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Received August 15, 2020, accepted September 2, 2020, date of publication September 8, 2020, date of current version September 28, 2020. Digital Object Identifier 10.1109/ACCESS.2020.
The Penetration of Renewable and Sustainable
Energy in Asia: A State-of-the-Art Review
on Net-Metering
WAQAS UR REHMAN 1 , (Graduate Student Member, IEEE), ABDUL RAUF BHATTI 2 ,
AHMED BILAL AWAN 3 , INTISAR ALI SAJJAD 4 , (Member, IEEE), ASAD ALI KHAN^5 , (Graduate Student Member, IEEE), RUI BO^1 , (Senior Member, IEEE),
SHAIKH SAAQIB HAROON^4 , (Member, IEEE), SALMAN AMIN 4 , ISKANDER TLILI 6,7, AND OROGHENE OBOREH-SNAPPS^1 , (Graduate Student Member, IEEE) (^1) Department of Electrical and Computer Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA (^2) Department of Electrical Engineering, Government College University Faisalabad (GCUF), Faisalabad 38000, Pakistan (^3) Department of Electrical and Computer Engineering, College of Engineering and Information Technology, Ajman University, Ajman, United Arab Emirates (^4) Department of Electrical Engineering Department, University of Engineering and Technology Taxila, Taxila 47050, Pakistan (^5) Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA (^6) Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam (^7) Faculty of Civil Engineering, Duy Tan University, Da Nang 550000, Vietnam
Corresponding author: Iskander Tlili (iskandertlili@duytan.edu.vn)
ABSTRACT Conventional fossil-fuel energy resources are being drastically depleted; thus, the current shift towards renewable energy (RE) resources has become imperative. However, there are many impediments to the adoption of renewable power generation. These impediments can be overcome by enacting policies to encourage the acceptance of sustainable energy resources. For instance, the net-metering policy can provide the necessary incentives to promote the development of local distributed energy sources, primarily solar photovoltaic and wind generators. While there has been significant advancement and development in net-metering in Asia with the increased penetration of RE, at present there is a lack of systematic review in this area. This paper aims to present an in-depth review on net-metering advances and challenges, current RE shares, and future RE targets in the Asian region. Additionally, a case study is performed and an economic analysis of net-metering regulations in an Asian country is carried out. In this study, the monetary benefits of net-metering policies for residential consumers are proved. It is envisaged that the information gathered in this paper will be a valuable one-stop source of information for Asian researchers working on this topic.
INDEX TERMS Renewable energy shares, renewable energy targets, net-metering policy, net-metering in Asia.
I. INTRODUCTION Energy production and consumption play a vital role in the development of nations. The amount of consumed energy per capita is one of the indicators of the developmental pace of a nation. The availability and accessibility of energy greatly influences the lifestyle and the living standards of the people of any country. On the contrary, the industrial and economic growth of a country may be paralyzed due to energy short- ages [1], [2]. With the growth of the economy, the energy demands of modern societies increase and the fossil-fuel energy resources
The associate editor coordinating the review of this manuscript and approving it for publication was Zheng H. Zhu.
are being depleted at an appalling rate [2]. Due to the increased usage of fossil-fuel resources, climate change has also become an alarming challenge to deal with. For instance, the emission of greenhouse gases from fossil-fuel produc- tion processes has raised widespread concern over global warming. The estimated global temperature change by human activities is 1◦C [3]. These seminal drivers have led both public and private sector decision-makers to believe that the transition towards renewable and sustainable energy is imperative. Consequently, in the past few years, renew- able energy (RE) resources have gained prodigious atten- tion [4]–[14]. In 2014, the European Council issued the Framework for Climate and Energy with a target of 27% share of renewable energy consumption by the year 2030 [15], [16].
170364 This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/^ VOLUME 8, 2020
Similarly, in 2015, to prevent the global mean temperature change from exceeding 2◦C, more than 30 nations contributed to the Paris climate change agreement that will take effect in 2020 [17]. According to the Global Status Report on Renewables 2019 (REN21 GSR-2019), renewable energy has a share of more than 33% of the global power gener- ation installed capacity. Solar photovoltaics (PV) accounts for 55%, wind 28% and hydro-electric 11% of the renewable power generating capacity world-wide [18]. The International Renewable Energy Agency (IRENA) predicts that the global RE share will reach 85% of the total energy supply by 2050 [19]. Significant increase in the utilization of RE resources could save considerable cost and greatly help to cope with the challenge of global warming [20], [21]. The emergence of RE technologies has evolved the concept of smart grid in the electrical power system. The ‘‘Smart grid’’ or the ‘‘intelli- gent grid’’ is an advancement to the traditional power grid. A traditional electrical power grid is an electromechanical, unidirectional grid that carries power from centralized and sometimes remote generation systems to a vast number of consumers who are spread out in the system. As opposed to a traditional grid, a smart grid is a digital, bidirectional network of distributed generators, which has various sensors and has capabilities of self-monitoring, self-healing, remote check/test, and pervasive control [22], [23]. A smart grid can offer unconventional benefits to consumers. For instance, consumers can meet their energy demands by taking energy from the grid, and at the same time they can be energy pro- ducers by injecting excessive energy into the grid and receiv- ing economic benefits in return. This mechanism requires net-metering as part of the supporting infrastructure [24]. Thus, net-metering is a policy incentive for RE owners that can encourage the deployment of RE technologies for gener- ating clean and sustainable energy. A comparative overview of various RE regulatory schemes for the restructured power sector is presented in [25] with a view of overcoming the hurdles in the advancement of renew- able energy technologies. The regulatory policies discussed in this paper include the Renewable Portfolio Standard, Net-metering Policy, Renewable Energy Certificate, Electric- ity Feed-in Law, Public Benefit Funds, Investment Support, Competitively Bid Renewable Resource Obligations, Cost Reduction Policies, Market Infrastructure Policies, Trans- port Bio-fuels Policies, Emissions Trading Policies, and the Renewable Energy Targets. Although a lot of research on net-metering has been car- ried out, there is an absence of a comprehensive review of net-metering in Asia. To bridge the gap, this paper aims to present an in-depth review of net-metering advances and challenges, current RE shares, and future RE targets in the Asian region. Additionally, a case study is performed and an economic analysis of net-metering regulations in an Asian country is carried out. It is envisaged that this contribution will serve as one-stop source of information for researchers working in this topic. More so, this work will provide the
guidance to Asian researchers about net-metering policies, rules, and regulations and promote the application of green energy in this region. This paper is organized as follows: Section II deals with the essential background of the net-metering mechanism, and Section III provides the international experience of net-metering policy. A detailed review of the advancements in net-metering mechanism and the research work available on the net-metering policy frameworks for Asian countries is presented in Section IV; the current RE penetrations and future targets are also given in detail in this section. Section V offers a brief discussion and insights on identified challenges to net-metering policy in some Asian countries. Section VI demonstrates a case study in which the economic evaluation of the current net-metering policy in Pakistan is carried out. Section VII concludes the paper.
