Cold Energy Utilization Research Articles

Condensation heat transfer and applicability assessment of a printed circuit heat exchanger as a condenser in a cryogenic CO2 capture and storage system

Global warming is accelerating due to the rapid increase in CO2 emissions and cold energy. CO2 capture and storage systems (CCSSs) using discarded cold energy have been suggested to prevent this problem. To utilize cold energy, a printed circuit heat exchanger (PCHE) with high structural integrity was applied as a condenser in the CCSS. However, studies on condensation heat transfer in PCHE are still lacking, and conventional condensation heat transfer correlations developed in circular-channels do not sufficiently predict heat transfer performance in PCHE. Additionally, evaluating the local heat transfer performance is difficult because PCHE is an all-in-one type heat exchanger. Therefore, in this study, a CO2 condensation experiment in PCHE was conducted using an optical fiber sensor as a measurement, which can evaluate the local heat transfer performance, and a new condensation heat transfer correlation for CO2 in PCHE was developed. The correlation was approximately 20 % smaller than the conventional correlations developed in circular-channels, indicating that CO2 would not be fully condensed if the condenser was designed by conventional correlations. Based on the developed correlation, in-house code was developed and the CCSS using cold energy was compared with the conventional CCSS, which condenses CO2 after pressurizing it to a high pressure. As a result, cold energy based CCSS could replace the conventional CCSS because the CCSS using cold energy was approximately 5.7 million-USD per year more economical than the conventional CCSS when condensing CO2 at 200 tons/h. These results contribute to the design of PCHE-type condensers used in the CCSS.

Carbon sequestration with enhanced gas recovery (CSEGR) for a novel natural gas value chain: Synergy with cold energy utilization

Liquefied natural gas (LNG) plays a primary role in long-distance transportation; however, its production is energy-intensive, and CO2 emissions from its use are unavoidable. To address these challenges, a liquid CO2-mixed refrigerant (LCO2MR) process is proposed, utilizing CO2 in two distinct ways: (i) recovering cold energy from LNG regasification for use in the natural gas liquefaction process and (ii) injecting CO2 into gas fields for enhanced gas recovery (EGR), boosting natural gas production. This study comprehensively analyzes the proposed process, focusing on thermodynamic, economic, and environmental impacts. The energy consumptions for the propane precooled mixed refrigerant (C3MR) and LCO2MR processes are 970 and 815 kJ/kg of LNG, respectively. The LCO2MR process has an annual expense 18.94 % lower than C3MR process when considering carbon tax, due to its simpler structure and lower energy requirements. Environmentally, the LCO2MR process reduces CO2 emissions by 53.33 % across the value chain compared to the C3MR process. Additionally, using CO2 for EGR is projected to increase natural gas production by 81.67 tons/h. These results indicate that utilizing CO2 as a cold energy carrier and for increasing natural gas production is energetically and economically advantageous, significantly reducing CO2 emissions and contributing to a cleaner LNG value chain.

Analysis of LNG cold energy utilization and regasification process for a gas turbine power plant integrated with a novel polygeneration process

In the presented study, a polygeneration process is presented. This process consists of a gas turbine cycle, an internal trigeneration unit, an internal cogeneration unit, a proton exchange membrane electrolyzer, and a seawater desalination unit. This configuration is evaluated using thermodynamic, economic, and environmental analyses, and the outcomes are compared with similar examinations. The problem addressed is the enhancement of energy efficiency and reduction of carbon emissions in gas turbine power plants. This is crucial for improving sustainability and economic viability in power generation. Thermodynamic evaluation indicates that the energy efficiency, exergy efficiency, electrical efficiency, thermal efficiency, energy usage factor, and primary energy saving for the proposed process are 84 %, 76.09 %, 36.25 %, 39.91 %, 76.16 %, and 41.43 %, respectively. The system demonstrated a low CO2 emission intensity of 0.14 kgCO2/kWh. Key outputs include 2638.57 kg/s of hot water, 145.44 kg/s of chilled water, 1.12 kg/s of hydrogen, 8.89 kg/s of oxygen, 145.2 kg/s of fresh water, and 732300 kW of power. Economic analysis revealed a positive net present value with the total unit cost of the product at 6.104 USD/GJ and the cost of energy at 0.042 USD/kWh. The novelty of this work lies in its extensive heat recovery network, significantly enhancing thermodynamic efficiency and minimizing carbon emissions. The proposed system does not have any indirect CO2 emissions, making it environmentally superior to other methods. This integrated polygeneration process not only improves energy efficiency and environmental performance but also provides a sustainable and economically attractive solution for future power generation and resource production.

