100 MW급 Power-to-Gas 시스템의 사전 경제성 분석

고아름(Areum Ko),박성호(Sung-Ho Park),김수현(Suhyun Kim) 한국청정기술학회 2020 청정기술 Vol.26 No.1

재생에너지 3020 이행계획에 따라 재생에너지 발전 비중 증가에 대비해 잉여전력 저장 및 전력 공급 안정화 기술 필요성이 대두되고 있다. 이를 위해 수요 공급의 불균형으로 활용할 수 없는 전력을 수소 또는 메탄으로 전환하여 저장하는 Power-to-Gas 기술 개발이 활발히 진행되고 있다. 본 연구에서는 국내 실정을 반영한 Power-to-Gas 경제성분석을 수행하였다. 균등화 수소원가를 산정하기 위하여 Total revenue requirement 방법론을 활용하여 경제성 분석 방법론을 재정립하고, 국제에너지기구의 경제성 분석 결과를 통해 검증하였다. 연구결과 국내 기준 100 MW급 Power-to-Gas 시스템 균등화 수소원가는 kg당 8,344원으로 나타났다. 전기 비용, 수전해 장비 비용, 작동 연한에 따른 민감도 분석이 수행되었고, 재생에너지 이용 수소 생산비용과 천연가스 개질 수소 생산비용을 비교하여 경제성을 확보할 수 있는 조건을 제시하였다. According to the Korean Renewable Energy 3020 Implementation Plan, the installation capacity of renewable energy is expected to increase whereas technology for storing excess electricity and stabilizing the power supply of renewable energy sources is extremely required. Power-to-Gas is one of energy storage technologies where electricity is converted into gas fuel such as hydrogen and methane. Basically, Power-to-Gas system could be effectively utilized to store excess electricity generated by an imbalance between supply and demand. In this study, the economic feasibility analysis of Power-to-Gas reflecting the domestic situation was carried out. Total revenue requirement method was utilized to estimate the levelized cost of hydrogen. Validation on the economic analysis method in this study was conducted by comparison of the result, which is published by the International Energy Agency. The levelized cost of hydrogen of a 100-MW Power-to-Gas system reflecting the current economic status in Korea is 8,344 won kg<SUP>-1</SUP>. The sensitivity analysis was carried out, applying the main analysis economic factors such as electricity cost, electrolyser cost, and operating year. Based on the sensitivity analysis, the conditions for economic feasibility were suggested by comparing the cost of producing hydrogen using renewable energy with the cost of producing natural gas reformed hydrogen with carbon capture and storage.

Power-to-Gas 플랜트 연계 순산소 연소 보일러 공정 해석

손근(Geun Sohn),류주열(Ju-Yeol Ryu),박혜민(Hye-Min Park),박성호(Sung-Ho Park) 한국열환경공학회 2021 열환경공학 Vol.16 No.1

Power-to-Gas(PtG) is a promising technology that produces hydrogen by the electrochemical reaction in water electrolyzer to manage the intermittent power generation from renewable energy such as wind and solar. Water electrolyzer generates hydrogen and highly purified oxygen as a by-product. In this study, the process was examined in coal fired oxy-fuel combustion power plant and in PtG plant to use highly purified oxygen obtained from water electrolyzer. The power generation efficiency of a coal-fired oxy-fuel power plant supplied with oxygen through an air separation unit and that of a coal-fired oxy-fuel power plant supplied with oxygen in a polymer electrolyte membrane (PEM) water electrolysis process were compared. As a result of the analysis, in the case of the combined system of the coal-fired oxy-fuel power plant and the PtG plant, the net power generation and power generation efficiency were higher than the case of individual coal-fired oxy-fuel power plant supplied with oxygen through the air separation unit. The process efficiency is further improved when using biomass, fueling the oxy-fuel combustion boiler rather than coal and when steam-water is in supercritical conditions.

Power-to-Gas 기반 섹터커플링 시스템 구축을 위한 대중의 지불의사액

김준규(Joon-Kyu Kim),김주희(Ju-Hee Kim),유승훈(Seung-Hoon Yoo) 한국에너지학회 2024 에너지공학 Vol.33 No.1

The government is considering the introduction of sector coupling as a way to compensate for the instability of the power system and solve the power generation constraints caused by the shortage of the power grid. In particular, the government intends to introduce Power-to-Gas (P2G), which uses surplus power to generate hydrogen. This study seeks to evaluate public acceptance of introducing P2G by using contingent valuation method (CV). For this purpose, CV survey was conducted through person-to-person interviews targeting 1,000 households in South Korea. At this time, the annual income tax per household and the one-and-one-half bounded dichotomous choice model (OOHB) were adopted as payment vehicle and willingness to pay (WTP) elicitation methods, respectively. In addition, a single bounded model (SB) is applied to examine the response effects that may occur in the OOHB model. In both models, the spike model is used to handle many zero WTPs. As a result, the estimation results of the SB spike model were adopted and the average annual WTP per household for the P2G project was estimated to be KRW 5,317. The total WTP for the project was derived at KRW 117.1 billion per year, and the present value of the total benefits generated over the decade totaled KRW 926.5 billion as of 2021. Comparing the total benefit derived in this study with the cost involved in the project to be evaluated, the benefit/cost ratio is calculated as 1.99. Therefore, the project was found to secure economic feasibility.