II. NET-METERING – ESSENTIAL BACKGROUND Net-metering is a billing agreement between electricity util- ity provider and consumers that mandates the consumers to possess, operate and benefit from a distributed generation system (Solar PV or other generation system) meeting some or all of their energy consumption needs and getting finan- cial paybacks for any surplus energy injected into the main grid [26]. The local generation consumed ( Gconsi , j , k ), excess energy ( Exci , j , k ), and the net consumption ( Cneti , j , k ) can be expressed as follows [27]:
Gconsi , j , k = Geni , j , k for Cbasei , j , k ≥ Geni , j , k (1) Gconsi , j , k = Cbasei , j , k for Cbasei , j , k < Geni , j , k (2) Exci , j , k = Geni , j , k − Cbasei , j , k for Cbasei , j , k ≤ Geni , j , k (3) Exci , j , k = 0 for Cbasei , j , k > Geni , j , k (4) Cneti , j , k = Cbasei , j , k − Geni , j , k for Cbasei , j , k ≥ Geni , j , k (5) Cneti , j , k = 0 for Geni , j , k > Cbasei , j , k (6)
where Cbase = Energy consumption Gen = Total generated energy Gcons = Generation which is consumed locally Exc = Excess energy injected into the grid (when local consumption is lower than generation) Cnet = Net consumption by the occupants (when local consumption is higher than generation) And ‘‘i’’ represents each day ranging from 1 to 365 days, and ‘‘j’’ represents the day-moment. For example, for a 15-minute interval ‘‘j’’ ranges from 1 to 96 and the interval ‘‘k’’ can be 1 minute, 15 minutes, 30 minutes, 1 hour, or 1 day. The expressions (7 and 8) present the annual economic benefits of the net-metering and net-billing mechanisms. Net- billing is a variation in the net-metering mechanism where the energy consumed is kept in a different record than the excess energy injected into the grid; total energy consumed and excess energy injection to the network are valued separately
announced the net-metering regulations. As per announced regulations, the three-phase consumers who own solar or wind generators can sell their excess energy to the distribution companies (DISCOs) after getting licensed under current NEPRA regulations [44], [45]. In 2017, Pakistan expanded net-metering from a few cities to the entire country. As of year-end 2019, a total of ∼1150 net-metered distributed generation systems of the net gross capacity of 19.55 MW, including 1 MW solar installation in Parliament House and 178.08 kW each in PEC and Planning Commission buildings, have been installed. Pakistan aims to achieve 1 GW and 4.5 GW of net-metered installed capacity by 2020-21 and 2025, respectively [18], [37], [38], [46], [47]. In Ref. [48], a case study of the solar irradiance and the prospect of a grid-tied solar power generation system with a net-metering mechanism in Pakistan was presented. This paper investigates the solar irradiance in Pakistan and the necessity of grid-tied solar generated power systems to under- mine the ongoing energy crises in developing nations like Pakistan. The potential obstacles in the path of implemen- tation of the net-metered on-grid solar generation systems are also discussed, along with the proposed solutions. The discussed barriers include discouragement by electric util- ity companies, lack of local production of equipment and technical capability at different organizational levels of the DISCOs, lack of awareness, inadequate access to tailored finance options, and reliable indigenous suppliers [49]. Energy security, energy shortfalls, energy access, and cli- mate change are the fundamental drivers for the advancement and implementation of new and renewable energy resources in India. Between the years 2014-2015, energy shortfall was found to be 2.4%. Numerous efforts were made to bridge the energy supply-demand gap in the country. India has an estimated RE potential of approximately 900 GW by utiliz- ing commercially exploitable resources, especially 750 GW by solar means. India has increased its targets to utilize renewable resources, and the government has set a target of achieving 175 GW by exploiting the RE resources by 2022 with 100 GW by solar energy only. The 100 GW target was set under the Jawaharlal Nehru National Solar Mission (JNNSM) and it would comprise of 40 GW by Rooftop Solar PV (RTPV) and 60 GW by large and medium scale grid-tied solar systems. The Indian government has also set a target of achieving 40% share of its total electricity gen- eration by RE means by 2030 as per Global Status Report 2019 on Renewables. It is important to note that India does not classify hydropower generation greater than 25 MW as Renewables, so the hydropower installations greater than 25 MW are not included in the share and future RE targets for India. The Ministry of New and Renewable Energy (MNRE) and the announcement of the 2010 National Solar Mis- sion emphasized the implementation of net-metering along- side the Feed-in Tariffs (FiT) policy [18], [47], [50], [51]. With the advent of net-metering incentive policies in India, the dream of achieving the goals of solar-based clean energy seems to be realistic. According to the available statistics of
