Do solar panels work at night?

No. Panels convert light, and at night there is none. Moonlight is far too weak to produce anything usable.

The question is almost always really about something else: what covers your evening and overnight consumption, given that it arrives when generation does not. That is a good question, it has three answers, and each of them has a price attached that you can look up today.

The mismatch, stated plainly

Solar generates in the middle of the day. Household demand peaks in the morning and again in the evening, and continues at a low level overnight.

So there are two separate problems: a midday surplus you may not be able to use, worth only the export rate of around 12p, and an evening demand your panels cannot meet, costing the full capped import rate of 26.11p. They are the same problem seen from both ends, that gap between 12p and 26.11p is what every solution below is actually harvesting, and everything that helps addresses both at once.

Answer one: the grid

Overnight, you import. This is normal and not a failure of the system.

A grid-connected solar installation is not attempting to make you self-sufficient. It reduces what you buy when the sun is up and earns a little for the surplus. Overnight you are an ordinary customer.

The lever available here is the tariff. A time-of-use tariff with a cheap overnight window, Intelligent Octopus Go’s 8p rate being the reference example, reduces the cost of the electricity you cannot avoid importing by two thirds against the cap. For a household importing 2,000 overnight kilowatt hours a year, that is over £350, from one form and no hardware. That is worth more to most households than any technical measure, which is why it is answer one.

Answer two: a battery

Storage is what most people are really asking about.

A battery charges from surplus generation during the day and discharges in the evening. It does not extend generation into the night; it moves daytime generation into the night, at roughly 10.7p of net gain per cycled unit on current rates once the forgone export and the round trip losses are counted.

Two things follow:

It is capped by surplus. The battery can only store what you generate and do not immediately use. On a dull winter day there may be almost nothing, which is why the seasonal shape belongs in the decision.

It is capped by capacity. Whatever it holds is what you get, and the right size is your evening’s consumption, not your array’s output.

So a battery reduces overnight import substantially in summer and modestly in winter, and does not eliminate it in either.

The other thing a battery does, and this is underrated, is charge cheaply from the grid overnight and discharge during expensive hours. At 8p in and 26.11p avoided, that earns around 14.7p per cycled unit after losses, more than solar-shifting does, it works with no sunshine at all, and in a British winter it is often the larger part of the return.

Answer three: move your consumption

Free, and the most overlooked.

Anything with a timer can run during daylight instead of after dark. Dishwasher, washing machine, tumble dryer: every shifted unit is worth the full 14p gap between import and export, which across a few hundred units a year quietly outearns much of what the hardware answers deliver, as the self-consumption arithmetic shows. An immersion heater with a diverter converts midday surplus into hot water for the evening, which is a form of storage costing a fraction of a battery.

None of this changes what the panels do. It changes how much of what they do you actually keep.

A night on the meter, worked

Put a typical night into numbers, because it sets the size of the problem the three answers are solving. From early evening to morning a household might use 6 kilowatt hours: cooking’s tail, lighting, the fridge’s cycles, the router, some television, an overnight baseline. At the capped rate that night costs about £1.57. On an 8p window with the big loads shifted into it, nearer 50p. With a battery carrying 5 of those kilowatt hours from the day’s surplus, the imported remainder costs pennies either way.

Across a year those nightly figures are the whole game: £570 of unmanaged nights on the cap, against roughly £180 of managed ones on a cheap window, against less still with storage. None of the three outcomes involves the panels working at night, and the spread between them is wider than most of the daytime decisions people agonise over, which is why the question this page answers matters more than its literal answer.

What about going off grid?

Technically possible, and in the UK almost always a poor financial decision for a property with a grid connection.

Off-grid means sizing for the worst week of the year rather than the average, which in a British winter, when whole days can generate a couple of kilowatt hours, means a very large array and a very large battery, most of which sits idle for eight months, degrading and earning nothing.

The grid is a better battery than any battery: it absorbs your surplus and supplies your shortfall, at a price. Paying to replicate it is expensive, and the arithmetic rarely closes for a connected home.

What to expect

A solar system reduces your daytime import, earns a little on export, and leaves your overnight consumption largely untouched unless you add storage.

A battery moves a chunk of daytime generation into the evening and lets you arbitrage a time-of-use tariff overnight, which is currently its stronger trade.

Neither makes the meter stop at night, and any projection implying otherwise is worth examining closely. An honest projection treats the night as what it is: imported, ideally at the cheapest rate you can arrange, with the panels’ work done in daylight and their value decided by how much of it you keep.