An evaluation model for smart grids in support of smart cities based on the Hierarchy of Needs Theory

Hongyu Lin,Yajun Zou,Hongyi Chen

1.School of Management,Harbin Institute of Technology,Harbin 150000,P.R.China

2.Global Energy Interconnection Development and Cooperation Organization,Beijing 100031,P.R.China

3.Mechanical and Industrial Engineering Department,University of Minnesota,Duluth MN,55812,USA

Abstract: Smart cities depend highly on an intelligent electrical networks to provide a reliable,safe,and clean power supplies.A smart grid achieves such aforementioned power supply by ensuring resilient energy delivery,which presents opportunities to improve the cost-effectiveness of power supply and minimize environmental impacts.A systematic evaluation of the comprehensive benefits brought by smart grid to smart cities can provide necessary theoretical fundamentals for urban planning and construction towards a sustainable energy future.However,most of the present methods of assessing smart cities do not fully take into account the benefits expected from the smart grid.To comprehensively evaluate the development levels of smart cities while revealing the supporting roles of smart grids,this article proposes a model of smart city development needs from the perspective of residents’ needs based on Maslow’s Hierarchy of Needs theory,which serves the primary purpose of building a smart city.By classifying and reintegrating the needs,an evaluation index system of smart grids supporting smart cities was further constructed.A case analysis concluded that smart grids,as an essential foundation and objective requirement for smart cities,are important in promoting scientific urban management,intelligent infrastructure,refined public services,efficient energy utilization,and industrial development and modernization.Further optimization suggestions were given to the city analyzed in the case include strengthening urban management and infrastructure constructions,such as electric vehicle charging facilities and wireless coverage.

Keywords: Smart city; Smart grid; Evaluation index system; Hierarchy of needs; Benefits of smart grid

0 Introduction

Since the concept of smart cities was proposed in 2009,research on smart cities has developed rapidly worldwide from the concept to the planning and construction stages [1].According to IBM,smart cities are those advanced cities supported by a new information technology generation that integrates various urban systems into a whole to optimize resource utilization.As the primary resource,electrical energy is critical in the process of city development.It is an essential foundation for smart cities [2].A smart grid,defined as an integration of the Information Communication Technology (ICT),Internet of Things (IoT) technologies,sensors,along with technologies with generating,transmitting,and distributing grids,are essential for ensuring the resilient delivery of energy in smart cities to realize energy conservation,improve efficiency and enable the coordination between infrastructure operators and the public [3].

The last decade has seen a rapid increase in the studies conducted on the evaluation methods for smart cities[4-6].A thorough discussion of benefits expected from smart grids towards smart cities can serve as a precondition for reducing uncertainties and avoiding incentivize investments.However,the existing evaluation index systems cannot fully reflect the supporting role of the smart grid as an energy carrier for smart cities.The established index systems also fail to focus on the true needs of urban residents.In this study,a model of city development needs based on Maslow's Hierarchy of Needs theory is proposed to analyze the specific support of smart grids for smart cities.An example is presented to illustrate the use of the model using a city in China as a case.The proposed evaluation method is expected to quantify the comprehensive benefits generated by smart grids that are needed to practically guide the development of smart grids in the future.

1 The benefits of smart grids in the development of smart cities

Smart cities provide a variety of services such as smart energy management (i.e.solar,wind,hydroelectric energy),smart home and buildings,green transportation,energy saving,safety and security,commercial activities,healthcare,etc.In order to manage all these tasks,smart grids with the involvement of ICT,IoT,sensors,and smart meters will make way for a truly sustainable smart city with a variety of requirements (see Fig.1).

Fig.1 Smart grids in supporting the development of smart cities

The benefits of developing smart grids in smart cities have been recognized globally.Smart grids empower a future smart city by main features listed below [2]:1) The benefits of smart grids start with modernizing power systems in smart cities by means of real-time monitoring,automation and self-controlling functionalities.As a result,a more reliable and sustainable energy supply will drive the transformation of urban settings,such as smart buildings and smart houses.2) Environmental benefits can be also expected from smart grids.The smart grid provides the capacity of managing vastly distributed generation,enabling large integration of distributed renewable energy resources (RES) and the electrification of transport,which will minimize the carbon emissions in the power sector.3) Significant economic benefits will be offered given that smart grids can reduce costs for providers and consumers,by enabling the interconnection of demand response services,responsive distributed generation for further steering of the end customers’ response.In addition,smart grids will enable almost real-time participation of consumers in the electricity market which will facilitate the development of new products and services.4) The incorporation of smart grids will improve social service friendliness through intelligent electricity management and two-way interactive service platforms,which is a crucial component in building smart cities.

