Solar has stopped being a niche asset class and become a load-bearing part of the UK and European power system. That changes what a solar installation needs from its communications link. In 2026 the question is no longer “can we see the inverter?” – it is “can the grid, the regulator and the owner rely on this site being reachable, controllable and secure for the next 25 years?”
Solar connectivity in 2026: the numbers behind the shift
The UK is in its strongest period of solar deployment for more than a decade. Provisional government data shows cumulative UK capacity reached 23.2GW across roughly 2.13 million installations by the end of August 2026, with around 291,000 new installations in the preceding twelve months. More than 1GW of that was domestic rooftop, spread across over 195,000 homes. Between Q2 2025 and Q2 2026, solar delivered 2.1GW of the 2.7GW of new renewable capacity added in the UK – three quarters of the total.
The pipeline behind those figures is weighted heavily towards large sites. The seventh Contracts for Difference round (AR7) secured a record 4.9GW of solar across 157 plants, with around 1.87GW expected online by 2028 and a further 3GW in 2029. In July 2026 the government granted consent for 1.2GW of new capacity, including the 740MW One Earth Solar Park near Lincoln, the 320MW Peartree Hill scheme in East Yorkshire and the 150MW Dean Moor project in Cumbria – each with co-located battery storage. In August, Beacon Fen Energy Park in Lincolnshire was approved with 400MW of solar alongside a 600MW battery.
At the other end of the scale, the market is broadening. The government committed to legalising plug-in “balcony” solar in time for summer 2026, the Warm Homes Plan is putting grants and state-backed loans behind rooftop solar and batteries, and the Future Homes Standard is pushing panels onto new-build roofs as standard.
The gap to target is still significant. Getting from roughly 23GW today to the 45-47GW ambition by 2030 means sustaining something like 5GW of new capacity a year – more than double the current run rate. Every one of those gigawatts will need to be monitored, and an increasing share will need to be remotely controllable.
Europe: record generation, a softer market and a grid problem
Across the EU the picture is more mixed. SolarPower Europe’s mid-year analysis recorded at least 33.8GW installed in the first half of 2026, a 1.9% increase on the same period in 2025. Its central forecast is 68.1GW for the full year, just 2.1% below 2025’s record 69.6GW. Utility-scale projects are expected to account for around 56% of new capacity, with rooftop at 44% as residential demand softens in several mature markets.
Generation, however, is setting records. Solar supplied around a quarter of EU electricity in June 2026, producing 52TWh and becoming the bloc’s single largest source of power for the month. The flip side is growing pressure from curtailment, negative prices and falling capture rates – which is exactly why SolarPower Europe expects EU battery installations to rise to around 52GWh in 2026, up from 36GWh in 2025, and why it still judges the EU to be off track for its 2030 solar target without faster progress on storage, grids and flexibility.
Regulation is also pushing solar onto more buildings. The EU Solar Standard within the Energy Performance of Buildings Directive phases in solar requirements on new public and commercial buildings from 2026, renovated non-residential buildings from 2027 and new residential buildings from 2029.
The common thread: as solar’s share of the system grows, grid operators need to see and steer it. Visibility alone is no longer enough. Controllability – and the secure communications link that makes it possible – is becoming a condition of connection.
Why connectivity has moved from “nice to have” to grid-critical
For most of the last decade, solar comms meant an inverter logger on the customer’s Wi-Fi sending five-minute data to a manufacturer’s cloud. If it dropped off, the owner lost a graph. In 2026 four forces are changing that.
1. Controllability is being written into law
Germany is the clearest example. Under the Solarspitzengesetz (“solar peak law”), new PV systems of 7kWp and above must be fitted with a smart meter gateway and control box so the grid operator can manage their output. Until that equipment is installed and commissioned, smaller systems are limited to feeding in 60% of their rated output. In practice, the communications link now directly affects the revenue a system earns.
The UK is building its own framework through the Smart Secure Electricity Systems (SSES) programme. The first-phase Energy Smart Appliances regulations set minimum smart functionality, grid-stability and cyber security requirements and include a definition for domestic and small non-domestic battery storage. Alongside them, a new load control licence regime is due to be laid in autumn 2026, with applications opening by the end of the year and the licence requirement coming into force by the end of 2027. Anyone remotely switching or dispatching solar-plus-storage assets at scale needs to plan for that.
2. Inverter security has become a geopolitical issue
Around 70% of the solar inverters installed in the EU come from Chinese manufacturers, and those inverters are internet-connected. The IEA notes that a compromised inverter connection could allow an attacker to alter or shut down the equipment behind it. The European Commission has identified inverters as a high-risk dependency, moved to restrict EU funding for projects using inverters from high-risk suppliers, and proposed a revision of the Cybersecurity Act that could allow such suppliers to be banned from the market altogether. Lithuania’s rules on remote control of inverters have applied to existing installations since May 2026, meaning some sites have had to be retrofitted.
Whatever your view of the politics, the engineering lesson is the same: how a site connects to the outside world is now a security decision, not just a convenience. Who can reach the inverter, through what path, and whether that path is segregated from the building’s own network are questions that auditors, insurers and grid operators are increasingly asking.
3. Storage turns monitoring into real-time control
A solar array on its own needs telemetry. A solar farm with a co-located battery trading in balancing and wholesale markets needs a link that is always on, low latency and resilient. With most large UK schemes now consented with storage on site, the communications requirement for a typical new solar project has moved up a tier.
