Encyclopedia
Please note this is an old version of this entry, which may differ significantly from the current revision.
Subjects:
Energy & Fuels
Sustainable campus management includes energy-saving measures and waste reduction and has become an important objective to many universities, being part of the institution’s societal responsibility. Smart energy systems (SESs), as part of campus energy management, can bring many benefits, including increased efficiency, reduced energy consumption, reduced emissions, increased reliability, and real-time control, and facilitate the integration of the renewable energy systems (RES). Despite the growing interest in energy efficiency and for the initiatives and projects to implement SESs, there are no universally accepted standards for assessing the performance of SESs, with most techniques being dedicated to subsystems. A KPI (key performance indicator) framework for evaluating the SESs’ performance from university campuses is proposed, starting from the current findings and priorities from the scientific literature, energy standards, legislation, and university rankings. The framework can support the implementation, operation, and evaluation of the SESs from university campuses, based on SES requirements and the stakeholders’ goals. Unlike previously developed solutions, the framework is focused not only on the technical side of SESs but also on the role that education, research, and innovation should have in sustainable development, making universities key contributors to achieving these goals.
- smart energy system (SES)
- key performance indicators (KPI)
- sustainable university
1. Resources
Previous studies approaching SESs suggested that such systems should be based 100% on RESs: solar, wind, geothermal, biomass, hydro, hydrogen, waves, and tides [12,14,15].
However, of these types of energy, the solar energy [46,47,48] and wind energy [49,50,51,52] are mentioned most frequently in the category of the so-called fluctuating RESs.
Particular attention is given to the use of hydrogen [21,53,54,55], the integration of geothermal energy [56], or hybrid systems that use solar and geothermal energy [11,57].
Other studies suggested the need for power-to-gas to reduce the use of biomass to a sustainable level, using electrofuels [58,59,60,61]. Electrofuels are defined as fuels produced from electricity, water, and carbon or nitrogen, and are considered a useful option in all energy sectors to replace fossil fuels [16,62]. In 2014, Lund et al. described the process of obtaining electrofuels starting from the conversion of electricity through electrolysis into hydrogen. Subsequently, the produced hydrogen is used in two possible ways [13]:
-
in a process called hydrogenation which represents the stimulation of gasified or fermented biomass;
-
merged with CO2 emissions from such sources as energy or industrial facilities.
Depending on the chosen method of obtaining electrofuels, they are called bio-electrofuels or CO2-electrofuels [13].
2. Conversion
The flexibility of the SESs depends primarily on the conversion system, thus making the transition from simple approaches used today in energy systems, to interconnected approaches [8,14].
The main conversion systems found in the literature are as follows: photovoltaics [14,63,64,65]; solar panels [14,66,67,68]; solar plants [66,69]; wind turbine [70,71,72]; combined heat and power (CHP) [22,73,74,75]; heat pumps [66,76,77,78]; boilers [66,79,80]; and power plants [67].
There is a focus of the authors on fluctuating energy conversion systems, and almost every design of a SES involves photovoltaics [14,66] and wind turbines [64,81,82]. Less popular than photovoltaics, wind turbines are preferred in Nordic European countries such as Denmark (the leader in the implementation of these conversion systems). In 2020, wind turbines in Denmark supplied 50% of the final demand for electricity [83].
Lund et al. (2012) considered that heat pumps as well as additional heat storage capacities should be combined in SES together with cogeneration plants and operated in such a way that RES can be efficiently integrated, without losing the overall efficiency of the system [18].
Several studies showed that heat pumps represent the key conversion solution, connecting electrical and thermal sectors [14,84,85]. Buffa et al. (2018) considered that heat pumps should be integrated in low-temperature excess heat recovery installations [86]. Dincer and Acarac, (2017) emphasized that increasing the number of products from the same energy source will lead to a decrease in emissions per product unit and an increase in efficiency, referring to multigeneration systems such as the following [11]: cogeneration—heat and electricity production (CHP); trigeneration—heat, cooling, and electricity production (CCHP); and quadgeneration—heat, cooling, hydrogen, and electricity production (CCHP-H2).
