Korea Institute Of Energy Research Research Articles

Application of green hydrogen with theoretical and empirical approaches of alkaline water electrolysis: Life cycle-based techno economic and environmental assessments of renewable urea synthesis

Alkaline water electrolysis which is the most commercialized and mature technology of water electrolysis was researched to improve performance by the Korea Institute of Energy Research (KIER). In line with the trend of energy shift, renewable urea production through hydrogen production from alkaline water electrolysis was proposed in this work. To validate the process modeling of renewable urea production and hydrogen performance analysis with I–V curves was assessed. Economic and life cycle assessments were conducted to provide quantitative guidelines for renewable urea production. Absolutely, the influential factor of unit urea production cost was hydrogen from alkaline water electrolysis and environmental assessment results as well. Moreover, the guidelines for renewable urea production were provided through cost estimation and life cycle assessment. In summary, hydrogen production from alkaline water electrolysis had a significant impact on urea production and for this reason, research on alkaline water electrolysis should continue for further development.

Information Analysis on Foreign Institution for International R&D Collaboration Using Natural Language Processing

The number of international collaborations in research and development (R&D) has been increasing in the energy sector to solve global environmental problems—such as climate change and the energy crisis—and to reduce the time, cost, and risk of failure. Successful international project planning requires the analysis of research fields and the technology expertise of cooperative partner institutions or countries, but this takes time and resources. In this study, we developed a method to analyze the information on research organizations and topics, taking advantage of data analysis as well as deep learning natural language processing (NLP) models. A method to evaluate the relative superiority of efficient international collaboration was suggested, assuming international collaboration of the National Renewable Energy Laboratory (NREL) and the Korea Institute of Energy Research (KIER). Additionally, a workflow of an automated executive summary and a translation of tens of web-posted articles is also suggested for a quick glance. The valuation of the suggested methodology is estimated as much as the annual salary of an experienced employee.

Improved Clear Sky Model from In Situ Observations and Spatial Distribution of Aerosol Optical Depth for Satellite-Derived Solar Irradiance over the Korean Peninsula

In solar resource assessment, the climatological environment of the target area is objectively quantified by the cloudiness or clear sky index, which is defined as the ratio of global horizontal irradiance to clear sky solar insolation. The clear sky model calculates incoming solar irradiance on the ground surface considering several atmospheric parameters such as water vapor and aerosol optical depth. This study investigated the importance of aerosol optical depth for deriving clear sky irradiance in radiative transfer models and examined its viability in a universal or community model for public use. The evaluation was conducted based on ground observations at the Korea Institute of Energy Research (KIER) station from January to December 2021. The original simulation was performed using the monthly mean of aerosol optical depth obtained from the Aerosol Robotic Network station; the mean absolute error was 29.9 W m−2. When the daily mean of in situ observations at KIER was incorporated into the clear sky model, the mean absolute error was reduced to 9.7 W m−2. Our results confirm that the clear sky model using gridded datasets of aerosol optical depth is suitable for use as a universal or community model.

Hydrogen Production in Methane Decomposition Reactor Using Solar Thermal Energy

This study investigates the decomposition of methane using solar thermal energy as a heat source. Instead of the direct thermal decomposition of the methane at a temperature of 1200 °C or higher, a catalyst coated with carbon black on a metal foam was used to lower the temperature and activation energy required for the reaction, and to increase the yield. To supply solar heat during the reaction, a reactor suitable for a solar concentrating system was developed. In this process, a direct heating type reactor with quartz was initially applied, and a number of problems were identified. An indirect heating type reactor with an insulated cavity and a rotating part was subsequently developed, followed by a thermal barrier coating application. Methane decomposition experiments were conducted in a 40 kW solar furnace at the Korea Institute of Energy Research. Conversion rates of 96.7% and 82.6% were achieved when the methane flow rate was 20 L/min and 40 L/min, respectively.

Integrative techno-economic and environmental assessment for green H2 production by alkaline water electrolysis based on experimental data

