover late.

When Vester takes over O&M for a system installed and previously managed by someone else, the same handful of problems tend to surface. Monitoring thresholds are usually generic, carried over from commissioning rather than tuned to the site’s own generation profile, so genuine underperformance sits below the alert line for months. Communication gateways go offline quietly and nobody notices, because the fault produces no alarm, only silence. String-level faults hide behind array-level totals: a system generating at a fraction of expectation can still look fine on a dashboard that only reports the whole array. Battery dispatch settings are frequently still configured for the tariff in place at installation, sometimes years after that tariff changed. And warranty windows lapse unclaimed, because nobody was tracking degradation against the manufacturer’s curve closely enough to notice a shortfall while a claim was still possible.

Monitoring is the contract that matters

An O&M agreement is only as good as the monitoring behind it. The test of a monitoring arrangement is simple: does it compare actual generation against expected generation for the conditions, and does a drop trigger a human response within a defined time? Dashboards that display data nobody reads fail this test. So do arrangements where the party monitoring the system is the party that sold it, marking its own homework on the performance claims it made.

Independent monitoring means the party watching the system has no reason to look away from bad news. When the installer also monitors performance, a shortfall against the original business case reflects on their own work, which is not an incentive to escalate it. An independent monitor has the opposite incentive: catching underperformance early is the entire value of the service. The same logic applies to warranty enforcement. Manufacturer warranties on inverters and panels are not self-executing; someone has to track actual output against the expected degradation curve, document the shortfall with evidence the manufacturer will accept, and pursue the claim before the window closes. That work is unglamorous and easy to defer, which is exactly why it gets skipped when the party responsible for doing it is also the party who would rather not raise it.

The asset and the tariff must be run together

A system’s value depends on the tariff around it, and tariffs change. A battery dispatching against last year’s price structure, or a site that moved contracts without revisiting its self-consumption strategy, leaks value at the interface between asset and tariff. Running the two together, as one system under one feedback loop, is what keeps the original business case true over the asset’s life.

If you own a system and cannot say with confidence how it performed last month, that is the finding. Book a review at /book or request a benchmark at /benchmark.