Solar vs Grid Electricity for Cold Storage

A cold store is the most electricity-hungry building most logistics operators run, and it never switches off. Compressors hold temperature through the night, at the weekend and over Christmas, which makes the headline question a fair one: if you cover the roof in panels, can solar actually cover the refrigeration load, or are you still tied to the grid? This guide compares a solar-led strategy against staying fully grid-supplied, and gives a realistic answer rather than a sales line. The short version is that solar offsets a substantial share of the load at unusually high value, but it does not run a 24/7 cold store on its own.

The two strategies in plain terms

Stay fully grid-supplied. You buy every kilowatt-hour from your supplier at the prevailing commercial rate, plus the network and policy charges layered on top. There is nothing to install and no capital outlay, but you carry the full exposure to tariff rises and to the network charges that have climbed steeply since 2022. For a building that draws power around the clock, that exposure is large and permanent.

Go solar-led, with the grid behind it. You install rooftop PV sized to your demand and consume what it generates directly, drawing from the grid only when the panels cannot meet the load, at night and on dull winter days. You are not leaving the grid, you are shrinking your dependence on it. The trade is upfront capital, or a finance or PPA arrangement, in exchange for a large slice of your electricity coming from your own roof at a fixed, low cost for twenty-plus years.

The honest framing is that this is not solar versus grid as an either or. It is grid-only versus solar-plus-grid. No rooftop array keeps the compressors running through a January night, so the real comparison is how much of your annual bill solar can take out, not whether it can replace the grid entirely.

Why self-consumption is unusually high for cold stores

The reason cold storage is such a strong fit for solar comes down to one number: self-consumption, the share of generated electricity you use on site rather than exporting at a lower price. The more you self-consume, the better the return, and a cold store typically self-consumes 90% or more of what its panels produce.

That figure is exceptional. A nine-to-five office exports much of its midday generation because nobody is there to use it. A cold store is the opposite: refrigeration is a constant baseload sitting underneath everything else the building does, so whenever the sun is up there is always demand to soak up the output. Very little is exported, almost all of it offsets electricity you would otherwise have bought at full retail. This is why cold storage delivers the fastest payback in UK commercial solar, around 4.5 years, and why the economics beat a standard ambient warehouse on the same roof.

Daytime versus night: where solar fits and where it does not

Solar only generates in daylight, and that single fact defines the boundary of what it can do for a cold store. Across a UK year the panels produce most of their output in the middle of the day and across the lighter months, and nothing at all overnight.

A cold store’s demand, by contrast, is close to flat across the 24 hours. So the picture is straightforward: in daylight the array can meet a large part, sometimes the bulk, of the refrigeration load directly, and through the night the grid carries all of it. Over a full year, a well-sized system on a cold store will realistically offset somewhere in the region of a quarter to two-fifths of total electricity, with the exact figure driven by your roof area, your demand and how much you install. That is a major reduction in a very large bill, but it is a reduction, not elimination. Anyone promising a cold store can run on solar alone is not being straight with you.

Weighing the options

The practical gaps show up across the two strategies:

Factor	Grid-only	Solar + grid
Upfront capex	None	Full system cost (or financed / PPA)
Bill exposure	Full, every kWh at retail + network charges	Reduced, you buy fewer kWh
Share of annual load offset	0%	Typically ~25-40%, site-dependent
Self-consumption of what you generate	n/a	90%+
Night and winter cover	Grid	Grid (solar cannot cover it)
Exposure to future price rises	Full	Partially hedged for 20+ years
Resilience to tariff shocks	Low	Higher on the self-supplied portion
Carbon (Scope 2)	Full grid intensity	Lower, auditable reduction
Best for	Sites that cannot install (lease, roof, capital)	Almost every cold store that can install

The headline trade is exposure versus capital. Grid-only means no outlay but full, permanent exposure to a rising bill on a building that draws power every hour of every day. Solar-plus-grid means an upfront investment in exchange for taking a large, fixed-cost slice out of that bill for the life of the system. For a cold store, where electricity is the single biggest operating cost and self-consumption is near the theoretical maximum, the second column wins on the numbers far more reliably than it does for most other buildings.

A framework: how much solar can your cold store actually use?

Because a cold store self-consumes nearly everything it generates, the question is rarely whether the building can use the power. It is how much you can fit and fund. Work through it in this order.

1. Start with your half-hourly meter data, not the roof. Your daytime baseload sets how much solar you can absorb directly. For a true 24/7 cold store that baseload is high and steady, which is exactly why you can size aggressively without exporting much.
2. Check the roof and the structure. Cold stores often sit under insulated panel roofs, so the array has to be designed to respect panel integrity and penetration detail. Roof area caps the maximum system, but on a large facility it is rarely the binding limit.
3. Confirm grid capacity. The connection your DNO will allow can cap the system before the roof does. This is the constraint that most often decides the final size.
4. Decide where a battery earns its place. For a 24/7 cold store, a battery is not about saving daytime solar for the evening, because you are already using almost all of it as it is made. Its role is shifting cheap night-rate grid power or providing resilience, so it is a separate decision from the array, justified on its own terms rather than assumed.
5. Factor refrigeration efficiency in parallel. The cheapest kilowatt-hour is the one you never use. Efficient compressors, good door discipline, heat recovery and an F-gas-compliant refrigeration upgrade all cut the load solar has to chase. Pairing efficiency work with PV means a smaller array offsets a larger share.

The output of this framework is a system sized to your demand and your constraints, designed to push self-consumption as close to that 90%-plus ceiling as possible.

A worked example

To make it concrete, here is an illustrative case, not a real client. A family-owned cold store running 24/7 spends roughly £390,000 a year on electricity. It installs around 780 kW of rooftop PV, generating in the region of 725,000 kWh a year. Because refrigeration runs around the clock, self-consumption sits near 92%, so almost none of that generation is exported, it displaces power the site would otherwise have bought. The annual saving comes out near £187,000, for a payback close to 4.3 years. Crucially, the site is still firmly connected to the grid: the array covers a large share of the daytime load and trims the annual bill hard, but the grid still carries every overnight hour. The figures are illustrative and depend entirely on your tariff, roof, load profile and how much you install.

How to choose

The decision is simpler for cold storage than for almost any other building, because the constant load removes the usual doubt about whether you will use the power.

If your facility runs around the clock and you can install on the roof, solar-plus-grid is almost always the right answer, because you will self-consume nearly everything you generate and take a fixed-cost slice out of your largest operating cost for twenty years. Stay grid-only only where you genuinely cannot install, a short lease with no consent, a roof that cannot take the array, or no capital and no appetite for finance or a PPA. In every other case, the question is not whether to add solar but how large a system your demand, roof and grid connection will support.

The right number is specific to your site, so the sensible next step is to model it against your real load. Review the cost guide for the underlying numbers, the funding routes for the schemes that apply to the cold chain, and run the savings calculator for an instant indicative figure. If you are still weighing up the case in principle, start with is solar worth it for cold storage. When you are ready, request a free feasibility and we will model your real demand against a solar-plus-grid design for your facility.