Alectrona
Commercial solar by sectorA purpose-built student block carries a round-the-clock residential load through term, but its occupancy falls away over the summer just as generation peaks, so the design is built around that seasonal dip rather than ignoring it.
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.
This is for the owners and operators of purpose-built student accommodation: cluster-flat and studio blocks, mixed schemes with retail or amenity at ground level, and the investors and managing agents who hold them. The load here is residential rather than office. Hundreds of bedrooms draw hot water, lighting, kitchen appliances, charging and in-room heating around the clock, and the common parts add lifts, corridor and external lighting, ventilation, laundry, gym and reception load on top.
That makes a PBSA block a different proposition from the offices and let property we cover. An office concentrates its demand into weekday daytime and empties at the weekend. A student block barely switches off through term, and the question that shapes the whole design is what happens to that demand over the summer, when the building is at its emptiest and the roof is at its most productive.
An on-site drone survey and a PV*SOL model before anything is specified.
Solar earns most when the power is used on site. A unit consumed in the building offsets an expensive import unit, while a unit exported to the grid is paid far less. For a residential block the term-time picture reads well on that test: a large body of occupants drawing hot water, appliance and in-room load gives a broad, sustained daytime base that keeps consuming through the middle of the day when generation peaks, with the common parts running continuously underneath it.
The honest counterweight is the academic calendar, and it is the opposite of the weekend problem an office faces. A PBSA scheme empties out across the summer void, roughly the months from June to September, which is exactly the stretch when a roof generates most. Left unaddressed, a system sized to the full term-time load would spill its strongest months cheaply to export. We design around that dip rather than pretending it is not there. There are three honest levers, and we model which combination fits before anything is specified: sizing the array toward the common-area and base load that runs all year, adding commercial battery storage to shift surplus into the evening and overnight residential peak, or securing an export route for the genuine summer surplus under the Smart Export Guarantee. The right answer depends on your real half-hourly profile and your void pattern, which is why we read those rather than assume a sector average. Where the building has separately metered tenancies the landlord-tenant metering split also governs how the benefit is shared, and we work that out at the same time.
A PBSA block is usually a tall, dense footprint, so the usable roof is smaller relative to the load than a single-storey shed, and it tends to come with rooftop plant, lift overruns, parapets and amenity terraces to design around. Many schemes carry flat or shallow-pitch roof areas that take a clean, well-orientated array, and a mixed scheme may also offer canopy or podium roof area. For orientation only, medium-to-large blocks in this sector tend to sit in an indicative band of 100–500 kWp. Treat that as a sense of scale rather than a quote. The real figure comes from the on-site survey and the PV*SOL model, and on a residential block it is often sized toward the load that runs all year round rather than toward the maximum the roof could physically hold.
A roof on a tall residential block is a working environment that has to be treated as one. A purpose-built block is a high-rise residential building, so the array sits above occupied bedrooms and circulation, and the install has to respect the fire-safety regime the building already lives under. Cabling routes, roof penetrations and any plant additions are designed not to compromise compartmentation or the external wall make-up, and the documentation feeds the building's fire safety information rather than sitting apart from it. Where the scheme falls within the higher-risk building regime, the building's accountable person and the principal-accountable-person duties stay with the client; our role is to deliver the works under CDM 2015 with appointed Principal Designer and Principal Contractor duties so the design risk is managed and the as-built information is handed over clean for the building's safety case.
Access and the summer void shape the programme more than the kit does. A block has a single core, a finite number of lifts and resident movement to manage, so deliveries, roof access and any internal containment runs are sequenced around the building rather than imposed on it. Most operators turn the building over in the summer for cleaning, redecoration and re-let, and that void is the natural window for the noisier and more disruptive works. We programme the install to land in that gap wherever the grid timeline allows, which keeps the array productive for the term-time load it is sized around while the disruptive phase happens when the bedrooms are empty. Lift overruns, parapets, plant screens and amenity terraces are all picked up in the survey so the layout is set against the real roof.
The metering reality decides who actually sees the benefit. A PBSA scheme can be on a single landlord supply with rent-inclusive utilities, or it can have separately metered tenancies, or a mix where the common parts are landlord-metered and the bedrooms are not. That arrangement governs whether self-consumed generation lands on the landlord's bill or a tenant's, and it is the same question we work through for offices and let property. We map the supply and metering arrangement at survey stage so the benefit case is built on how the building is genuinely occupied and billed, because no two PBSA supplies share the same metering map and a single-account assumption would overstate the self-consumption value.
