1. Introduction
Agrivoltaics is an emerging field of critical importance to ensure an appropriate energy transition, since it addresses head-on the potential conflict in the use of agricultural land for renewable energy sources related applications. The awareness of the critical importance of agrivoltaics in the energy transition is gaining momentum worldwide. This momentum reflects in all aspects of agrivoltaics activities from commercial applications to technology demonstration projects, and to applied and basic research. The urgency to address the climate crisis makes it imperative to accelerate the pace of innovation and technological development. The time it takes from an innovative idea to go from a research concept to a technical product must be reduced. One good recipe to accelerate innovation is to accelerate the diffusion of ideas and to elicit international collaborations among researchers and innovators which are pursuing ideas which are closely related or complementary. To contribute to this, a bibliometric system is being developed, which long term goal is to continuously assist the international agrivoltaics research community in assessing the status of agrivoltaics research worldwide; understanding how the community itself is structured in research groups and communities of research groups; and understanding how these groups and communities of groups are related and are interacting among them. This bibliometric system is based on the use, adaptation, and development of Free Open Source Software (FOSS) and available open access resources. Its development is open to contributions from anyone interested.
2. Approach and system architecture
The approach being used in the development of the bibliometric system follows a typical open source software development approach, in which a prototype of the system is rapidly deployed and then, based on the feedback from users and developers, it is improved or expanded in a continuous basis, through short development cycles. Instead of a monolithic application, the bibliometrics system is being built as an ecosystem of tools composed, as much as possible, of already available tools and components. The emphasis is on the integration of the tools to achieve specific functionalities and on the increased automatization of the overall system. The key components of the system are: (1) The data sources, (2) the database, (3) the data-adaptation tools, and (4) the data analyses tools. The set of bibliographical references is the critical data source. The representativeness of this set in relation to the evolution and status of agrivoltaics research is of paramount importance. The other data sources are ancillary sources used either to improve the information provided in a bibliographical reference or to add information related to it. The database is a standard relational database. Most of the data-adaptation tools are Python scripts, while the data analysis tools are based on different technologies.
3. Status, preliminary results and roadmap
The status of the FOSS-based bibliometric system is as follows: The core set of bibliographical references was obtained using an approach useful to periodically update it. The core structure of the relational database
established, and the database defined and implemented. Key data-adaptation tools to transfer the information from the bibliographical dataset, exported as a RIS file, to the relational database was developed and used to populate the database. Key available open source data-analysis tools identified and applied to analyze the data set. A series of Mathematica notebooks was developed to provide additional analyses of the dataset and as preliminary versions of the data-analysis tools to be developed in Python as fully open source tools.
The core set of bibliographical references contains a total of 410 references, from 1982 to 2023, since some of the references it includes are scheduled to be part of journal volumes to be published next year. The set is a closed set of references in the sense that, for any article in the set, the references in that article to any other relevant agrivoltaics articles are to be found within the set itself, with very few exceptions, such as references to articles in Japanese or other exotic languages, references to urban rooftops, and references to low-tech grain driers. To build the closed set, the titles and abstracts of more than 7,000 documents were reviewed, following an iterative process consisting in exploring the references and citations of each document added to the set, identifying those that classify as agrivoltaics references and integrating them into the next iteration of the set. It took seven iterations to reach the closed set. In terms of references, the documents in the set contain a total of 15,351 references, associated to 8,641 unique documents. In terms of citations, the documents in the set have been cited 9,341 times so far, from a total of 3,919 documents.
Many different bibliographical analyses have been carried out, such as: (a) Frequency analyses to understand the main terms and concepts considered in the published articles, to identify the most prolific agrivoltaics authors; or to determine distribution of number of authors per article; (b) networks analyses to identify relations between technical concepts; community of authors; and relations among community of authors; and (c) time domain analysis to understand the evolution of key indicators and the evolution of the research networks and communities. As an example, Fig. 1 shows the distribution of number of publications per article, as well as a high level view of the network of the communities of authors.
In total 410 peer-reviewed agrivoltaics articles were identified. The analyses carried out on this set of articles, which will be presented in the full article, show that these articles were authored by 1,292 researchers, which are structured into 186 communities, ranging from 1 to 32 authors, with an average community size of 5 authors. The maximum number of articles per author is 15, with most authors (1,022) having published only one agrivoltaics article. These preliminary results show that agrivoltaics is clearly an emerging field of research, which is gaining momentum fast, and represents a huge opportunity to make a difference. The next steps will be to increase the automation of the developed FOSS-based bibliometric system, make its results available to the international research community via a specialized website, and establish the endeavor as a full-fledge open source project open to the contribution of anyone interested