Alkaline water electrolysis has been in the spotlight for green H2 production using electricity generated from renewable energy because of its high technology readiness level and low investment. However, commercialization of alkaline water electrolysis is challenging because of the low current density. Therefore, a techno-economic and environmental assessment was conducted for green H2 production by alkaline water electrolysis with experimental data from the advanced alkaline water electrolysis system of the Korea Institute of Energy Research (KIER) to identify the potential of this technology. Based on techno-economic analysis results, the stack cost and unit electricity price must be below 0.035 $ kWh−1 and 406 $ kW−1, respectively, to make this technology cost-competitive compared to the conventional H2 production method (< 2 $ kgH2−1). Furthermore, CO2 emissions of 30.7, 17.4, 7.04, and 3.12 kgCO2-eq kgH2−1 were obtained for the current, 2030, 2050, and renewable Korean electricity mix scenarios, respectively, indicating that both scenarios (Korean electricity mix in 2050 and renewable) have lower CO2 emissions than the conventional H2 production method (11.5 kgCO2-eq kgH2−1). In addition, environmental impact reductions of 89.8%, 83.6%, 65.9%, and 91.0% for CO2 emissions, stratospheric ozone depletion, fine particulate matter formation, and fossil resource scarcity, respectively, were obtained for the renewable scenario compared to the current Korean electricity mix. Therefore, the electricity source has significant effects on the economic feasibility and environmental impacts for green H2 production.

Understanding of Fouling of Ion Exchange Membranes in Reverse Electrodialysis

Reverse electrodialysis(RED) is an energy conversion technology to convert chemical energy generated by concentration gradient into electrochemical energy. Mixing of two bodies with different concentration is common phenomena observed at places where river water meets sea water. When two bodies are mixed, energy of high concentration body suddenly transport to that of low concentration body. It is too short to extract the energy from the process. Thus, controlled concentration gradient could be formed in RED stacks which are alternately arranged by a cation- and an anion-exchange membrane between two electrodes. For the application of RED in several field sites, most of the technology using membranes needs fouling control to minimize a decrease in performance. In this study, the fouling phenomena of ion exchange membranes for various foulants possibly found in seawater and river water were investigated. Electrical resistance is used as indicator to evalue the degree of contamination by positively, negatively and non-charged foulants. The fouled membranes were regenerated, and the electric resistance and the degree of contamination with regeneration time were measured.AcknolwedgmentThis work was conducted under the framework of the Research and Development Program of the Korea Institute of Energy Research (KIER) (Project Number: B9-2441).

Preface

The International Conference of Biomass and Bioenergy 2019 was successfully conducted by Surfactant and Bioenergy Research Center (SBRC), IPB University in cooperation with International Society of Biomass and Bioenergy (ISBB); Niigata University of International and Information Studies; Universiti Teknologi PETRONAS, Malaysia; Korea Institute of Energy Research, South Korea; College of Engineering, Villanova University, USA; Biomass Project Research Center, Hiroshima University, Japan; and was supported by The Indonesian Oil Palm Estate Fund (BPDP Sawit), PT. Bogor Life Science and Technology IPB, PT. Adev Natural Indonesia, Indonesian Biofuel Producers Association (APROBI), and IPB University, on 19-20 August 2019 in Bogor, Indonesia. This conference with the theme of Biomass and Bioenergy, A Pathway for Sustainable Development Goals was the fourth international scientific conference on biomass and bioenergy in Indonesia. This conference is conducted annually to raise current global issues in biomass and bioenergy fields.The committee accepted 45 of over 54 papers which were presented in the conference and the selected papers are published in this ICBB 2019 proceedings. These papers were classified into the following groups:1. Production Technology of Bioenergy,2. Biomaterial and Biochemical,3. Feedstock, Business, Environment.List of Reviewers of International Conference of Biomass and Bioenergy 2019 are available in this pdf.

Preparation and Characterization of the Glycerol-Embedded Hybrid Coal

The molasses embedded hybrid coal (Hybrid Coal by Korea Institute of Energy Research; HCK) was previously proposed as an attractive alternative to low-rank coals that tend to show low calorific values and high CO2 emissions. HCK was synthesized by mixing molasses with a low-rank coal to enhance its heating value. Nevertheless, food ethics regarding molasses additives still have impeded its commercial acceptance. In this study, we propose a glycerol (nonfood)-based coal upgrading process to improve the combustion kinetics and heating value of hybrid coal in comparison to the previous HCK. The process involves drying at 105 °C followed by torrefaction process at 250 °C. During torrefaction, the glycerol additive starts to evaporate at about 180 °C and then is almost vaporized out to the coal surface. To avoid glycerol loss, we employ sulfuric acid as a torrefaction catalyst to suppress glycerol evaporation. In comparison to the molasses yield of 65% after torrefaction in the previous HCK synthesis process, ...

Development of SEED (solar energy estimator for Daejeon) using chollian satellite imagery

Daejeon Metropolitan City and the Korea Institute of Energy Research (KIER) have developed a platform with the Solar Energy Estimator for Daejeon (SEED) for Daejeon citizens and solar power generation companies according to the government plan to expand new and renewable energy. Developed through four phases, the platform can calculate the solar irradiance by reflecting the shading variation of urban buildings and compute the power generation considering the module performance. The estimated power generation by the platform exhibited high accuracy of R2 = 0.89 compared with the ground power generation amount. The SEED was developed to satisfy both accuracy and convenience requirements, and it is expected to meet the purpose of solar energy expansion and promotion.

