## 3 Materials and Method
### REOPEN Approach. Context and Task Distribution
The European universities participating in the REOPEN project are Guglielmo Marconi University (Italy), University of Applied Sciences Technikum Wien (Austria), Munster Technological University (Ireland), Norwegian University of Science and Technology (Norway) and the University of Huelva (Spain). Each of these universities is in charge of one intellectual output (IO), as shown in Figure 2.  
Munster Technological University (MTU) oversees IO1 to collect experiences in development and use of hands-on, virtual, and remote laboratories. Additionally, MTU is in charge of analyzing the use of remote laboratories in Engineering and science, technology, engineering, and mathematics (STEM) careers and designing a pedagogical model of remote laboratories. The consortium has distributed surveys to professors (Figure 3a), students (Figure 3b), and industry workers (Figure 3c) between the five member countries. The results obtained from these surveys are detailed in [22]. Figure 3: Survey data collection: (**a**) Responses to professors’ survey; (**b**) Responses to students survey; (**c**) Responses to industry survey. Figure 2: Intellectual outputs (IOs) of each European university. One of the objectives of these surveys was to find out how motivating students, professors, and industry workers found the laboratory experience, their levels of enjoyment with the laboratory, and their overall satisfaction and levels of interest in the laboratory. Figure 4 shows how the University of Huelva (UHU) achieved the highest degree of satisfaction (4.5/5). On the other hand, the University of Huelva (UHU) is responsible for IO2, defining the standard ICT for the remote laboratory, establishing the communication system, including the use of programmable devices for the remote connection of the experimental devices, establishing the harmonized and standardized remote lab infrastructure, and the elaboration of guidelines for the user. The implementation of the remote laboratory ICT infrastructure is based on the architecture shown in Figure 5. The user, who must have a computer with Internet connection (item 1, Figure 5), accesses the REOPEN Moodle platform (item 2, Figure 5), where the five remote laboratories are hosted. Next, the REOPEN Moodle platform accesses the university's local area network (LAN) through a server (item 3, Figure 5). The intranet and server are located at the university, where the experiment hardware is located. A computer is also connected to the university's LAN. The computer (item 4, Figure 5) can be a personal computer (PC), a mini-PC, a Raspberry Pi, or a similar device that allows the installation of an operating system (OS) and has an Internet connection. Thus, the user interface (UI) is a software tool, for example a LabVIEW(r) file, that runs on the computer. The user accesses the UI via the Internet and, therefore, can operate the physical plant (item 5, Figure 5). The last element in the architecture is the physical plant. In the scheme, the plant refers not only to the renewable-based device but also all the necessary elements for the experiment automation. A proper control and monitoring system is key, gathering the functions of operating the plant, monitoring its status, and exchanging data with the UI; that is, it is connected to the minicomputer. A detailed description of the remote laboratory implementation is given in Section 3.2. As authors have commented, the proposed educational model and the intended EU collaborative network are built over a common basis: a renewable-based residential microgrid. Institutions have selected different remote laboratories related to different renewable energy sources to be part of the residential microgrid. As an example, this paper describes the remote laboratory developed by the University of Huelva. The ICT and infrastructure are replicated by the rest of the entities.