Discussion on LNG Cold Energy Utilization Methods

Natural gas is known as a clean energy source due to its environmental benefits and economic viability, widely used in both industrial and residential sectors. Liquefied natural gas (LNG) is characterized by its small volume and low-cost transportation over long distances (by ship), with about 25% of international trade conducted using LNG. In recent years, China's LNG supply has been steadily increasing, and it is expected that by 2040, China's demand for LNG will exceed 15% of the global total. LNG is a low-temperature (−162°C) liquid mixture formed by purifying natural gas to remove acids and water, followed by low-temperature condensation. LNG receiving stations typically use seawater heating to vaporize LNG into gaseous natural gas for export, with the large amount of cold energy released during vaporization absorbed by seawater and discharged into the ocean, approximately 830 kWh/kg. Based on China's receiving capacity in 2018, the cold energy from LNG was equivalent to 2.07 billion kWh, and it is projected to reach 5.98 billion kWh by 2023, indicating a rich resource of cold energy. As China imports significant amounts of LNG, the comprehensive utilization of LNG cold energy becomes increasingly important.

Transportation of Liquefied Natural Gas (LNG) via Long-Distance Low-Temperature Pipeline and Cascade Utilization of Cold Energy

In addition to methane, liquefied natural gas (LNG) typically contains valuable light hydrocarbons such as ethane, propane, and butane. Establishing LNG receiving stations for imported LNG can effectively alleviate regional energy supply-demand conflicts, optimize energy consumption structures, promote sustainable regional economic development, and improve ecological environments. The technology for long-distance low-temperature pipeline transportation of LNG facilitates the efficient transfer and cascading utilization of the cold energy contained in LNG, allowing for deep coupling with cold networks and natural gas pipelines, thereby promoting the integrated development of LNG, cold energy, and natural gas transportation. This paper systematically summarizes the current status of LNG long-distance low-temperature pipeline transportation technology, cold energy cascading utilization technology, pipeline regulation technology, and multi-network integration technology. It analyzes the key challenges these technologies face under new strategies and looks ahead to future development trends, aiming to provide scientific insights and directions for the application of LNG long-distance low-temperature transportation and multi-network integration in China.

Simultaneous Optimization of Exergy and Economy and Environment (3E) for a Multistage Nested LNG Power Generation System

The study introduces an innovative three-stage nested power generation system that enables the cascading utilization of LNG cold energy. It makes the most of wasted energy by using ship jacket cooling water (JCW) and exhaust gas (EG) as heat sources, a trans-critical carbon dioxide cycle as internal circulation, and utilizing the pressure exergy of LNG. We choose two azeotrope mixing fluids that match the requirements and create four cases for the outer and middle cycle working fluids in the three-stage nested system. To discover the ideal system performance from the perspectives of exergy (E), economy (E), and environment (E), four cases were subjected to multi-objective optimization using the multi-objective particle swarm optimization technique (MOPSO). Finally, the optimal solution was found by applying the TOPSIS decision-making method. Through comparative analysis, the optimal system is selected among the four optimization results. R170 (22.66%) and R1150 (77.34%) are used as the outer circulating working medium, while R170 (90.86%) and R1270 (9.14%) are utilized as the inter-cycle working fluid. The net output work is 575.75 kW, the optimal exergy efficiency is 46.09%, the optimal electricity production cost is $0.04009 per kWh, the carbon dioxide emissions can be reduced by 36,910 tons, and the payback period is 2.548 years. After optimization, a more energy-efficient and environmentally friendly power generation system is obtained.