MNRE, as of 2016 the Indian government has formulated the net-metering regulations on a sub-national level for 26 of its states and all union territories out of 29 states and 7 union territories [18], [47], [52]. Net-metering regulations were implemented in 2015 in some of the major Indian states including Rajasthan, Punjab, Maharashtra, Andhra Pradesh, and Madhya Pradesh. The maximum allowable capacity cap in these states is up-to 1 MWp, except Madhya Pradesh where it is up-to 2 MWp. In Andhra Pradesh, only three phase consumers are eligible for net-metering, whereas in Rajasthan, all the consumers are eligible to take advantage of the net-metering policy. In Delhi, Haryana, and Tamil Nadu, net-metering regulations came out in 2014. Delhi, Tamil Nadu, and West Bengal imposed no limit on maximum allowable capacity, but in Haryana this limit is up-to 1 MWp. In Haryana, Delhi, and Tamil Nadu, all the consumers are eligible, but in West Bengal, only institu- tional consumers like hospitals, colleges, government depart- ments are eligible for net-metering. Moreover, there is no capacity cap for eligible RE sources; however, the lower limit is 5 kWp is imposed. Gujarat and Karnataka implemented the net-metering policy in 2016 with a maximum capacity limit of up-to 1 MWp. Karnataka considers all the consumers in their net-metering regulations. In Gujarat, government, residential, commercial, and industrial institutions are considered eligible for implemented policy [53]–[57]. Thakur and Chakraborty [58] investigated seven different novel net-metering billing arrangements for RE resources with a view of their appropriateness for different kinds of consumers in the Indian scenario. For a vast seg- ment of the Indian population, the per capita energy con- sumption is quite low (i.e., 917 kWh) and the individual net-metering mechanism is impractical; hence, it is vital to introduce alternative and more feasible net-metering policies for the success of grid-connected RE sources. The discussed net-metering systems are community net-metering, aggre- gate net-metering, virtual net-metering, multi-site aggrega- tion, utility-sponsored model, special purpose entity, and the nonprofit model. This paper also suggests improvements in the current net-metering policy and standards for the Indian market. In [59], Thakur et al. presented a more practical and efficient model of a net-metering billing mechanism for solar PV generation in India. In this paper, the data collected from three different types of consumers is simulated and the proposed model is found to be more scalable and financially viable than the plain net-metering scheme; more customers are anticipated to participate in new the net-metering arrange- ment as it presents fewer risks and more benefits in terms of finance and optimal location. Table 1 summarizes the development of net-metering pol- icy, range of tariff rate at which excess energy is injected into the grid, capital investment cost of RE sources, and future targets and current shares of power generation from RE sources in South Asian countries. It is found out that on average the capital investment cost for solar PV is in the range of $850-1000 per kWp.
TABLE 1. Net-metering development in South Asia.
TABLE 2. Net-metering development in West Asian region.
TABLE 2. (Continued.) Net-metering development in West Asian region.
the domestic residents of Dhaka is investigated [92]. GSR- 2019 on Renewables states that Bangladesh has not adopted any regulatory policy except tendering [18]. Wijayatunga [66] discussed the policies for the promotion of energy generated by renewable technologies for the Sri Lankan scenario. The energy policies and strategies of the Sri Lankan government for the growth of non-conventional renewable energy sources (NCRE) are analyzed in this paper. The energy policy recognized biogas, small hydro, and wind-based energy generation as the prominent NCRE sources to be adopted in Sri Lanka. It set renewable power generation targets of 20%, 50% and 100% by 2020, 2030 and 2050, respectively [18]. The author also discussed the imple- mentation of the net-metering policy in Sri Lanka. on the advice of Sustainable Energy Authority (SEA), the Ceylon Electricity Board (CEB) and the government agreed to prac- tice the net-metering regulations for the connection of NCRE to the national grid by 2009. The author further maintained that if properly designed, the net-metered based systems could make the dream of carbon-free energy a reality. This paper infers that Sri Lanka has been successful thus far in implementing various RE policy frameworks, and it has set a precedent for similar nations to make their dreams of green energy generation come true [47], [63]. Nepal announced net-metering regulations in 2018, at the national level, for distributed generation systems no more than 1 MWp. Nepal has set the target of achieving 100% share of electricity generation with RE resources by 2050 [18], [72], [75]. In Nepal, the majority of the population
has no access to electricity, and the planned load shedding duration is as lengthy as 20 hours in dry season [93], [94]. In Nepal, independent power producers (IPPs) has applied the concept of net-metering to get more monetary benefits [72]. In [94], the impact of the small-scale distributed grid-tied solar generation systems on load shedding in Nepal is dis- cussed. The five 1.11 kWp grid-tied solar PV systems were installed at three different locations within the Khathmandu valley and their performance was monitored for a year with a view of analyzing their impact on the reduction of load shedding of the electric power. Bhutan, Maldives, and Afghanistan have set the tar- gets of achieving 100% share of electricity genera- tion by RE resources by 2050 [18]. The Maldives Energy Authority (MEA) inaugurated the net-metering regulations in December 2015 [70]. However, as per REN21 GSR-2019, there are no net-metering regulations announced for Afghanistan thus far. Fig. 3 shows the targets to generate electric power from RE sources for South Asian countries.
