# Autonomous Cyber-Physical Systems Enabling Smart Positive Energy Districts
## 1 Introduction  
One of the European Union's (EU) primary objectives in addressing global warming is to become the world's first climate-neutral continent by 2050. As is outlined in the European Green Deal, this goal involves measures to decrease greenhouse gas (GHG) emissions, increase renewable energy use, and improve energy efficiency [1]. Challenges include the need for further policy changes and reliance on the capabilities of diverse member states. The energy systems of buildings are important for realizing net zero emissions, and achieving this goal has prompted contemporary advancements in intelligent buildings, intelligent cities, and intelligent regions. Urban areas are responsible for utilizing approximately 65-70% of global energy and producing 70-75% of global GHG emissions [2]. Hence, European cities are increasingly encouraged to mitigate building and urban infrastructure emissions. Buildings together with transport are responsible for more than 70% of global energy consumption and at present only 20% is supplied by renewable energy sources [3]. As a result, buildings and electric vehicles have considerable potential to enable the optimization and balance of energy supply and demand. Distributed energy generation is rapidly growing through the utilization of Renewable Energy Sources (RESs) for both cooling and heating, as well as through their integration into electric vehicle charging infrastructure. The production of renewable energy is affected by various meteorological factors, including wind speed, cloud cover, temperature, and precipitation [4]. The enhancement in the utilization of RESs, prosumer engagement, Distributed Energy Resources (DERs), and smart grids has created new challenges regarding the energy supply balance, complexity, and stability of the overall energy system [5]. DERs represent small-scale energy systems that supply power to a neighboring location. Following the initial initiative in 2008, the Strategic Energy Technology (SET) Plan, revised in 2015, was adopted by the EU to create effective energy technology policies for Europe [6]. The aims were to speed up knowledge creation, technology transfer, and knowledge uptake to achieve energy transition, address climate change, and achieve the sustainable development goals. The SET Plan includes ten key action areas. In this context, action 3.2, \"_Smart Cities and Communities_\", was established to support the design, planning, organization, implementation, and replication of \"100 Positive Energy Districts\" (PEDs) by 2025, as part of broader actions and efforts to promote greener initiatives and sustainable urban development [6]. The PED stores the surplus energy produced by RESs or exports it to the overlapped grid and, when there is a shortage at the local level, it buys energy from the grid [5]. A definition of a PED is as follows: \"_Positive Energy Districts are energy-efficient and energy-flexible urban areas or groups of connected buildings which produce net zero greenhouse gas emissions and actively manage an annual local or regional surplus production of renewable energy. They require integration of different systems and infrastructures and interaction between buildings, the users and the regional energy, mobility and ICT systems, while securing the energy supply and a good life for all in line with social, economic and environmental sustainability_\" [7]. At the district level, earlier ideas of Nearly/Net/Positive Zero Energy Buildings (ZEBs) were extended with energy generation, consumption, and storage interoperability and interaction [8]. Results and data from existing PED approaches across Europe have been collected by JPI Urban Europe [9; 10]. Being energy-efficient and energy-flexible, PEDs require the integration of different energy systems (electricity, heat, cooling, energy storage) as well as interaction between regional, building, and user energy; information and communication technologies (ICT); transport; and cyber-physical systems (CPS).