Exclusive data from Australian market research company SunWiz reveals how the UK is performing in battery attachment rates.
Running a business without reliable data is like flying through clouds without instruments—you might stay airborne for a while, but you’re flying blind and you might find yourself hurtling towards the ground without time to pull up.
For solar PV, the MCS database provides a valuable read on total installations below 50kW. But when it comes to battery energy storage systems (BESS), the picture is incomplete. That leaves a gaping hole in the industry’s understanding of what’s really happening on the ground, and makes it difficult for brands to track their performance accurately.
The problem with the current view
The MCS data shows an attachment rate of roughly 20 batteries per 100 PV systems. Yet SunWiz’s analysis tells a very different story.
Many battery installations aren’t being recorded. Why? According to what we have heard, UK installers face additional costs and administrative hurdles when attempting to add battery accreditation to their solar licence. With limited incentive to do so, thousands of legitimate installations never get included in the official database.
The result: under-reported battery adoption, distorted market trends, and brands left second-guessing their performance.
And that’s not a small problem. If the market is actually much larger than you think, then your market share is smaller than you realise. You may believe you’re maintaining position—when in truth, the market is accelerating past you.
In this kind of fog, strategy tends to drift. Pricing decisions, channel priorities, and product launches are often based on flawed assumptions. Marketing teams overestimate their traction; sales teams underestimate the competition. Meanwhile, faster-moving brands—those reading the real market pulse—quietly gain ground.
Without an accurate picture of battery adoption, companies risk optimising for the wrong reality. What appears to be stability may, in fact, be a slow decline.
SunWiz’s data tracks closely with MCS, which shows the UK regions where solar and storage are being installed—confirming that we’re viewing the same market landscape. But look closer, and the difference is striking: while MCS sees batteries in one out of five systems, SunWiz’s view suggests that in many regions, storage has become the norm rather than the exception. The real attachment rate is fast approaching universality.
Read more: Solar Power Portal