Thus,smart grids can have a positive function in the setting up of smart cities by serving as the backbone for the combination of techniques,markets,financial streams,and services.Further benefits can considered in more adequate quantitative or qualitative metrics,as discussed in the sections below.

2 Current status of smart grid enabled smart cities

The report “Super Smart City: Happier Society with Higher Quality” released by Deloitte shows that over 1000 smart cities have been being launched or under construction globally since 2019.China alone has 500 smart cities under construction,far surpassing the second-ranked Europe (around 90 smart cities) [7].The construction of smart cities involves various aspects of public services such as electricity,transportation,and healthcare,among which electricity is most basic requirement of any smart city construction [8].In order to promote the construction of smart cities,relevant explorations have been conducted internationally on the integration of smart grids and smart cities [9-11],as listed in Table 1.

Table 1 Practices of smart cities supported by smart grids

Overall,due to the significantly different domestic conditions,the primary focus in the design and construction of smart cities varies from country to country.Smart cities in countries and regions such as Europe,North America,and Japan focus more on building intelligence,and emphasize the maximum utilization of the building environment and the effective management of resources.The construction of smart cities in China emphasizes the integrated application of computer,information,and communication technologies in buildings to automatically monitor equipment,manage information resources,and optimize service to create a comfortable,convenient,efficient,safe,and intelligent living environment.While the smart city construction in China has achieved remarkable results,there exist issues that should be addressed: 1) The top-level design of smart cities needs to be strengthened to guide overall planning and design; 2) The lack of cross-department collaboration and data integration is common; 3) The development levels of smartness in urban and rural regions are unbalanced,etc.

3 Current evaluation methods of smart cities

With the rapid development of smart cities,many scholars,developed and used different ranking methods to evaluate the smartness of smart cities [2-5,12].In 2008,AT Kearney proposed one of the oldest smart city indexes,namely the Global Cities Index (GCI) [13].The GCI measures 29 indicators under five criteria,including(a) business activity,(b) human capital,(c) information exchange,(d) cultural experience,and (d) political engagement.More recently,the International Institute for Management Development (IMD) introduced a smart city index (I-SCI) to evaluate the economic,technological and humane aspects of smart cities [14].This index first categorizes cities into four groups according to the Human Development Index (HDI) scores provided by the United Nations.Cities within each group are rated based on residents’ perceptions of over five key criteria: (a) health and safety,(b) mobility,(c) activities,(d) opportunities,and(e) governance.For the year 2023,the I-SCI ranked 141 cities globally,and the top three places were Zurich,Oslo and Canberra.Beijing has seen a remarkable improvement,from ranking 30th in 2019 to 12th in 2023.

From the perspective of a calculation methodology,conventional subjective assignment methods,such as a combination of the Analytic Hierarchy Process (AHP) and Delphi [15],were commonly used.Such approaches can effectively utilize expert resources and experience,and qualitative and quantitative factors can be both considered.In addition,indicator systems that do not include evaluation criteria often use objective assignment methods,such as gray relation analysis (GRA),principal component analysis(PCA),the technique for order preference by similarity to an ideal solution (TOPSIS),and fuzzy comprehensive evaluation (FCE) [16-20],mainly to assign weights and exclude the influence of closely related indicators.

The above discussion shows that various smart city evaluation index systems have been investigated.Current research on smart city evaluation mainly focuses on the dimensions and indicators of assessment schemes,and the guidelines for the structural features of the assessment tools have evolved over the past ten years [21,22].Recently,an important research theme addressed in existing research is the implementation aspects of smart city assessments and the impact of technologies on a city’s development [23,24].With regard to the smart grids,a fundamental component for smart cities,limited research has been found on the quantitative assessment of their benefits.Moreover,many evaluation indexes focus on urban intellectual technologies but lack sufficient consideration of the needs of residents.In fact,the development of smart cities should meet the needs of residents as the premise,which is the true purpose of building a smart city.In view of the problems existing in the current assessment methods of smart cities,Therefore,this study attempts to fill this research gap by establishing an evaluation index system of smart cities enabled by smart grids based on hierarchy of needs theory,in order to provide a data basis for the decision making and the transition toward smart cities.