4. Legacy networks are disappearing
All four UK networks have now switched off 3G. EE plans to begin switching off 2G from May 2029, Vodafone during 2030, and all operators have committed to closing 2G by 2033 at the latest. Many inverter loggers on the market still list 2G and 3G fallback on their datasheets. Any solar or storage asset expected to operate into the 2030s should be specified on 4G or 5G from day one.
Preferred connectivity options by segment
There is no single right answer for every site. What follows reflects where the market is settling in 2026.
| Segment | Typical connectivity today | Where it is heading |
|---|---|---|
| Domestic rooftop and plug-in | Inverter Wi-Fi dongle on the homeowner’s broadband | Bundled 4G dongles with multi-year data included; Wi-Fi with automatic 4G fallback |
| Commercial and industrial rooftop | Logger on the tenant’s or landlord’s LAN, often unmanaged | Dedicated industrial 4G/5G router, private APN or VPN, fully segregated from the building network |
| Solar farms and co-located BESS | Fibre or leased line where available, single cellular link elsewhere | Fibre primary with dual-SIM multi-network 4G/5G failover; satellite as a tertiary path on remote sites |
| Distributed portfolios (car parks, schools, depots) | Mixed, often whatever was available at install | Standardised cellular router estate with central management, eSIM profiles and 5G RedCap on new deployments |
Domestic: the 4G dongle comes of age
Customer Wi-Fi remains the default, but it is also the most common reason systems drop offline – a new broadband router, a changed password or a garage just out of range. Manufacturers have responded with cellular dongles that bundle long-term data. GivEnergy, for example, offers an IP65 4G dongle with a five-year data plan, Fox ESS markets a 4G logger with a 12.5-year communication plan, and SolaX’s latest dongle runs on Wi-Fi with 4G as a backup. As battery-backed homes are increasingly enrolled in flexibility schemes, expect cellular to become the expected install standard rather than the workaround.
Commercial and industrial: get off the corporate LAN
This is the segment where we see the most risk. Putting an inverter or battery controller on a tenant’s corporate network creates two problems: the IT team rightly sees an unmanaged, internet-connected device as a threat, and the asset owner loses visibility every time the network changes. A dedicated industrial cellular router, ideally with a private APN or VPN and fixed addressing, gives the asset its own path, keeps it isolated from building systems and produces a clean, auditable boundary. For landlords and estate managers responding to ESG reporting requirements, that independent data path is also what makes the numbers trustworthy.
Utility-scale and storage: resilience by design
Where fibre is available, it remains the preferred primary link for SCADA and grid operator communications. But fibre to rural sites is slow and expensive, and a single path is a single point of failure. The emerging norm is fibre or 4G/5G as the primary, a second cellular link on a different network as failover, and satellite broadband as a last resort on remote sites. 5G is increasingly used for the bandwidth-heavy side of site operations – CCTV, perimeter security and drone inspection – where 4G capacity can struggle.
5G RedCap: the long-life option arriving now
5G Reduced Capability (RedCap) is designed for exactly the kind of mid-bandwidth, long-life devices the energy sector uses: more capable than LTE-M, cheaper and less power-hungry than full 5G. O2 Telefónica in Germany has been trialling RedCap with smart meter gateway specialist Power Plus Communications specifically for the energy sector. For anyone specifying a site today that will still be running in 2040, RedCap-capable hardware with LTE fallback is worth considering as the 5G standalone footprint grows.
Looking ahead to 2027
Based on the policy and market signals visible today, these are the milestones and trends we expect to shape solar connectivity over the next 12-18 months:
- Late 2026: UK load control licence applications open; Germany’s deadline for retrofitting smart meter gateways to most new PV connected since February 2025.
- 2027: The EU Solar Standard extends to renovated non-residential buildings, adding more commercial rooftops that need monitoring and control.
- 2027: SolarPower Europe’s medium scenario expects a second year of modest EU market contraction before a recovery towards 2030 – with storage, rather than panels, the growth story.
- By end of 2027: The UK load control licence requirement comes into force, making secure, auditable control paths a regulatory expectation for flexibility providers.
- Through 2027: EU inverter security rules continue to tighten, with growing attention on where remote-access traffic goes and who controls it.
- 2027-2029: AR7 solar farms move into construction ahead of 2028 and 2029 delivery, most with co-located storage requiring resilient, multi-path comms.
- 2029: EE begins its 2G switch-off – now close enough that any remaining 2G-dependent loggers and meters should already be on a replacement plan.
Three broader shifts sit behind those dates. First, connectivity will be specified at design stage, not added at commissioning, because grid connection terms and flexibility revenues increasingly depend on it. Second, independence from the host site’s network will become the default for anything beyond a domestic rooftop, driven by cyber security and data integrity. Third, resilience will be measured – owners, insurers and grid operators will want evidence of uptime and failover, not just a promise that the site is online.
What this means for estate operators and asset owners
- Audit what you have. Identify every solar, battery and EV asset on your estate, how it connects and who can reach it remotely.
- Separate the energy network. Move inverters and controllers off shared building LANs onto dedicated, managed connections.
- Retire legacy radio. Replace anything relying on 2G or 3G fallback now, while it is a planned project rather than an outage.
- Design for two paths. For any asset that earns revenue from flexibility or sits under a grid control agreement, specify a primary and a failover link on different networks.
- Treat comms as a 25-year decision. Choose hardware with a credible upgrade path to 5G standalone and RedCap, and remote management that will outlive today’s SIM contracts.
Not sure where your estate stands? Utility Kings maps existing energy infrastructure, identifies the connectivity and visibility gaps, and presents a resilient deployment architecture – technology-agnostic and built around your assets. Request an infrastructure assessment.