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Power system stability issues and the lack of studies of the impact of relevant renewable energy networks are factors hindering the use of large-scale integration of renewable energy sources. This study focuses on examining the impact of photovoltaic system integration on the power stability of the power grid. The integration of this photovoltaic involves the analysis of the static and dynamic state of the electrical network. Load flow simulation is performed to assess the performance of static conditions of the power grid. Furthermore, dynamic analysis is carried out by applying 3-phase short circuits at critical points of the network and observing how harmonic and stability in the system. The simulation was carried out using the ETAP 19.0. Simulations of existing conditions and after penetration of the photovoltaic system showed the buses had THDv and THDI values below the permissible standards, respectively. In addition, the existing power flow simulation experiences a voltage drop from the nominal voltage. Masalah stabilitas sistem tenaga dan kurangnya studi akan dampak dari jaringan energi terbarukan yang relevan merupakan faktor yang menghambat penggunaan integrasi skala besar dari sumber energi terbarukan. Penelitian ini fokus mengkaji dampak integrasi sistem fotovoltaik pada stabilitas daya jaringan listrik. Integrasi sistem fotovoltaik ini melibatkan analisis keadaan statis dan dinamis dari jaringan listrik. Simulasi aliran beban dilakukan untuk menilai kinerja kondisi statis dari jaringan listrik. Selanjutnya, analisis dinamik dilakukan dengan menerapkan hubung singkat 3 fasa pada titik-titik kritis jaringan dan mengamati bagaimana harmonisa dan stabilitas pada sistem. Simulasi dilakukan dengan menggunakan perangkat lunak ETAP 19.0. Simulasi kondisi sebelum dan setelah penetrasi sistem fotovoltaik menunjukkan bus masing-masing memiliki nilai THDv dan THDI dibawah standar yang diperbolehkan. Selain itu, simulasi aliran daya kondisi sebelum integrasi mengalami jatuh tegangan dari tegangan nominal.

One-dimensional ZnO exhibits high polarization but is considered to be non-ferroelectric. Here, we show ferroelectricity in carbon-doped ZnO nanocolumnars deposited using one-step DC-unbalanced magnetron sputtering. Doping carbon effectively increases its lattice strain and turns the ZnO nanocolumnars into a ferroelectric material. The existence of a reversible permanent electric dipole is found from the P–E hysteresis loop of the carbon-doped ZnO nanocolumnars, where the highest coercivity (11.1 kV/cm) originated from zinc vacancies and remnant polarization (4.7 μC/cm2) originated from oxygen vacancies. Moreover, the presence of carbon modified the optical bandgap of the system. Supporting the experimental results, the first-principle calculation shows that the increment of C concentration decreases bandgap contributed by C 2p. Furthermore, the existence of ferroelectricity in ZnO has the potential to bring out the multiferroic properties for developing next-generation ZnO-based storage devices.

This study focuses on the public building in Indonesia that has implemented an energy management system compliant with ISO 50001 standard. The main objectives of this study are to review the implementation of the energy management system in the building, highlighting the main aspect of the ISO cycle deployment and key lessons learned for further dissemination. We performed the study of the implementation of energy management in the building sector based on the ISO 50001 framework that aims to enhance an organization to pursue the continuous improvement of energy management with a systematic approach. Implementing the plan, do, check and act cycle of the ISO’s framework, it is found that the management keeps a strong commitment to continuous improvement. As part of the energy management system cycle, an Investment Grade Audit (IGA) was performed in 2018. Implementing the IGA recommendation, both passive and active designs have been applied in the Slamet Bratanata building. Active design strategies that have been implemented include building automation system utilization, chiller and lighting replacement and Energy Monitoring System (EMonS) application. Implemented passive designs include windows film installation and an efficient room redesigned for optimizing natural light. To implement the ISO 50001 Energy Management System in the building, the energy management team has also held various activities. It includes developing Standard Operating Procedures, appointing a Person in Charge on each floor, conducting capacity building and performing an energy efficiency campaign. It is estimated that the energy management system has succeeded in reducing energy consumption by 613.188 kWh (in 2018–2020) and the Energy Efficiency Index by 129.06 kWh/m2/year in 2020. Furthermore, management energy implementation also reduced greenhouse gas emissions by 539.60 tons of CO2 equivalent. This study provides a reference for energy management in another building for improving its energy performance.

Street lighting can be considered the main energy consumer and greenhouse gas emitter at Indonesia's city level. In addition, public street lighting systems throughout Indonesia still use inefficient technologies, resulting in a significant portion of a municipality’s operating expenditure. We conduct techno-economy analysis and formulate financing mechanisms to support energy efficiency improvements on street lighting systems. In doing so, a pilot case based on a survey in one of the provincial capitals in Kalimantan is performed. From the survey, it is found that around half of the street lighting systems in the observed city are unmetered, dominated by CFL (Compact Fluorescent Lamp) lamps. Efficiency through street lighting system improvement can be achieved through, among others, replacement with a highly efficient light-emitting diode (LED) lamp, power meters installation and the replacement of high-efficiency armatures. Our analysis shows that energy consumption reduction potential from street light system improvements can reach 69% from existing conditions. In the showcase, it can save 9,466,465 kWh, equal to energy costs of IDR 13,676,202,724 and a 7,667-ton emission reduction. From the analysis, we also delivered a financial scheme for the project that incorporated local government and special mission vehicles under the coordination of the Ministry of Finance. Having great potential, a financing support mechanism can become a reference to another local government with a limited budget constraint. These findings can also provide policymakers with important inputs while improving street lighting systems as a key service provided by local and municipal governments.

