How to Size Solar for a Brewery: Start With Refrigeration

Most solar quotes a brewery receives are sized wrong from the first line. The installer takes your total annual energy spend, gas and electricity lumped together, and works backwards to an array big enough to “cover the bill”. For a brewery, that produces a system that is far too large, exports most of what it makes at a poor price, and takes years longer to pay back than it should.

The honest starting point is uncomfortable but it is the whole game: around 70% of a brewery’s energy is thermal, the wort boil, the hot liquor tank, steam and space heating, and that heat is almost always made by burning gas. Solar PV produces electricity. It cannot offset that thermal 70% directly. Only about 30% of your energy is electrical, and that electrical slice is the only part a rooftop array touches. Size to the total bill and you have designed a system for a demand that doesn’t exist.

So the correct question is never “how big an array covers my energy bill?” It is “how big an array matches my electrical load, hour by hour?” And the answer to that starts with your fridges.

Refrigeration is the anchor load

Break a typical brewery’s electricity consumption into its parts and one load dominates:

• Refrigeration and glycol chilling, around 35%. This is the single biggest electrical load, and crucially it runs 24/7 during fermentation. Your fermentation vessels have to hold temperature whether the sun is up or not.
• Packaging (cask, keg, can and bottle lines), around 25%.
• Compressed air, 15–25%.
• Pumps (CIP, transfer, process), 15–20%.
• Lighting, 8–12%.

Refrigeration is the anchor for one reason: it is a large, flat, continuous baseload. During active fermentation your glycol plant is drawing power around the clock. When the sun comes up, every kilowatt-hour your panels make lands straight on top of that constant chilling demand and gets used on site instead of being exported. That is why a well-sized brewery array typically achieves 75–90% self-consumption, far higher than an office or a shop, where demand collapses at weekends and overnight.

Get this idea straight and everything else follows. You are not trying to generate your annual electricity total. You are trying to shave the daytime portion of a load that never fully switches off.

Start with your half-hourly meter data

Any brewery drawing more than 16A per phase, which is all of them, connects under a G99 arrangement on a three-phase supply, and almost certainly has a half-hourly (HH) meter. That meter is the most valuable sizing tool you own, and most installers never ask for it.

Request 12 months of half-hourly consumption data from your energy supplier or through your meter operator. Then look for three things:

1. The overnight baseload floor. The kW you draw at 3am, when only refrigeration, controls and a little lighting are running. That floor is your glycol plant’s signature.
2. The daytime shape. How much your load rises during brewing and packaging shifts.
3. The overlap with solar hours. A UK array generates meaningfully from roughly 8am to 5pm. The consumption sitting inside that window is what solar can realistically displace.

This is the difference between a guess and a design. Half-hourly data lets an installer size the array so that generation rarely exceeds on-site demand, which keeps self-consumption high. Feed the last 12 months into our savings calculator to see the shape of it before you commit to anything.

Estimating before you have the data: kWh per hectolitre

If you’re planning ahead, a new brewhouse, a capacity expansion, or you simply can’t lay hands on the HH file yet, you can estimate the electrical load from output.

UK breweries use roughly 8–16 kWh of electricity per hectolitre produced. The smaller and less automated the operation, the higher the figure: nanobreweries and small craft sites often sit at 15–20+ kWh/hl because they lack the efficiencies of scale, while a large regional site with heat recovery and modern chillers trends toward the bottom of the range.

A worked example. Say a craft brewery produces 5,000 hl a year at 12 kWh/hl:

5,000 hl × 12 kWh/hl = 60,000 kWh/year of electricity

That 60,000 kWh is your electrical target, not your gas, not your combined bill. It is the number that decides array size. Note how different this is from the total energy figure: if electricity is 30% of energy, the full energy demand behind that brewery might be around 200,000 kWh equivalent, and sizing to that would triple the array for no benefit.

Turning kWh into kWp, and the roof reality

Two rules of thumb convert an electrical target into a real system:

• UK yield: ~850 kWh per kWp per year. A well-oriented, unshaded array in Britain generates about 850 units annually for every kilowatt-peak installed.
• Roof area: ~6 m² per kWp. That’s the footprint modern panels need, including row spacing.

Take our 60,000 kWh brewery. Generating that entire total would need roughly 70 kWp (60,000 ÷ 850). But, and this is the whole point of sizing to self-consumption, you almost never want to match 100% of annual demand, because summer midday generation would spill over into low-value export. A 50 kWp array is often the sweeter spot: it produces about 42,500 kWh/year (50 × 850), needs around 300 m² of roof (50 × 6), and if 80% is self-consumed it displaces roughly 34,000 kWh of expensive imported electricity every year.