Performance analysis and multi-objective optimization for an integrated air separation, power generation, refrigeration and ice thermal storage system based on the LNG cold energy utilization

Against the backdrop of escalating resource depletion and the urgent quest for alternative sources, liquefied natural gas (LNG) is increasingly gaining prominence as a sustainable solution, particularly in refrigeration applications. However, its underutilization results in wasted resources. To efficiently harness the released cold energy from LNG gasification, this study proposes an integrated system comprising air separation, power generation, refrigeration, and ice thermal storage. The system undergoes optimization using the non-dominated sorting genetic algorithm II (NSGA-II) to determine the optimal operating parameters. The optimized system is comprehensively analyzed from energy, exergy, economic, and environmental perspectives. Results show that the system, with a 70t/h LNG capacity, achieves an energy efficiency of 42.52% and an exergy efficiency of 48.09%. Economically, the system incurs a cost of approximately 0.0711 $/kWh and can mitigate over 1.4504*107kg of CO2 emissions. Compared to traditional LNG utilization systems, the integrated system demonstrates a 22.32% improvement in energy efficiency, a 7.69% enhancement in exergy efficiency, and a cost reduction of 0.0049 $/kWh. In summary, this technologically advanced and economically viable system offers a significant alternative to optimize LNG cold energy utilization.

Thermodynamic performance analysis of a new air energy storage multigeneration system

This paper proposes a chemical looping hydrogen generation-solid oxide fuel cell combined cooling, heating, and power system that utilizes compressed air energy storage and liquefied natural gas, aiming to address the issues of instability in renewable energy power generation and waste of liquefied natural gas cold energy. The scheme achieves CO2 capture and efficient power generation while also addressing grid fluctuations and the utilization of waste cold energy. The compressed air energy storage system is employed to supply air centrally, eliminating the power consumption of traditional air compressors while improving discharging efficiency. Aspen Plus software and embedded Fortran are used for system simulation. The system is comprehensively evaluated through energy analysis, exergy analysis, and sensitivity analysis. The results indicate that the discharging efficiency, energy round-trip efficiency, and round-trip electrical efficiency are 87.56%, 81.57%, and 67.82%, respectively. The purity of CO2 capture is 99.72%. Sensitivity analysis indicates that the outlet pressure of the air storage tank and fuel flow are the main influencing parameters for system performance. Increasing the fuel flow can effectively enhance system power output, but efficiency will decrease. The outlet pressure primarily influences the power output of the gas turbine and discharging time. Overall, this system provides theoretical guidance and new ideas for efficient energy utilization.

Regulating Cold Energy from the Universe by Bifunctional Phase Change Materials for Sustainable Cooling

AbstractHarvesting cold energy from the universe by radiative cooling (RC) is a promising zero‐carbon route for green cooling. However, low power density and spatiotemporal energy mismatch of RC are great challenges for realizing efficient space cooling. Herein, a facile strategy for regulating cold energy from the universe by bifunctional phase change materials (PCM) for sustainable cooling is proposed. A bifunctional phase‐change composite film (PCCF) by integrating RC coating with PCM for 24‐h cold energy harvesting, storage, and utilization is demonstrated. The bifunctional PCCF can harvest cold energy from the universe and regulate the redundant cold energy generated by nighttime RC to compensate for the cold shortage of daytime RC, realizing flexible regulation of all‐day RC and setting new records of cooling power up to 180 W m−2 with sub‐ambient temperature drop of 11.95 °C. The work offers a promising strategy for zero‐carbon sustainable cooling by maximizing RC with cold energy storage.

Study on recovery and utilization of cold energy for insulation design of liquid hydrogen tanks

Insulation design is one of the key technologies for Liquid Hydrogen (LH2) tanks. To enhance the insulation efficiency and energy utilization of the LH2, this study proposes a novel approach to enhance the insulation performance of LH2 tank and cold energy cascade utilization of LH2. Three Cryo-cooling Insulation Systems (CIS) with various insulation schemes are designed, analyzed and compared from the perspectives of insulation performance, consumption and energy utilization efficiency. An optimal insulation scheme among three CISs is identified and evaluated. Additionally, a dimensionless number (Ψ) is proposed to assess the insulation advantages of the CISs. And the insulation performance and economic feasibility of the system be effectively balanced. The findings reveal that the insulation performance of the proposed CIS outperforms previous insulation methods by a factor of 239.13. Among the schemes in three CISs, Schemes 2 (Position of CSs at 6th, 25th and 35th layers), Schemes 3 (Position of CSs at 10th, 40th and 45th layers), and Schemes 3 (Position of CSs at 3rd, 40th and 45th layers) exhibit superior insulation performance in Cases #1 (CIS of LN2-LAr), Cases #2 (CIS of R14-R170), and Cases #3 (CIS of R1150-R23). Notably, Case #1 achieves the highest insulation performance, showing improvements of 2.58 and 1.63 times over Case #2 and Case #3, respectively. However, the energy output in Case #1 is approximately 248.12 W, constituting 83.10 % and 71.60 % of Case #2 and Case #3, respectively. Case #1 demonstrates the highest specific energy output, with improvements of 30.12 % and 81.05 % compared to Case #2 and Case #3, respectively. In terms of the exergy utilization rate of each equipment, the exergy utilization rate of equipment in Case #1 is the highest among the three cases. The study underscore the feasibility of cold energy utilization for insulation, providing solutions for energy conversion and thermal management of LH2 tanks through cryo-cooling cascade utilization.

