Secure yields, keep deadlines.

For the electrical side of an energy asset, the same basic rule applies as everywhere. The employer ensures that electrical installations and equipment are installed, modified and maintained only by a qualified electrician or under their direction and supervision. The employer also ensures that they are inspected before first commissioning, after every modification or repair, and at specified intervals. That applies equally to inverters, storage systems, charging points, medium-voltage panels, transformers and standby generators.

The intervals must be set so that defects show up in time. As a guide, the implementation instructions give four years for fixed electrical installations and equipment, and one year for installations in premises, rooms and installations of a special kind. Whether your installation falls into the second group is assessed by the qualified electrician under the electrotechnical rules. In addition, insurers and grid operators may require their own proof and intervals. Read your insurance terms and your grid connection agreement.

The effort is usually in the overview. With several locations and service providers, records and dates are scattered. vi reads the reports and files intervals and findings for each asset.

A hot spot on a module, a connector or a terminal points to a fault in an electrical installation. It means lost yield and, in the worst case, a fire hazard. DGUV Regulation 3 says: if a defect is found, meaning the installation no longer complies with the electrotechnical rules, it must be fixed without delay. If there is an urgent danger until then, the installation or the equipment must not be used in its defective condition. Whether a finding is such a defect is judged by a qualified electrician. The thermography report alone does not decide that.

Ask the inspector for each finding for the location (string, module, terminal), the measured value, a photo, a rating of urgency and the recommended action. Order the repair in writing, quoting the report, set a deadline and ask for a follow-up measurement as proof after the work.

Before you replace anything, check whether the part is still covered by a manufacturer warranty or by the seller's statutory liability for defects, and report the case to the manufacturer or seller before the defective component is disposed of. The date of the report counts. vi turns every finding that needs action into a ticket and attaches the proof once it arrives.

Manufacturer warranty and statutory liability for defects are often mixed up. The warranty is a promise by the manufacturer or seller. What applies is in the warranty terms: duration, start, exclusions and the proof that is required. The statutory liability for defects (Gewährleistung) is the legal responsibility of the seller or installer for defects. Its duration follows from the contract and the law, and if in doubt, have a lawyer clarify it.

In practice, the start date counts first. Delivery, acceptance, commissioning or grid connection: depending on the document, a different date is stated, and it decides whether a defect still falls within the period. So put into the asset file, for each device, meaning inverter, storage unit and module, the serial number, purchase date, acceptance date, warranty start and warranty end, plus the terms. If the manufacturer requires maintenance records or a registration, a missing one can be a reason for refusal.

A few months before the warranty ends, schedule an inspection of inverters and storage systems and document anything unusual. That way a developing defect can still be shown within the period. Also check whether a defect is covered by the warranty before you order a paid replacement. vi reads warranty start and end from data sheets and warranty documents and reminds you before they expire.

An availability promise is only as good as its definition. First read what counts as available, the plant as a whole or each inverter on its own. Clarify which periods are taken out of the calculation, such as grid shutdowns, force majeure, maintenance windows or curtailment by the grid operator, and over what period availability is measured, the month or the year. It also matters who measures with which data and whether you can access it. The contract should also say what applies if the figure is missed: a flat sum, lost revenue, a contractual penalty or a right to terminate. Finally, check whether the promise also applies when a fault persists because a spare part is missing.

Then compare. Put the faults from service reports and monitoring next to the promise. If three inverters are down for two weeks, that produces a different availability than the monthly report from the operations manager. Ask for the raw data, meaning fault messages with start and end, and recalculate before you approve the annual statement.

Pay attention to response times: receipt of the report, start of troubleshooting, resolution. Record the date and time each time. Also check in the contract by when you have to report deviations, otherwise the claim may lapse. vi puts faults from service reports next to the availability promised in the contract.

For stationary battery storage, the EU Battery Regulation creates a data right of its own. Since August 18, 2024, stationary battery energy storage systems must contain up-to-date data in the battery management system on the parameters that determine the state of health and expected lifetime. Whoever has legally purchased the battery receives read-only access to it at any time, on a non-discriminatory basis and respecting the intellectual property rights of the manufacturer. The access explicitly extends to independent operators and to third parties acting on your behalf.

The purpose is stated in the law: making the battery available to independent aggregators or market participants, assessing residual value and remaining lifetime from the state of health, and facilitating reuse or repurposing.

For your business, this means: at purchase, have the access described, including the interface and the format. File the state-of-health value of the storage system at regular intervals, because it supports claims for performance and capacity against the manufacturer and the residual value at sale. For older storage systems, check whether the regulation applies to your model, and settle data access in the contract. vi files state reports of the storage system for each asset and places them next to the warranty terms.

With inverters, storage systems and charging points, updates often run remotely, without anyone on site noticing. That is convenient until an update causes a fault or a missing update leaves a vulnerability open.

For manufacturers, a lot changes. The new Product Liability Directive applies to products placed on the market from December 9, 2026, and it expressly counts software as a product. A manufacturer cannot argue that the defect arose only after the product was placed on the market if it comes from software, updates or a missing update needed for safety, and the manufacturer had it in its control. The Directive does protect people who are injured. For property used for professional purposes, it provides no compensation, so it does not cover lost yield. In addition, under the Cyber Resilience Act the manufacturer must inform users about actively exploited vulnerabilities as soon as it knows of them.

For your relationship with the manufacturer and the service company, therefore, the contract decides. Settle who may access remotely, who approves updates, whether they are announced in advance, how the software version is documented and who bears the costs if a fault follows an update. vi keeps update records together for each asset.

Switchgear that uses SF6 or other fluorinated gases as an insulating or switching medium falls under the F-gas Regulation (EU) 2024/573. For operation, leak tightness comes first. Operators must ensure that such equipment is checked for leaks unless one of three exceptions applies. The equipment has a tested leakage rate below 0.1 percent per year, stated in the manufacturer's documents and labeled, or it has a sensor for pressure or gas density with an automatic alert, or it contains less than 6 kg of the gases concerned. For all other equipment, the check intervals depend on the charge. For each piece of equipment, you keep records of gas quantity, top-ups, recovered quantities, checks and the companies that carried them out, and you keep them for at least five years.

For new purchases, putting medium-voltage switchgear up to and including 24 kV for primary and secondary distribution into operation with F-gases has been prohibited since January 1, 2026. There are exceptions, for example if the order was placed before March 11, 2024. Anyone who relies on that must prove it and keep the documents for at least five years. The date of the order therefore belongs in the file.