Market subjects (genera­ tors, traders and consum­ ers connected to the trans­ mission grid) and other participants in the electri­ city system, such as agents (generators, distributors or consumers) requesting access to the grid, mana­ gers of the distribution network, the Iberian Spot Market Operator (OMI, Polo Español S.A. (OMIE)), neighbouring electricity system operators as well as suppliers of the inter­ ruptibility demand-side management service.