3rd International Conference on Biomass: Accelerating the Technical Development and Commercialization for Sustainable Bio-based Products and Energy

The 3rd International Conference on Biomass 2018 was successfully conducted by Surfactant and Bioenergy Research Center (SBRC), Bogor Agricultural University (IPB) in cooperation with Indonesian Bioenergy Expert Association (IKABI), Indonesian Biogas Association (AbgI), Niigata University of International and Information Studies; University of Science Malaysia (USM), Malaysia; Japan International Research Center for Agricultural Sciences (JIRCAS), Japan; College of Engineering, Villanova University, USA; Biomass Project Research Center, Hiroshima University, Japan; Korea Institute of Energy Research (KIER), Republic of Korea; Graduate School of Energy Science, Kyoto University, Japan; Head of Energy and Environment Unit, Malaysian Palm Oil Board, Malaysia; and was supported by Indonesia Estate Crop Fund Palm Oil; PT Indocement Tunggal Prakarsa Tbk; The Ministry of Research, Technology, and Higher Education Republic of Indonesia; Bogor Agricultural University on 1-2 August 2018 in Bogor, Indonesia. This conference with the theme of Accelerating the Technical Development and Commercialization for Sustainable Bio-based Product and Energy was the third international scientific conference on biomass in Indonesia. This biomass-themed conference is conducted annually to raise current global issues in biomass.The committee accepted 56 of over 95 papers which were presented in the conference and the selected papers are published in this ICB 2018 proceeding. These papers were classified into the following groups:1. Production Technology of Bioenergy2. Biomaterial and Biochemical3. Feedstock, Environment, Sustainability, Policy4. Management, Business, Economy, ICT, Other Products/Applications.

A study on heat transfer characteristics of quinary molten salt mixture

In this study, experimental analysis of the heat transfer characteristics of a quinary molten salt mixture was carried out. This mixture was developed at Korea Institute of Energy Research as a heat storage material for a solar thermal power plant. Experiments were conducted to obtain the heat transfer coefficient in a vertical tube and to generate steam in a heat exchanger. To obtain the heat transfer coefficient, the temperatures of the outer wall, inlet, and outlet were measured in upward molten salt flow. Heat transfer correlations were proposed for the molten salt based on experimental data. The accuracies of the correlations were 60% and 88% for the transition and turbulent flow regions, respectively, with an error range of ±20%. A concentric heat exchanger was used for steam production to use the molten salt for power generation. Superheated steam at 100 bar and 400 °C was generated through heat transfer between the high temperature molten salt and water, with an efficiency of 81–91%.

Fouling Mitigation of Ion Exchange Membranes in Reverse Electrodialysis

Reverse electrodialysis converts electrochemically into energy conversion technology due to the difference in salinity between diluted salt solutions such as seawater and dilute salt solutions such as fresh water. The RED stack has a cation exchange membrane and anion exchange membrane alternately arranged between two electrodes that selectively transmit anions and cations. Ion exchange membranes are easily contaminated with multivalent ions and organic matter, which affects the performance of RED. In this study, the fouling phenomena of cation and anion exchange membranes for various foulants possibly found in seawater and river water were investigated. Ion exchange membranes were contaminated with NaCl solution containing foulants, and the electrical resistance and the degree of contamination with contamination time were measured. The cation exchange membrane is contaminated with a cationic foulants and the anion exchange membrane is contaminated with anionic foulants. The fouled membranes were regenerated, and the electric resistance and the degree of contamination with regeneration time were measured. Acknowledgment This work was conducted under the framework of Research and Development Program of the Korea Institute of Energy Research (KIER) (B8-2441).

Numerical study on thermal performances of 2.0 kW burner for the cabin heater of an electric passenger vehicle

This study used a numerical method to investigate the thermal performance of a 2.0 kW burner in heating the cabin of an electric passenger vehicle. The thermal performance (including temperature distribution, velocity distribution, heat flux, burner efficiency) and fuel performance (including species variation, NOx concentration) with the fuel types, mass flow rates and the inlet temperature were investigated with a numerical simulation using the standard k-ε, RNG k-ε and realizable k-ε turbulence models. The results were validated within 8% that of experimental data obtained by the Korea Institute of Energy Research, Republic of Korea. The standard k-ε turbulence model with the eddy dissipation combustion model showed a close agreement with the experimental data, compared to the RNG k-ε and realizable k-ε turbulence models. As a result, a maximum heat flux of 2171.5 W was observed for butane at a fuel mass flow rate of 0.000057 kg/s and an air inlet temperature of 0 °C. The maximum burner efficiency of 96.7% was observed for methane at a fuel mass flow rate of 0.000030 kg/s and at an inlet air temperature of 0 °C. A minimum NOx concentration of 5.5 ppm was observed for propane at a fuel mass flow rate of 0.000030 kg/s and inlet air temperature of −20 °C. In addition, the butane fuel could be suggested to be effective for the 2.0 kW burner to heat the cabin of an electric passenger vehicle.

