1. A computer implemented system for optimal market dispatch for clearance and pricing of energy and ancillary services in an electricity market of at least one market participant wherein load prediction is performed considering load system requirements, said system comprising: means for inputting transmission security constraints of said at least one market participant; means for clearing energy and ancillary bids; means for optimizing the dispatch of energy and ancillary services considering said load security constraints of said at least one market participant using mixed integer linear programming techniques; and means for pricing the dispatch of energy considering said load security constraints.