Thermo-enviro-economic analyses of a landfill biogas-fed polygeneration process combined with a liquefied natural gas cold energy utilization unit

Landfill biogas offers a promising opportunity to supply society’s energy requirements, following the waste-to-energy approach, which issuitable for sustainable production. However, structural modification for its utilization is the main gap, requiring additional research efforts. Considering this issue, the current study aims to design an eco-friendly polygeneration method for landfill biogas utilization for a cutting-edge heat recovery system that integrates a cold energy recovery and utilization unit for liquefied natural gas. The liquefied natural gas recovery section, the organic Rankine cycle with a zeotropic mixture, and the Kalina cycle are all started using the flue gas from the combustion of biogas in a cascade process. In addition, the waste heat of the Kalina cycle is recovered by a single-effect desalination cycle and liquefied natural gas recovery section. Also, a water electrolysis process is integrated into the whole system. As a result, the products include hydrogen, electricity, natural gas, hot and cold water, and freshwater. The Aspen HYSYS software is utilized to design the system and investigate its thermodynamic, environmental, and economic aspects. The results demonstrate an energy efficiency of 57.54 % and an exergy efficiency of 18.78 %. Also, the carbon dioxide footprint associated with the system equals 0.34 kg/kWh, and the specific cost of products is 73.96 $/GJ. An optimal exergy efficiency of 25.8 % and a specific cost of products of 69.7 $/GJ are obtained by means of an intelligent optimization approach that ultimately makes use of non-dominated sorting genetic algorithm-II and artificial neural networks.

Techno-economic analysis on a hybrid system with carbon capture and energy storage for liquefied natural gas cold energy utilization

For cold energy utilization in the liquefied natural gas (LNG) regasification process, integrated cryogenic CO2 capture using high-grade cold energy is a mainstream method. However, high-grade cold energy for carbon capture may lead to a decrease in cold energy utilization efficiency. This paper aims to propose a hybrid system in which high-grade cold energy is used for liquid air energy storage (LAES) and post-combustion amine scrubbing technology is considered to replace cryogenic carbon capture for improved working efficiency. The medium and low-grade cold energy is utilized for similar working processes, e.g., organic Rankine cycle (ORC), carbon dioxide liquefaction, and data center cooling for comparison. Results show that the proposed hybrid system can produce 437.7 MW of power, 28.8 t·h−1 of CO2 capture capacity, and 23.0 MW of cooling capacity, respectively. The levelized cost of electricity and the annual revenue are 112.3 $·MWh−1 and 2.17 million $, respectively. LNG cold energy utilization efficiency, system energy efficiency, and cold exergy efficiency are 53.4 %, 24.0 %, and 51.5 %, higher than similar processes using cryogenic CO2 capture. It is demonstrated that the proposed system could be a promising method for cold energy utilization and post-combustion capture.

Enhancing thermodynamic performance with an advanced combined power and refrigeration cycle with dual LNG cold energy utilization

Utilizing waste heat to drive thermodynamic systems is imperative for improving energy efficiency, thereby improving sustainability. A combined cooling and power systems (CCP) utilizes heat from a temperature source to deliver both power and cooling. However, CCP systems utilizing LNG cold energy suffers from low second law efficiency due to significant temperature differences. To address this, an “Advanced Power and Cooling with LNG Utilization (ACPLU)” system is proposed, integrating a cascaded transcritical carbon dioxide (TCO2)-LNG cycle with an Organic Rankine cycle (ORC) for improved power generation and an absorption refrigeration system (ARS) for simultaneous cooling. This study evaluates the second law efficiency, net work output, and exergy destruction performance through a sensitivity analysis, optimizing variables such as heat source temperature, superheater temperature difference, ORC and CO2 turbine inlet and condenser pressures, evaporator temperature, and pinch point temperatures of heat exchangers and generator. Compared to previous studies on CCP systems, the ACPLU shows a superior performance, with a second law efficiency of 27.3 % and a net work output of 11.76 MW. Cyclopentane as an ORC working fluid resulted in the highest second law efficiency of 29.06 % and net work output of 12.27 MW. Parametric analysis suggested that heat source temperature significantly impacts net power output. The exergy analysis concluded that a high-pressure ratio and good thermal match between the heat exchangers enhance overall performance. Utilizing artificial neural network (ANN) to produce a multiple-input-multiple-output (MIMO) objective function and performing multi-objective optimization (MOO) using genetic algorithm (GA), an improved second law efficiency and net power output by 28.11 % and 14.16 MW respectively, with pentane as the working fluid, is demonstrated. An average cost rate of 9.121 $/GJ was observed through a thermo-economic analysis. The ACPLU system is promising for medium temperature waste heat recovery, such as, pharmaceutical manufacturing plants.