Check that against your actual roof. A 50 kWp system wants 300 m² of sound, reasonably unshaded roof with the structural capacity to carry it, worth confirming early, because MCS structural rules (MIS 3002) and any pre-2000 asbestos will shape what’s possible. If the roof is tight, the array shrinks to fit, and that’s fine: a smaller, fully self-consumed system beats an oversized one that exports half its output.

Self-consumption is the number that decides payback

Here is why self-consumption, not raw generation, is the figure that matters. The value of a solar kWh depends entirely on what it replaces:

• A unit you use on site avoids buying electricity at roughly 25p/kWh (the DESNZ Q2 2026 non-domestic average; large half-hourly brewery sites negotiate lower, often 15–24p).
• A unit you export earns a Smart Export Guarantee tariff, which is supplier-set and currently sits in a 12–16p/kWh range, Octopus, for instance, cut its rate to 12p on 1 March 2026. You can compare live rates on Ofgem’s Smart Export Guarantee pages.

An avoided import unit is worth up to twice an exported one. So every kWh you can keep on site, which, for a brewery, means every kWh you can drop onto that 24/7 refrigeration baseload, earns far more than one you push to the grid. Refrigeration is what makes brewery self-consumption unusually high, and high self-consumption is what makes the payback attractive. Most correctly sized brewery arrays land in a 4–7 year payback window, with regional sites at the faster end.

Typical brewery array sizes

As a sanity check against your own numbers:

Operation	Typical array	Rough roof
Nanobrewery / start-up	6–30 kW	40–180 m²
Craft microbrewery	20–50 kW	120–300 m²
Growing craft	50–200 kW	300–1,200 m²
Regional independent	250–750 kW	1,500–4,500 m²
National	1 MW+	6,000 m²+

Where you fall depends on output, roof and, always, your half-hourly demand shape. See how the sizing plays out for a craft microbrewery or a leaner nanobrewery or start-up, where the kWh/hl figure runs highest.

Don’t forget the thermal 70%

Sizing to the electrical load is right, but it isn’t the end of the story. Once your array is chewing through daytime demand, summer surplus that would otherwise export at 12–16p can be pushed into an immersion element in the hot liquor tank, or drive an industrial heat pump (COP typically 2.5–3.5) to start attacking that thermal 70%. That’s a second-stage decision, but it’s worth designing the array with it in mind. Whether the whole package stacks up for your site is the question we work through in is solar worth it for a brewery.

On the money side, commercial solar is special-rate plant for capital allowances (HMRC’s CA22335), so it qualifies for the Annual Investment Allowance at 100% in year one up to £1m, though not for full expensing or the 40% first-year allowance, which specifically exclude solar. The detail sits on gov.uk’s Annual Investment Allowance guidance, and we cover the brewery-specific reliefs, including the sector Climate Change Agreement, on our grants and funding page. For system pricing by size, see what commercial solar costs.

Common questions

Should I size solar to cover my whole energy bill?

No. Around 70% of a brewery’s energy is thermal (the boil, hot liquor, steam) and made by gas, solar PV can’t offset that directly. Size to the ~30% electrical load, and specifically to the portion you use in daylight. Sizing to the total bill produces an oversized, over-exporting system.

How much roof do I need per kilowatt?

About 6 m² per kWp once you allow for spacing. A 50 kWp array needs roughly 300 m² of sound, reasonably unshaded roof, plus the structural capacity to carry the load.

Do I need half-hourly data before getting a quote?

It sharpens everything, so it’s worth pulling 12 months from your supplier. But you don’t have to wait, we can produce a solid first estimate from your annual output using 8–16 kWh per hectolitre, then refine it against your meter data. Start on our quote form.

Is a bigger array always better value?

No. Once the array is large enough that summer midday generation exceeds on-site demand, the surplus exports at 12–16p SEG instead of displacing ~25p imported power. Beyond the point of high self-consumption, extra capacity earns roughly half as much per unit. Size to the load, not the roof.

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Every brewery’s demand shape is different, and the anchor, your refrigeration baseload, is exactly what a generic quote ignores. Send us 12 months of half-hourly data, or just your annual output, and we’ll size to the electrical load properly. Start with our quote form.