Synthetic Natural Gas Production Research Articles

Proposal of an open-source computational toolbox for solving PDEs in the context of chemical reaction engineering using FEniCS and complementary components

In this contribution, an open-source computational toolbox composed of FEniCS and complementary packages is introduced to the chemical and process engineering field by addressing two case studies. First, the oxidation of o-xylene to phthalic anhydride is modelled and used as a FEniCS′ proof-of-concept based on a comparison with the software Aspen Custom Modeler (ACM). The results show a maximum absolute error of 2% and thus a good FEniCS/ACM agreement. Second, synthetic natural gas (SNG) production through CO2 methanation is covered in further detail. In this instance, a parametric study is performed for a tube bundle fixed-bed reactor employing a two-dimensional and transient pseudo-homogeneous model. An operating window for critical variables is evaluated, discussed, and successfully contrasted with the literature. Therefore, the computational toolbox methodology and the consistency of the results are validated, strengthening FEniCS and complements as an interesting alternative to solve mathematical models concerning chemical reaction engineering.

Power-to-Gas, Hydrogen, and a Spotlight on New York's Emerging Climate and Energy Policy

This paper examines the role of law and regulation in advancing technology-based energy decarbonization options such as hydrogen compatible networks and power-to-gas (P2G) in the context of New York’s energy and climate change mitigation goals. By exemplifying the potential of P2G and hydrogen, it underscores the need for a more comprehensive legal and regulatory framework that (i) reflects the peculiarities of gas and electricity systems (on the one hand) and (ii) facilitates a more effective and integrated energy decarbonization pathway (on the other hand). Hydrogen is an energy carrier with a significant potential to deliver zero and low-carbon energy depending on how it is produced. Also, when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a by-product. It has been used for several years in bespoke applications in the aeronautics, industrial, and transportation sectors. About ten million metric tons of hydrogen is currently produced in the US every year, and ninety-five percent of which is via centralized reforming of natural gas (i.e. steam methane reformation (SMR) and known as “Blue Hydrogen”) used mostly in petroleum refining and ammonia industries. Other modes of utilization include fuel cell vehicles, metals refining, and synthetic natural gas production. Notably, the P2G process leads to the production of “green hydrogen” by using electricity that would otherwise be curtailed or lost, from variable renewable energy (VRE) sources such as solar and wind. Such VRE sourced energy can be used to split water into its hydrogen and oxygen components. The ‘green hydrogen’ process is becoming increasingly relevant to the issues of (i) decarbonization of gas and electricity networks; and (ii) solving the ‘curtailment’ ‘intermittency’ and ‘storage’ challenge in an energy system where renewables are gradually playing a larger role. It may also be key to facilitating the integration of a growing share of VREs in existing networks and in the same vein helping to avoid the ‘stranded assets’ dilemma faced by operators of natural gas pipeline and storage networks which can be compatible with hydrogen or synthetic methane produced as a result. Law and regulation provide a facilitative means through which relevant institutions and operators can work towards decarbonization and develop the requisite technology-based solutions while addressing the energy policy challenges created by the increasing role of VREs. Such considerations are even more relevant for a state such as New York. Even though the state’s Clean Energy Standard revised in 2019 requires 100% carbon-free electricity by 2040; in 2019, 29% of New York's in-state generation came from renewable sources. One-third of its utility-scale net generation came from in-state nuclear power plants that are scheduled to be decommissioned soon, while it was the sixth-largest natural gas consumer in the US, and three in five households used natural gas for home heating. The emerging energy decarbonization issues can be met if, among other things, law and regulation are viewed from a functional lens. In this regard, ‘regulation’ is considered as part of a legal framework that is instrumentalist in orientation with the aim of pursuing defined energy policy objectives which typically comprise of ensuring (i) secure and reliable supplies, (ii) sustainability while protecting the environment, and (iii) ensuring that costs and rates are just and reasonable both for the suppliers and consumers. The (ii) dimension is crucial in a carbon-constrained world. Thus, the paper will consider these highlighted issues and in Part II discuss the growth and challenges with VREs in the US energy mix and then highlight potential role(s) for hydrogen and P2G as an example of innovative technology-based decarbonization solution as well as a means of efficiently integrating growing VREs in electricity context with natural gas networks. Part III will examine the regulatory issues in the regulation of gas and electricity systems in a carbon-constrained world and the challenges and potential for decarbonization by deploying hydrogen and P2G. Part IV examines New York’s emerging climate and energy regulation framework and points out the possible issues with deploying P2G and hydrogen in the state. The paper concludes by highlighting that in the pathways to decarbonization the overarching objective in determining how and what to regulate should be ‘curbing greenhouse gas emissions’. It also underscores the need to develop an integrated policy and regulatory framework that can enhance the required technologies and energy systems in the path towards decarbonization.

