Alectrona
Use caseA standard grid-tied battery does not keep you running when the grid fails. Backup is a deliberate design choice: an islanding capability, an automatic changeover, and a defined critical-load circuit, sized for the load that has to stay up.
These are representative example reviews, not yet-collected customer feedback. They are written to illustrate the kind of feedback Alectrona aims to earn and are shown as design placeholders while we gather and verify reviews from our first commercial clients. Alectrona is the commercial solar trading brand of RVTC LTD.
What set Alectrona apart was the documented design pack. We had quotes from three installers, but only Alectrona handed us a full set of drawings, a single-line diagram and a design referencing BS 7671 and the G99 connection process. The whole thing read like an engineering submission rather than a sales brochure. Our M&E consultant reviewed it and signed it off without a single query. That gave the board the confidence to release the capital.
Other firms priced our roof off a satellite image and a desktop guess. Alectrona flew an in-house drone survey, fully insured and flown by a qualified commercial drone pilot, and built a 3D model of the actual roof. It picked up plant, vents and a parapet line that a flat aerial photo had completely missed, which changed the panel layout. I would rather find that out at design stage than on the day the scaffold goes up. The accuracy of that survey is the reason I trusted everything that followed.
As a finance director I was wary of being oversold a system bigger than we could use. Alectrona modelled the array against our actual half-hourly consumption data rather than an annual total, so it is sized to what we genuinely draw on site during the day. They were honest that exporting surplus is worth far less than self-consumption, and built the design around that. The capital case stacked up because the engineering was honest, not because the numbers were inflated.
We were undecided between buying outright, leasing and a PPA. Alectrona laid out all three side by side with the pros and cons of each against our balance sheet, instead of pushing the one that pays them best. They were clear about where a PPA makes sense and where capex wins, and pointed us at our own accountant for the tax treatment. The survey and design took a little longer than I expected, but the thoroughness was worth the wait. Genuinely consultative.
The install crew were tidy and well run, and worked to a clear CDM 2015 plan with a proper site induction and RAMS. What impressed me most was the handover. We received a full commissioning pack with the IEC 62446-1 test results, certification, O&M documentation and an as-built record for our maintenance team. As the people who have to live with this asset for the next twenty years, having that paperwork in order matters enormously. Nothing was left loose.
I expected the usual hard sell and got the opposite. After surveying our site Alectrona told us one roof section was not worth covering because of shading, and that a smaller, well-sited array was the better investment than filling every square metre. There was no commission-driven upselling and no pressure. For a six-figure capital project, that straight talk is exactly what you want from the people advising you. We will be using them again on our second site.
The most common misconception we correct on site is that any battery is a backup battery. It is not. A grid-tied BESS is built to import, store and export against the grid. When the grid drops, G99 protection disconnects the inverter for safety, and an unconfigured battery goes dark with everything else.
Backup is something you specify; it is never something you can assume. It needs the right inverter capability and a wiring design that separates the loads you must keep alive from the loads you can let go. The value here is resilience, the cost of an outage avoided, rather than a saving on your bill.
Engineer-led, assured to the non-MCS standard (CDM 2015).
Grid-tied inverters are required to stop exporting the instant they lose the grid. This is anti-islanding protection under G99, and it exists to keep the network safe for anyone working on the fault. It is correct behaviour, but it means a battery with no backup design switches off alongside the rest of the site.
To ride through an outage, the system has to be able to form its own grid, an island, safely disconnected from the network, and then hand back automatically when supply returns. That capability is not standard on every commercial inverter, and where it exists it usually has a defined power and energy limit. It is a specification decision made before contract, not a setting toggled afterwards.
Backup is an engineered subsystem rather than a feature you tick. A functioning design brings together a few things that have to be specified together:
Get the board wiring wrong and you either try to back up the whole site, which is rarely affordable, or you leave a circuit you needed on the wrong side of the changeover. This is decided on the drawings, then proven at commissioning.
On small-to-mid commercial sites an integrated gateway can provide this in a single device. A Sigenergy gateway, for example, sits between your supply and the protected circuits, disconnects the site from the grid in an outage, and keeps a defined backup load running from the battery and any solar.
Backup sizing starts from two questions: which loads must stay alive, and for how long. We do not size backup against your annual consumption. We size it against the critical-load circuit, the inverter power that load draws at once, and the duration you need to bridge.
A short ride-through to cover brief outages and protect against data loss is a very different battery and inverter from one that holds a refrigerated store or a production line through a long fault. Whole-site backup for an industrial load is rarely the right answer on cost, which is why the critical-load circuit matters. We define it with you, from the half-hourly load profile our survey produces, so the rating is yours and not a rule of thumb.
On most commercial sites resilience is one job a battery does, alongside lifting solar self-consumption and shaving the expensive peak. Backup capability adds inverter and wiring requirements on top of the energy and economic case, so it is designed in from the start rather than bolted on.
For longer or whole-site resilience, a battery is sometimes paired with a generator: the battery covers the instant transfer and the short ride-through, the generator carries the long haul. Whether that is justified depends on what an outage actually costs you, which is a facilities and finance decision we help you frame rather than assume.
