Assessment Of Greenhouse Gas Emissions Research Articles

Assessment of Greenhouse Gas Emissions and Energetic Potential from Solid Waste Landfills in Jordan: A Comparative Modelling Analysis

Landfilling of solid waste has been and continues to be among the most common practices of solid waste disposal. This is particularly true for Jordan, where approximately 3.3 million tons of municipal solid waste (MSW) is annually generated, with 90% of the generated amount disposed into landfills. The main objective of this study is to estimate the quantities of landfill gas (LFG) generated from the solid waste disposal and its potential as a source of clean energy in Jordan using four different models, namely, GasSim 2.5, LandGEM, Afvalzorg, and Mexico Landfill Gas Model V2 (MLFGM V2). Furthermore, the greenhouse gas (GHG) mitigation potential of LFG projects was estimated. Currently, there are 18 active landfills that are distributed across the country. Based on screening criteria, the landfills were grouped into three categories: five landfills were considered for energy production, four were strong candidates for LFG collection and flaring, while the remaining nine landfills do not receive enough waste to be considered for either energy recovery or flaring. The total amount of LFG emissions was found to be 1.6 billion M3 of LFG, while the landfill energetic potential of the recovered LFG was estimated to be 34.8 MW. On the other hand, GHG mitigation potential was assessed between the years 2020 and 2030, which was found to be 18 million ton CO2 eq. The proposed LFG energy recovery projects will lead to increased biogas contribution to Jordan’s local renewable energy mix from a current level of 1% to 6%.

Assessment of greenhouse gases emissions and intensity from Chinese marine aquaculture in the past three decades

Marine aquaculture is increasingly gaining importance as a source of food with high nutritional value. However, the expansion of aquaculture could be responsible for water contamination that influences the environmental quality of coastal ecosystems, and emissions of greenhouse gases (GHG) that affect global climate. China is the world's largest producer of marine aquaculture protein, which demands robust studies to assess the corresponding GHG emissions and intensity. To fill in this knowledge gap, the current study quantifies and analyzes GHG emissions and intensity (emission intensity is defined as GHG emissions per unit of production) from Chinese marine aquaculture (marine aquaculture production) over the past 30 years (1991–2020). The production of marine aquaculture comes from the China Fisheries Statistical Yearbooks. And the GHG emissions and intensity were calculated based on five sectors (commercial feed, trash fish, N2O, CH4, and energy) by Emission-Factor Approach. The results suggest that, excluding shellfish and algae, GHG emissions of ten coastal provinces (excluding Shanghai, Hong Kong, Taiwan, and Macau) increased from 2 Mt (109 kg) CO2-eq in 1991 to 25 Mt CO2-eq in 2020. In contrast, GHG emission intensity decreased in the same period from 7.33 (t CO2-eq/t production) to 6.34 (t CO2-eq/t production), indicating a progressive mitigation in GHG emissions per unit of product, hence sustainably satisfying a growing demand for food. As a result, China's marine aquaculture seems to be paving a promising way towards the neutrality of GHG emissions. In most provinces, GHG is on the rise, and only in Tianjin is on the decline in recent years. For the emissions intensity, the values of more than half provinces showed the downtrends. In addition, by considering the ratio of shellfish and algae, Chinese marine aquaculture can improve the net zero goal for GHG emissions of the sector. Finally, results also reveal for the first time the changes in taxonomic composition and spatial GHG emissions and intensity, providing new understanding and scientific bases to elaborate consistent mitigation strategies for an expanding global marine aquaculture.

