재생에너지 확대가 탄소배출 및 지역경제에 미치는 영향 연구

학위논문(박사) -- 서울대학교대학원 : 환경대학원 환경계획학과, 2023. 8. 홍종호.지속가능한 미래세대를 위해 에너지 사용으로 인한 탄소배출을 대폭 감축해야 한다. 이 과제는 수입 화석연료에 의존하는 에너지 다소비 산업을 기반으로 성장한 우리나라에는 엄청난 도전이다. 따라서 충분한 논의가 선행되어야 한다. 풍력과 태양광 등의 재생에너지는 자연의 힘으로만 전력을 생산하기 때문에 전력 생산 과정에서 이산화탄소를 배출하지 않는 대표적인 청정에너지원이다. 그러나 재생에너지는 전통적인 중앙발전원과 큰 차이가 있으므로 상당한 변화를 수반한다. 재생에너지는 간헐성으로 인하여 유연성 자원이 필수적이다. 따라서 재생에너지의 광범위한 전후방산업에 의한 탄소배출량까지 고려할 필요가 있다. 한편, 재생에너지는 분산에너지원으로써 지역주민 생활반경에 가까이 위치하기 때문에 수용성 문제가 중요하며, 재생에너지 확대가 지역경제에 미치는 영향에 대한 사회적 관심도 매우 높다. 최근, 녹색 보호주의에 따른 무역분쟁이 전 세계적으로 심화되고 있고, 국가 재생에너지 산업경쟁력 육성 또한 강조되고 있는 추세이다. 본 연구는 재생에너지 시스템의 탄소저감 효과를 극대화하고, 지역사회와 상생할 방안을 마련하기 위하여 재생에너지 확대가 탄소배출과 지역경제에 미치는 영향을 전주기 가치사슬, 국가 및 지역 산업역량 강화, 지역적 특성 등 재생에너지의 고유한 특성을 고려하여 분석하는 데에 목적을 두었다. 본 연구는 크게 세 가지로 구분된다. 첫 번째 연구에서는 제주도에 211MW 규모의 육상풍력 발전이 확대됨에 따라 발생하는 전주기 탄소 배출량을 분석하였다. 방법론으로 비용 분석과 Environmentally-Extended Input-Output (EEIO) 분석에 기반한 Economic Input-Output Life-cycle Assessment (EIO-LCA)를 활용하여 주요 배출원을 파악하고 탄소배출 저감 방안을 제시하였다. 에너지저장시스템 (ESS)의 배터리 제조가 탄소배출의 가장 큰 발생원으로 나타났으며, 터빈 부품 제조가 그 뒤를 이었다. 이 결과는 유연성 자원의 탄소배출 저감 노력이 필요함을 시사한다. 또한 민감도 분석에 따르면 육상풍력 발전소의 설비 이용률과 운영기간 증가가 탄소 배출량 감축 잠재력을 더욱 높일 수 있는 요인으로 파악되었다. 주요 탄소배출 산업으로 1) 전기, 가스 및 증기 2) 1차 금속제품(철강 생산), 3) 비금속 광물제품(시멘트 생산)이 확인되었다. 궁극적으로 에너지산업의 재생에너지의 비중을 높이는 것뿐만 아니라 산업공정의 탄소 저감이 중요함을 시사한다. 두 번째 연구는 육상풍력 확대가 제주도 지역경제에 미치는 영향을 비용 분석과 Interregional Input-Output (IRIO) 분석을 활용하여 국가 및 지역 산업역량을 수준을 수치화한 국가 및 지역 자급률(%) 시나리오 아래 분석하였다. 육상풍력 및 유연성 자원 확대는 광범위한 가치사슬로 인하여 운영기간에 다양한 산업에 걸쳐 부가가치 및 고용 기회를 창출함을 확인하였다. 또한, 운영기간에 발생하는 부가가치 유발효과는 제주도의 건설업, 요식업.숙박업, 농수산업과 비슷한 수준으로 나타났다. 재생에너지 시스템은 육상풍력과 직접적으로 관련된 산업 외에도 다양한 분야에 걸쳐 일자리를 창출한다는 점에서 화력발전소와는 차별된다. 이는 향후 다양한 기술을 보유한 인력을 확보하는 것이 중요한 과제가 될 것임을 시사한다. 지역 자급률의 증가가 국가 전체 일자리 창출에 미치는 영향은 미미하지만, 국가 자급률의 증가는 지역 일자리 증가로 이어진다는 결과가 도출되었다. 따라서 일부 지역 자급률 정책은 재생에너지 관련 지역수용성 문제를 효과적으로 개선할 수 있을 것으로 사료된다. 세 번째 연구는 앞선 두 연구를 바탕으로 IRIO와 다지역 EIO-LCA를 활용하여 국내 19GW 규모 육상풍력 및 태양광 발전 확대를 중심으로 탄소 배출량과 경제적 영향의 관계를 분석하였다. 재생에너지 확대시 국가 자급률을 높이고 많은 유연성 자원을 통합할수록 고용이 상당히 증가하는 반면, 탄소 배출량도 함께 증가한다. 또한, 소비 기반의 배출량 관점에서 제주도의 육상풍력 및 태양광 발전 운영이 국내 타 지역의 탄소배출과 일자리에 미치는 영향을 분석하였다. ESS 조달 지역에 따라 탄소배출 및 고용 창출의 지역적 분포 및 총량이 상이함을 확인하였다. 따라서, 재생에너지 확대가 저탄소 공급망 전략과 연계된다면 탄소배출을 최소화하면서 일자리 창출을 극대화할 수 있다. 이는 기업이 저탄소 산업활동을 채택하도록 하는 유인책으로 작용할 수 있을 것이다. 결론적으로 이 연구는 재생에너지 확대와 저탄소 산업활동의 통합을 강조한다. 태양광과 풍력발전은 탄소배출을 매우 효과적으로 저감할 수 있는 에너지원이지만 간헐성과 분산성으로 인하여 탄소배출과 지역경제에 미치는 영향이 크다. 그러나 에너지산업 및 산업공정의 탈탄소화, 재생에너지 운영 조건 개선, 순환경제 및 저탄소 공급망 선별 등 재생에너지 확대를 저탄소 산업활동과 긴밀히 연계한다면 탄소배출 영향을 최소화하는 동시에 국가 경쟁력을 확보하고 지역 경제를 활성화할 수 있을 것이다.The energy sector is the largest contributor to climate change. Drastically reducing carbon emissions from energy use is imperative to ensure a sustainable future. Renewable energy sources, such as wind and solar photovoltaic (PV) emerged as leading clean energy alternatives, However, the