Using the analytical heirarchy process to select specific methanation catalysts based on their extraction impacts

SummaryMethanation is an exothermic process that utilizes catalysts to convert the carbon dioxide and carbon monoxide in biogas to methane, forming synthetic natural gas. The criteria for determining a suitable catalyst should not only be its effectiveness, but also the environmental impact of extracting and refining the metal. The authors examine the environmental impacts of implementing a select group of methanation catalysts in the field for industrial scale synthetic natural gas production using the analytical hierarchy process (AHP). Catalysts containing a combination of rare earth metals are investigated separately and AHP is used to rank the catalysts based on their environmental impact per kg of CO2 converted. It is determined that catalysts containing common metals, such as nickel, have the lowest environmental impact per conversion rate across a number of metrics and represented the catalysts with the second and third highest conversion rates analyzed. Catalysts containing ruthenium are found to be the most detrimental to the environment, in spite of the favorable conversion rate offered by a ruthenium‐cesium catalyst in methanation reactors.

Carbon footprint of synthetic natural gas through biogas catalytic methanation

The carbon footprint of synthetic natural gas production from biogas catalytic methanation was determined. The material and energy data inputs required to produce 1 kWh of synthetic natural gas were experimentally collected from a pilot plant operating in a waste water treatment plant as a relevant environment. The experimental plant had a capacity of 37 kW and consisted of biogas and water conditioning, water electrolysis and 2-step carbon dioxide catalytic methanation unit, by compact technology of micro-reactor and micro-size catalysts al mild pressure conditions. The technology evaluated in this study is ready for scalability to MW-scale. The carbon footprint was evaluated by means of the Global Warming potential impact in kg CO2-eq/kWh. Life Cycle Assessment methodology was used according to ISO:14040 and ISO:14067 thorough Ecoinvent data. The carbon footprint analysis showed that producing synthetic natural gas using the current electricity mix led to high carbon impact. However, the utilization of renewable electricity sources and a more efficient electrolyzer technology is able to reduce the carbon footprint to 0.100 kg CO2-eq/kWh. This value represents an interesting reduction of the climate change impact of 57%, using currently available technologies. Therefore, synthetic natural gas from biogas catalytic methanation process represents a feasible option to partially decarbonize the gas grid infrastructure. In this way, synthetic natural gas can support the penetration of random renewable sources by allowing its seasonal storage, as well as, to provide a low-carbon gas alternative.

A comprehensive analysis of a power-to-gas energy storage unit utilizing captured carbon dioxide as a raw material in a large-scale power plant

The global destructive effects of carbon dioxide emissions and the importance of energy storage for grid stability and peak shaving applications are in deep concern. In this regard, this paper investigates the recycling of carbon dioxide from gas-fired power plant emissions into synthetic natural gas based on a novel power-to-gas process with the aim of chemical energy storage and emission reduction. The hybrid power-to-gas process proposed in this paper integrates the power generated from the gas plant and renewable energies. To make a precise evaluation of system performance, the referenced system is analyzed from technical, economic, and environmental points of view. The process is optimized through the reaction operation conditions and the energy utilization of the process. The results demonstrate that the power-to-gas process achieves a reaction synthetic natural gas production yield of over 97% at the optimal operation conditions. Regarding energy and environmental outlook, the power plant provides 15.4% of the power-to-gas total energy consumption, with the remaining 84.6% supplied from renewable energy resources. From the synthetic natural gas produced, the power-to-gas process provides total annual energy storage of 2.9 × 107 GJ and recycles 1.6 Mton of carbon dioxide for the power plant flues, resulting in a reduction of the plant emissions by around 66%. According to the economic data, with the consideration of the selling price of oxygen, the cost of the synthetic natural gas produced results in 1738 $/ton. The obtained results indicate that the system designed can reduce production costs due to hybrid electricity and offers two unique attributes: energy storage capability and drastic reduction of carbon dioxide emissions.

