Exclusive data from Australian market research firm SunWiz sheds light on the UK's battery attachment rates.
MCS data indicates an attachment rate of about 20 batteries per 100 PV systems, but SunWiz’s analysis paints a very different picture.
Running a business without reliable data is like flying through clouds without instruments - you might stay airborne for a while, but you’re essentially flying blind and could be heading for trouble without warning.
For solar PV, the MCS database offers valuable insight into total installations below 50kW. However, when it comes to battery energy storage systems (BESS), the data is incomplete. This gap leaves the industry uncertain about actual market conditions and makes it challenging for brands to accurately track their performance.
The issue with the current perspective is clear. While MCS reports an attachment rate of roughly 20 batteries per 100 PV systems, SunWiz’s findings differ significantly.
Many battery installations go unrecorded. The reason? UK installers face extra costs and administrative barriers when adding battery accreditation to their solar licence. With little incentive, thousands of legitimate installations are left out of the official database.
This leads to under-reported battery adoption, skewed market trends, and brands left guessing about their true performance.
This is no minor issue. If the market is larger than perceived, your market share is actually smaller than you think. You may believe you’re holding your position, but the market could be moving ahead without you.
In such uncertainty, strategy can drift. Pricing, channel priorities, and product launches may be based on flawed assumptions. Marketing teams might overestimate their impact, while sales teams underestimate the competition. Meanwhile, brands with a clearer view of the market quietly gain ground.
Without an accurate understanding of battery adoption, companies risk optimizing for the wrong reality. What seems like stability could actually be a slow decline.
SunWiz’s data aligns closely with MCS in showing where solar and storage are being installed across UK regions, confirming both are observing the same market. However, the difference is striking: while MCS sees batteries in one out of five systems, SunWiz suggests that in many regions, storage is becoming the norm. The true attachment rate is rapidly approaching universality.
Emerging trends in UK battery adoption reveal unique characteristics compared to Australia.
In Australia, many battery installations are retrofits added to existing PV systems. In contrast, almost all UK installations observed by SunWiz are concurrent PV and BESS, with homeowners opting to install both generation and storage from the start. This points to a more integrated approach to self-consumption and energy independence.
There are also early signs of BESS-only installations in the UK - systems added without new PV. These are typically larger-scale setups, featuring fewer 5kWh units and more installations of 25kWh or greater, reflecting a growing demand for flexible, backup, or tariff-shifting storage solutions.
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