Thermodynamic and economic analysis of multi-generation system based on LNG-LAES integrating with air separation unit

LNG consumption is rising globally, releasing significant cold energy during regasification. Coupling LNG vaporization with liquid air energy storage (LAES) maximizes this cold energy recovery, enhancing LAES efficiency. However, current LNG-LAES systems face issues like insufficient high-grade cold energy use and high liquid air temperatures. LAES's inability to recover LNG cold energy during energy release necessitates cold storage fluid, increasing costs. Safety concerns also arise from LNG and air coexisting in the same heat exchanger, and LNG vaporization fluctuations can destabilize LAES operations. This study proposes a multi-generation system (LNG-LAES-ASU) incorporating an air separation unit (ASU) to address these challenges. The ASU recovers LNG cold energy during energy release, adapts to LNG vaporization fluctuations, and reduces ASU energy consumption. Energy, economic, and peak-shaving performance analyses show the system achieves a 91.07 % round-trip efficiency (RTE). The ASU's average energy consumption is 0.1356–0.1506 kWh/Nm³ O₂, much lower than a standalone ASU's 0.4 kWh/Nm³ O₂. Over 30 years, the system yields a net present value (NPV) of $56,111,291 and a dynamic payback period of 3.23 years. Its peak-shaving capacity is 2.47–2.57 times greater than LNG-LAES alone. This research offers valuable insights into efficient LNG cold energy utilization.

Power generation system utilizing cold energy from liquid hydrogen: Integration with a liquid air storage system for peak load shaving

Liquid hydrogen (LH2) can serve as a carrier for hydrogen and renewable energy by recovering the cold energy during LH2 regasification to generate electricity. However, the fluctuating nature of power demand throughout the day often does not align with hydrogen demand. To address this challenge, this study focuses on integrating liquid air energy storage with a power generation system based on LH2 regasification. Three configurations are proposed and compared: no-storage, partial-storage, and full-storage. In the no-storage system, power is generated using recuperated Brayton cycle and two organic Rankine cycles without energy storage. In contrast, the partial-storage system offers flexible operational modes. During peak times, cold energy is utilized for power generation, while it is diverted to store liquid air during off-peak times. In the full-storage system, produced energy is partially reserved throughout the day. Thus, compared to the partial-storage system, the full-storage system boasts a simplified configuration, eliminating the need for operational mode transitions. Furthermore, its larger liquid air storage capacity maximizes the difference in power production up to 4.53 MW between on- and off-peak times. Consequently, despite its higher capital costs, the full-storage system demonstrates greater economic viability, especially when considering government subsidies.

Investigation on hourly characteristics of solar absorption refrigeration cycle integrated with a dual-cooling grade-compression cycle

Solar absorption refrigeration cycle consumes almost no electricity, but its low refrigeration efficiency and intermittent operation issues need addressing. Based on the viewpoint of cold energy grade production matching air-conditioning cooling load grade, a solar absorption refrigeration cycle integrated with a dual-cooling grade-compression cycle (SARC-DGC) is proposed to boost the solar utilization and achieve all-weather cooling, which includes solar absorption refrigeration (SAR) subsystem, subcooled water circulating (SWC) subsystem and dual-cooling grade-compression refrigeration (DGR) subsystem. The simulation models of proposed cycle are developed by lumped-parameter and distributed-parameter methods, and the simulation results are validated with experimental results. The hourly characteristics of SARC-DGC cycle on a typical day are evaluated and compared with those of the conventional solar absorption refrigeration (SAR) cycle and air-cooled compression refrigeration (ACR) cycle. The results show that the hourly cooling performance of SARC-DGC cycle is well matched with the building cooling load demand, so as to realize the cold energy grade production and utilization. The working hours of SAR subsystem are 42.86 % longer than that of conventional SAR cycle, with a 31.92 % increase in daily cooling capacity, while the daily power consumption of the proposed cycle is on average 27.31 % lower than that of conventional ACR cycle.