Flexibility of Power‐to‐Gas Plants: A Case Study

AbstractDue to the increasing share of renewable energies in the power sector, the need for energy storage and flexible performance is rising. This study provides an in‐depth investigation of the flexibility of a Power‐to‐Gas plant for the production of synthetic natural gas. Model‐based analysis is conducted for the individual technologies PEM electrolysis, MEA absorption and fixed‐bed methanation as well as for the continuously operated process. This study reveals that the Power‐to‐Gas plant offers a capacity flexibility of 87–125 %, corresponding to 4.79–6.88 MW electrical input power.

Effect of reducibility on the performance of Co-based catalysts for the production of high-calorie synthetic natural gas

Co-based catalysts were developed for the production of high-calorie synthetic natural gas. The Co reduction in Al2O3- and SiO2-supported catalysts prepared with different Co loading, and their catalytic properties for high-calorie methanation were investigated. The CO conversion of the Co/SiO2 catalysts was superior to that of the Co/ Al2O3 with the same Co loading, due to their better reducibility at 400°C. The activities of both the Al2O3 and SiO2-supported catalysts increased with Co loading, while the growth of hydrocarbon chains decreased as the Co loading increased. As the reduction temperature increased, crystallite size of Co increased in 10Co/SiO2, resulting in decrease of CO conversion and increase of C2+ selectivity. The highest CO conversion (98.7%) was obtained over 10Co/SiO2 reduced at 400 °C. Moreover, the heating value of the product gas (10,405 kcal/Nm3) exceeded the standard heating value without requiring a high reduction temperature (700 °C) or a noble metal (Ru).

Membrane-Assisted Removal of Hydrogen and Nitrogen from Synthetic Natural Gas for Energy-Efficient Liquefaction

Synthetic natural gas (SNG) production from coal is one of the well-matured options to make clean utilization of coal a reality. For the ease of transportation and supply, liquefaction of SNG is highly desirable. In the liquefaction of SNG, efficient removal of low boiling point impurities such as hydrogen (H2) and nitrogen (N2) is highly desirable to lower the power of the liquefaction process. Among several separation processes, membrane-based separation exhibits the potential for the separation of low boiling point impurities at low power consumption as compared to the existing separation processes. In this study, the membrane unit was used to simulate the membrane module by using Aspen HYSYS V10 (Version 10, AspenTech, Bedford, MA, United States). The two-stage and two-step system designs of the N2-selective membrane are utilized for SNG separation. The two-stage membrane process feasibly recovers methane (CH4) at more than 95% (by mol) recovery with a H2 composition of ≤0.05% by mol, but requires a larger membrane area than a two-stage system. While maintaining the minimum internal temperature approach value of 3 °C inside a cryogenic heat exchanger, the optimization of the SNG liquefaction process shows a large reduction in power consumption. Membrane-assisted removal of H2 and N2 for the liquefaction process exhibits the beneficial removal of H2 before liquefaction by achieving low net specific power at 0.4010 kW·h/kg·CH4.

“Potential carbon efficiency” as a new index to track the performance of biofuels production processes

In a carbon constrained economy which targets a massive reduction of the CO2 emissions, biogenic carbon is bound to be a scarce resource with high economic value. In such scenario, the carbon efficiency may become the key performance index to represent the revenues of the biomass-to-X conversion plants.In this work, the potential carbon efficiency (PCE) indicator is defined to quantify the achievable carbon efficiency (i.e. the amount of carbon contained in the final product with respect to the available input carbon), of a stream or of a process unit. Compared to the conventional carbon efficiency (CE), that is affected only by the separation/addition of carbon-containing species, the PCE allows quantifying the potential variation of the achievable carbon efficiency in process units where no carbon separation occurs, but where a limiting element is added (e.g. hydrogen through steam addition) or oxygen content is increased (e.g. oxygen injection in a reformer).The difference between the CE and the PCE along a biomass conversion process is typically due to the excess of oxygen atoms in the syngas, which is removed as CO2 in the syngas conditioning unit. Therefore, the difference between CE and PCE shows the potential gain in carbon efficiency that can be obtained by the addition of H2 from an electrolysis process.In this paper, the PCE and the CE have been calculated along the process units of different biomass-to-X plants. The selected case studies allow comparing different gasification technologies (direct gasification, indirect gasification and sorption enhanced gasification) in plants for the production of methanol and synthetic natural gas, showing how CE and PCE are influenced by process units such as the gasification technology, syngas reforming, syngas conditioning and hydrogen addition.