B. WEST ASIAN REGION This section highlights the progress in net-metering and the research work available on net-metering policies for the pro- motion of RE technologies in the West Asian region. Addi- tionally, it presents the future Renewable Energy goals of the countries in this region. West Asian countries considered in this study include United Arab Emirates (UAE), Jordan,
implemented the net-metering regulations on a national level in 2013, with an established installation cap of 400 MW till
These policy frameworks were introduced to encourage the RE-based small scale producers to collect financial advan- tages for the excess energy injected into the grid [102], [119]. Global Status Report 2018 on Renewables states that the Israeli government previously set a target of attaining 10% RE shares by 2020; recently in 2015, it revised its goal to achieve 17% RE shares by 2030 [18], [47]. According to the Global Status Report on Renewables 2019 [18], [47], Kuwait aims to achieve 6.6 GW installed capacity and/or generation of power from solar and wind sources by 2030. It also set a target of producing a total of 5% and 10% electricity by RE resources by 2020 and 2030, respectively. Qatar, on the other hand, has vowed to attain 2% and 20% RE shares of its electricity generation by 2020 and 2030, respectively [130]. Iran has pledged to achieve 5 GW installed capacity and/or generation of power from solar and wind sources, and it also announced the Feed-in Tariffs, on a national level, for the promotion of clean energy [18]. In Ref. [131], the authors state that Iran aims to achieve 15% of its total power generation by utilizing renewable means by 2030, and The Kingdom of Saudi Arabia (KSA) pledges to generate 30% of its total electric power with RE sources by 2030 [110]. Also, Saudi Arabia aims to achieve 54 GW installed capacity and/or generation of electricity from RE sources (with 16 GW solar only) by 2040 which is roughly more than 90% of its current installed capacity (∼58 GW). In 2017, the Saudi Arabian government approved a net-metering scheme for solar PV generation up to 2 MW. Recently, the KSA pledged to embrace ‘‘the Saudi Vision 2030’’ to make a transition from its traditional state into a sustainable and green state [132]. The targets for electricity generation from RE means for Yemen and Iraq are set to 15% and 10% by 2025 and 2030, respectively. Yemen also has a target for achieving 100% power generation from RE means by 2050. Lebanon pledged to achieve the RE shares of 12% and 100% of total electricity generation respectively by 2020 and 2050, respectively [18], [47], [95]. The government of Iraq has not announced any net-metering policy thus far; how- ever, the Ministry of Electricity is considering the revision of electricity tariffs to introduce a net-metering incentive policy for the advancement of RE sources [126]. The net-metering/net-billing regulations are already in place on a national level in Lebanon. The net-metering regu- lations were formulated and adopted by the ‘‘Electricité du Liban (EDL)’’ board in 2011. The EDL board’s decision was approved by the Ministry of Energy and Water and the Ministry of Finance, and the net-metering policy was enacted for the integration of distributed generators (solar, wind biomass, and small hydro generators) with the national grid. As of 2014, 2 MW net-metered projects have been implemented in Lebanon [126], [133]. Azerbaijan plans to attain 20% of its electricity genera- tion from renewable resources by 2020 as per GSR-2019 on
FIGURE 4. RE targets set by West Asian countries.
Renewables [18]. The state of Palestine pledged to gen- erate 10% and 100% of its total electricity by RE means by 2020 and 2050, respectively; to achieve this goal, its cabinet approved net-metering regulations in 2012. As of 2014, 4 MW net-metered projects have been implemented in the State of Palestine. Syria also announced net-metering regulatory frameworks in 2010 on a national level for the proliferation of clean and sustainable energy technologies, but the advancement in the promotion of net-metering policy has significantly staggered, mainly due to the difficult politi- cal situation in Syria. It also vowed to achieve 1.1 GW and 1.5 GW installed capacity and/or generation, respectively, from solar and wind sources by 2025. The Syrian government also set a target of meeting 4.3% of its primary energy needs from renewable sources by 2030 [18], [47], [95], [122], [126]. As per GSR-2018, Bahrain is one of the six countries which announced their net-metering policy in 2017; further- more, it pledged to achieve 5% renewable power target by 2030 [18], [47]. As of year-end 2017, Oman’s RE share of the installed capacity was only 0.11%, and it pledged to achieve 10% RE share by 2020 [95]. Fig. 4 shows the future targets to generate electricity from RE sources for West Asian countries.
C. CENTRAL AND EAST ASIAN REGION Central Asia includes Turkmenistan, Kyrgyzstan, Tajikistan, Kazakhstan, and Uzbekistan. East Asian countries are Japan, China, Hong Kong, Macao, South Korea (the Republic of Korea), North Korea, and Mongolia [134], [135]. The small-scale hydro-power target set by Tajikistan is to achieve the installed capacity and/or generation of 100 MW by 2020. Kazakhstan aims to attain 3% and 50% of electric- ity generation from renewables by 2020 and 2050, respec- tively. The FiT policy frameworks exist on a national level in Kazakhstan; however, no net-metering legislation has been
TABLE 3. Net-metering development in Central and East Asian Countries.
announced yet. As of 2017, the renewable energy share of Uzbekistan was 12.6%. Moreover, it aims to achieve 19.7% of its total electricity generation by RE resources by 2025 [18]. However, no data on future RE targets and net-metering reg- ulations have been found for Turkmenistan and Kyrgyzstan. Table 3 summarizes the development of net-metering pol- icy, range of tariff rate at which excess energy is injected into the grid, capital investment cost of RE sources, and future targets and current shares of power generation from RE sources in Central and East Asian countries. It is found out that on average the capital investment cost for solar PV is around $1400 per kWp. As of 2014, the RE share of electricity in Japan was 12.2%. Japan previously set the targets to achieve 13.5% and 20% RE shares by 2020 and 2030 respectively; however, it recently increased its RE targets to 22-24% by 2030. Japan also pledged to tap ocean power (wave and tidal means) by setting the goal of attaining 1.5 GW installed capacity and/or power generation by 2030. Japan is the leading country in Asia to introduce the net-metering policy for the exploitation of distributed generation systems in the country; it adopted net-metering in 1990 and set the precedent for other countries to promote the sustainable and green energy technologies by embracing net-metering policy [18], [47], [49], [136]. As of 2014, 94% of the photovoltaic systems installed in Japan are residentially grid-tied systems under net-metering policy frameworks [143]. Table 4 summarizes the develop- ment of net-metering/net-billing policy in the East Asian region. China previously vowed to enhance its solar power installed capacity and/or generation to 100 GW by 2020, and in 2015, it revised its target of realizing 150 GW with solar generation by 2020. As of 2015, the installed solar PV capacity and/or generation was 17.8 GW and it is expected to be increased to 70 GW by 2017. In 2015, the government of
China also increased its wind power targets from 200 GW to 250 GW by 2020. As of 2016, the total national consumption of renewable electricity was 25.3% of the total electricity consumption with yearly growth of 0.9%. Previously, the overall renewable energy target set by China was 27% by
- Recently, China set a target of generating 35% of power from RE means by 2030; however, it has not yet adopted the net-metering policy [18], [47], [144]. As of 2014, RE share of electricity generation for Mongolia was found to be 4%. Previously, Mongolia has set a target to generate 20-25% of its electricity from alternative sources by 2020. In 2015, it revised its RE goals and pledged to produce 20%, 30%, and 100% of total electricity demand from clean resources by 2020, 2030, and 2050 respectively; nonetheless, no net-metering policy has been announced by the government of Mongolia. The Republic of Korea plans to realize future targets of meeting 5%, 6%, 7%, and 20% of its total electricity generation by exploiting the renewable tech- nologies by 2018, 2019, 2020 and 2030, respectively [18]. Net-metering regulations have already been enacted on a national scale in South Korea for integrating locally dis- tributed generation systems with the national grid [47], [136]. Fig. 5 shows the targets to generate electricity from RE sources for Central and East Asian countries.