4 Developing the evaluation model based on hierarchy of needs

4.1 The BSICS model

Maslow’s hierarchy of needs theory divides human needs into five levels: physiological,security,social,selfrespect,and self-realization needs.Maslow’s hierarchy of needs model (PSSRR) is expressed as follows:

whereAexpresses individual needs,andAiandρi(i=1,2,3,4,5) represent the individual’s physiological,safety,social,self-respect,and self-realization needs and their weights,respectively.ρivaries with individuals,0≤ρi≤1,and

The needs corresponding to these five different aspects range from low to high,gradually increasing according to the level.Once after the lower-level needs are satisfied,people move to higher-level needs.Maslow’s hierarchy of needs theory conforms to the general law of the human need development and also applies to the city development hierarchy of needs.In other words,the hierarchy of needs in city development progress from low to high levels depend on the city function and stage of development.

By combining PSSRR theory,this study analyzes the different characteristics of city development needs and proposes the city development hierarchy of needs theory,also known as BSICS.BSICS also includes five levels:basic needs for survival,such as food,clothing,housing and transportation,safeguard needs relating to people’s physical health,knowledge acquisition,and social security and employment; interactive needs relating to interaction and growth between different individuals,and enterprises and cities; characteristic needs that differentiate and personalize city development to provide soft power; and sustainable needs for achieving the ultimate goals of city development,such as economic development and sustainable ecological environment.The corresponding relationship between the BSICS theory and PSSRR models is shown in Fig.2.

Fig.2 Theory of city development hierarchy of needs

Using the PSSRR model,the city development hierarchy of the needs (BSICS) model can be expressed as:

whereBexpresses the needs of city development,Biandεi(i=1,2,3,4,5) denotes the basic,security,interaction,characteristic and sustainable needs of city development and their weights,respectively,Bij(i=1,2,3,4,5;j=1,2,3)means thejth specific connotation of the need corresponding toith level of need,andYn(n=1,22,...,49) represents the specific needs derived from the five-level needs.According to the theory of city development hierarchy of needs,only when basic needs are met,city development move will toward a higher level of demand; therefore,εiis positively related to the importance of this level of need.The corresponding relationships between city needs and their connotations are presented in Table 2.A three-level index system was constructed,in order to take into full consideration all the aspects that are necessary in the smart city development,which is an extension and improvement of the model in [25],where a two-level index system based on hierarchy of needs was proposed.

Table 2 Correspondence table of the city development hierarchy need model

4.2 Indexation of city development hierarchy of needs

The needs of a smart city are indexed to facilitate the calculation and comparison of the degree of needs satisfaction of different city developments.To highlight the difference in importance given by city development to each level of need and by referring to the idea that social development usually changes with an exponential law or an approximate exponential law,an index model of the city development hierarchy of needs is constructed,and a decreasing factor of need importanceρ(0 ≤ρ≤ 1) is introduced.SupposeB→bexpresses the mapping space from city development needs to the degree of satisfaction of city development needs.Then,the model of the degree of satisfaction of city development needs can be expressed as:

Then,the city development hierarchy of needs are as follows:

The corresponding relationship of the weight of each level of needεi(i=1,2,3,4,5) and the decreasing importance factorλis as follows:

i.e.when 0 ≤ρ≤ 1,the weight of each level of need is as follows: 0 ≤ε5≤ε4≤ε3≤ε2≤ε1≤ 1.

5 Evaluation index system for smart gridenabled smart cities

5.1 Evaluation index system design

Based on the above BSICS model and the essential characteristics of smart cities,which include scientific city management,intelligent infrastructure,refined public services,efficient energy utilization,and modern industrial development,the specific needs of city development including 49 need indexes are classified and integrated according to the supporting roles of smart grids,and the evaluation index system of smart grids supporting smart cities was obtained,involving 5 first-level indicators (city management,infrastructure,public services,energy and environmental protection,industrial economy),13 secondlevel indicators and 49 third-level indicators.Among them,the three-level indicators were set asyn(n=1,2,…,49)corresponding to the specific needs of city developmentYn(n=1,2,...,49),as shown in the Table 3.