Life Cycle Assessment of Synthetic Natural Gas Production from Different CO2 Sources: A Cradle-to-Gate Study

Fuel production from hydrogen and carbon dioxide is considered an attractive solution as long-term storage of electric energy and as temporary storage of carbon dioxide. A large variety of CO2 sources are suitable for Carbon Capture Utilization (CCU), and the process energy intensity depends on the separation technology and, ultimately, on the CO2 concentration in the flue gas. Since the carbon capture process emits more CO2 than the expected demand for CO2 utilization, the most sustainable CO2 sources must be selected. This work aimed at modeling a Power-to-Gas (PtG) plant and assessing the most suitable carbon sources from a Life Cycle Assessment (LCA) perspective. The PtG plant was supplied by electricity from a 2030 scenario for Italian electricity generation. The plant impacts were assessed using data from the ecoinvent database version 3.5, for different CO2 sources (e.g., air, cement, iron, and steel plants). A detailed discussion on how to handle multi-functionality was also carried out. The results showed that capturing CO2 from hydrogen production plants and integrated pulp and paper mills led to the lowest impacts concerning all investigated indicators. The choice of how to handle multi-functional activities had a crucial impact on the assessment.

Thermodynamic investigation of SNG production based on dual fluidized bed gasification of biogenic residues

Natural gas is an important commodity in the European energy market. The gasification of biogenic residues and the further reaction to a methane-rich gas represent a promising concept for the production of synthetic natural gas on a fossil-free basis. This paper investigates the thermodynamics of methanation in a fluidized bed reactor for different product gas compositions of the dual fluidized bed gasification technology. The investigated product gases range from conventional steam gasification, over CO2 gasification, to product gases from the sorption enhanced reforming process. All investigated product gases from conventional steam gasification show an understoichiometric composition and therefore require a proper handling of carbon depositions and a CO2 separation unit downstream of the methanation reactor. The product gas from CO2 gasification is considered disadvantageous for the investigated process, because it only exhibits a carbon utilization efficiency of 23%. Due to the high flexibility of the sorption enhanced reforming process, a nearly complete methanation of the carbonaceous species is possible without the need for a CO2 separation step or the addition of steam upstream of the methanation reactor. Furthermore, the carbon utilization efficiency is found to be between 36 and 38%, similar to the results for conventional steam gasification. Temperature and pressure variations allow a thermodynamically optimized operation, which can increase the performance of the methanation and lower the extent of gas upgrading for grid feed-in. Additionally, if a higher hydrogen content in the natural gas grid would be allowed, the overall process chain could be further optimized and simplified.

Renewable power-to-gas by direct catalytic methanation of biogas

Abstract Two processes (with cooled and adiabatic fixed bed reactors) for direct biogas methanation were assessed using detailed balances and rate-based models. The simulations show that they are capable to produce synthetic natural gas (SNG) in one or two steps without further upgrading after the reactors. The sizes for cooled beds are smaller than for adiabatic reactors due to heat transfer that reduces the needs for recirculation and allows for more favorable temperature profiles; although a more complex heat exchanger systems is then required for cooling. Thus, the processes are compared to identify the most cost-effective operating conditions for each system, since all considered optimized systems can meet product specifications and technical aspects alone are not enough to decide which the most beneficial approach is. The economic analysis shows that the costs dominant come from biogas and hydrogen and total costs production of SNG (0.54–0.58 €/Nm3SNG) is still high compared to natural gas. Cheap biogas and electricity may lead to more competitive SNG costs, while the methanation step can effectively remove the problems related to biogas or hydrogen uses at the same time that is a minor part of final costs.

Thermodynamic analysis and techno-economic assessment of synthetic natural gas production via ash agglomerating fluidized bed gasification using coal as fuel

Implementing coal to synthetic natural gas (SNG) is a key way to deal with the conflict between supply and demand of natural gas in China. For the coal to SNG process, gasification is a crucial unit, which determines the syngas composition and influences cost of coal to SNG system. In this current study, a coal to SNG system using ash agglomerating fluidized bed gasification is designed and modeled. According to the above results, the thermal performance and technoeconomic assessment of the coal to SNG system are performed. The research demonstrates that exergy efficiency and energy efficiency of the whole system are 55.37% and 61.50%, respectively. Additionally, the results of the economic evaluation show that the SNG production cost is 1.87 CNY/Nm3 with a coal price of 250 CNY/t and an electricity price of 0.65 CNY/kWh. Sensitivities to variables such as water price, electricity price, total equipment cost and coal price are performed. Coal price represents the most important sensitivity, but the sensitivity to water price is relatively small.

