This Decree, implementing provisions of the Energy Act and the Environment Act, provides for laying down rules on energy markets and energy systems. The Decree defines the following relevant terms: protection of a transmission or distribution system; party responsible for measurement; investment plan; emergency supplier; gas peak delivery; definition of energy poverty for monitoring purposes. The Decree concerns the following matters: contractual relationship between end purchaser and supplier or active purchaser and market participant; content of supply agreement and supply agreement regarding peer-to-peer trade; classification of customers, including micro-enterprises; management of electricity and gas system; appointment, certification, and recognition of system administrators; designation of data, tools, materials, working methods and processes; tasks and obligations of system operators, including investment planning, emergency planning, gas storage governance; recognition of the measurement-responsible party; implementation, monitoring and enforcement.