The case for a residential block turns on how much of the generation you keep on site rather than export, which is why the seasonal model comes before any spend figure. A unit consumed in the building offsets an expensive import unit; a unit exported earns far less. For PBSA the term-time self-consumption reads well, but the summer void pulls the annual self-consumption figure down, and that split is exactly what the PV*SOL model against your half-hourly data is for. The output is an honest annual picture of self-consumed versus exported energy across the full calendar, void included, and that is what any sensible finance decision rests on.
The funding route follows the way the asset is held. Plant bought outright qualifies for the capital allowances we set out in our commercial solar finance guidance, which matters where the holding entity is a taxpaying company carrying the asset on its own balance sheet. Where capital is tight, or the scheme sits in a fund or SPV that wants the asset off its books, a power purchase agreement or a lease keeps the system off the balance sheet while still delivering the on-site generation. For an investor holding stock for income, the relevant levers also include what the array does to the building's energy performance and to the sustainability questions universities and nomination partners increasingly ask of the bed stock they recommend.
We do not publish a payback figure for this sector, and that is deliberate. A PBSA payback that quietly ignores the summer void would flatter the numbers, so the honest version is modelled on your own load and the survey rather than printed from a sector average. The wider economics, including how to weigh export against storage and how the finance routes compare, are walked through in is commercial solar worth it, and the way we have approached comparable buildings is shown in our commercial case studies. The first feasibility read is free: we model the block before we quote, so the number you eventually see is itemised against your roof.
It is the defining issue for the sector, and we design around it rather than ignore it. Occupancy falls away from roughly June to September, which is exactly when the roof generates most, so a block sized naively to full term-time demand would export its strongest months cheaply. We model your real half-hourly load and void pattern, then look at three honest levers: sizing the array toward the common-area and base load that runs all year, adding battery storage to shift surplus into the evening and overnight peak, or securing an export route for the genuine summer surplus. The right mix depends on your numbers, which is why we read them first.
The load shape. An office concentrates demand into weekday daytime and empties at the weekend, so the design works around quiet Saturdays. A purpose-built student block carries a round-the-clock residential load through term, then empties across the long summer instead. The honesty problem moves from a weekly gap to a seasonal one. The metering question can be shared, though: where tenancies are separately metered, the landlord-tenant split still governs how the benefit is divided, which we cover on the offices and landlords page.
The indicative band for medium-to-large blocks is roughly 100 to 500 kWp, but that is for orientation only and carries no price. A PBSA block is tall and dense, so the usable roof is smaller relative to the load than a single-storey building, and the array is often sized toward the load that runs all year rather than the roof's physical maximum. Your real figure comes from the on-site drone survey and the PV*SOL model, sized to your actual half-hourly load.
It tends to, and for PBSA the case is a landlord one rather than an occupier one. On-site generation reduces the building's modelled energy use and its carbon, which matters to owners and investors holding the asset and answers a growing question from universities and nomination partners about the sustainability of the stock. We keep the framing honest: the energy case is settled on your real load and the survey, not on a sector figure, and the economic claims live in our dedicated guidance rather than on this page.
We do not quote a price from a sector page, because the cost of a PBSA block turns on the roof, the array size and whether storage is in scope, and an honest figure has to follow the survey. What we can tell you is how it is built up: the panels and inverters, the mounting suited to a flat or shallow-pitch residential roof, the G99 connection works and any battery. The drone survey and PV*SOL model give you a fixed, itemised figure for your building. We walk through how commercial solar pricing works in our finance guidance.
Allow several months from first survey to energisation, and the long pole is usually the grid. Because a PBSA block sits well above 50 kWp it needs a G99 connection from Northern Powergrid, and that application typically runs to around 45 days, sometimes longer where the network needs reinforcement. The drone survey, PV*SOL design and quote take a couple of weeks, and the install itself is measured in weeks. We often programme the works for the summer void so disruption to residents is lowest.
We model your half-hourly consumption against a system sized from an on-site drone survey, so the figure you get is yours, not a from-price. No obligation, no MCS gatekeeping on systems this size.