Built to fail: the silent crisis in green infrastructure

Over the past decade, the UK has seen a rapid deployment of renewable energy sites. Solar and wind farms are being rolled out at scale and, on the surface, it’s a clean, green revolution. But step behind the glossy headlines and you’ll find an uncomfortable truth: the power infrastructure supporting these sites is being built to a dangerously low standard.

This isn’t just about cutting corners – it’s about systemic failure in how we treat the backbone of renewable power delivery.

Real failures, real fast

At Johnson & Phillips, the power engineering firm where I am project lead, we’ve recently replaced four transformers across different solar sites – none older than five years. We’ve also had to rebuild switchboards that suffered flashovers – a short circuit in layman’s terms – due to basic design flaws. These weren’t isolated incidents. They’re becoming common.

Each case ties back to the same root cause: sites that were engineered to meet deadlines and financial models, not long-term operational resilience.

Why are they failing?

Let’s break down the key issues in simple terms:

Thermal cycling: Solar power, in particular, causes extreme day-night thermal expansion and contraction of transformers. The latter are hermetically sealed, and have thin-walled cooling fins, which expand and contract daily. While transformers are often sold as ‘zero service’, over time, the seal integrity can fail. If that happens, positive pressure during the day can force oil out of the system, and negative pressure at night can draw in moist air, which then degrades insulation on the components, eventually leading to internal arcing.

Underspecified materials: We’re seeing widespread use of aluminium for the windings – the coils of wire around the transformer cores. These are generally chosen over copper for price, not performance, reasons. While suitable in some cases, when poorly matched with duty cycles and environment, aluminium windings can degrade quickly.

Harmonics and power quality: The inverters which convert the direct current generated by, say, a solar farm, into the alternating current used by the grid, can dump so-called ‘harmonic currents’ back into the system. These can accelerate wear on transformers and switchgear. Sites are rarely designed with mitigation of these effects in mind.

Poor design and installation: We’ve witnessed shocking layouts, cramped substations, inadequate protection settings, and cable installations that don’t stand a chance under real load.

Training and oversight: A blunt truth – some of the engineers involved in these installations are barely trained. One-week online certifications and ‘Facetube tutorials’ don’t replace a real engineering background. Yet these are the people wiring up critical national infrastructure.

Standards without enforcement: The UK, like North America, has a host of standards – ENA guidelines, BS codes, IEC rules – all meant to ensure safety and longevity. But standards are meaningless without enforcement. In many of these projects, there’s little accountability past the energisation date. By the time failures start, ownership has changed hands, warranties are blurred, and the cost of replacement is someone else’s problem.

A costly cycle

These aren’t just technical problems – they’re economic time bombs. When a transformer fails on a solar site, generation stops. Mobilisation, removal, repair, and retesting can take weeks. The cost isn’t just equipment – it’s lost revenue and long-term investor trust.

We’re not against renewables. We’re fully in support of them. But we are absolutely against pretending that speed and scale are enough. If we want clean energy that’s truly sustainable, we need to treat its infrastructure with the seriousness it deserves. We need to:

• specify transformers for actual duty conditions

• build substations with 25-year thinking, not 5-year budgets

• enforce design and commissioning standards

• train engineers properly.

Closing thought

The Heathrow fire has reminded us that when transformers fail, the consequences can be severe. The renewable sector must take note: you don’t get grid resilience from bargain-bin engineering. If we don’t change course, today’s green dreams will become tomorrow’s infrastructure nightmares.

Glossary of key terms

Transformer: An electrical device that changes the voltage of electricity as it moves through the grid. In renewables, transformers step up voltage for export to the national grid or step down for use.

Thermal cycling: The repeated heating and cooling of electrical equipment (such as transformers) during daily operation. In solar sites, this happens every day between sun-up and sun-down and can stress components over time.

Hermetically sealed transformer: A transformer completely sealed from the environment, usually without an expansion tank. These use thin-walled cooling fins that expand and contract with temperature changes, which can lead to internal pressure fluctuations, oil loss, and eventual moisture ingress.

Harmonics: Unwanted electrical frequencies that distort power quality. Often caused by modern power electronics like solar inverters, harmonics can accelerate wear and damage to transformers and switchgear.

Flashover: A dangerous electrical fault where an arc of current jumps across air or insulation due to voltage stress, often causing damage to switchgear or substations.

Inverter: A device that converts DC electricity (from solar panels) into AC electricity used by the grid. Inverters are often a source of harmonics.

Protection scheme: The system of relays and circuit breakers designed to detect electrical faults and safely disconnect power to prevent damage or fire.

Switchboard: A large panel housing switches, fuses, and breakers used to control power flow. In substations, it connects transformers to the rest of the grid.