Development of Reversible Solid Oxide Cell System at Korea Institute of Energy Research

Korea Institute of Energy Research (KIER) is placed on Daejeon, South Korea, which has had focused on energy technology R&D related with our living standards and national security since 1977. KIER`s R&D areas include improving efficiency and securing environment friendly way in use of limited conventional energy resources (oil, coal, natural gas) and exploring new energy sources (solar, wind, hydrogen and water). The KIER is conducting a consortium project (~ $ 10m/yr) of MSIT( Ministry of Science and ICT), ME (Ministry of Environment), MOTIE(Ministry of Trade, Industry and Energy). This is about Research and Development of Future Energy Storage Technology by Using Hybrid Renewable Energy System, based on solid oxide electrolysis technology. In this project, Energy Materials Laboratory in KIER is charge of development of 30 kW stack consisted with modules of flat-tube type unit cells to produce electricity on fuel cell mode and hydrogen on electrolysis mode. The unit cell is consisting with Ni-YSZ anode support, YSZ electrolyte, GDC buffer layer, LSCF cathode and LSF interconnector. Ni-YSZ support and LSF layer exposed to reducing/high steam environment, has been optimizing to stabilize their phases. Energy saving Laboratory in KIER is development of combustion boiler using waste to supply steam and heat. In addition, Hydrogen Laboratory is developing Hydrogen storage system. In this presentation, the detailed research plans and cooperation system for diverse groups will be presented, as well as current core research results from SOC unit cell to stack system.

Kinetically Controlled Growth of Phase‐Pure SnS Absorbers for Thin Film Solar Cells: Achieving Efficiency Near 3% with Long‐Term Stability Using an SnS/CdS Heterojunction

AbstractFacile control over the morphology of phase pure tin monosulfide (SnS) thin films, a promising future absorber for thin film solar cells, is enabled by controlling the growth kinetics in vapor transport deposition of congruently evaporated SnS. The pressure during growth is found to be a key factor in modifying the final shape of the SnS grains. The optimized cube‐like SnS shows p‐type with the apparent carrier concentration of ≈1017 cm−3 with an optical bandgap of 1.32 eV. The dense and flat surface morphology of 1 µm thick SnS combined with the minimization of pinholes directly leads to improved diode quality and increased shunt resistance of the SnS/CdS heterojunction (cell area of 0.30 cm2). An open‐circuit voltage of up to 0.3068 V is achieved, which is independently characterized at the Korea Institute of Energy Research (KIER). Detailed high‐resolution transmission electron microscopy analysis confirms the absence of detrimental secondary phases such as Sn2S3 or SnS2 in the SnS grains or at intergrain boundaries. The initial efficiency level of 98.5% is maintained even after six months of storage in air, and the final efficiency of the champion SnS/CdS cell, certified at the KIER, is 2.938% with an open‐circuit voltage of 0.2912 V.

Preliminary experimental study of a supercritical CO2 power cycle test loop with a high-speed turbo-generator using R134a under similarity conditions

Research on applying a supercritical carbon dioxide power cycle (S-CO2) to concentrating solar power (CSP) instead of a steam Rankine cycle or an air Brayton cycle has been recently conducted. An S-CO2 system is suitable for CSP owing to its compactness, higher efficiency, and dry-cooling capability. At the Korea Institute of Energy Research (KIER), to implement an S-CO2 system, a 10 kWe class test loop with a turbinealternator-compressor (TAC) using gas foil bearings was developed. A basic sub-kWe class test loop with a highspeed radial type turbo-generator and a test loop with a capability of tens of kWe with an axial type turbogenerator were then developed. To solve the technical bottleneck of S-CO2 turbomachinery, a partial admission nozzle and oil-lubrication bearings were used in the turbogenerators. To experience the closed-power cycle and develop an operational strategy of S-CO2 operated at high pressure, an organic Rankine cycle (ORC) operating test using a refrigerant as the working fluid was conducted owing to its operational capability at relatively lowpressure conditions of approximately 30 to 40 bar. By operating the sub-kWe class test loop using R134a as the working fluid instead of CO2, an average turbine power of 400 W was obtained.