A novel technology for liquefied synthetic natural gas production powered by renewable electricity: Process development and impact analysis on vehicular transportation

Overgeneration of wind energy conversion systems represents a grid issue, limiting the growth of renewable energy utilization. Alternative fuels utilization such as liquefied natural gas is emerging as a new market with a big potential in freight transport. In order to mitigate wind energy production curtailment, a power to liquefied synthetic natural gas process is proposed. Solid oxide electrolyser and catalytic methanation integrated system is applied to produce hydromethane. After a dehydration step in a temperature swing adsorption unit, low temperature gas upgrading techniques are applied for the first time to hydromethane mixture. Liquified synthetic natural gas is produced, meeting grid injection and endothermic engines requirements after regasification. A higher energy efficiency with respect to the application of traditional technologies is achieved. Plant configuration was optimized for internal thermal and chemical energy recovery and exploitation, achieving an overall electrical to chemical efficiency of about 50%. A case study was analyzed for the Irpinia (Italy) territory, strongly affected by wind energy overgeneration. Impact on local transport infrastructure was assessed through well-to-wheel analysis, considering the use of produced liquified synthetic natural gas in heavy duty vehicles. Greenhouse gas avoided emissions are expected to correspond to 7.1% of the vehicular emissions related to local traffic statistics for 2016.

Synthetic natural gas production from the three stage (i) pyrolysis (ii) catalytic steam reforming (iii) catalytic hydrogenation of waste biomass

Synthetic natural gas (methane) production was systematically investigated by optimizing various operating parameters using a three stage (i) biomass pyrolysis (ii) catalytic steam reforming (iii) catalytic hydrogenation reactor system. Several operating parameters were optimized including catalytic steam reforming temperature, steam weight hourly space velocity (WHSV), catalytic hydrogenation temperature and hydrogen gas space velocity. In addition, the influence of different metal catalysts (Ni/Al2O3, Fe/Al2O3, Co/Al2O3, and Mo/Al2O3), catalyst calcination temperature, catalyst metal loadings, and different catalyst support materials (Al2O3, SiO2, and MCM-41) was carried out specifically to optimize catalytic hydrogenation in the third stage reactor. The highest methane yield of 13.73 mmoles g−1biomass (22.02 g CH4 100 g−1biomass) was obtained with a second stage catalytic steam reforming temperature of 800 °C over a 10 wt% Ni/Al2O3 catalyst and with a steam WHSV of 5 mL h−1 g−1catalyst together with a third stage catalytic hydrogenation temperature of 350 °C over a 10 wt% Ni/Al2O3 catalyst with added hydrogen gas space velocity of 2400 mL h−1 g−1catalyst.

Bimetallic Ni-Co catalysts for co-production of methane and liquid fuels from syngas

With the rapid expansion of the natural gas consumption market worldwide, methanation of coal- or biomass-derived syngas for production of synthetic natural gas (SNG) is gaining considerable interest. In order to solve the problem of natural gas “peak shaving”, adjusting product distribution of the SNG plant is an efficient method to meet the demand fluctuation of natural gas in peak and off season. Herein, the conversion of syngas to SNG (CH4) and co-production of liquid fuels (C5+) over bimetallic Ni-Co catalysts was investigated at industrially relevant conditions. The effects of integration manner of the Ni-Co components, Ni/Co mass ratio, and the operating conditions on the catalytic performance were investigated. Due to the synergistic interaction between Ni and Co, silica supported Ni-Co bimetallic catalyst shows higher activity and total yield of methane and liquid fuels compared to the physically mixed sample. In addition, a good balance between Ni and Co content is crucial for the high efficiency co-production of SNG and liquid fuels. It is found that the optimum operating range in the present study is 550–578 K, H2/CO = 3, 3.0 MPa and W/F = 5 gcat h mol−1, in which more than 80 % total yield of methane and liquid fuels can be obtained on the 2Ni-1Co/SiO2 bimetallic catalyst. Moreover, it shows good thermal stability during the 55 h reaction time. All catalysts were examined by XRD, TEM, H2-TPR and XPS.