Having great potential, a mechanism that can leverage private involvement in energy efficiency deployment should be developed in emerging markets such as Indonesia. This study aimed to formulate an implementable financial innovative scheme for leveraging energy efficiency deployment in the country. Scrutinizing relevant studies and interviewing relevant stakeholders such as the Ministry of Finance, Ministry of Energy and the Financial Institution, we formulated a blended financial scheme for an energy efficiency project. Main stakeholders will include the scheme, including fund facilitator, trustee, custodian bank and energy user/energy service company. In our proposed scheme, Indonesia Environment Fund (IEF) is obtained the fund from the fund facilitator. IEF will act as a trustee that delivers funds for the Custodian Bank. The bank will disburse the fund to the feasible energy efficiency project or through an energy service company. In this scheme, since banks get lower interest rate funds from the trustee, they will disburse the fund to the customer with a lower interest rate than a commercial rate. Consumers utilize the fund for their energy efficiency projects. Utilizing a proposed scheme to an energy efficiency project case study, it is found that the proposed scheme potentially reduces the interest rate and leverages the project viability in a certain condition. Doing the sensitivity analysis by comparing interest rate and IRR (Internal Rate of Return) in several loan periods, we found that the shorter period of the loan and lower interest rate can improve projects feasibility. For instance, simulating a 5-year loan, it is found that reducing the interest rate from 12% to 7% could improve up to 2% IRR of the project case. Therefore, the scheme can catalyze private-sector investments mobilization for energy efficiency deployment in the country. Furthermore, it can support the country's energy security enhancement.

We report a new direct fabrication of the ZnO nanorods (NR) by hydrothermal method, in which the preparation of seed layer is eliminated. We show that the tuning of initial temperature rate during the hydrothermal process plays a key role in the structural modification of the ZnO NR. A highly oriented ZnO NR is successfully fabricated by using a low rate of initial temperature. The increase of optical absorption and electron transport was obtained by reducing the diameter and increasing distribution of the ZnO NR on the substrate. Interestingly, an additional absorption from the defects is obtained in the system, which plays an important role in expanding the optical absorption. Our system will provide a favourable characteristic for developing the high-performance optoelectronic devices with high optical absorption and high electron transport.

The aim of this research is to investigate the photodegradation of Methylene Blue with Fe3O4/ZnO core-shells. Fe3O4/ZnO core-shells were synthesized by a simple two-step chemical method (co-precipi...

Rock art comprises various forms of images and markings, including paintings, drawings, and engravings, created by prehistoric people on immobile surfaces of rocks. In Indonesia, the distribution of rock art sites has been relatively well studied and documented. Indeed, Uranium-series analysis of speleothem materials overlying negative hand stencils and naturalistic animal paintings from the limestone karsts of Maros in southern Sulawesi shows that the rock art in this region dates to at least 40,000 years ago, and is thus among the world's oldest. To our knowledge, the chemistry of the Sulawesi rock art, including that of the pigments used for making these images, and with particular regard to the topology and morphology of these materials, have not yet been systematically investigated. In this study, we report the results of our spectroscopic and microscopic analyses of two samples of pigment collected from rock art motifs at Leang Sumpang Bita 2 in Pangkep, South Sulawesi. The first and second samples possess dark red and purple colours, respectively. Analysis shows that both samples contain iron oxide, which may explain their reddish colours. Nevertheless, microstructural differences are evident, including crystal morphology and size, and, in our view, are responsible for the discrepancy in the observed pigment colours. Our findings suggest that the sampled dark red and purple pigments are from the same raw material source (ochre), but differ in colour because of mechanically-induced alteration, presumably the result of varying pigment-processing methods used by the prehistoric artists.

Efforts to reduce carbon dioxide (CO2) emissions remain elusive due to the strong correlation with economic development. The progress of economic development therefore needs to be assessed by considering the harmful effects of CO2 emissions as a loss of intergenerational well-being. This has been the motivation behind the development of the inclusive wealth (IW) index, which is proposed as a viable alternative to the conventional gross domestic product for tracking the progress towards the well-being of a nation. By using nonparametric machine learning methods, this study aims to explore the impact of CO2 emission reduction on well-being under the IW framework via three different energy pathways, namely, the supply, mix and efficiency pathways, involving 105 countries from 1992 to 2014. Results showed that the lowest growth in global CO2 emissions was projected by the efficiency scenario, which forecasted an increase by 2040 of 15.12% relative to the 2014 level. However, this scenario might lead to a potential loss in future well-being by up to 0.3%, compared to the two other scenarios. These findings suggest that the commitment to CO2 emission reduction needs to be evaluated cautiously by considering its impact on intergenerational well-being, particularly for developing economies. In contrast, high-income economies were encouraged to set up a more ambitious target of CO2 emission reduction since doing so would also lead to a potential increase of their intergenerational well-being. This study verifies a robust link between sustainable development and CO2 emission mitigation scenarios, which is essential for promoting future climate actions.