천연가스의 계절별 변동유량을 고려한 이중터보팽창기 감압시스템을 이용한 전기에너지회수에 관한 연구

박철우,유한빛,김효 한국가스학회 2019 한국가스학회지 Vol.23 No.2

천연가스 운송기지에서 전기에너지를 회수하기위하여 팽창 터빈시스템을 사용하는 것은 잘 알려진 기술이다. 터보팽창기의 효율은 천연가스의 유량과 터보팽창기 설계유량의 비에 따라 달라진다. 그러나 감압기지에서 계절적 공급패턴, 즉 여름에는 낮은 유량으로 반면에 겨울에는 높은 유량으로 공급되기 때문에, 단일 터보팽창기로는낮은 유량의 천연가스로부터 감압에너지를 충분히 회수하기가 비효율적이다. 따라서 본 연구에서는 대용량과 소용량의 이중 터보팽창기의 새로운 개념을 제안하게 되었다. 본 연구에서는 저압 정압기지에서 팽창밸브의 평균 입구, 출구 압력조건인 18.5 bar에서 7.5 bar로 감압될 때 입구의 온도, 유량조건에 따라서 생산 가능한 전력을 이론적배경을 통해 계산하였다. 최저 설계 효율 0.72에서 회수 가능한 전력생산량은 단일 터보팽창기로 운전될 때에는12.4 MW이었으나, 여기서 제안한 이중터보팽창기에서는 16.1 MW로 약 30% 증가한 결과를 얻게 되었다. Expansion turbine system to recover the electricity energy from natural gas transmission stations is a well-known technique. The turbo-expander efficiency depends on the ratio of the natural gas flow rates to the design flow rate of the turbo-expander. However, if there is a big difference of the natural gas flow rate through the pressure letdown station because of seasonal supply pattern, that is, high flow rate in winter while low flow rate in summer, single turbo-expander system is not so efficient as to recover the pressurized energy from the low flow-rate natural gas. Therefore, we have proposed a new concept of double turbo-expander system: one is a big capacity and the other a small capacity. Here we have theoretically computed the electric powers at the pressure reduction from 18.5 bar to 7.5 bar depending on the inlet conditions of temperature and flow rate. The calculated electricity generation has been increased by 30% from 12.4 MW in a single turbo expander to 16.1 MW in the proposed double turbo-expander system when a minimal design efficiency of 0.72 is applied.

Performance characteristics of an integrated power generation system combining gas turbine combined cycle, carbon capture and methanation

Dong Hyeok Won,Min Jae Kim,Jae Hong Lee,Tong Seop Kim 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.10

This study analyzes the performance of an integrated power generation system that combines a gas turbine combined cycle (GTCC) with a methanation process. The methanation process uses hydrogen provided by a power-to-gas (PtG) process and carbon dioxide captured from the exhaust gas of the GTCC. The research aim was to maximize the GTCC performance through an effective integration between the GTCC and methanation. Two methods were proposed to utilize the steam generated from the methanation process. One was to supply it to the steam turbine bottoming cycle of the GTCC, and the other was to inject it into the GT combustor. Also investigated was the injection of oxygen generated in the PtG process into the gas turbine combustor. The largest improvements in the power and efficiency were predicted to be 19.3 % and 4.9 % through the combination of the steam supply to the bottoming cycle and the oxygen injection to the combustor.

P2G 기술 연계형 풍력발전 기반 독립형 마이크로그리드 최적 운영 방안

손영건(Yeong-Geon Son),황성욱(Sung-Wook Hwang),이학주(Hak-Ju Lee),김성열(Sung-Yul Kim),김동섭(Dong-Sub Kim) 대한전기학회 2021 전기학회논문지 Vol.70 No.11

The purpose of this study is to optimize the operation of wind power generation-based standalone microgrid linking P2G technology. Renewable energy sources, such as wind turbine, photovoltaic, etc., use natural energy as a power source, so the system operator could not control the power of the renewable energy sources. Failure may occur and damage such as power failure may occur if the facilities of the RES that cannot be controlled output increase and the balance of power supply and demand in the power system is not matched. In this study, insufficient power is supplemented by power supply using diesel generator, and excess power is supplemented by Battery Energy Storage System (BESS) and Power-to-Gas (P2G) technologies. In particular, P2G technology using hydrogen energy is mainly dealt with, and multi-objective optimization programming that satisfies both objective functions is interpreted based on pareto-front optimization by deriving the power limit of wind power generators and system costs incurred when building and operating microgrids.

