What you're looking at

One source: the GDA lake

Every dial and chart here is computed from the GDA data lake — a self-refreshing archive of official, published GB grid data. GridGlass only displays that data; it runs no forecasts and no models. Each figure is shown exactly as published, with the timestamp of the latest reading available in the lake, so you always know how fresh it is.

The datasets on the board

• Frequency — Elexon FREQ (system frequency, Hz).
• Generation by fuel & interconnectors — Elexon FUELINST (instantaneous MW per fuel).
• Demand — Elexon INDO (initial national demand out-turn).
• Inertia — computed live from the synchronous generation mix using industry-standard inertia constants (H); an approximation of the real rotational energy present at T+0. It excludes “synthetic inertia” by design — a fast inverter response isn't present at the instant of a loss, so it isn't counted. NESO Outturn Inertia (GVA·s) is shown for comparison: a lumped figure that includes synthetic.
• Embedded solar — Sheffield Solar PV_Live national out-turn.
• Carbon intensity — derived from the live fuel mix (gCO₂/kWh).

Freshness

The lake refreshes continuously as its acquirers pull new public data. GridGlass reads the newest partitions on each poll and shows each tile's own "as of" time — a dial marked stale simply means its dataset hasn't published a newer reading yet.

Part of the estate

GridGlass is one of the Twin Scroll Grid Balancer sites. If you'd like to interrogate the underlying data in plain English, see the GDA data portal. You can sign in with your estate account, but nothing here needs an account.