**6. Conclusions**

Energy efficiency has been one of the basic managemen<sup>t</sup> strategies in the UAH up until 2018. This has meant that, at present, the UAH is a world leader in Energy and Climate Change, according to the 2019 edition of the Green Metrics ranking.

There are two key elements to achieving this sustained result over time: first, the actions of the UAH managemen<sup>t</sup> team, and, second, the public–private collaboration considering different stakeholders.

The energy savings and efficiency actions include the creation of the EcoCampus office to raise awareness of energy saving among the university community, the introduction of environmental criteria in public tender procedures (green contracting), the energy audits of all buildings and the efficient rehabilitation works, the implementation of initiatives in lighting systems and in information systems, the installation of thermostatic valves in radiators, and solar shield panels, and the increase of its renewable energy pool by means of thermal solar technology for ACS, the use of plant waste as biomass, the use of alternative energies for pumping.

They have allowed the University's energy consumption first to fall and then to be maintained, thereby contributing to meeting the objectives of the Spanish Government's Action Plan for Energy Saving and Efficiency (2011–2020) but with a worrying change of trend in recent years. The UAH's has managed to stabilize electricity consumption, and it has registered a downturn by 13.8% from 2006 until 2017. The electricity consumption per user and per m2 has fallen by 20% and by 37%, respectively, in the same period. In recent years, however, the efforts developed to increase its renewable energy pool seem to have run out of steam. The functioning of Learning and Research Resource Centre, an 11,000 m<sup>2</sup> heritage building, open 24 hours a day, 7 days a week and the regulatory barriers to operate the Trigeneration Plant and its technological obsolescence are the main factors explain that negative trend. Its required investment policies that are conditioned by budgetary restrictions or by new public–private partnership actions, which allow investment in efficiency by paying with the savings generated in future years.

Regarding the UAH's footprint, the available data show that in 2010 the UAH was already in a position to consider itself a low-carbon organization, meeting even then the objectives fixed for reduction by 2040. Currently, the UAH is continuing to work on updating its carbon footprint for the period 2015–2018. However, its commitment to directly reducing the emissions due to electricity usage (100 percent of renewable sources) or the compensation policies for emissions, as in the case of gas (all gas consumed is compensated) has enabled UAH to reach the 2050 targets already, with reductions above 80% in 2008–2011 and additional reductions of 25% in 2012–2014.

On the other hand, the public–private partnership signed in 2014 made it possible to mobilize very substantial financial resources of the order of EUR 7 million.

It allowed the remodeling of obsolete installations (lighting, computer servers) by introducing the latest available technologies and contributing to a managemen<sup>t</sup> scheme in accordance with international certifications ISO 14,000 and ISO 50,000. However, e fforts need to be redoubled and public–private collaboration maintained. Legislative changes and changes in University governmen<sup>t</sup> teams have not contributed in recent years.

The UAH's energy saving actions findings from a thorough document analysis and the energy efficiency indicators are in the line of other similar studies as for example those referred to University of Coimbra [21], UK higher education institutions [4], Canadian post-secondary institutes [24] or in the case of a Malaysian public university [25]. In some of these studies a set of di fficulties to analyze the impacts of energy e fficiency intervention on HEIs are highlighted including lack of methodology, ambiguity with respect to energy consumption indicators, problems in establishing assessment boundaries, lack of clear targets for carbon reductions within the HEIs, among others.

The case analyzed of the UAH's energy e fficiency has been guide by the Spanish Government's Action Plan for Energy Saving and E fficiency (2011–2020) to o ffer an objective analysis. However, carrying out a survey among the responsible of the energy e fficiency program in the UAH could have given more understanding about the e fficacy of internal programs carried out, the limitations faced, and the need to develop future actions as sectorization strategies of energy consumption and the modernization of infrastructures to introduce sensing mechanisms. The knowledge of the users' behavior is also key to undertake saving policies aimed at reducing further the consumption of all energy sources. The use of data and centralized managemen<sup>t</sup> will allow, in the future, for advancing in this direction. For this reason, a survey among the academic community could give a more accurate comprehension about their patterns of energy-environmental behaviors and take action to raise awareness of energy e fficiency in the campus.

Historically, the UAH has shown that a Sustainability Strategy not only corresponds to its basic Social Responsibility Policies, but that it is a profitable option, stabilizing consumptions and seeking, with industry, the most sustainable options in the market.

E fficiency actions in World Heritage buildings is a challenge for the future. The will of both university managemen<sup>t</sup> and public authorities (archaeological and construction regulations) is necessary to provide these facilities with the most e fficient technologies.

For example, geothermal energy installation on the scientific campus has proven to be an excellent solution for energy saving. This can be done on the historic campus but requires a shared vision from all stakeholders: University managers (General, Construction O fficer, and Contracts O fficer); local services and authorities that oversee the protection of Heritage.

Although the results cannot be generalized due to the limitations of the methodology used, the findings show that internal and external strategies including searching for alliances are essential elements to improving the contribution of the University to the fulfillment of the Sustainable Development Goals, not only because of its direct actions but also because of the multiplying effect that the University has as an agen<sup>t</sup> of social change.

**Author Contributions:** R.G.-Y. served as general manager of UAH during 2010–2018 contributed data collection, method, data analysis as well as discussion and conclusion. M.-T.G.-R. wrote introduction, background, case description as well as discussion and conclusion. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding. **Conflicts of Interest:** The authors declare no conflict of interest.