D. SOUTHEAST ASIAN REGION This section underlines the developments in net-metering and the research work available on net-metering policies for the promotion of RE technologies in Southeast Asian coun- tries and their future Renewable Energy targets. Southeast Asia includes Thailand, Philippines, Indonesia, Singapore, Malaysia, Myanmar, Brunei, Laos, Cambodia, Vietnam, and Timor-Leste [145]. In Thailand as of 2014, the share of RE sources for elec- tricity generation was found to be 5% and the government
FIGURE 5. RE targets set by Central and East Asian countries.
planned to achieve 20% by 2036. In 2015, the RE goals were revised and the government pledged to generate 20% of the total electricity by utilizing renewable sources by
- It is important to note that Thailand does not clas- sify hydropower generation greater than 6 MW as renew- able, so the hydropower installations greater than 6 MW are not included in the share and future RE targets for Thai- land [18], [47]. Thailand is also one of the pioneers in the Asian region to introduce the net-metering regulations for the promotion of green energy in the country. The government of Thailand first passed its net-metering legislation in 2002. Greacen et al. [28] discussed the introduction of net-metering policy in Thailand, future financial opportunities for rural- based small-scale green energy producers, and potential chal- lenges to net-metering in Thailand. The author also discussed the solutions to surmount the barriers in the promotion of net- metering policy. In Thailand, the allowed power production from grid-connected resources, such as solar, biogas, wind, and micro-hydro generators, is up to 1MW per installation. The producers are paid at a rate that is 80% of the retail rate if the injected net energy to the grid is more than the net consumption in a monthly period [29]. As of 2006, 95 very small renewable energy power producers (VSREPP) projects were completed, and 67 of those were solar PV based projects. VSREPP are the energy producers that sell less than 1MW to the utility company and capitalize the renewable energy means, such as agricultural and facto- ries wastes, residuum or by-product steam, for electricity production [146]. In [147], Tongsopit et al. discussed the business mod- els and economic options for the fast expansion of rooftop solar generation in Thailand. The author investigated the drivers for the advent of business models, challenges to their development, and hazards from the business owners’ and customers’ point of view. He also emphasized that the com- prehensive regulations on tariffs, rolling credit timeframes, and capacity caps should be devised judiciously to ensure
evenhandedness between net-metered and non-net-metered consumers. He further maintained that presently there is no agreement on the definition and details of net-metering. The author inferred that the government should play a part in assisting the involvement of stakeholders at the time of outlining net-metering legislation. The stakeholders should comprehend the influence of various net-metering policies on the economics of solar system acceptance among dif- ferent consumer factions and the price and recompenses of net-metering to the utility company. Such an understand- ing would be a helping hand in designing a net-metering scheme which would assist the expansion of solar PV production as well as make the utility companies pre- pared for potential adjustments of business models in the future. As of 2014, the share of RE sources for electricity gener- ation in the Philippines was found to be 29%, and it aims to achieve 40% and 100% RE shares by 2020 and 2050, respec- tively. The government of the Philippines officially approved net-metering regulations on a national scale in July 2013 and mandated the RE owners to connect their distributed genera- tion systems (up to 100 kWp) with the national grid and get paid for the excess energy injection [18], [47], [148], [149]. Dellosa, in [150], presented the analysis of economic payback of solar PV based systems and the potential influence of net-metering regulations in Butuan City, Philippines. The Philippines is enhancing its RE based generation, particularly grid-tied residential solar PV generation; however, the net- metering is in its nascent stages. The net-metering policy in the Philippines mandates the residents and the business owners to interconnect their solar PV based systems of ratings no more than 100 kW power with the distribution utility network. This study reveals that majority of the residential and commercial consumers of ‘‘Agusan del Norte Electric Cooperative, Inc. (ANECO)’’ are well-aware of the benefits of the solar PV systems, but a vast majority of consumers are unaware of the net-metering incentives. The financial feasi- bility of the 1.5 kW and 5 kW power systems is investigated and the investment on solar PV based installations is found out to be worthwhile. It is inferred that the government must accelerate the awareness campaign to educate its denizens about the monetary incentives of net-metering policy so that the investment in this sector could flourish. Table 4 summarizes the development of net-metering pol- icy, range of tariff rate at which excess energy is injected into the grid, capital investment cost of RE sources, and future targets and current shares of power generation from RE sources in Southeast Asian countries. It is found out that on average the capital investment cost for solar PV is around $1640-1865 per kWp, which is highest among all studied Asian sub-regions. In 2000, Singapore had the installed solar PV capacity of 10 kWp, and it remarkably improved the capacity to 2000 kWp in 2009. However, there are various impedi- ments in the development of Solar PV technology in Singa- pore: one of the potential challenges to solar PV is that the
government is resolutely committed to meet its energy demands by consuming fossil fuels. Secondly, the installed capacity of power plants in Singapore is far more than its current energy demands; roughly 43% of the installed power plant capacity is being utilized to meet its energy needs. This poses a hurdle in the promotion of alternate energy resources in Singapore. Lastly, the government of Singapore is gener- ally wary of incentive schemes and subsidies. On the whole, in the presence of such challenges, the future of solar PV in Singapore is undecided [151]. The net-metering regulations were announced in 2011-2012 in Singapore, on a national level, for the integration of distributed RE sources within the national grid. The solar power installed capacity and/or gen- eration goal set by the government was 350 MW by 2020. An overall goal to achieve 8% RE shares of the total electricity generation was set in 2015, but no deadline was set for reach- ing this target [18]. Indonesia set its medium-term renewable energy target to 26% by 2025 and its long-term renewable energy target to 31% by 2050 [18], [179]. In December 2013, net-metering regulations (PLN No. 0733.K/DIR/2013) were introduced by ‘‘Perusahaan Listrik Negara (PLN)’’ in Indonesia for the integration of distributed generators within the grid [180], [181]. The government of Vietnam vowed to generate 7%, 10%, and 100% of its total electricity from renewable sources by 2020, 2030, and 2050, respectively [18]. Feed-in Tariff regulations were enacted on a national level in the country. Malaysia has also set future goals for producing 9%, 11%, and 15% of its total electric power by exploiting clean energy sources by 2020, 2030, and 2050, respectively. Malaysia announced net-metering policy for rooftop solar generation in 2015 and revised in 2018. Eligible sectors include residen- tial, commercial, industrial, and agriculture. Vietnam intro- duced net-metering regulations in 2017 for residential con- sumers and recently revised in 2019. Myanmar has also set a target of 27% power generation from RE sources by 2030. Cambodia set its RE goals to 25% and 100% by 2035 and 2050 respectively [18], [47]. However, no data is found for future renewable targets and net-metering policy regulations in Brunei, Laos, and Timor-Leste. Fig. 6 shows the targets to generate electricity from RE sources for Southeast Asian countries.
