Alectrona
Commercial solar system sizes · over 50 kWpThe right size is the one that matches your building's daytime load, not the one that fills your roof. We frame commercial solar in four bands so you can find your scale, then size the actual system to your half-hourly consumption and an on-site survey.
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.
Almost every commercial solar enquiry starts with the wrong question. People ask how many panels fit on the roof, when the question that decides the economics is how much electricity the building uses in daylight. A roof that could physically take 400 kWp is the wrong place to put 400 kWp if the site only draws 120 kW on a working afternoon, because everything the array makes above what the building uses has to be exported, and export is worth a fraction of what you save by using the power yourself. Size follows consumption first, and the roof is the constraint that comes second.
That is why these pages are organised into four bands by capacity, from 50 to 150 kWp up to 1 MW and above. The bands are a way to navigate, not a menu to order from. Each one is led by the engineering and regulatory facts that genuinely change at that scale, because a 100 kWp system and a 700 kWp system are different projects, not the same project with more panels. The grid connection route, the construction duties, the metering, the safety and shutdown requirements and the network charges all shift as the system grows, and those shifts are what make one band distinct from the next.
Find the band that fits your likely consumption and read the page for it. It will tell you what activates at that scale, what drives the cost, and which kinds of business the band typically suits. Then the system we actually design comes from your real load and your real roof, modelled before anything is specified.
| Band | Indicative modules | Usable roof area | Indicative output | What activates |
|---|---|---|---|---|
| 50 to 150 kWp | roughly 85 to 280 modules | roughly 250 to 1,050 m² | roughly 42,000 to 145,000 kWh per year | G99 grid connection |
| 200 to 300 kWp | roughly 340 to 555 modules | roughly 1,000 to 2,100 m² | roughly 170,000 to 285,000 kWh per year | CDM 2015 and half-hourly metering |
| 500 to 750 kWp | roughly 850 to 1,390 modules | roughly 2,500 to 5,250 m² | roughly 425,000 to 712,000 kWh per year | RC62 shutdown and G100 export limit |
| 1 MW and above | roughly 1,665 to 1,850 modules per MW | roughly 5,000 to 7,000 m² rooftop, or 2 to 2.5 hectares ground-mount, per MW | roughly 850,000 to 950,000 kWh per MW per year | Grid queue and network charges |
There is no cost column, and that is deliberate. A meaningful figure for a commercial system comes from an on-site survey and a PV*SOL model of your roof and your load, not from a price per kWp. The figures above are indicative engineering rules of thumb, modelled for your site before anything is specified.
Sizing a commercial system is an exercise in matching generation to load, and the input that matters most is your half-hourly consumption data. Your Distribution Network Operator and your supplier hold it, and it shows exactly how much power the building draws through the working day across the year. A system sized to sit comfortably under that daytime demand is a system whose output you mostly use on site, and self-consumed power is worth far more to you than exported power. That is the single most important number in the design, and it is the reason we ask for consumption before we ask about the roof.
The indicative arithmetic gives you a feel for what a given size means in physical terms. As a rule of thumb, expect roughly 1.7 to 1.85 commercial modules of 540 to 600 W per kWp, so around 185 modules for a 100 kWp array; roughly 5 to 7 m² of flat roof per kWp once you allow for the spacing between rows; and a Yorkshire yield of roughly 850 to 950 kWh per kWp installed each year. These are engineering rules of thumb, useful for orientation and nothing more. Your real panel count, roof area and output come from a PV*SOL model of your specific roof, its pitch, its shading and its orientation.
There is an honest tension to be aware of when you size. Going larger lowers the cost per kWp, because the fixed elements of a project, the survey, the design, the grid application and the scaffold, spread across more capacity. Going larger also pushes more of your generation into export the moment the array exceeds your daytime load, and export earns less than self-consumption. The right size lives at the point where you still use most of what you make, sometimes lifted by adding battery storage to shift midday generation into the early evening, or by an export limit agreed with the network operator. We model that trade-off against your actual consumption rather than guessing it. We deliberately do not publish a cost per kWp or a payback figure here: the cost is built from the survey and the model, and how the economics and returns work is set out on the commercial finance page and in the ROI and payback guide.
The honest answer is that it is set by your consumption, not by your roof. Start with your half-hourly electricity data, which your supplier or network operator can provide, and look at how much power the building draws through daylight hours across the year. A system sized to sit under that daytime demand is one whose output you mostly use on site, which is where the value is, because self-consumed power saves you far more than exported power earns. The roof area is the second constraint, not the first. We model your real load against a system sized from an on-site survey, so the size you end up with is matched to your building rather than to a band on this page.
As an indicative rule of thumb, a commercial array needs roughly 1.7 to 1.85 modules per kWp, using panels of 540 to 600 W, so a 100 kWp system works out at about 185 modules, a 250 kWp system at around 460, and so on up the bands. Treat that as orientation only. The real count depends on the exact module wattage specified, how the roof is broken up by plant and rooflights, and how much of the roof is usable once spacing and access are allowed for. Your firm number comes from a PV*SOL model of your specific roof, not from this calculation.
There is no useful price per kWp for a commercial system, and we do not publish one, because the cost is driven by things that vary site to site: the modules and inverters specified, the mounting system the roof demands, the DC and AC works, access and scaffold, and above all the grid connection, including any reinforcement the network operator requires. As a general direction, the cost per kWp falls as the system grows, because the fixed elements of a project spread across more capacity, but that is a trend, not a figure. A meaningful number comes from an on-site survey and a PV*SOL model of your roof and your load. How the cost translates into returns is covered on the finance page and in the ROI and payback guide.
Size to your consumption first. Filling the roof feels efficient, but every kilowatt-hour the array makes above what the building is using at that moment has to be exported, and export is worth a fraction of what you save by using the power yourself. A larger array does lower the cost per kWp, so there is a genuine trade-off, and the right answer is the size where you still self-consume most of what you generate. You can push that balance further by adding battery storage to move midday generation into the early evening, or by agreeing an export limit with the network operator. We model that trade-off against your real half-hourly data rather than assuming the roof should simply be full.
The pace is set by the grid connection, not by travel or the panels. The survey reaches you quickly from our Yorkshire base, and the design and install rarely hold things up. What governs the programme is the G99 application to your network operator, Northern Powergrid across Yorkshire and North and North East Lincolnshire, and that step scales with size: a larger array means a heavier application and sometimes network reinforcement, which the operator times. We will not invent a duration here. Your proposal carries a dated programme built around the connection your specific system needs, and the installation timeline guide walks through each stage.
Send us your half-hourly data and the site. We model the right size against your real load and come back with a designed system and a figure built for you.