transition implicates significant changes due to their major distinctions from the conventional energy system. Renewable energy encompasses a broad range of value chain, particularly requiring flexibility resources due to its intermittency. Consequently, it is essential to evaluate carbon emissions over the complete lifecycle, from development to decommissioning. Moreover, as a distributed energy source, renewable energy is often located close to residential areas raising both public concerns and interest in regional job creation. The recent rise in green protectionism has further amplified the focus on enhancing the national competitiveness of renewable energy industries. The thesis aims to analyze the impact of renewable energy expansion on carbon emissions and regional economy. It considers the inherent characteristics of the renewable energy system, such as the 1) lifecycle value chain, 2) capacity building, 3) regional characteristics such as natural resources, and industry structure. By doing so, it seeks to propose sustainable development strategies related to carbon emission reduction. The study consists of three essays, each exploring different aspects of renewable energy characteristics in the impact assessment. The research employs various analytical methods, including input-output analysis, lifecycle assessment, and cost analysis. The first essay assesses the lifecycle carbon emissions resulting from the expansion of 211MW onshore wind power in Jeju. It utilizes the Economic Input-Output Life-cycle Assessment (EIO-LCA) based on cost analysis and Environmentally Extended Input-Output (EEIO) analysis. The study identifies primary sources of emissions, providing recommendations to mitigate carbon emission. Battery manufacturing of Energy Storage System (ESS) emerges as the single largest source of carbon emission, followed by manufacturing of turbine elements. The results highlight the significance of carbon emission of flexibility resources and the importance of employing various mitigation efforts such as reusing batteries from electric vehicles and other flexible resources such as DR and V2G that require relatively little additional infrastructure. In addition, sensitivity analysis reveals that increasing both the capacity factor and operational period of onshore wind farms could further enhance carbon emission reduction potential. The most notable carbon emission contributing industries are identified as 1) Electricity, gas and steam supply, 2) Primary metal products (Steel production) 3) Non-metallic mineral products (Cement production). Ultimately, it is crucial not only to increase the share of renewable energy in the electricity generation sector but also to actively transform unsustainable industrial processes. The second essay evaluates the impact of onshore wind power expansion