V. CHALLENGES TO NET-METERING GROWTH This section presents some of the major barriers in the devel- opment of net-metering policy in Asian countries. Some of the identified barriers include absence of net- metering regulations, resistance by distribution companies (DISCOs), capacity cap for net-metered RE installation, country-wide (or state-wide) net-metering capacity cap, lack of aware- ness in authorities about the implementation process, lack of appropriate technical staff training for net-metering system installation, procedural barriers, lack of awareness in con- sumers, high investment cost, inconsistent regulations among different states, lack of coordination between government policies and state regulators, and unattractive net-metering
FIGURE 6. RE targets set by Southeast Asian countries.
compensation practices, and additional charges for intercon- nection with the grid. One of the major barriers to net metered renewable generation in Asia is the absence of regulatory frame- works. This study identifies that net-metering has not been announced/implemented in following countries yet: Bangladesh, Afghanistan, Bhutan, Turkey, Kuwait, Iran, Qatar, Yemen, Iraq, Oman, Azerbaijan, Turkmenistan, Kyrgyzstan, Tajikistan, Kazakhstan, Uzbekistan, China, Hong Kong, Macao, North Korea, Mongolia, Myanmar, Brunei, Laos, Cambodia, and Timor-Leste. Some countries have not announced net-metering on national level, for example India has implemented net-metering regulations on sub-national level in 26 of its 29 states [47], [52], [182]. Similarly, UAE has implemented the net-metering policy in only 2 of its 7 emirates [98], [183]. Second chief hindrance to net-metering growth is the pas- sive opposition from DISCOs; they express concern about loss of usage-based revenues. Some utilities maintain that paying the excess energy injection from net-metered DGs at retail tariff rate is tantamount to giving subsidy to DG owners since retail tariffs include the cost of energy gen- eration, cost of transmission and distribution infrastruc- ture and its maintenance, administrative cost, and utilities’ profit. Some utilities believe that net-metering policy causes safety concerns and loss of true information about customers load [48], [54], [184]. Currently, net-metering regulations in most Asian coun- tries impose a maximum capacity limit of 1 MWp on eligible RE installations. In majority cases, this capacity limit is same for all the eligible sectors participating in net-metering, which poses a major hurdle for industrial and commercial RE instal- lations. This bottleneck can be overcome by allowing the grid integration of eligible RE installations having the maximum capacity equal to their sanctioned load [54]. Another related hurdle to net-metering is the country-wide (or state-wide) capacity cap: for example, Israel have a country-wide cap
TABLE 5. Electricity tariffs (PKR/kWh) for IESCO consumers.
In this study, two types of electric tariffs [62] are used:
- General Residential Supply tariff: this type of tariff is used for billing the energy consumption of individual residential consumers.
- Single-point Bulk Supply tariff: this type of tariff is used for billing the aggregate energy consumption of the whole building. As per net-metering regulations in Pakistan, the excess energy injected in the distribution network is credited at off- peak rate. The peak demand period begins at 0500 pm and lasts till 0900 pm. To compute the monthly energy expen- diture for each individual apartment, all fixed charges are considered, including general sales taxes (GST), monthly Pakistan Television (PTV) fees, monthly connection charges, and electricity duty. However, fuel price adjustment (FPA) and other variable surcharges are not considered in this work. This assumption is valid since inclusion of variable rate of FPA and other variable surcharges can manipulate the net-metering benefits. Monthly individual apartment energy expenditure can be computed by using expression (9) [45]:
Energy expenditure = Costelect + CostTaxes + CostUQA
- CostPTV + CostED + CostCC
- CostFPA + CostOVS (9)
where Coselect : monthly electricity cost [PKR /kWh] CostTaxes : General Sales Tax (GST – percentage of elec- tricity cost) CostUQA : Applicable Uniform Quarterly Adjustment cost [PKR/kWh]
TABLE 6. The composition of the residential building.
CostPTV : Pakistan Television fee [PKR/connection] CostED : electricity duty cost (percentage of monthly elec- tricity cost) CostCC : connection cost [PKR/connection] CostFPA : Fuel Price Adjustment (FPA) surcharge (variable) CostOVS : other variable surcharges (variable)
B. AGGREGATION OF THE RESIDENTIAL BUILDING DEMAND The residential building considered in this study consists of 10 floors, three sets of elevators and stairs, and 100 res- idential apartments. The composition of the building under study is shown in Table 6. The aggregated demand of the residential building consists of the energy demand of all types of residential apartments and the lighting and elevator demand of the common area services inside the building.
