The Solar Knowledge Gap Nobody Wants to Talk About

The moment that made me start paying proper attention had nothing to do with my solar panels. It happened while an electrician was installing my EV charger.

He was competent, friendly, and clearly experienced with the physical work. He mounted the unit cleanly, ran the cable properly, and got everything terminated the way you would want. Then the commissioning app threw up a configuration screen, and one of the options was labelled G98. He paused. He read it twice. And then he did the thing that told me everything I needed to know: he took out his phone and rang another installer to ask what it meant.

The advice came back down the line, and I could hear it clearly enough to write it down.

“Just press OK. It’ll go away.”

He pressed OK. It went away. He later admitted, without much embarrassment, that he did not actually know what G98 was. It was a box on a screen that appeared between him and finishing the job, and the fastest way through it was to make it disappear.

I want to be very careful here, because this article is not about that electrician, and it is certainly not about the company he worked for. He was doing what almost anyone would do under time pressure on a job that was, from his point of view, essentially finished. The problem is not one person. The problem is that a screen asking about grid connection compliance appeared during a domestic installation, and nobody in the chain — not him, not the person he phoned — could say what it was for. That is not a personal failing. That is a knowledge gap, and it is systemic, and it is getting wider.

Why a single dismissed dialog box bothered me so much

On its own, pressing OK on a G98 prompt during an EV charger install is probably harmless. An EV charger is a load, not a generator, and in most configurations the grid-code question is not the thing that will burn your house down. If that were the whole story I would have forgotten about it by the weekend.

What bothered me was what it implied about everything else.

I already had solar panels and a home battery. I run a battery optimiser that schedules charge and discharge against the Octopus Agile price curve and a solar forecast, so I had spent a fair amount of time living inside the technical detail of my own installation. I knew that G98 was not a nuisance dialog. It was a reference to the rules that govern how generation connects to the distribution network — the same rules that decide how much I am allowed to export, whether my setup was notified or approved, and crucially what I am allowed to add later without going back to the network operator for permission.

If the person installing energy equipment in my home treated that as a box to dismiss, the obvious question was: how much of the rest of it had been treated the same way? Not by him specifically — by the industry. How many systems have been signed off with a setting nobody understood, a limit nobody checked, and an export configuration that made sense to a piece of software and to no human being in the process?

The dismissed dialog was not the danger. It was the symptom. It told me that the complexity of these systems had outrun the average installer’s understanding of them, and that the gap was being papered over with “just press OK” rather than closed with knowledge.

The technology got hard while nobody was looking

Here is the thing that I think genuinely explains the gap, and it is worth saying plainly because it is nobody’s fault in particular.

A domestic solar installation used to be simple. Ten or fifteen years ago, a typical job was panels on a roof, a string inverter on a wall, and a connection that pushed whatever you generated back into the grid when you were not using it. The electrician’s job was electrical: mount, wire, terminate, test, certify. The “smart” part of the system was a generation meter and a Feed-in Tariff form. You could be a superb installer and never once have to reason about grid interaction beyond “it exports when the sun shines.”

Compare that to what a modern installation actually contains. A current job might include:

• Solar panels, often more of them than the old Feed-in Tariff era, on multiple roof faces with different orientations.
• A home battery, with its own chemistry, its own state-of-charge management, and its own safety envelope.
• A hybrid inverter that does the job of a solar inverter and a battery inverter at once, and makes real-time decisions about where energy flows.
• Smart tariffs with half-hourly pricing, which turn “when should this charge” from a fixed setting into a moving optimisation problem.
• An EV charger, which is frequently the single largest load in the house and increasingly wants to coordinate with everything else.
• Home automation, because people want to see and control all of this, usually through something like Home Assistant.
• Backup or islanding capability, so the house can keep some circuits alive when the grid drops.
• Export limitation, where the system is deliberately configured to cap how much it pushes back to the grid.

Every one of those is a discipline. A hybrid inverter is a power-electronics device running control software that decides, many times a second, whether to charge the battery, discharge it, import, export, or hold. Battery chemistry determines how hard you can push the cells and for how long. Export limitation is a grid-compliance function that has legal weight behind it. Smart tariffs turn the whole thing into a scheduling problem where the wrong default quietly costs you money every single day.

The installation is no longer an electrical job with some software bolted on. It is a small energy system, and it has the property that every good system has and every difficult one has too: the components interact. The battery’s behaviour depends on the tariff. The export limit depends on the inverter’s firmware. The EV charger’s load-management depends on whether it can see the rest of the system. You cannot fully understand any one part by looking at it in isolation, which is exactly the property that makes these systems hard to install well and easy to install badly.

And here is the uncomfortable part. The trade that installs these systems is, for entirely understandable reasons, still largely trained and certified around the electrical work. The electrical work is genuinely the safety-critical bit, and I would never diminish it. But the electrical competence that gets someone qualified says very little about whether they understand hybrid inverter firmware behaviour, DNO application processes, battery cycle economics, or how a half-hourly tariff should shape the system’s configuration. The certification kept pace with the wiring. It did not keep pace with the system.

