D-1 versus D+4

Currently ‘Synergy Service’ publishes the planned electricity price for the following day. This is called the D-1 price. Four days after the trading day, the final market price is settled. This price is called the D+4 price and it is the price used to settle trades among the players in the electricity pool. It is interesting to see how close plan and actual turn out to be. If the D+4 (actual) turns out to be significantly different from the D-1 (plan) then the wrong price signals are being sent by Synergy Service and the optimal demand response (DR) will not be achieved by the Synergy Modules using Synergy Service.

The following chart from Synergy Data shows two days from last week. D-1 (plan) is shown as a solid bar chart and the settled D+4 (actual) price is drawn as a line graph. It is clear that for most of the time D+4 and D-1 are very close. An electricity cost reduction algorithm based on D-1 would yield good cost optimisation. However at around 9:00pm, for about 1 hour, the cost of electricity deviated significantly from D-1.


What we are now focussed on, at Synergy Module, is trying to find some way to improve our Synergy Service signals to bring them closer to the eventual D+4. Obviously, this will reduce the cost of electricity for our customers by enabling them avoid usage during such a peak. Reducing usage at that time will lower the peak and bring down the cost of electricity for all users.