3. Storage
Energy storage is another important element in assuring the flexibility of the SESs [12,87] permitting to integrate a higher share of fluctuating RES [12,18,19], and it facilitates the transition to 100% RES [14]. Several authors emphasized the need to use storage solutions for system reliability and flexibility [88,89]. Three main types of storage in the SES framework can be identified in the literature: electricity [21,52,66], thermal [10,72], and fuel [10,64,72].
Regarding electricity storage, the main storage systems identified in the literature are as follows: batteries [14,63,66,72] and electric vehicles (Evs) [4,79,90]. Some studies have shown that the electricity surplus should not be directly stored in the battery (off grid) [91], with other solutions being recommended: thermal storage by transforming electrical energy into thermal energy, storage in the heating networks, or chemical storage (hydrogen and methane) [92].
Electric energy storage systems are very expensive, especially because fluctuating RES require numerous conversion systems. The losses are very high, for example, electrical energy storage is approximately 100 times more expensive than thermal storage [14]. Thus, except for powering heat pumps, electric storage is not feasible to meet the flexible demands of consumers. Electricity storage systems should facilitate power saving or securing grid stability [76]. However, some authors indicated that electric vehicles offer the possibility of sources of electrical energy that can be programmed on demand, but also of storing the electrical energy itself that can later be reintroduced into the grid [93,94]. The solution of electric energy storage through EVs due to the flexibility advantages of the system they offer has become a topic increasingly researched by authors in recent years, and integrated in their models and scenarios [95,96,97,98].
Thermal storage is a much more efficient method of storage that involves lower costs compared to electrical storage [14,92]. The main thermal energy storage systems identified in the literature are as follows: water tank [21,64,67,90] and pit thermal energy storage [99,100,101].
4. Demand
In the case of a city, or, at a smaller scale, a university campus, there are three main types of useful energy demand [14,102]: electricity, thermal (heating and cooling), and fuel.
Lund et al. (2014) considered that the energy supply can be facilitated by using systems such as heat pumps and electric boilers [76]. Some authors believed that due to their high consumption and thermal inertia, buildings can ensure flexible demand [103].
Bačeković and Østergaard proposed a balance between demand, production, and storage [64], that should be updated, including the energy losses.
Regarding energy consumption in the building sector, one of the main concerns was related to the energy performance difference between the designed energy consumption of buildings and their actual operation consumption [25,27,28,104]. This difference is influenced by three factors: the performance of energy systems, the user behavior, and the insulation performance, especially in the case of buildings [105,106]. Numerous studies conducted in recent years have shown that one of the most influential factors affecting the energy consumption of buildings is the behavior of the occupants [31,107]. The difference between the estimated consumption when designing the building and the actual final consumption can be 200% higher [35], or even 300% higher [36], depending on user behavior. Electricity demand should be the main concern for energy conservation in universities, according to some authors who considered that the key factor involved in energy consumption is the cooling system [108]. Other authors emphasized the consumption of electricity for lighting; in this case, the estimated percentage of energy consumption varies between 20% [109] and 45% [110] of the building’s total energy consumption. In what concerns the educational institutions, classrooms are the biggest consumers of energy in terms of lighting, reaching up to 50% of the total building’s energy consumption [111].
5. SESs and Sustainable Universities
Sustainable campus management includes energy-saving measures, resource efficiency, and waste reduction, and has become important to many universities, and considered part of the institution’s societal responsibility [112].
The role of higher education in sustainable development has not always been very clear, because many institutions have not realized that integrating the Sustainable Development Goals (SDGs) [42] in their teaching and research programs could provide the opportunity to expand education for sustainable development [113], and, at the same time, it could serve as an important catalyst for student involvement [114].
