Why does demand peak in the evening?

Because domestic activity concentrates there. Cooking, lighting, heating and entertainment all rise as people get home, and they do it at roughly the same time, so millions of small decisions add into one national spike.

Is this all the electricity Britain uses?

It is transmission-level demand, which excludes generation embedded in the distribution network — most notably rooftop solar. On a sunny afternoon real consumption is higher than this line shows, because some of it never touches the transmission grid.

Yes. It comes from Elexon's BMRS demand outturn feed, key-free. Nothing is invented or simulated, and if the source cannot be reached the saver reports that instead of drawing something plausible.

Does it cost anything or need an account?

No. Every screensaver here is free, runs in the browser and needs no sign-up. This one uses a public API that requires no key.

Britain's Demand Curve Screensaver

The Britain's Demand Curve screensaver plots national electricity demand in megawatts at five-minute resolution across two days, so the previous day's shape sits behind today's. It runs in the browser with nothing to install; press ESC to exit.

How the Britain's Demand Curve screensaver works

The saver reads Elexon's BMRS demand outturn feed, key-free.

No account and no key: the request goes straight from your browser, or from this site's own refreshed copy of the feed where the source does not permit browser access.

Values are drawn on a canvas that resizes with the window, so it works on a laptop or a wall display.

If the source is unreachable the saver says so on screen rather than showing stale numbers as though they were current.

A worked example

A single line across two days with dashed rules at midnight. The shape is the most predictable thing in the energy system and still worth watching: a trough around four in the morning, a climb through breakfast, a working-day plateau and the evening peak as a country comes home and starts cooking. Current demand, the peak and the trough are named beneath.

Settings & tips

Accent and Background recolour the display without changing the data.
Add it to a Multi-view grid to watch it alongside other live savers.
Press ESC at any time to leave fullscreen.

Frequently asked questions

Why does demand peak in the evening?: Because domestic activity concentrates there. Cooking, lighting, heating and entertainment all rise as people get home, and they do it at roughly the same time, so millions of small decisions add into one national spike.
Is this all the electricity Britain uses?: It is transmission-level demand, which excludes generation embedded in the distribution network — most notably rooftop solar. On a sunny afternoon real consumption is higher than this line shows, because some of it never touches the transmission grid.
Is this real data?: Yes. It comes from Elexon's BMRS demand outturn feed, key-free. Nothing is invented or simulated, and if the source cannot be reached the saver reports that instead of drawing something plausible.
Does it cost anything or need an account?: No. Every screensaver here is free, runs in the browser and needs no sign-up. This one uses a public API that requires no key.

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