on Jejus regional economy based on cost analysis and Interregional Input-Output (IRIO) analysis considering various levels of capacity building in the form of local content (%). The study accentuates the extensive value chain activities of renewable energy, generating value-added and employment opportunities across various sectors. The induced value added by onshore wind Operation& Maintenance (O&M) is comparable to that of Jejus construction, restaurant and hotel, and agriculture and fisheries industries. Moreover, renewable energy system creates jobs across various sectors, even beyond those directly related to onshore wind energy, distinguishing it from conventional power plants. This also implicates that finding personnel with diverse skill sets and talents will be a significant challenge in the future. Furthermore, the results indicate that an increase in regional local content has a minimal effect on the total number of jobs created in the country, while an increase in national manufacturing leads to a rise in regional jobs. Hence, regional local content can effectively address local acceptance issues associated with renewable energy. Building upon preceding studies, the third essay analyzes the relationship between carbon emissions and economic impacts, focusing on onshore wind and solar PV expansion in Korea utilizing IRIO and multi-regional EIO-LCA. By studying the installation of 19GW of renewable energy, the essay highlights that incorporating flexibility options and increasing local content rate substantially increases employment opportunities but can also lead to higher carbon emissions, indicating a trade-off. The case of Jeju Island is examined from a consumption-based emission perspective to analyze the regional distribution of carbon emissions and job creation during the operation of onshore wind and solar PV. It is discovered that there are regional variations in carbon emissions and job creation depending on the ESS production region. Interestingly, the region with the highest carbon emissions does not necessarily create the most jobs. Therefore, aligning renewable energy expansion with sustainable supply chain strategies can ensure job creation while minimizing carbon emissions. This approach could provide incentives for corporations to adopt sustainable practices. In conclusion, this study emphasizes the integration of renewable energy expansion with sustainable industrial activities. The findings have implications for countries facing similar challenges in managing intermittent renewable energy and energy-intensive industries. While renewable energy presents advantages, it also entails complexities due to intermittency and distributed nature. Flexibility resources play a crucial role but can have significant environmental and economic impacts. However, aligning clean energy