Backup from a battery is not the same thing as an uninterruptible power supply, and the difference matters for sensitive equipment. A grid-forming inverter detects the loss of supply, opens the changeover, and starts to feed the critical-load circuit from the battery. That transfer is quick, but it is a break-before-make event measured in a fraction of a second, so the handover is brief rather than instant. Most loads, lighting, sockets, refrigeration, pumps and space heating, ride through it without noticing. Equipment that cannot tolerate even a momentary dip will not.
That is where a true UPS still has a role. An online, double-conversion UPS to IEC 62040, the international standard for uninterruptible power systems, runs the load from its own inverter continuously, so there is genuinely no break when the grid fails. Servers, certain medical and laboratory instruments, and some process controllers are specified to sit behind one. The clean design on many sites is layered: a small UPS holds the no-break loads through the transfer, and the battery then carries the wider critical-load circuit for the duration. We identify which of your loads are break-tolerant and which are not at survey, because that decision changes the wiring and the kit, and it is far cheaper to get right on the drawings than to retrofit. The control logic that orchestrates the transfer and reserves capacity for it is part of the EMS we configure for the system.
An islanding circuit is not ordinary wiring, and it is held to specific rules. The whole installation is designed and certified to BS 7671, the IET Wiring Regulations, and a system that can run as its own island brings the requirements for switched alternative supplies into play, including how the neutral and the earth reference are handled when the site is disconnected from the network. A grid-tied system borrows its earthing arrangement from the distribution network; an islanded system has to provide a safe reference of its own while it is separated. That is a design item, decided on the drawings and proven at commissioning rather than assumed.
The grid side is governed by Engineering Recommendation G99, administered through your distribution network operator, which for our region is Northern Powergrid. G99 is what requires the anti-islanding protection that disconnects a standard system in an outage, and it is also the framework under which a grid-forming, backup-capable system is applied for and approved. The transfer arrangement, the protection settings and the way the system reconnects to the network when supply returns all form part of that application. Commissioning is verified to IEC 62446-1, the standard for testing and documenting a connected system, so the backup function is recorded as proven rather than assumed. Where the battery shares an enclosure or a plant room, the fire and thermal design that sits alongside this is covered on our fire safety page.
Backup earns its place when the cost of an outage is real and quantifiable, and it does not when it is merely a comfort. The honest test is your own continuity exposure: what stops, what spoils, and what it costs you per hour when the supply goes. A cold store losing a stocked chamber, a production line that scraps a batch on an unplanned stop, a data room, or a site where a power loss is a safety event are the cases where resilience pays for itself. An office that simply sends people home early usually is not. This is the business-continuity question that frameworks such as ISO 22301, the standard for business continuity management, exist to make explicit, and it is a facilities and finance decision rather than an electrical one.
Grid reliability in Britain is high, and the National Energy System Operator (NESO) reports on security of supply, but high average reliability is cold comfort to a site for which a single bad hour is expensive. Backup is bought against the worst hour rather than the average one. We help you frame that exposure from your half-hourly load profile and the critical-load circuit we define together, then size the ride-through to it. Because backup adds inverter and wiring requirements on top of the energy case, it is specified from the start alongside the jobs that pay, solar self-consumption and peak shaving, rather than bolted on afterwards. The sizing method that turns your critical load into a rating is set out on our sizing page.
Only if it was specified to. A standard grid-tied battery disconnects in an outage under G99 anti-islanding protection and provides no backup. Ride-through needs an inverter with an islanding or grid-forming capability, an automatic changeover, and a critical-load circuit wired at design stage. That is a decision made before contract.
Technically sometimes, but it is rarely the right answer on cost for a commercial load. Backup is sized on the critical-load circuit, the loads that must stay alive, and the duration you need to bridge. We define that circuit with you from your half-hourly load profile, so you are paying to protect what matters rather than carrying the whole site on the battery.
It depends on how much you choose to back up and how much energy and inverter power you specify for it, so there is no single figure. A short ride-through to protect against data loss and brief outages is a different design from one that holds a critical process through a long fault. We size the ride-through to the duration you define, and for very long or whole-site resilience a battery is sometimes paired with a generator.
For most sites, no. The economic case is built on self-consumption of your own solar and shaving the expensive peak; backup is resilience, the cost of an outage avoided rather than a saving. If continuity is genuinely business-critical it can be the deciding factor, but it adds inverter and wiring requirements, so it is designed in from the start.
There is no standard figure, because the cost depends on the critical-load circuit you choose to protect, the inverter power and stored energy that load needs, and whether sensitive equipment also requires a UPS. Adding a grid-forming capability and a separate critical-load board costs more than a battery with no backup design. We price it from your half-hourly load profile after survey. See our battery costs page or the wider commercial solar cost guide.
There is no fixed figure, because the pacing item is usually the grid connection rather than the install. The sequence runs survey and half-hourly modelling, design of the critical-load circuit and islanding to BS 7671, the G99 application to your network operator, Northern Powergrid in our region, then delivery under CDM 2015 and commissioning verified to IEC 62446-1. A site with spare capacity moves quickly; a constrained one waits on the connection. We confirm a project-specific programme from the survey rather than promise a date we cannot hold.
We model your half-hourly load and your solar against a battery sized from an on-site survey, so the figure you get is yours, not a from-price. Capex first, with the bankable brand that fits the project.