A cuttlefish bone contains Ca of 96.24% that is highly potential to be used in HA production. This study is focused to synthesize the HA by using starting materials of Ca(OH)2 from cuttlefish bone. A sonochemical method was implemented for preparing the HA/CS composites. The composition of HA/CS composites was maintained with a ratio of 90:10, 80:20, 70:30, and 60:40 (in %wt.). The synthesized of HA has a crystal size of 25.40 nm and the Ca/P ratio of 1.67. The XRD analysis showed that the increase of the chitosan content change crystal size of HA and HA/CS composites in nano-scale.

Increasing the efficiency of the household sector's energy consumption plays a significant role in reducing CO2 emissions, particularly for Indonesia, the world's fourth most populous country. However, there is a lack of analytical studies on the driving forces of emissions from the household sector in Indonesia, including the contribution of one of the world's largest efforts to promote a cleaner cooking fuel program. We intend to examine the characteristics of the Indonesian energy matrix and its evolution in the household sector alongside the impact of kerosene to the Liquid Petroleum Gas (LPG) conversion program to the Indonesian emissions change in the sector. We also investigate the underlying determinant of emissions change, both directly and indirectly, from household energy consumption in Indonesia from 2000 to 2015. For this purpose, we conduct the Logarithmic Mean Divisia Index (LMDI) decomposition analysis. We found that population and income led to increases of both direct and indirect energy emission, while the impact of energy intensity was the opposite. The fuel mix and carbon intensity effect, which reflects the conversion of kerosene to LPG, contributes to reducing direct emissions with limited effect. High share growth of coal in electricity generation led to increasing indirect emissions for the period. Our findings have important policy implications, particularly for increasing the share of new and renewable energy in the national energy mix and for intensifying energy efficiency in the household sector.

The main keys in developing solar cells are their optical absorption and electron transfer (optical conductivity) levels. To enhance these two characteristics, an electron transport layer (ETL) was added to the solar cell, which is used to prevent electron recombination. Zinc oxide nanorod (ZnO NR) is one of the potential ETL candidates in the new generation of solar cells due to its high electron transfer. To optimize the use of ZnO NR in new generation solar cells, we combine NR ZnO with graphene, into a hybrid ZnO NR/graphene system. Optical absorption and conductivity of hybrid ZnO NR/graphene were studied using spectroscopic ellipsometry. A significant change in ellipsometry spectra has been observed, which increases with a higher number of graphene in the hybrid systems. Furthermore, the role of graphene on the optical absorption and conductivity of hybrid systems was investigated through fittings by applying the effective medium approximation (EMA) model. This study will provide a good understanding of optical absorption and optical conductivity of hybrid ZnO NR/graphene, which is an important key in the development of high-performance new generation solar cells.

Fe2O3/ZnO heterojunction has attracted great attention due to the possibility of overcoming low Photoelectrochemical (PEC) cell efficiency the limitation of a single layer of semiconductor electrodes. The aim of this study is to investigate the effect of Fe2O3, ZnO and Fe2O3/ZnO films on PEC efficiency. The Fe2O3, ZnO and Fe2O3/ZnO films were fabricated by spin coating and doctor blade methods, respectively. All the films were characterized by XRD, SEM, and Cyclic Voltammetry (CV). Based on structural results, Fe2O3 and ZnO nanoparticles can grow well on the ITO substrate and they exhibit trigonal and hexagonal crystal structures, respectively. Moreover, we found that the PEC efficiency increases after ZnO are coated on Fe2O3 film. The combination of Fe2O3 and ZnO can effectively increase the separation of electrons and holes that can improve the photocatalytic activity of PEC cells based on the structural coordinates of their energy levels.

This paper explores the effects of economic growth, urbanization, industry, and trade openness on coal consumption in Indonesia over the period 1970–2015. To closely adhere to the Environmental Kuznets curve narratives, we consider coal consumption which has been scarcely explored in the EKC debate, as a proxy of environmental pressure. We estimate the autoregressive distributed lag (ARDL) method and confirm that the variables are cointegrated for long run linkage with the presence of structural breaks. The empirical evidence showed that economic growth, urbanization and trade openness increase coal consumption while decreasing share of secondary industry reduce it. We also verify the existence of environmental Kuznets curve. Having a vital role in the energy mix, Indonesia needs to restrain excessive coal consumption to enhance environmental quality. Our results also imply urbanization and trade openness are crucial factors on coal consumption. Consequently, it should be taken into consideration in energy policy-making process, such as energy conservation policies in the residential sector and prioritize foreign investment which brings cutting-edge coal technologies.