production with clean industry practices allows for the minimization of carbon emissions impact while ensuring national competitiveness and revitalizing the regional economy. This paves the way for a sustainable future for generations to come.ABSTRACT TABLES FIGURES LIST OF ABBREVIATIONS CHAPTER 1. INTRODUCTION 1 1.1. MOTIVATION 1 1.2. RESEARCH OBJECTIVES 5 1.3. SCOPE AND METHODOLOGY 6 CHAPTER 2. THEORETICAL BACKGROUND 11 2.1. CLEAN ENERGY TRANSITION 11 2.1.1. Sustainable Development and Renewable Energy System 11 2.1.2. Stability of Variable Renewable Energy 16 2.1.3. Regional Perspective 22 2.2. INDUSTRY AND CARBON EMISSIONS 25 2.2.1. Value chain Perspective 27 2.2.2. Lifecycle Perspective 31 2.2.3. Local Capacity Building 32 2.3. LITERATURE REVIEW 39 2.3.1. Carbon Emission Assessment of Renewable Energy 39 2.3.2. Regional Economic Impact Assessment of Renewable Energy 43 2.3.3. Distinction from Previous Studies 49 2.4. SUMMARY 51 CHAPTER 3. DATA AND METHODOLOGY 52 3.1. VALUE CHAIN AND COST ANALYSIS 52 3.1.1. Onshore Wind 52 3.1.2. Solar PV 54 3.1.3. Energy Storage System 55 3.2. VARIABLE PARAMETERS 58 3.2.1. Local Content 58 3.2.2. Operating Conditions 66 3.3. INPUT-OUTPUT ANALYSIS 67 3.3.1. Input-Output Table and Multipliers 67 3.3.2. Demand Vector Creation 74 3.3.3. Economic Input Output Life-cycle Assessment (EIO-LCA) 77 3.3.4. Consumption-based, Production-based Emission Accounting 81 3.4. SUMMARY 86 CHAPTER 4. CARBON EMISSION IMPACT OF WIND ENERGY: A CASE STUDY OF JEJU 88 4.1. ANALYTICAL PROCEDURE 90 4.2. RESULTS 93 4.2.1. Lifecycle Electricity Generation 93 4.2.2. Lifecycle Carbon Emission 94 4.3. DISCUSSION 98 4.3.1. Sensitivity Analysis 98 4.3.2. Emission by Industry 101 4.3.3. Carbon Emission Reduction Potential 105 4.4. CONCLUSION 107 CHAPTER 5. REGIONAL ECONOMIC IMPACT OF WIND ENERGY: A CASE STUDY OF JEJU 109 5.1. ANALYTICAL PROCEDURE 111 5.2. RESULTS 115 5.2.1. Value-added 115 5.2.2. Job Creation 116 5.3. DISCUSSION 117 5.3.1. Industrial Impact 117 5.3.2. Comparison with Conventional Power Source 121 5.3.3. Impact of Local Content 124 5.4. CONCLUSION 127 CHAPTER 6. THE IMPACT OF RENEWABLE ENERGY IN KOREA 129 6.1. ANALYTICAL PROCEDURE 130 6.1.1. Analytical Steps and Assumptions 130 6.1.2. Onshore Wind and Solar PV Potential in Korea 132 6.2. RESULTS & DISCUSSION 136 6.2.1. National Impact of Renewable Energy 136 6.2.2. Regional Distribution Effect of Carbon Emission 140 6.3. CONCLUSION 147 CHAPTER 7. CONCLUSION 149 7.1. SUMMARY AND IMPLICATIONS 149 7.2. POLICY RECOMMENDATIONS FOR JEJU 155 7.3. RESEARCH CONTRIBUTION AND LIMITATIONS 157 REFERENCES 159 APPENDIX 170 1. NEW& RENEWABLE ENERGY CLASSIFICATION 170 2. AVERAGE CAPACITY FACTOR 171 3. NATIONAL GHG INVENTORY SECTOR CLASSIFICATION 173 4. IO INDUSTRY CORRELATION 178 5. JEJU DATA 180 6. MREEIO 182 국문초록 186 ACKNOWLEDGEMENTS 189박

