Methodology & data sources
What's real, what's modelled, where the numbers come from, and what we simplify. Last updated 16 October 2026.
GridTradingDesk is a learning tool. We'd rather you know exactly where the line sits between real data and our own modelling than have the two blur together, so this page spells it out.
At a glance: real vs modelled
| Part of the game | Status |
|---|---|
| The pricing mechanism (merit order: cheapest plants first, the last one needed sets the price) | Real mechanism |
| Live UK Data days: national demand and settlement prices for a real date | Real data, rescaled to the game's size |
| The live grid-mix and carbon-intensity widget | Real data, shown with an “updated” time |
| The six Challenge Days (cold snap, windy spring, heatwave and so on) | Illustrative, modelled on well-known patterns, not a replay of one date |
| Your fleet, plant costs, build prices, carbon adders and cash | Game values chosen for teaching |
| Weather, random events and offers | Simulated |
| UK Energy Co and everything that happens to it | Fictional |
Data sources
Elexon Insights Solution (BMRS). Elexon publishes Great Britain's settlement data. For Live UK Data days, our server fetches the national demand and the system price for the settlement date you pick. These are public figures, and we pass them through our own server before they reach the game. Elexon's own site is at bmrs.elexon.co.uk.
NESO Carbon Intensity API. The homepage's live widget reads Great Britain's current generation mix and carbon intensity from the public Carbon Intensity API run by the National Energy System Operator (NESO). Its figures are national estimates and forecasts, so they can be revised.
GridTradingDesk is an independent project. It is not affiliated with, endorsed by, or supplied by Elexon, NESO or any energy company.
How fresh is “live”?
Live numbers on the homepage and in the game are refreshed periodically (about every five minutes on the homepage) and are labelled with the time they were last updated. They are not a trading screen: the upstream sources publish on their own schedule, so figures can lag real life by a few minutes or more. If a feed is unavailable, we hide the number rather than show a stale one as if it were current.
How the game sets a price
Each of the 48 half-hours in a game day, every plant that is available offers its running cost. The game stacks them cheapest-first until demand is met; the last plant needed sets the single clearing price, which every running plant is paid. That is the merit-order idea behind real wholesale pricing, and the “Why this price?” panel in the game shows it step by step.
What we simplify
Real wholesale trading in Great Britain is spread across forward, day-ahead, intraday and balancing markets, with network constraints on top. The game collapses all of that into one clearing price per half-hour, with no transmission limits, so that the core cause-and-effect is easy to see.
Real demand runs from roughly 18 GW to 45 GW. The game works at a much smaller scale (peaks around 1,500 MW) so that a handful of plants can matter. For Live UK Data days we keep the shape of the real day and rescale its size; the megawatts you see are therefore not the real megawatts.
Plant running costs, build prices and the carbon adder are round, illustrative numbers chosen to produce realistic-looking merit orders. They are not quotes for any real power station, and the explanations and debriefs in the game are hedged for the same reason.
Not advice
Nothing in the game or on this site is trading, investment, or financial advice, and no real money is traded. The only real money involved is an optional subscription.
Spotted something wrong?
If a figure, a claim or an explanation looks off, tell us through the feedback page and we'll look at it. Corrections are the most useful feedback we get.