Boundary Flows

About

The Boundary Flows chart uses National Grid’s forecasted levels of locational demand and levels of locational generation to find zones where levels of generation might need to be reduced in order to match up supply and demand.

This can be most commonly seen on the England-Scotland border where too much generation can result in large volumes of bid actions at Scottish wind farms (sometimes creating negative system prices):

All these values are based upon forecasts, so could be known in advance, but when the generation minus the demand exceeds the boundary limits, bid actions are inevitable in the limiting region.

The boundaries can be seen in the following map:

Figure: Map of Boundaries and Zones

Included Data

The data on this chart is as follows:

• Bid Volumes - The levels of bid volume to turn down via the Balancing Mechanism occurring behind the boundary.
• Generation - The levels of post-balancing generation measured behind the the boundary.
• Expected Generation (INDGEN) - The indicated generation forecast (sum of all the PNs submitted for BM Units which are forecast to be exporting energy) behind the the boundary.
• Expected Demand (TSDF) -The transmission system demand forecast (INCLUDES Interconnector flows and demand from station transformers and pumped storage units) behind the the boundary.
• Boundary Limit - the limits of the boundaries with key infrastrucutre split out to aid in the discovery of any outages.
• Expected Export (IMBALNGC) - The Indicated Imbalance forecast (the difference between the sum of the PNs submitted for generation BM Units (i.e. the Indicated Generation), and the Demand Forecast) behind the the boundary.

Data Service

The Boundary Flow Projections data can be extracted from the API. The parameters used are as follows: