**2. Methods**

The goals of this research project are as follows: (i) To compare the environmental impacts of the university in relation to the impacts of the city in which the university is located; (ii) to analyse the difference between scenarios simulated using the assessment tool and actual monitoring data to rapidly validate refurbishment scenarios; and (iii) to establish a scenario of joint reform between the university and the city in response to the city's environmental improvement plan to comply with international environmental commitments.

#### *2.1. Study Case: The University Campus and the City*

As discussed above, the aim of the project is to analyse the potential of the university to establish synergies with the city to meet environmental sustainability commitments at the international level, that is, the new Global Covenant of Mayors for Climate and Energy that was signed by the city of Donostia-San Sebastián in 2017. After separately evaluating the environmental impacts for the city and the university, a scenario for sustainable reform is proposed based on a joint plan, specific to the city, called the Sustainable Energy Action Plan (SEAP) of Donostia-San Sebastián. The environmental impacts for University of the Basque Country UPV/EHU are obtained by modelling and analysis of the Donostia-San Sebastián campus. The city of Donostia-San Sebastián is studied considering the main districts in relation to municipal plans and its pacts for sustainability at the international level. A 3D model of the university campus and the districts of the city is used to evaluate the environmental impact of the "building" and "transport" sectors, which have the most significant impacts. The "industry" and "waste" sectors are not considered. The industry that was located in what is now considered the centre of the Donostia-San Sebastián moved to the periphery and other places in the province in the 1980s and was replaced by the university campus, which did not maintain the industrial character. In terms of university waste management, di fferent faculties have specific plans for the selective collection of waste (paper-cardboard, plastic-packaging, organic, batteries, toner, pens, computers, etc.), and the quantity of waste collected is monitored; however, there is no directive common to the entire university. In addition, in the comparison with the city there is a di fference of criteria in the selection of conflicting waste to be monitored. The university and the city have di fferent main activities: For example, the municipality is focused on reducing waste, such as baby diapers, whereas the university has begun to realise the significance of the impact of computers that have become obsolete increasingly quickly.

In summary, 3D modelling of the university campus and the main districts of the city is performed using the NEST tool to determine baseline scenarios of energy assessment. These results are compared with actual consumption to evaluate the accuracy of the simulation method relative to monitoring. Then, NEST is used to simulate scenarios of joint and interrelated energy improvement for both the university and the city and to analyse the feasibility of meeting the proposed goal of compliance with the Global Covenant of Mayors for Climate and Energy. To describe the characteristics and dimensions of the case study, we briefly present the two elements in the comparative analysis of the di fferent phases of the proposed method.

#### 2.1.1. City of Donostia-San Sebastián

The city of Donostia-San Sebastián can be mainly characterised by an approximate area of 60.89 km<sup>2</sup> and a population of 186,665 (year 2018) (Figure 1). According to the Köppen climate classification [39], the climate of Donostia-San Sebastián is an oceanic climate (Cfb), which is a climate with cool summers and cool (but not cold) winters and with a relatively narrow annual temperature range.

**Figure 1.** Aerial image of the city of Donostia-San Sebastián. The University campus is represented to the northwest of the city. Source: Google Earth.

Donostia-San Sebastián has been consistently committed to climate change over the past 20 years. The city has made the following significant commitments, among others: The Carta de Aalborg (Aalborg Letter) (1998); the First Local Plan to Combat Climate Change 2008–2013 (2008); the Safe and Sustainable Mobility Plan 2008–2024 (2008); a municipal ordinance on energy efficiency in buildings (2009); signature of the Covenant of Mayors (2011); Sustainable Energy Action Plan (2011); the environmental strategy Hiri Berdea 2030 (2014); Mayors for Adaptation to Climate Change (2014); a Plan of Action III of Local Agenda 21 2015–2022 (2015); the Adaptation to Climate Change Plan (2017); Plan de Accion Clima 2050 DSS (2017); and adherence to the new Global Covenant of Mayors for Climate and Energy (2017).