Table 3 Evaluation index system of smart grid supporting smart cities

5.2 Indicator weight calculation

This study determines the corresponding three-level indicator weights of smart cities according to the weights of each level of needs in the above-mentioned city development need satisfaction model,that is,the weight of the specific need satisfaction degree in the city development need satisfaction modelbi(i=1,2,3,4,5) is used as the weight of the corresponding three-level index in the above evaluation index system (Yn,wheren=1,2,...,49).Here,we setρ=0.8; then,the corresponding weights of the five levels of needεi(i=1,2,3,4,5) are 0.297,0.238,0.191,0.152,and 0.122,respectively.

As the index weights determined according to the model of the city development hierarchy of needs are entirely determined according to the relationship between the data,itmay not conform to the actual situation in some cases,and the weights determined by experts are obtained from actual experience.Therefore,this paper adopts a combination of methods to determine the comprehensive weight of indicators.Ifε′irepresents the subjective weight,εiindicates the objective weight (that is,the above weight),and the comprehensive weightε′i′can be expressed as:

where 0 ≤α≤ 1 indicates the proportion of subjective weight in the comprehensive weight.Based on the actual situation,this study takesα=0.5.To ensure the weights of the three-level indicators of the smart city sum up to 1,this paper normalizes the weights of the three-level indicators,i.e.,the weights of the three-level indicators of the smart city=weight of corresponding level of needs of this indicator/number of three-level indicators of corresponding need level

The results of the three-level indicator weights are presented in Table 4.

Table 4 Weight calculation table of the three-level indicators of smart cities based on the needs of various levels of city development

6 Case study of evaluating smart gridenabled smart city development

A pilot city for smart grid construction in China was taken as an example,and the index evaluation system was used to measure the city’s smart city construction level and the supporting role of the smart grid.Because the dimensions and types of each evaluation index are different,the index value and comprehensive score were dimensionless and normalized to facilitate calculation and comparison.

First,the index scores were dimensionless.This study referred to Paul A.Samuelson’s happiness equation,that is,happiness=utility/desire,to perform dimensionless processing on the indicators: The value of the dimensionless of the three-level indicators=Actual value of the index/Expected value of the index.

Second,the scores of the five first-level indicators and the overall score of the smart city were normalized as followes: score of index=sum of the weighted value of the corresponding three-level indicator of this indicator/sum of the weight of corresponding three-level indicator of this indicator.

The support provided by smart grids to smart cities was quantified: the proportion of smart cities supported by smart grids=sum of the weight of the three-level indicator supported by the smart grids/sum of the weight of the corresponding three-level indicator.

The values and weights of the city’s three-level indicators and the scoring results of the first-level indicators are listed in Tables 5-9.The total score for each first-level indicator was one point.The actual score of the five firstlevel indicators can be used to measure its corresponding construction situation or development level; for example,0 ≤ Score ≤ 0.4,which means that the indicator is at a low level; 0.4 ＜ Score ≤ 0.8,which means that the indicator is at a medium level; and 0.8 ＜ Score ≤ 1,which means that the indicator is at a reasonable level.The three-level indicators marked with★are indicators for smart grids to support smart cities.

From Table 5,it can be observed that the city’s construction level in city management were average.The proportion of smart grids supporting smart cities accounted for 75%,primarily through the following two aspects to promote scientific city management: First,the city nervous system was built through the 95598 power supply service center,a two-way interactive service platform of the power fiber-to-the-home,and an intelligent power consumption interactive terminal,etc.Second,the smart grid can realize high-speed transmission of various types of information while delivering electrical energy to the city.Power information transmission networks that support the transmission lines can also become critical neural networks for urban informatization.

Table 5 Smart grid supports urban management

Table 6 shows that the city’s infrastructure construction level is average.The proportion of smart grids supporting smart cities accounted for 61.24%,mainly through the following two aspects to promote the intelligentization of infrastructure: First,fiber-to-the-home for smart grid construction extends urban nerve endings.Not only can it meet the requirements of smart grid informatization,automation and interaction,but it can also effectively carry telecommunication networks,radio and television networks,and internet signals,integrates the three networks,and improve the foundation of urban network; second,with the construction of smart grid,electric automobile charging and swapping facilities scale-up,and become interconnected.The efficient interaction between electric vehicles and the power grid will be fully applied,facilitating the entry of electric vehicles into the urban space.

