energy-grid-viewer-uk

GB Grid Battery Storage Dashboard

Real-time monitoring of GB grid-scale Battery Energy Storage Systems (BESS). All data comes from free public APIs. No API keys are needed.

Live at grid.xelantis.com.

What it shows

• Live Overview: BESS fleet output for today (London day) at 5-minute resolution, plus pumped hydro from FUELINST. Optional overlays:
  • Agile price
  • Carbon intensity
  • BM bid/offer prices
  • System (imbalance) price with net imbalance volume
  • Estimated P&L at the wholesale Market Index Price or the system price
  • Wind
  • Grid frequency (last hour, 15-second resolution)
  • Yesterday’s curve for comparison
• Live Sites: per-site leaderboard of current output, with a “BM” tag where a System Operator instruction is in force, and a per-site history modal
• Fleet Directory: about 155 BESS units (about 7.5 GW) from the Elexon unit reference data
• Site Map: sites with town-level coordinates, or a regional centroid where the location is unknown

Positive MW means discharging; negative means charging. The page auto-refreshes every 5 minutes.

Architecture

Browser → /api/elexon          → Elexon PN + BOALF + FUELINST (main series)
Browser → /api/elexon/history  → Elexon PN + BOALF for a past date, optionally one site
Browser → /api/sites           → Elexon PN + BOALF, aggregated per site
Browser → /api/units           → Elexon /reference/bmunits/all
Browser → /api/bm-prices       → Elexon BOD/stream (submitted bid/offer prices)
Browser → /api/market-price    → Elexon market index (APXMIDP)
Browser → /api/system-prices   → Elexon system prices (SSP/SBP, NIV)
Browser → /api/frequency       → Elexon system frequency
Browser → /api/prices          → Octopus Agile (Region A)
Browser → /api/carbon          → api.carbonintensity.org.uk

The proxy routes avoid CORS problems: every upstream request is made server-side. /api is kept as an alias of /api/elexon so existing links still work. If Elexon is unreachable, /api/elexon returns clearly flagged simulated data.

src/app/page.tsx is a server component that fetches the initial data at request time, so the first render is complete.

Data notes

• Output per unit = BOALF if an instruction is in force, otherwise PN. PN (Physical Notification) is the operator’s own plan, including merchant trading. BOALF levels are System Operator instructions in absolute MW, so they replace PN while active. Each row is a linear segment over [timeFrom, timeTo). When acceptances overlap, the latest one wins. If PN is unavailable, the app falls back to BOALF only, which shows SO dispatch but not merchant charging.
• BESS identification: a unit counts as a battery if its name contains battery/BESS/storage, or if its National Grid ID matches the <site>B-<n> pattern (PILLB-1, KILSB-3). bmUnitType: "S" means supplier unit, not storage.
• All “today” windows use the London day. Settlement days start at 23:00Z during BST.
• FUELINST provides pumped hydro (PS) and wind. It has no solar field, and its OTHER category never shows battery charging.

Getting started

npm install
npm run dev     # http://localhost:3000
npm test        # unit + behaviour tests
npm run lint    # includes Sonar cognitive complexity ≤ 15

Deployment

Deployed on Railway as a long-running Node.js process (Dockerfile, output: "standalone"), which keeps the in-memory unit cache warm. Every route is dynamic, so the app can’t be exported as a static site.