## 2 Smart Grid Project Overview in the EU  
Smart grids are a response to the need for modernizing existing grid infrastructure so as to increase efficiency, maintain safety and reliability and achieve large-scale integration of RES [21; 22]. Smart grid is an umbrella term which covers multiple technologies, concepts and application domains. The authors of [22; 23; 24] provide a comprehensive overview on the status of smart grid technologies. All of these studies clearly have shown that future grids increasingly are going to be digitized under the foundation of ICT infrastructure and will use large amounts of data to perform better decision making.  
To track the progress of smart grids in the EU, the Joint Research Centre (JRC) periodically publishes a report under the smart grid project outlook (hereafter, SGP report), the latest of which was published in 2017 [25]. In this report, the JRC categorized smart grid projects under six domains, of which smart network management is the domain which had most of the projects and, thus, investments. Smart network management comprises applications such as tools for network observability, advanced sensors on network equipment to identify anomalies and communicate with nearby devices when a fault occurs, tools for self-healing and tools for reactive power control and energy storage, to name a few.  
As much of DERs (including RES) are expected to be connected to a distribution grid, the distribution system operators (DSOs) have been identified as key players in the transition towards a clean energy system [26]. DSOs shall be crucial to sustainable energy transition and, thus, have a central role in the revised Directive on Common Rules for the internal market for electricity, which is part of the Clean Energy for all Europeans legislative package, issued in 2019. DSOs in the EU have acknowledged this role, and to equip themselves, they have been investing in smart grid projects, as reflected in the SGP report [27; 28]. Furthermore, according to [29], DSOs are expected to invest heavily so as to establish complete system innovations to their traditional businesses.  
Based upon the SGP report, there are more R&D projects compared to demonstration projects. This suggests that more R&D is needed before solutions can reach market. It should be noted that demonstration projects are more capital-intensive than R&D projects. This makes demonstration projects more difficult to implement from a financial point of view and require more confidence in the technology. About 60% of investments in demonstration projects come from private investments, while for R&D projects, they account for  
Figure 1: Organization of the research.  
only 40%. The remaining investments in R&D projects come from either EU or national funding schemes, which, ultimately, is public money. This observation has also been seconded by [30]. Thus, if technological innovations from R&D projects are not adopted by the market, it results in a loss of public money. Developing new grid technologies and processes involves high uncertainties concerning, for instance, performance, replicability, scalability and consumer response [31,32]. These uncertainties can negatively affect investment decisions and can be reduced by decreasing the gap between technology developers' perceptions and customer needs in the early phases of R&D.