Table 6 Smart grid supporting infrastructure

As shown in Table 7,the city had a moderate level of public service construction.The proportion of smart grids supporting smart cities accounted for 51.65%,which mainly promoted the refinement of public services through thefollowing two aspects: first,it allows electricity consumption information collection,energy efficiency management and other means to achieve user-side two-way interaction of energy efficiency intelligent management and service,and the establishment of community forums by connecting with the municipal management system,allowing the public participate in community management and government opinion polls directly; second,the construction of smart grids covers clean energy,electric vehicles,smart communities/buildings,power communications,and other fields,providing a large number of jobs in these fields.According to estimates,an investment of 25 billion yuan in grid intelligence will create approximately 370,000 jobs.

Table 7 Smart grid supports public services

The scores in Table 8 show that the city’s construction level in terms of energy and environmental protection was excellent.The proportion of smart grids supporting smart cities accounted for 60.32%,mainly through the following four aspects to promote the efficient use of energy: first,by constructing robust,reasonable and scientific urban grid grids to make the urban power supply safer and more reliable; second,to realize long-distance clean energy utilization,the use of distributed clean energy is made more convenient; and third,advanced smart grid technology allows users to achieve energy conservation through interactive methods and enables urban energy conservation and emission reduction.Fourth,the smart grid promotes the development of electric vehicles through the construction of charging stations and charging piles and allows urban green transportation to enter daily life.

The scores in Table 9 show that the construction level of the city’s industrial economy was above average.The proportion of smart grids supporting smart cities accounted for 85.72%,mainly promoting industrial development modernization through the following two aspects: First,in the smart grid construction process,power grid enterprises,related software and hardware equipment research and manufacturing enterprises,service suppliers,equipment integration enterprises,scientific research institutions,and universities will participate in the research and development,thereby optimizing and upgrading of traditional industries;Second,the demand for strong smart grid construction itself has a vast market effect.The huge market spaceprovides favorable conditions for the rise of smart grid related technical standards to international standards,such as electric vehicles and smart home appliances.Also,it creates conditions for smart grid-related industries to enter the international market,thereby driving the development of emerging industries.

These results indicate that the overall rating of the city was 0.637,signifying that the city’s level of intelligent development was above average.More efforts should be devoted to strengthening urban management and infrastructure construction in the future,such as smart distribution network technology,need to be continuously improved to achieve safer and more reliable access to distributed power sources and fiber-to-the-home (FTTH)technology to support intelligent power utilization more effectively.In addition,from the above indicator system,it can be seen that smart grids,as an essential foundation and objective need for smart cities,have played an important supporting role in the construction and development of smart cities in different aspects,levels,and dimensions.In the above example,the proportion of smart grid support for all three levels indicators in the city was 60.38%,indicating that the construction of smart grids can effectively support the development of smart cities.

7 Conclusions

Based on Maslow’s hierarchy of needs theory,this study constructed a comprehensive evaluation index system for smart grids that enables smart cities.The model divides a smart city’s smartness into five dimensions: city management,infrastructure,public services,energy and environmental protection,and industrial economy according to the the needs of city development.The proposed system was applied to a smart city in China.Several conclusions were drawn: 1) Quantitative assessment showed that the case city had a moderate level of city’s infrastructure construction,and public service construction,while the construction level of industrial economy,intelligent development,energy and environmental protection is satisfied.The overall rating of the city was 0.638,signifying that the city’s level of intelligent development was above average.2) The evaluation results also revealed that among the actual supporting roles of smart grids in the development of smart cities,the promotion industrial economy accounted for the highest proportion of 85.71%,mainly by optimizing and upgrading of traditional industries,and creates conditions for smart grid-related industries to enter the international market.3) To overcome the deficiency in the smartness development of the case city,specific suggestions were given,including strengthening urban management and infrastructure construction,such as smart distribution network technology to make distributed power sources more accessible.

Declaration of Competing Interest

We declare that we have no conflict of interest.