The main objective of this thesis is to study the ex post pricing in electricity market by implementing two new methods (quantity based method... Show moreThe main objective of this thesis is to study the ex post pricing in electricity market by implementing two new methods (quantity based method and price based method). The quantity based method measures the difference between the actual performance of an individual resource and its bid-based profit-maximizing response to the ex post prices. The price based method measures the different between the ex post price and the supporting price which supports the actual outputs. These two methods are based on a co-optimization market for energy and ancillary service. They are very flexible and can solve the ex post price efficiently and simultaneously. M.S. in Electrical Engineering, May 2011 Show less