The customer now often knows more than the installer, and that is new

There is a second shift that makes the gap more visible than it used to be, and it genuinely surprised me: the customer is frequently the most technically curious person in the room.

The people buying these systems now are often not passive. They have spent evenings reading forums. They have watched people on YouTube tear down inverters and benchmark battery round-trip efficiency. They arrive with a spreadsheet modelling their own consumption. Some of them — and I will happily put myself in this category — run home automation and monitoring that gives them more visibility into their own system’s real behaviour than the installer has ever had into any system they have fitted, because the installer moves on to the next job and never sees the year of data that follows.

I do not say this to flatter customers or to embarrass installers. I say it because it inverts an assumption that both sides still quietly operate on: that the professional in the van is the most knowledgeable person present. For the electrical safety of the installation, they absolutely should be, and usually are. But for the system design — the sizing, the tariff strategy, the export configuration, the future expansion path — the balance has shifted in a way that neither party is quite prepared for.

I have watched this play out. I have asked installers questions about export limits and future battery expansion and watched a flicker of “I’ll have to check” cross their face — which, to be clear, is the right answer, and far better than a confident wrong one. The failure mode is not “I don’t know.” The failure mode is “just press OK.” One is honesty about the edge of your knowledge. The other is the pretence that the edge is not there.

The dangerous installer is not the one who says “I’m not sure.” It’s the one who has never noticed there was anything to be unsure about.

What actually goes wrong in the gap

Let me be concrete, because “knowledge gap” is a soft phrase and the consequences are not soft. These are the failure patterns I have either seen, been warned about by people I trust, or come close to living myself. None of them are dramatic. All of them cost money, options, or both.

The system that cannot grow

The most common one, and the subject of much of the rest of this series, is the installation that works perfectly on day one and quietly forecloses your future. An inverter sized with no headroom, so adding a second battery later means replacing it. Conduit packed exactly full, so pulling one more cable means lifting the drive. An export configuration chosen to make a form go away, which caps you at a limit you did not know you were accepting. The system meets the brief. The brief just never included next year.

The configuration nobody can explain

A setting was chosen — an export limit, a charge rate, a grid-code parameter — and the reason lives in nobody’s head. When something needs to change, or when a second installer is called to expand the system, they inherit a black box. I have written before about the load-bearing thing nobody documented in the context of a homelab, and it is exactly the same disease here: a system whose current state cannot be explained is a system you cannot safely modify.

The tariff left on the table

A battery and a half-hourly tariff are a money-making combination if the system is configured to exploit the price spread. Left on a naive default — “charge overnight, discharge in the evening” — the battery does something plausible and mediocre, and the owner never knows how much they are leaving on the table because nobody told them there was a table. This one is invisible precisely because the system still works. It just works worse than it should, every day, forever.

The compliance box ticked without being true

This is the one the opening story points at. Somewhere in the chain a grid-code question was answered, a form was submitted or not submitted, an export limit was set or assumed — and the person who did it could not have told you what it meant. Most of the time nothing visible happens, which is the trap. The network operator has a record of your connection that may not match reality, and you find out only when you try to expand, or when someone eventually audits, or when a neighbour’s complaint about voltage brings scrutiny you did not expect.

Notice the common thread. In every case, the system works. That is what makes the gap so hard to see and so easy to sell around. A dismissed dialog box does not throw an error. A too-small inverter still inverts. A naive tariff schedule still charges the battery. The cost is not a failure you can point at. It is an option you no longer have, a bill that is quietly higher than it needed to be, or a record that does not match your installation. The gap does not announce itself. It just sits there, priced into your next ten years.

Why the cheapest quote is a question, not an answer

I understand the appeal of the cheapest installer. Solar is expensive, the panels are largely a commodity, and if two companies will bolt the same modules to your roof, why pay more? For a simple grid-tied array with no battery and no ambitions, that reasoning is often fine, and I am not going to pretend otherwise.

But the moment your system crosses into the territory above — battery, hybrid inverter, smart tariff, EV, any thought of future expansion — the cheapest quote stops being a straightforward answer and becomes a question you have to interrogate. Cheap on what, exactly?

Price competition pushes on the things a customer can compare on a quote: panel wattage, battery capacity, headline cost. It does not push on the things that are invisible on a quote and expensive later: whether the inverter has headroom, whether the export was applied for correctly, whether the cable routes leave room to grow, whether anyone in the company can explain the grid-code settings they applied. Those things cost the installer time and knowledge, which is precisely what gets squeezed out when the only competition is on price.

I am not arguing that expensive means competent. Plenty of expensive installers are coasting on the same knowledge gap with a better van. The point is subtler and more useful: price tells you almost nothing about the thing that actually matters here, which is understanding. A cheap installer who can talk fluently about DNO applications and future expansion is a bargain. An expensive one who reaches for “just press OK” is a rip-off at any price. The number on the quote is not measuring the variable you care about.

This is the same instinct I bring to enterprise infrastructure, where the cheapest bid is routinely the most expensive decision once you price in what it cannot do later. I will draw that comparison out properly in what enterprise IT taught me about designing better solar systems, because it is not a loose analogy — the failure modes are structurally identical.