APARTMENT ENERGY DEMAND The energy demand of individual apartments is computed by modeling the domestic appliances’ daily energy consumption patterns based on their operational characteristics, frequency of use, ownership rate, probability of use, and probability of time of use. The energy consumption of an apartment is contingent upon the number of apartment residents and their living standards, types and number of appliances owned, and seasonal variations in the area [32], [45], [186]–[188]. Potential household appliances’ load consumption data is taken from [32], [189], [190] for modeling the daily energy consumption of different types of apartments in a residential building. Monte Carlo Simulations and Gaussian Probability Distribution is used to obtain the aggregate energy consump- tion of all apartments in the building. A comparison of energy consumption of different types of apartments for typical working day and non-working day is shown in Fig. 7 and 8, respectively.
COMMON AREA SERVICES ENERGY DEMAND Energy demand for common area services include building’s lighting demands and the elevator energy demand. Lighting demand makes up the major portion of the energy demand for common area services. In this work, lighting demand for stairs-elevator and general lighting demand for the building is considered. For simplicity, approximate lighting demand of 300 Watt/floor (for stair-elevator and general lighting demand for building) is considered.
FIGURE 7. Comparison of energy consumption of different types of apartments for a typical working day.
FIGURE 8. Comparison of energy consumption of different types of apartments for a typical non-working day.
TABLE 7. Parameters for computation of elevator energy consumption.
To compute the elevator energy demand, geared trac- tion technology is considered and data is taken from [191]. Elevator energy consumption depends on the motor power, speed, load of the elevator, and the rise height. The proce- dure of computing elevator’s energy consumption is adopted from [191], [192]. Table 7 presents the parameters used for computing the elevator energy consumption.
FIGURE 9. Common area services energy demand for typical working day and non-working day.
Eq. (10) and (11) are used to calculate the annual elevator energy consumption.
E = ESB +
(( 2 × γ × λ × EOOC × ( 1 −β) × n )) (10)
where,
ESB = 0. 001 × PSB ×
8760 − λ × h ×
n 3600 × s
ESB : energy consumption in standby operation (Wh) EOOC : elevator’s one operating cycle energy (Wh) γ : average motor load factor β: balancing factor λ: average travel distance factor h : elevator’s rise height (m) n : number of annual trips PSB : standby power (W) s : speed of elevator (m/s) Fig. 9 presents the common area services energy demand for a typical working day and non-working day.
- BUILDING AGGREGATE ENERGY DEMAND Building aggregate energy demand is the sum of residen- tial apartments’ energy consumption and common area ser- vices energy consumption. Fig. 10 presents the aggregated energy demand of the building for typical working day and non-working day.
C. ESTIMATION OF PV SYSTEM POWER GENERATION PROFILES The estimation of PV system generation profiles has been carried out by using the method presented in [31], [32] with the help of mean global irradiance level and the temperature of the selected location in Islamabad, Pakistan. An online software tool PVGIS was used for obtaining the mean global irradiance level [193]. Another PV related software called
FIGURE 12. Net monthly energy expenditure of the building with different installed capacity of the solar PV system.
installed PV capacity. Nonetheless, a noticeable reduction in the energy cost curve of Case 2c can be observed with the increasing values of the PV installed capacity, due to the increased injection of solar generation into the grid. It is obvious from Fig. 13 that no positive savings are observed for Case 2b at any value of installed PV capacity, which makes it a completely unviable net-metering scheme for residential DG owners. On the other hand, for Case 2a, the increas- ing trend of positive annual savings (per apartment) can be observed up to 50 kWp PV installed capacity, and after that per apartment annual savings remain constant for all the higher values of PV installed capacity because of the imposed restriction on the annual surplus energy injection into the grid: according to the ‘‘NEPRA net-metering regulations 2015’’, the yearly surplus energy injection cannot surpass the yearly energy expenditure. On the contrary, the per apartment annual savings for Case 2c exhibit the increasing trend for all values of the PV installed capacity, and the positive savings are realized above the installed PV capacity 110 kWp. It is impor- tant to note that the energy expenditure, which is computed based on Single-Point Bulk Supply tariff, is comparatively high compared to the energy expenditure that is computed based on the General Residential Supply Tariff. This makes the Case 2c net-metering scheme uneconomical for a PV installed capacity of less than 110 kWp.
F. NET PRESENT VALUE ANALYSIS OF CASE STUDY SCENARIOS Net present value (NPV) is a measure of the profit that is determined by deducting the present value of cash outflows (including the capital investment cost of PV system) from present value of the cash inflows for a period ‘t’ [195], [196], as represented by Eq. 14.
NPV =
t ∑= N
t = 1
Ft ( 1 + ψ) t^
− FC (14)
FIGURE 13. Comparison of per apartment average annual savings with different installed capacity of the solar PV system.
TABLE 9. Parameters to carry out the NPV and payback periods.
where Ft : net cash inflows during period ‘t’ FC : capital investment cost of PV system ψ: discount rate t : time in years Table 9 presents the parameters and values used to carry out the economic analysis of the case study scenarios. Fig. 14 and 15 presents the results of the present values of the cash flows and net present values, respectively, for the considered case study scenarios for the period of 25 years. Capital investment cost of the Case 2c is highest because of its larger installed capacity as compared to rest of the scenarios, which is also evident by large negative NPV and cash inflow at the start of the project life. The results show that the cash inflows of the Case 2c are highest among all the studied scenarios followed by Case 2a. The profit for Case 2a and 2c is ∼2.77 and ∼12.2 million PKR, respectively; however, it is negative for Case 2b, rendering it to be an infeasible net-metering option. From Fig. 15, the payback period for Case 2a and 2c is found to be 7.5 and 8.1 years, respectively. Based on the considered PV system lifetime, the payback periods for Case 2a and 2c seem very attractive. In conclusion, high NPV
FIGURE 14. Present values of the cash flows for considered case study scenarios.