Stability and interaction analysis in islanded power systems including VSC-HVDC and LCC-HVDC power converters

Islanded power systems are often connected to larger mainland power systems using HVDC cables. These interconnections are used to import power at lower cost compared to local generation and improve the security of supply. The increase of HVDC interconnectors in islanded systems will allow the reduction of local synchronous generation, which might lead to new interaction and stability problems due to the low inertia and short-circuit power available in the system. Traditionally LCC-HVDC technology has been used to connect island grids, but recently VSCs are presented as an alternative solution that offers more controllability to the islanded grid. Therefore, in order to increase the power transfer to the islands multi-infeed hybrid HVSC systems with VSCs and LCCs might become a common solution. The introduction of VSCs in islanded systems will allow operations in weak grids, but possible interactions with LCCs must be analysed in detail. This paper introduces the potential interactions in multi-infeed HVDC systems with LCCs and VSCs. An initial benchmark model of an islanded power system with a LCC and a VSC-HVDC link is presented to analyse new interaction phenomena between the converters and the islanded AC grid. Simulation results in PSCAD/EMTDC are presented to validate the benchmark model for voltage stability and commutation failure analysis.Postprint (published version

Stochastic Optimization for Network-Constrained Power System Scheduling Problem

The stochastic nature of demand and wind generation has a considerable effect on solving the scheduling problem of a modern power system. Network constraints such as power flow equations and transmission capacities also need to be considered for a comprehensive approach to model renewable energy integration and analyze generation system flexibility. Firstly, this paper accounts for the stochastic inputs in such a way that the uncertainties are modeled as normally distributed forecast errors. The forecast errors are then superimposed on the outputs of load and wind forecasting tools. Secondly, it efficiently models the network constraints and tests an iterative algorithm and a piecewise linear approximation for representing transmission losses in mixed integer linear programming (MILP). It also integrates load shedding according to priority factors set by the system operator. Moreover, the different interactions among stochastic programming, network constraints, and prioritized load shedding are thoroughly investigated in the paper. The stochastic model is tested on a power system adopted from Jeju Island, South Korea. Results demonstrate the impact of wind speed variability and network constraints on the flexibility of the generation system. Further analysis shows the effect of loss modeling approaches on total cost, accuracy, computational time, and memory requirement

Interaction analysis in islanded power systems with HVDC interconnections

Postprint (published version

FINANCE MODELING OF A FLOATING OFFSHORE WIND PROJECT IN SOUTH KOREA WITHOUT GOVERNMENT SUBSIDES

The South Korean government is encouraging the active participation of power generation companies in the offshore wind power project by announcing the renewable energy certificates (REC) weighting plan. However, from a long-term perspective, offshore wind power must be able to generate profits without government support to demonstrate its business feasibility and attract the voluntary participation of power generation companies. This is because government support may be subject to change, depending on the internal and external political circumstances of the country. This report calculates the expected costs for a 495 MW floating offshore wind farm in the South Korea’s market environment and examine how the feasibility of the project shifts depending on the country’s current REC weights. Furthermore, this study intends to determine whether floating offshore wind power can generate profits without the Korean government’s support by calculating the expected profit in combination with the green hydrogen project. The net present value (NPV), levelized cost of energy (LCoE) and internal rate of return (IRR) indexes are calculated according to the project’s specific particularities, such as power purchase agreement, REC Weighting, distance from shore and sea depth. Based on this, an index-based comparison is revealed and the margin for profitability for such an investment is discussed

Modeling and Analysis of an LCC HVDC System Using DC Voltage Control to Improve Transient Response and Short-Term Power Transfer Capability

A new control method for a line-commutated converter-based (LCC) high-voltage direct-current (HVDC) system is presented and compared to a conventional strategy. In the proposed method, both the DC voltage and current of an LCC HVDC system are regulated to increase the short-term operating margin of DC power transfer and improve transient responses to DC power references. In particular, an increased operating margin of DC power transfer is achieved via the DC voltage regulation method. To verify the effectiveness of the proposed method, a state space model of an LCC HVDC system is developed considering DC voltage and current references as input variables and analyzed for various values of the DC line inductance and converter controller gains. The state space model can be used for time-efficient analyses of the dynamic characteristics of an LCC HVDC system. Simulation case studies are performed using MATLAB, where the state space model of the Jeju-Haenam HVDC system is implemented as a test case and compared to its comprehensive PSCAD model. The case study results suggest that the proposed method increases the short-term operating margin and speeds up the transient response of the HVDC system. Therefore, it will effectively improve real-time grid frequency regulation.11sciescopu