Best practice, from someone who lives with the result

If the gap is real, what do you actually do about it as a homeowner? Not become an expert — you do not have to. But you do have to change the shape of the conversation. Here is what I would tell anyone about to spend serious money on one of these systems.

Treat the installer’s answers as data about the installer. When you ask a question, you are not only gathering information about your system. You are measuring whether the person answering understands what they are fitting. A good installer welcomes the questions and answers them, or tells you honestly where the edge of their knowledge is. A worrying one gets defensive, hand-waves, or reaches for reassurance instead of explanation. The questions are a competence probe as much as a fact-finding exercise.

Ask about the future, not just the install. “Can I add a second battery later?” “What’s my export limit and why?” “If I want to add an EV charger next year, does this design leave room for load management?” These questions reveal whether the system was designed as a snapshot or as something that can grow. I have a whole checklist of the questions worth asking later in this series, precisely because the right questions are the cheapest insurance you can buy.

Get the reasoning, not just the number. For every non-obvious choice — the inverter size, the export limit, the charge rate, the grid code — ask why that value. You are not trying to catch anyone out. You are trying to establish that a reason exists and lives in a human head, because a value chosen with a reason can be revisited and a value chosen to dismiss a dialog cannot.

Insist on the paperwork being real. The DNO application, the commissioning certificate, the export configuration — these should be documents that describe your actual installation, handed to you, that you keep. If the grid connection was “notified,” you should have the notification. If it was “approved,” you should have the approval. A system whose paperwork matches its reality is a system someone understood well enough to document, which is most of the battle.

The lessons I actually took from it

I took three things from watching a competent tradesman dismiss a grid-code dialog he could not name, and they have shaped how I think about my own system and how I would advise anyone else.

The first is that complexity migrated into these systems faster than expertise did, and the two have not caught up with each other. This is not cynicism. It is just what happens when a product category evolves from “panels and an inverter” into “a coordinated energy system” in the span of a decade while the training and certification evolve at the pace institutions evolve, which is slower. The gap is a timing problem, and timing problems close eventually — but not before a lot of systems get installed inside the gap.

The second is that the customer’s curiosity is now a load-bearing part of getting a good outcome. That is a strange thing to have to say. You should be able to hand the job to a professional and trust it. For the electrical safety you largely can. For the system design, the honest reality of this moment is that an engaged, questioning customer gets a materially better installation than a passive one, because the questions force the design decisions into the open where they can be got right. I wish it were otherwise. It is not, yet.

The third is the one I keep relearning across every technical thing I touch: a system that works is not the same as a system that was understood. The whole trap of the knowledge gap is that its failures are silent. Nothing catches fire. The panels generate, the battery charges, the app shows a reassuring flow diagram. And underneath, a limit you did not choose, a form that does not match, or an option you have quietly lost sits waiting to matter. Working and understood are different properties, and only one of them protects your next ten years.

What I want you to do with this

I am not trying to make you distrust installers. Most are decent, skilled people doing hard physical work in a trade that changed under their feet. I am trying to make you distrust the quiet. The renewable industry has a strong incentive to keep the conversation smooth and reassuring, because friction loses sales, and “just press OK, it’ll go away” is the customer-facing version of that same instinct — smooth the friction, close the job, move on.

Your defence against the gap is not technical knowledge you do not have. It is the willingness to ask, and to keep asking until you get a reason rather than a reassurance. Ask what the grid code on your system is and why. Ask what your export limit is and whether it constrains your future. Ask whether the design leaves room to grow. Ask, when someone tells you to just press OK, what it is that you would be pressing OK to.

The marketing material will not prompt those questions, because the marketing material is designed to make you feel that everything is handled. Sometimes it is. But the only way to know the difference between a system that was understood and a system that merely works is to ask the questions that the “just press OK” school of installation is built to avoid.

Summary

• A skilled installer dismissed a G98 grid-code dialog during my EV charger install because neither he nor the person he phoned knew what it meant. The dismissed box was harmless in itself; what it revealed was not.
• Domestic renewable systems have evolved from “panels and an inverter” into coordinated energy systems — solar, batteries, hybrid inverters, smart tariffs, EV charging, automation, backup and export limitation — whose components interact in ways that are genuinely hard to reason about.
• Installer training and certification kept pace with the electrical work, which is the safety-critical part, but not with the system design — the grid applications, tariff strategy, sizing headroom and expansion planning that decide whether the system is any good over ten years.
• The failures in this gap are silent: the system still works. A too-small inverter still inverts, a naive tariff still charges, a mis-set export limit throws no error. The cost shows up as lost options, higher bills, and records that do not match reality.
• The cheapest quote is not an answer but a question. Price competes on what a customer can see on a quote and never on the invisible understanding that actually matters.
• Your defence is not expertise you lack. It is asking for reasons instead of reassurances, and treating the quality of the answers as a measure of the person giving them. When someone tells you to just press OK, ask what you would be agreeing to.

Next in the series: G98 vs G99 explained without the industry jargon — a plain-English guide to the exact regulation that dialog box was asking about, and why understanding it before you install can save you real money later.