The current cities’ urban challenges go through digitalization and integration of new technologies under the perspective of actual and future ecological, as well as socio-economic commitments. This process is translated into the Open Standardized Urban Data Platform, which plays a pivotal role. Within its main functionalities, data ingestion, analytics and services as vertical domains become necessary to create more environmentally friendly cities. However, there still exist some deficits. Among them, openness and interoperability are outlined. On the one hand, there is a lack of open data initiatives for increasing the smart services stock. On the other hand, interoperability depends upon vendors and integrators, reducing the possibilities of Smart City growth. In this context, under the mySMARTLife project (GA #731297) umbrella, an Open Specifications Framework has been developed in order to address four main issues: (1) data interoperability; (2) services or verticals interoperability; (3) openness; and (4) replicability. It enlightens the implementation and integration of multiple city domains (like infrastructures, mobility, energy, buildings) for smart management and big-data analytics. Its applicability is demonstrated in the three lighthouse cities of the project, Nantes (France), Hamburg (Germany) and Helsinki (Finland).

Districts can be considered as a system of complex interconnections, interactions, relationships and flows. Therefore, a comprehensive approach is essential for effective decision-making with regards to energy efficiency improvement. When addressing interventions with a wider scale, the range of possible interventions is greater, as well as the possibilities of new business models to make bankable the interventions. However certain barriers can appear linked to the interactions among stakeholders, which are usually more complex than when tackling individual actuations. To overcome these barriers it is necessary to establish integrated and systemic methodologies able to support stakeholders to implement better collaboration approaches and carry out more informed decisions. These decisions should be based on a set of relevant indicators, calculated at district level, capturing the different stages that form the retrofitting process (from the diagnosis to the final assessment). This paper presents a holistic design methodology based on the application of a Multi-Criteria Decision Making approach that allows designing optimised solutions. This methodology is based on the evaluation of a set of District Sustainability Indicators while proposing an Integrated Project Delivery method improving the communications among stakeholders and, therefore, the decision-making process.