Analysis of blue energy production using natural gas infrastructure: Case study for the Northern Adriatic

With the end of economic production in sight, the oil and gas industry is preparing for the decommissioning of the offshore facilities. Beside of removing the infrastructure, there are numerous possibilities for its future use. Paper analyses possible use of offshore infrastructure for blue energy production from wind. The conversion of excess electricity into chemical energy, which can easily be stored, can be achieved using P2G (Power-to-Gas) technologies. Chemical conversion units performing a balancing for the power system and transformers needed for electricity transportation from offshore wind farms can be built on oil and gas platforms. The main contribution of the paper, based on a case study of the Northern Adriatic, includes hydrocarbon production prediction, electricity generation and hydrogen production based on wind potential calculation and synthetic natural gas production analysis. Energy production comparison of different technologies and conversion efficiencies have been given. Authors found that the most beneficial reuse option for offshore facilities is electricity generation from wind. Paper concludes that it is not likely that blue energy will match current hydrocarbon production, but it suggests postponing the decommissioning for the possibility of the blue energy production for which further detailed case by case economic analysis will be needed.

Synthetic natural gas production from CO2 and renewable H2: Towards large-scale production of Ni–Fe alloy catalysts for commercialization

Synthetic natural gas (SNG) is one of the promising energy carriers for the excessive electricity generated from variable renewable energy sources. SNG production from renewable H2 and CO2 via catalytic CO2 methanation has gained much attention since CO2 emissions could be simultaneously reduced. In this study, Ni–Fe/(Mg,Al)Ox alloy catalysts for CO2 methanation were prepared via hydrotalcite precursors using a rapid coprecipitation method. The effect of total metal concentration on the physicochemical properties and catalytic behavior was investigated. Upon calcination, the catalysts showed high specific surface area of above 230 m2 g−1. Small particle sizes of about 5 nm were obtained for all catalysts, even though the produced catalyst amount was increased by 10 times. The catalysts exhibited excellent space-time yield under very high gas space velocity (34,000 h−1), irrespective of the metal concentration. The CO2 conversions reached 73–79% at 300 °C and CH4 selectivities were at 93–95%. Therefore, we demonstrated the potential of large-scale production of earth-abundant Ni–Fe based catalysts for CO2 methanation and the Power-to-Gas technology.

Can thermal energy recovery from digestate make renewable gas from household waste more cost effective? A case study for the Republic of Ireland

This article assesses the impact of energy recovery from digestate on the economics of biomethane produced from the organic fraction of municipal solid waste. Six waste-to-energy routes are investigated and assumed to be deployed in the regional context of the Republic of Ireland. Anaerobic digestion without energy recovery, and landspreading of dewatered digestate, presents the lowest levelised cost for the biomethane produced, from 86.8 to 108.9 €/MWh, and highest net present value, from 70.6 to 116.4 M€. However, if the digestate is dried, synthetic natural gas production from the digestate through steam gasification, maximising the amount of renewable gas produced, presents the lowest levelised cost, from 93.4 to 113.8 €/MWh, and highest net present value, from 65.5 to 111.8 M€ and highest net present value. Due to the largest substitution of natural gas, this process presents also the largest CO2 emission saving, from 12.1 to 20 kilotonnes of CO2 per annum. Transportation costs of the residues generated, because of the proximity of farm lands in which the digestate is landspread, and because of the small amount of ash generated, are negligible when compared to CapEx, OpEx and energy expenditure. CapEx and OpEx are the most sensitive parameters, and the more the energy demand of the process is not covered the more the expenditure for energy supplies become relevant. Although all the alternatives presented cost greater than natural gas price for household consumers, 70.3 €/MWh, additional revenues for waste management services would make the renewable gas produced profitable.

Projecting cost development for future large-scale power-to-gas implementations by scaling effects

Power-to-gas (PtG) is widely expected to play a valuable role in future renewable energy systems. In addition to partly allowing a further utilization of the existing gas infrastructure for energy transport and storage, hydrogen or synthetic natural gas (SNG) from electric power represents a high-density energy carrier and important feedstock material for further processing. This premise leads to a significant demand for large-scale PtG plants, which was evaluated with an amount of up to 4530 GWel for electrolysis and up to 1360 GWSNG for methanation capacities at a global scale. Together with the upscaling of single-MW plants available today, this will enable to achieve appropriate cost reduction effects through technological learning. Under given scenarios, reduction potentials for CAPEX of >75% are expected for multi-MW PtG plants in the long-term, with significant advantages of PEM and solid oxide electrolysis over alkaline systems in the short- and mid-term. The resulting effects on PtG product costs were evaluated via a holistic techno-economic assessment, resulting in SNG production costs of 15 €-cent/kWh and below for large-scale appliances in 2050, depending on the renewable electricity supply.