SolShare 2: Shared Solar and Battery Storage for UK Flats

UK flats have long been solar's blind spot. Just 3% of UK flats have solar panels, against 7% of houses and bungalows, according to Allume Energy's analysis of ONS Census data — and in dense urban blocks the figure falls even lower. The problem isn't demand, it's plumbing: a typical flat has no roof of its own, and fitting a separate solar-plus-inverter system to every unit in a block is rarely practical or affordable. Australian company Allume Energy's SolShare technology has been tackling that problem since 2015 by letting one rooftop array serve an entire block through a single shared inverter. Its second-generation product, SolShare 2, launched in the UK from August 2026, adding battery storage and roughly 50% more sharing capacity to the original design.

How SolShare actually splits the power

SolShare sits between the building's solar inverter and each flat's individual electricity meter. Rather than wiring a separate PV system to every unit, sensors take near-instant readings of each flat's live consumption, and a power-division control system allocates the available solar generation across units in real time — SolShare 2's control loop reassesses the building roughly every 200 milliseconds. A freeholder or managing agent can set fixed allocation splits between common areas (lifts, corridor lighting, door entry) and individual flats, and if a unit is empty or using less than its share, the unclaimed solar is redistributed to the flats that need it. No flat gets a dedicated inverter or its own panels — the array and its output are pooled and shared.

SolShare 2 raises the original system's ceiling from 20kW to 30kW and can now connect up to 15 flats to a single unit, with multiple units stackable for larger blocks. The headline addition is integrated community battery storage — the original SolShare only ever shared live solar generation, so any output a building didn't use in daylight hours was exported unpaid. SolShare 2's battery integration (launching paired with SigEnergy hardware) lets a block store surplus midday generation and share it out into the evening, when flats actually use most of their electricity.

Who buys it — and who pays

SolShare is not something an individual leaseholder can install on their own flat. Every confirmed UK deployment has been commissioned by a housing association or council, not a private leaseholder buying into a shared system independently. The UK's clearest working example is Odet Court in Cardiff, a 24-flat block owned by Wales & West Housing, fitted with the original SolShare and funded jointly with the Welsh Government's Optimised Retrofit Programme. Allume also markets SolShare as an Ofgem-recognised Substantial Innovation Measure, which can unlock ECO4 funding for eligible social housing installs — see our guide to solar panels on council and social housing for how ECO4 and other funding routes apply to landlords and housing providers more broadly.

For flats in the private sector, the practical buyer is the freeholder, the building's management company, or a housing association — the cost of the shared array, inverter, and battery is typically met through service charge reserves, a building improvement loan, or a grant scheme rather than paid for by an individual flat owner. If you rent or own a single flat and want to push for this, the realistic path is raising it with your freeholder, managing agent, or (if you're a council or housing association tenant) your landlord directly, rather than expecting to buy a SolShare unit yourself. For the wider picture on freeholder consent, permitted development rights, and communal solar options for leaseholders, see our full guide to solar panels for flats and leasehold homes.

What the numbers actually show

Allume's headline marketing claims for SolShare 2 — up to 40% off bills, and a 30–60% cut in grid-drawn electricity — are the company's own figures, not from an independent study. The most solid evidence available is the real-world data from Odet Court, the one confirmed UK installation: residents there saw 55–75% of their electricity demand covered by solar, a roughly 70% reduction in grid-drawn electricity, and savings in the range of £390–£690 a year depending on usage, alongside a 15-point uplift to the block's SAP energy-efficiency score. Those figures come from a single pilot scheme rather than a broad, independently verified UK dataset, so treat them as an illustration of what's achievable in a well-suited block rather than a guaranteed outcome for every building.

E.ON UK invested £4 million in Allume Energy in 2025 to support the company's UK growth, but the publicly available release describes this as a growth investment rather than an exclusive UK distribution or installation partnership — there's no evidence yet of E.ON directly rolling SolShare 2 out to customers itself. Expect SolShare 2 to reach UK blocks gradually through housing associations, retrofit programmes, and specialist installers rather than as an off-the-shelf consumer purchase.

SolShare 2 vs plug-in balcony solar

SolShare and plug-in balcony solar solve the same underlying problem — flats without roof access — from opposite ends. Plug-in solar, legal in the UK from 27 August 2026 for kits up to 800W, is something an individual leaseholder or renter can buy and self-install on their own balcony with the freeholder's consent, generating perhaps £80–£190 a year for a few hundred pounds outlay. SolShare 2 is the opposite: a whole-building system that needs a freeholder, housing association, or management company to commission it, but at building scale it can meaningfully offset most of a flat's demand rather than a small top-up. Neither reaches every flat — plug-in solar needs a suitable balcony or south-facing wall, and SolShare needs a landlord willing to invest in shared infrastructure — but between them they cover most of the routes into solar that don't require owning a roof. For the full breakdown of plug-in kit costs, DNO notification rules, and renter/leaseholder consent, see our guide to plug-in and balcony solar in the UK.

What to do if you live in a flat

If you own or manage a block, the ECO4-funded, housing-association-led route is the one with a proven UK case study behind it — worth raising with your managing agent or, for social housing, checking whether your landlord has looked at retrofit funding through the Warm Homes Plan or ECO4. If you're an individual leaseholder or renter with no say over building-wide investment, plug-in balcony solar remains the faster, cheaper option you can act on directly, provided your freeholder or landlord consents. Either way, UK flats are no longer stuck with zero solar options — the routes in have simply diverged between whole-building shared systems and individual plug-in kits, and the right one depends on whether you can influence a freeholder's capital spending or only your own balcony.