FIGURE 15. Net present values for considered case study scenarios.
makes Case 2c the most appealing net-metering scheme for the considered residential building demand.
VII. CONCLUSION The transition towards sustainable and clean energy technolo- gies has become inevitable due to growing concerns over the depletion of conventional energy resources and climate change. Renewable Energy technologies are facing numer- ous challenges; however, the related policies aim to lower these hurdles. Net-metering is one of the potential incentives that is introduced to promote the local distributed generation resources, primarily solar PV, and wind generators. This work encompassed the up-to-date status of net-metering policies along with the RE penetrations and future goals of Asian countries. A comprehensive review of the published research on net-metering policy in Asia is also presented to provide guidance for the future research in this field. Moreover, bar- riers to net-metering development in Asian countries and recommendations to overcome them are briefly discussed. In the conclusion, a case study is also demonstrated in which
the economic valuation of the existing net-metering policy for residential consumers in Pakistan is presented. It is noted that net-metering at the aggregate demand level becomes benefi- cial to residential consumers after a certain threshold of the installed PV capacity is reached. Furthermore, the net present value analysis of the considered case study scenarios suggests that the Case 2a and 2c are found to be feasible net-metering options with payback periods of 7.5 and 8.1 years, respectively.
ACKNOWLEDGMENT The authors would like to thank Ms. E. Seals and Ms. H. Coffman (Office of Graduate Studies, Missouri Uni- versity of Science and Technology, USA) for their assistance with technical editing that significantly improved quality of the manuscript.
REFERENCES [1] U. Mirza, N. Ahmad, T. Majeed, and K. Harijan, ‘‘Wind energy devel- opment in pakistan,’’ Renew. Sustain. Energy Rev. , vol. 11, no. 9, pp. 2179–2190, Dec. 2007. [2] M. Ashraf Chaudhry, R. Raza, and S. A. Hayat, ‘‘Renewable energy technologies in pakistan: Prospects and challenges,’’ Renew. Sustain. Energy Rev. , vol. 13, nos. 6–7, pp. 1657–1662, Aug. 2009. [3] D. Fernandez-Cerero, A. Fernandez-Montes, and A. Jakobik, ‘‘Limiting global warming by improving data-centre software,’’ IEEE Access , vol. 8, pp. 44048–44062, 2020. [4] M. Tükenmez and E. Demireli, ‘‘Renewable energy policy in turkey with the new legal regulations,’’ Renew. Energy , vol. 39, no. 1, pp. 1–9, Mar. 2012. [5] H. Abunima and J. Teh, ‘‘Reliability modeling of PV systems based on time-varying failure rates,’’ IEEE Access , vol. 8, pp. 14367–14376, 2020. [6] W. ur Rehman, M. F. N. Khan, I. A. Sajjad, and M. Umar Afzaal, ‘‘Probabilistic generation model for grid connected wind DG,’’ J. Renew. Sustain. Energy , vol. 11, no. 4, Jul. 2019, Art. no. 045301. [7] M. U. Afzaal, I. A. Sajjad, A. B. Awan, K. N. Paracha, M. F. N. Khan, A. R. Bhatti, M. Zubair, W. U. Rehman, S. Amin, S. S. Haroon, R. Liaqat, W. Hdidi, and I. Tlili, ‘‘Probabilistic generation model of solar irradiance for grid connected photovoltaic systems using weibull distribution,’’ Sus- tainability , vol. 12, no. 6, p. 2241, Mar. 2020. [8] A. A. Khan, M. Q. Khan, S. G. Satti, and M. Adil, ‘‘Robust control of hybrid distributed generation for frequency regulation,’’ in Proc. 14th Int. Bhurban Conf. Appl. Sci. Technol. (IBCAST) , Jan. 2017, pp. 285–290. [9] M. B. Hayat, D. Ali, K. C. Monyake, L. Alagha, and N. Ahmed, ‘‘Solar energy–A look into power generation, challenges, and a solar-powered future,’’ Int. J. Energy Res. , vol. 43, no. 3, pp. 1049–1067, Mar. 2019. [10] H. Mehdipoor and S. Jadid, ‘‘Scheduling of electrical vehicles consider- ing uncertainty of PV generations in smart homes,’’ in Proc. 19th Conf. Electr. Power Distrib. Netw. (EPDC) , May 2014, pp. 7–12. [11] A. Welfle, P. Thornley, and M. Röder, ‘‘A review of the role of bioenergy modelling in renewable energy research & policy development,’’ Biomass Bioenergy , vol. 136, May 2020, Art. no. 105542. [12] J. Z. Thellufsen, H. Lund, P. Sorknæs, P. A. Østergaard, M. Chang, D. Drysdale, S. Nielsen, S. R. Djørup, and K. Sperling, ‘‘Smart energy cities in a 100% renewable energy context,’’ Renew. Sustain. Energy Rev. , vol. 129, Sep. 2020, Art. no. 109922. [13] D. Ali and A. U. Rehman, ‘‘Adoption of autonomous mining system in Pakistan–Policy, skillset, awareness and preparedness of stakeholders,’’ Resour. Policy , vol. 68, Oct. 2020, Art. no. 101796. [14] S. Ayyadi and M. Maaroufi, ‘‘Optimal framework to maximize the work- place charging station owner profit while compensating electric vehicles users,’’ Math. Problems Eng. , vol. 2020, pp. 1–12, May 2020. [15] J. Blazquez, R. Fuentes-Bracamontes, C. A. Bollino, and N. Nezamuddin, ‘‘The renewable energy policy paradox,’’ Renew. Sustain. Energy Rev. , vol. 82, pp. 1–5, Feb. 2018. [16] S. Bigerna, C. A. Bollino, and S. Micheli, ‘‘Renewable energy scenarios for costs reductions in the European union,’’ Renew. Energy , vol. 96, pp. 80–90, Oct. 2016.