Development of load models and operation simulator for a building complex with mixtures of multi-type engines and renewable devices

A building load model for the electricity consumption of the KIER (Korea Institute of Energy Research) complex was developed by compiling the year-round hourly data of each member building. Heating and cooling load models for the complex were also estimated by building TRNSYS models for the member buildings. By matching measured data that are only available for a limited time on a building, suitable parameter values for the TRNSYS simulation were empirically determined. Then, an operational simulator that can accommodate arbitrary combinations of energy producing devices was developed. Our simulator allows for prioritization among the energy supplying devices, and cases where photovoltaic (PV) and solar thermal devices are mixed can be easily simulated. Several scenarios were composed for the KIER buildings. Tested components include small to medium-size conventional cogeneration systems and renewable energy production devices such as photovoltaic cells, solar collectors, fuel cells, and bio-ORC (organic Rankine cycle). Tests reveal that our tool produces reasonable results of physical quantities such as electricity production, fuel consumption, and the device operational characteristics. Scenario comparisons were made as a preliminary part of a feasibility study, and renewable energy contribution was estimated.

Design and Implementation of a Microgrid Energy Management System

A microgrid is characterized by the integration of distributed energy resources and controllable loads in a power distribution network. Such integration introduces new, unique challenges to microgrid management that have never been exposed to traditional power systems. To accommodate these challenges, it is necessary to redesign a conventional Energy Management System (EMS) so that it can cope with intrinsic characteristics of microgrids. While many projects have shown excellent research outcomes, they have either tackled portions of the characteristics or validated their EMSs only via simulations. This paper proposes a Microgrid Platform (MP), an advanced EMS for efficient microgrid operations. We design the MP by taking into consideration (i) all the functional requirements of a microgrid EMS (i.e., optimization, forecast, human–machine interface, and data analysis) and (ii) engineering challenges (i.e., interoperability, extensibility, and flexibility). Moreover, a prototype system is developed and deployed in two smart grid testbeds: UCLA Smart Grid Energy Research Center and Korea Institute of Energy Research. We then conduct experiments to verify the feasibility of the MP design in real-world settings. Our testbeds and experiments demonstrate that the MP is able to communicate with various energy devices and to perform an energy management task efficiently.

A Study on Uncertainty to Direct Normal Irradiance of Typical Meteorological Year Data

Typical meteorological year (TMY) data consist of hourly values of solar radiation and meteorological elements over a 1 year period. This reflects the long term meteorological characteristics because it is derived from a long term meteorological database. The data were produced by applying the Sandia method and weighting factor of National Renewable Energy Laboratory (NREL) by new and renewable energy resource center in Korea Institute of Energy Research (KIER), and it was registered as the qualified reference standards in 2015. The reliability of the solar radiation is important as weighting factor of the solar radiation in the TMY data is 50%. The hourly global horizontal irradiance (GHI) among the solar radiation was provided by Korea Meteorological Administration (KMA), and direct normal irradiance (DNI) was predicted by applying Reindl-2 model. The uncertainty of the DNI is higher than the experimental value as it is a predicted value. The GHI, extra-terrestrial radiation, and zenith angle were surmised as the principal factors of uncertainty. The uncertainty on the zenith angle was highest among the 3 factors. The procedure of the uncertainty evaluation obeyed the guide to the expression of uncertainty in the measurement (GUM). The uncertainty on the DNI of TMY data in Daejeon was calculated and analyzed in this paper.

Survey on R&amp;D Demand of New and Renewable Energy Resource Maps in Korea

Renewable energy resource maps that provide solar, wind, hydro, biomass, geothermal energy potential etc. have been used for the renewable energy basic plan and pre-feasibility analysis of renewable energy deployment. To determine the R&D demand for renewable energy resource maps in the Korea Institute of Energy Research, a structured questionnaire survey (about thousand person) and experts in-depth interviews (about hundred person) targeting the users and potential customers of resource maps were conducted from October to November 2015. The survey respondents who experienced resource maps mainly used map types, such as solar energy, hydropower, wind power etc. and mainly for business and academic purposes. 63% of respondents stated that resource maps update cycle should be per annum. Top priority needs to improve map utilization were updates for the latest resources data, higher map resolution, manual for using resource maps etc. 33% of the total respondents were using other institutions’ data. 26% of them purchased the data and spent about 8 million won annually on average for the data used. 48% of the total respondents said that mobile app of resource maps needs to be developed. The demand survey of resource maps contributes to future R&D strategy of renewable energy resource maps.