Navigating towards a zero-carbon world: Research progress of chemical solvent-based shipboard carbon capture system integration and renewable energy coupling

As the International Maritime Organization (IMO) tightens its requirements on greenhouse gas emissions from shipping, the imperative for carbon emission reduction in maritime transport is pressing. In the short to medium term, the Onboard Carbon Capture and Storage (OCCS) system combined with low-carbon fuel can be seen as an effective way to reduce CO2 emissions in ships. Presently, the technology of the OCCS system remains in its nascent stage, which necessitates further refinement. Based on the existing OCCS techniques, the efficient utilization of waste heat and cold energy from ships and further coupling with green renewable energy, hold the key to achieving highly integrated marine carbon capture systems, which not only meet the IMO long-term goal requirements for EEDI but also present the optimal choice for significantly reducing the economic costs associated with the OCCS system.

Utilization of Cold Energy of LNG for Carbon Dioxide Capture and Liquefaction in Amine-Based SMR

Utilization of Cold Energy of LNG for Carbon Dioxide Capture and Liquefaction in Amine-Based SMR

Efficient utilization of cold energy enabled by phase change cold storage brine gels with superior thermophysical properties towards biochemical reagent cold chain

Phase change cold storage, as an emerging cold chain method of maintaining a low-temperature environment and effectively ensuring the quality of biochemical reagents, is extensively utilized because of its benefits of high energy density, low cost, energy conservation and environmentally friendly mode. However, the low thermal conductivity of working medium affects its cold charging/discharging rate and operating efficiency. Meanwhile, the high leakage characteristic in the phase change process leads to a decrease of cold storage capacity and contamination of items. This work proposes the efficient utilization of cold energy enabled by leakage-free phase change cold storage brine gels with extraordinary high thermal conductivity towards biochemical reagent cold chain. Phase change thermal storage gel is prepared by confining brine in the sodium polyacrylate‑calcium alginate network and porous adsorption of expanded graphite. The prepared materials present leak free characteristics and almost 100% mass retention rate. Expanded graphite addition enables the thermal conductivity increase from 0.542 W m−1 K−1 to an extremely high value of 2.766 W m−1 K−1 (an increase of 510%). The enthalpy value of the cold storage brine gel is as high as 144 Jg−1, stably releasing cold at around −24 °C. By regulating the distribution of cold storage working medium, the minimum temperature difference inside the apparatus can be reduced from 6.7 °C to about 1 °C. Finally, performance-enhancing phase change cold storage materials and apparatus in the cold chain of biological reagents is fruitful, effectively providing a long-lasting and uniform low-temperature environment.

Simulation study of a novel methanol production process based on an off-grid Wind/Solar/Oxy-fuel power generation system

Power-to-methanol technology represents a promising energy storage solution to manage the fluctuating supply and demand of renewable energy effectively. A novel methanol production process based on an off-grid wind/solar/Oxy-fuel power plant is presented in the paper, which consists of solar-wind energy, oxy-fuel combined cycle, proton exchange membrane electrolyzer, and carbon dioxide hydrogenation to methanol unit. The hydrogen produced by the proton exchange membrane electrolyzer is used to synthesize methanol, and the by-product oxygen is used in the oxy-fuel combined cycle. At the same time, low-cost carbon capture is achieved with liquefied natural gas cold energy utilization, and the collected carbon dioxide is used to synthesize methanol. The system carbon emission is negative, about −0.344 kg carbon dioxide/kg methanol, the system has no other products except methanol. The structure of renewable energy has a significant impact on the technical and economic performance of the system. Therefore, a comparative analysis of different wind/photovoltaic installed capacity ratios is carried out. The case study shows that the proposed system has the best performance when the wind/photovoltaic installed capacity ratio is 25 %/75 %, with a renewable energy utilization of 97.62 %, methanol production cost of 1.34 $/kg methanol, and an energy efficiency of 63.5 %. The proposed system may be a practical solution for methanol production from renewable energy.