Can solar power a cold store? Day, night and winter load match

A cold store is a very electricity-hungry building 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 can offset a substantial share of the load, 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 changes and to network charges, which are a component of the delivered price and change each year. 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 tends to be high for cold stores

The reason cold storage tends to suit 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 the illustrative model assumes a cold store uses about 90% of what its panels produce on site; test that against twelve months of half-hourly meter data.

That assumption is high, and the reason is the load shape. 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 usually demand to soak up the output. Little should be exported, and most of the generation offsets electricity you would otherwise have bought at full retail. On those assumptions the site’s simple model gives an illustrative payback of around 4.5 years (assumed tariff and self-consumption; not a quote), and a constant load tends to suit solar better than a daytime-only ambient load 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:

The headline trade is exposure versus capital. Grid-only means no outlay but full, permanent exposure to tariff changes 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 a large operating cost and the illustrative model assumes a high share of generation is used on site, the second column wins on the model’s numbers; test that against your own meter data.

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

Because a cold store’s constant load tends to absorb most of what 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 most of it should already be used 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 high as the site’s load allows.

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. Suppose it fits around 780 kW of rooftop PV, expected to generate in the region of 725,000 kWh a year. Because refrigeration runs around the clock, the model assumes self-consumption would sit near 92%, so little of that generation would be exported, it would displace power the site would otherwise have bought. The annual saving would be expected to come out near £187,000, for an illustrative payback close to 4.3 years (assumed tariff and self-consumption; not a quote). Crucially, the site would still be firmly connected to the grid: the array would cover a large share of the daytime load and trim 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 tends to be simpler for cold storage than for an ambient 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 usually the strategy to model first, because a constant load means you should self-consume most of what you generate (test that against your meter data) 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 may 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 to ask about your own facility, send an enquiry and we reply by email.