Power-to-gas systems with a focus on biological methanation

Seongcheol Kang,Anil Kuruvilla Mathew,Amith Abraham,Okkyoung Choi,Byoung-In Sang 한양대학교 청정에너지연구소 2022 Journal of Ceramic Processing Research Vol.23 No.6

Power to Gas (P2G) systems aim to store surplus renewable electricity generated in the form of gaseous fuels such as hydrogenor methane. The concept is ideal for storing the surplus energy for long periods in gaseous form and can be used in the futurefor desired end applications, i.e. either in gaseous form or electricity. In the P2G process, the surplus renewable energyconverts into methane (gaseous form) in a two-step process: electrolysis followed by methanation. The electrolysis process isused as the source for hydrogen generation, which further reduces carbon dioxide to produce methane. In this review, differentelectrolyzers and methanation processes are compared for the P2G process. The major process parameters and hydrogen gasliquid mass transfer are discussed by comparing different process conditions and reactor configurations used in biologicalmethanation. An understanding of the techno-economic analysis indicates that cost of the hydrogen generation is the key factorthat determines the overall economics of the P2G system. The cost of hydrogen generation is associated with the capital costof the electrolyzer and the cost of the electricity. It is expected that once this technology becomes mature, the economics of P2Gsystems will improve in the future.

열화학적 메탄화 기술

김수현,유영돈 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Power-to-Gas는 재생에너지로부터 생산된 전기에너지를 수소 또는 메탄으로 전환시키는 기술을 의미한다. Power-to-Gas는 재생에너지의 간헐성과 출력 변동성을 보완함과 동시에 저장이 불가능한 전기를 장기간 대용량 저장이 가능한 수소나 메탄과 같은 가스 형태의 에너지원으로 변환시킬 수 있다는 점에서 태양광, 풍력에 너지원의 확대와 함께 강조되고 있는 기술 중 하나이다. Power-to-Gas 기술을 구성하는 2가지 핵심 기술은 전기분해에 의한 수소생산기술과 CO2 메탄화 기술이다. 이 중 CO2 메탄화 기술은 수전해를 통해 생산된 수소와 이산화탄소를 반응시켜 천연가스의 주성분인 메탄을 생산할 수 있다. CO2 메탄화 기술은 촉매를 사용하는 열화학적 메탄화 기술과 미생물을 사용하는 생물학적 메탄화 기술로 구분된다. 열화학적 메탄화 기술은 생물학적 메탄화 기술에 비해 기술적 성숙도가 높고 상대적으로 대용량 운전이 가능하다는 장점이 있지만 간헐적 운전에 대한 유연성 부족 및 열회수를 위한 온도제어의 복잡성은 극복해야 할 부분이다.

Power to Gas를 위한 수전해 수소생산 기술

김창희,조원철,조현석 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

정부의 재생에너지 3020 이행계획에 따라 2030년까지 재생에너지 발전량 비중을 20%로 늘리고 신규설비의 95% 이상을 태양광, 풍력등 청정에너지로 공급할 계획이다. 이에 따라 간헐적이고 불규칙적인 특성을 가지는 재생에너지를 기존 전력망에 안정적으로 연결하고 미유용의 전력을 장주기 대용량으로 저장 그리고 전환하기 위한 Power to Gas기술들이 많이 연구되고 있다. Power to Gas기술의 핵심은 재생에너지와 연계하여 어떻게 수소를 경제적으로 청정하게 생산하는가에 있다. 가장 유망한 기술로는 물을 전기분해 하여 수소를 생산하는 기술이다. 따라서 가격을 저감시키고 전극 등의 요소기술들의 내구성을 향상시키는 방향으로 많은 연구가 진행되고 있다. 본 연구에서는 수전해 수소생산 기술들에 대한 특징과 현황들을 분석하고 Power to Gas에서의 수전해의 역할 및 앞으로의 연구개발 방향에 대하여 제시하고자 한다.

Performance comparison of two newly isolated Methanothermobacter for Power-to-Gas system

전병승,홍문기,주고운,김민정,송효정,최옥경,상병인 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Power-to-Gas(P2G) is the one of systems storing electricity. Using this system, load fluctuations due to utilizing renewable energy can be appropriately coped. In this system, surplus electricity produced from renewable source can be converted into hydrogen by water-electrolysis and produced hydrogen would be utilized to methane along with carbon dioxide. In this study, two hydrogenotrophic methangen that are applicable to biological methane production was isolated from sludge and the performance for methane production was evaluated in same condition. Minimal medium such as basic anaerobic medium was utilized for cell maintenance and methane evaluation. Carbon dioxide and hydrogen were supplied as a carbon and energy source at various ratio and rate. Produced methane and cell growth was analysed using GC-TCD and spectrophotometer by time course, respectively. Based on these results, methanogen suitable for P2G system could be selected.