ENTSOE European Network of Transmission System Operators for Electricity, represents 43 electricity transmission system operators (TSOs) from 36 countries across Europe. The integration of renewables into the power system requires for their intermittency to be balanced. This can be tackled by electricity grids operating smartly and cost-efficiently.
European Energy Flexibility Platform and Interface (EF-PI) - link docs not really a standard, more a consortium of private companies trying to adopt a common toolset.
Project Haystack is an open source initiative to streamline working with data from the Internet of Things. Haystack standardize semantic data models and web services with the goal of making it easier to unlock value from the vast quantity of data being generated by the smart devices
ESOS is a mandatory energy assessment scheme for organisations in the UK that meet the qualification criteria established to implement Article 8 (4 to 6) of the EU Energy Efficiency Directive (2012/27/EU)
Streamlined energy and carbon reporting - SECR released Oct '17 and updated mid '18 gives guidelines for mandatory carbon reporting framework for UK big businesses, as well as directions for energy efficiency
energy performance certificate (private residence only?) EPC register there’s also a data set here: London domestic efficiency by boroughs