Velazquez, Munguia, Platt, and Taddei (2006) proposed a model to assist universities to improve the effectiveness of their potential or current sustainability initiatives through the identification of strategies and opportunities for sustainability within universities. The model is based on four strategies delivered through a set of tailored initiatives: developing a sustainability vision for the university; the mission; a sustainability committee creating policies, targets, and objectives; and sustainability strategies [115].
Grecu (2012) showed also that a sustainable university should be based on six fundamental principles: leadership and vision, social network, participation, education and learning, research integration, and performance management [116].
Universities need to more closely assess the operation and management of the campus as well as the energy performance of buildings and their systems and facilities [117].
A university campus is very similar to a city, facing similar problems in general [118], from the problem of parking spaces to the energetics’ administrative problems such as electricity, hot water, or the gas grid. Most studies have focused on the concept of a smart city and less on smart universities [118]. However, both problems and solutions can be similar. Thus, thorough research should consider the SES whether it is a university building, an office building, or even a smart city.
6. KPI Framework for SESs in Sustainable Universities
Although many universities adopted sustainability-oriented policies and implemented SESs, there is a little evidence on how such systems are assessed for their performance and the results of these assessments.
Efkarpidis, et al. (2022) proposed a generic KPI framework for the evaluation of SESs installed in application areas of different scales. The framework is based on four main layers, which are required for the definition of the application area, the involved stakeholders, the SES requirements, and the stakeholders’ objectives, and the application area of each SES deployment is determined based on four levels of spatial aggregation varying from single buildings to communities, cities, or regions [45].
The only framework we could identify for university campuses was proposed by Saleh et al. (2015) for Malaysian universities to ensure sustainability, and consists of five clusters: top management support, comprehensive energy management team, stakeholders’ involvement, awareness, and risk management [119]. The framework is based on the Talloires Declaration ten-point action plan for incorporating sustainability and environmental literacy in teaching, research, operations, and outreach at colleges and universities [120].
The most relevant assessments of universities from the sustainability point of view come from ranking institutions who created in the last years specific indexes (for instance, QS World University Rankings: Sustainability, Times Higher Education—Impact Ranking), to show how universities are developing towards the UN Sustainable Development Goals [121], or how universities are taking actions to tackle the world’s most pressing environmental and social issues [122]. There are also rankings (Green Metrics, for instance) providing an overview of the sustainability policies [123], assessing the universities based on the environmental protection and ethical issues (People & Planet University League) [124], or highlighting the schools that have launched the most important initiatives to reduce campus waste and energy consumption, promote alternative modes of transport, fund environmentally friendly proposals from students and faculties, and take other measures for the benefit of the environment (Best Colleges) [125].
The KPI framework proposed in our study (Figure 3) is developed starting from the current findings and priorities from the scientific literature, energy standards, legislation, university rankings, and specialized websites.
Figure 3. KPI framework for SESs in sustainable universities.
The framework is based on a bottom-up approach and can support the implementation, operation, and evaluation of the SESs from university campuses, based on SES requirements and the stakeholders’ goals. Unlike previously developed solutions, our framework is focused not only on the technical side of SESs but also on the role that education, research, and innovation should have in sustainable development, making universities key contributors to achieving the goals. Universities should adopt policies for clean energy and on separating investments from carbon-intensive energy industries, and the progress toward this goal needs to be continuously evaluated based on relevant KPIs.
The KPIs were organized in 4 clusters (management and assessment, research and education, environmental impact and efficient operation, and SES components) and 10 categories, suggesting that the evaluation of the SES performance should be part of a holistic approach. The scoring for each indicator was adapted from the UI Green Metric and THE—impact ranking [121,123], and this can be adjusted based on the results of the evaluations and, respectively, on the new rankings (QS, for instance). The KPIs are discussed and presented below in Table 1, Table 2, Table 3 and Table 4.
This entry is adapted from the peer-reviewed paper 10.3390/en16031246
This entry is offline, you can click here to edit this entry!
