Work of System Operators gathered in PTPiREE is also focused on tariffs in order to provide common approach and issue valid opinions. Currently, this work involves also close cooperation of the distribution system operators with representatives of the Energy Regulatory Office (supported by external experts) in order to develop a model of quality regulations to be applied from 2016. The operations in the area of tariffs are performed by representatives of the operators of distribution and transmission systems within the Board of Directors on Tariffs.