#### 2.1.2. Campus of the University of the Basque Country in Donostia-San Sebastián

The University of the Basque Country is located in the three provinces of the autonomous community: Gipuzkoa (1997 km2), Bizkaia (2217 km2), and Álava (3030 km2) [38]. The major university campuses are located in the three provincial capitals, Donostia-San Sebastián, Bilbao, and Vitoria-Gasteiz. The chosen campus for this study is the campus located in Donostia-San Sebastián (Figure 2), which will be evaluated and compared with the city that contains it.

The university campus in Donostia-San Sebastián can be considered to be an urban campus. The various faculties are located amidst pleasant green areas on a total area of 170,000 m<sup>2</sup> (Figure 1; Figure 3). The different university faculties and schools were originally scattered around different parts of the city, until Donostia-San Sebastián urban planning created a common campus for the development of new faculties and obtaining university degrees. Approximately 25% of the students of the entire university pursue higher education and the administration and services staff (PAS) and teaching and research lecturers (PDI) are located on this campus. This area is located northwest of the city and is crossed by an urban avenue with broad tracts of trees that allow access and exit of vehicles between the city and other towns in the province. There is a well-maintained public transportation network of trains and buses, as well as a network of cycling roads that connect practically the entire city.

**Figure 2.** Location of the Basque Country and the city of Donostia-San Sebastián.

**Figure 3.** The different university buildings studied on the Donostia-San Sebastián campus (information about each building is provided in Appendix A).

The sample used in the study consists of higher education institutions (faculties) and other buildings that are necessary for the teaching, research, or managemen<sup>t</sup> dynamics of the university (Figure 3). The faculties include the School of Engineering of Gipuzkoa; the Faculty of Economics and Business; the School of Education; Philosophy and Anthropology; the School of Computing; the School of Psychology; the School of Chemistry; the Technical School of Architecture; the Faculty of Law and the School of Education. Buildings with other uses are the Carlos Santamaria Centre (the central campus library), the Joxe Mari Korta Centre (RDI), the Ignacio Ma Barriola Centre (which contains the campus lecture hall consisting of 32 classrooms, rooms with other uses, an auditorium, and houses the majority of campus services); the Villa Julianategui (Campus Vice-Rectorship) and the most recent building, the Polyvalent Training and Innovation Centre (Centro Elbira Zipitria Zentroa). The aforementioned buildings are modelled using the NEST tool. To clearly investigate the area, private residential buildings adjoining the campus of Donostia-San Sebastián are also modelled.

#### *2.2. Assessment Tool: NEST*

NEST is a tool for the environmental, economic, and social analyses of an urban space and uses the Trimble SketchUp 3D modelling software; one of the most commonly used 3D graphic design programmes by designers and urban planners. NEST can be used to directly analyse a digital 3D model of a part of a city of interest. The tool is used to evaluate a series of indicators that have been developed on a scientific basis.

One of the grea<sup>t</sup> virtues of NEST is its graphical interface, which is very ergonomic because data can be simply entered into the geometric model to perform an easy, rapid, and e ffective analysis of real scenarios and proposed scenarios that are theoretically more sustainable. NEST takes into account four main elements of urban planning: (1) Buildings, (2) land use (roads, parking lots, green spaces, etc.), (3) infrastructure (street lighting), and (4) the mobility of the users of the urban space under study. NEST data can be entered or extracted in four di fferent ways: (i) Manually (MA), (ii) manually through the NEST drop-down menu (MN), (iii) automatically by NEST (A), and (iv) imported using the software program Integrated Environmental Solutions (IES) [40]. Oregi et al. [29], and also, Leon et al. describe the assessment process, indicators, assessment scope, and hypothesis considered by NEST [38].

#### *2.3. Scenarios and Strategies*

To determine the improvement produced by a more sustainable university campus in conjunction with the environmental proposals in the strategic plan of the city, a baseline scenario or the prior-current situation must be analysed. Data for both the campus and the city can then be used to propose a refurbishment scenario to comply with the Covenant of Mayors guidelines at the international level (Figure 4).

**Figure 4.** Scheme of the di fferent scenarios analysed.