Assessment of energy performance and GHG emissions for the urban water cycle toward sustainability

Abstract This study presents a holistic approach to evaluate energy performance and greenhouse gas (GHG) emissions from urban water supply and sanitation stages, which are important for sustainable water management and climate change mitigation. The study was conducted for Antalya city of Turkey to compare baseline and improved scenario conditions using the Energy Performance and Carbon Emissions Assessment and Monitoring (ECAM) tool. The current application of urban water and wastewater services was defined as the baseline scenario. For the improved urban water cycle, the reduction of non-revenue water, onsite sanitation prevention, increase in energy efficiency, biogas production and reuse of treated wastewater were investigated. Water supply and sanitation stages contributed to approximately 26 and 74% of total GHG emissions and 70 and 30% of energy consumption for the baseline scenario, respectively. GHG emissions were determined approximately as 52,423 tCO2eq/year for CO2 (40%), 47,029 tCO2eq/year for CH4 (35%) and 33,006 tCO2eq/year for N2O (25%) for the baseline scenario. The total GHG emissions of 132,457 tCO2eq/year and energy consumption of 136,328 MWh/year were reduced by 27.65% for GHG emissions and 16.48% for energy consumption for the improved urban water cycle. The outcomes of this research are expected to achieve sustainable cities and combat climate change.

Research on Greenhouse Gas Emissions and Economic Assessment of Biomass Gasification Power Generation Technology in China Based on LCA Method

China is rich in biomass resources, taking straw as an example, the amount of straw in China is 735 million tons in 2021. However, at the level of resource use, biomass resources have the practical difficulties of being widely distributed and difficult to achieve large-scale application. By collecting large amounts of biomass and generating electricity using gasification technology, we can effectively increase the resource utilization of biomass and also improve China’s energy security. By using a life cycle assessment (LCA) approach, this paper conducted a life cycle assessment with local biomass gasification power generation data in China and found that the LCA greenhouse gas emissions of biomass gasification power generation technology is 8.68 t CO2 e/104 kWh and the LCA cost is 674 USD/104 kWh. Biomass gasification power generation technology has a 14.7% reduction in whole life carbon emissions compared to coal power generation technology. This paper finds that gas-fired power generation processes result in the largest carbon emissions. In terms of economics, this paper finds that natural gas brings the most additional costs as an external heat source.

Life Cycle Greenhouse Gas Emission Assessment for Using Alternative Marine Fuels: A Very Large Crude Carrier (VLCC) Case Study

The International Maritime Organization (IMO) has set decarbonisation goals for the shipping industry. As a result, shipowners and operators are preparing to use low- or zero-carbon alternative fuels. The greenhouse gas (GHG) emission performances are fundamental for choosing suitable marine fuels. However, the current regulations adopt tank-to-wake (TTW) emission assessment methods that could misrepresent the total climate impacts of fuels. To better understand the well-to-wake (WTW) GHG emission performances, this work applied the life cycle assessment (LCA) method to a very large crude carrier (VLCC) sailing between the Middle East and China to investigate the emissions. The life cycle GHG emission impacts of using alternative fuels, including liquified natural gas (LNG), methanol, and ammonia, were evaluated and compared with using marine gas oil (MGO). The bunkering site of the VLCC was in Zhoushan port, China. The MGO and LNG were imported from overseas, while methanol and ammonia were produced in China. Four production pathways for methanol and three production pathways for ammonia were examined. The results showed that, compared with MGO, using fossil energy-based methanol and ammonia has no positive effect in terms of annual WTW GHG emissions. The emission reduction effects of fuels ranking from highest to lowest were full solar and battery-based methanol, full solar and battery-based ammonia, and LNG. Because marine ammonia-fuelled engines have not been commercialised, laboratory data were used to evaluate the nitrous oxide (N2O) emissions. The GHG emission reduction potential of ammonia can be exploited more effectively if the N2O emitted from engines is captured and disposed of through after-treatment technologies. This paper discussed three scenarios of N2O emission abatement ratios of 30%, 50%, and 90%. The resulting emission reduction effects showed that using full solar and battery-based ammonia with 90% N2O abatement performs better than using full solar and battery-based methanol. The main innovation of this work is realising the LCA GHG emission assessment for a deep-sea ship.

Assessment of Greenhouse Gas Emissions into the Atmosphere from the Northern Peatlands Using the Wetland-DNDC Simulation Model: A Case Study of the Great Vasyugan Mire, Western Siberia

The peatlands of Western Siberia occupy an area of about 1 million km2 and act as important regulator of carbon exchange between the earth and the atmosphere. Extrapolation of the results of discrete field measurements of CO2 fluxes in bog ecosystems to such a territory is a difficult task, and one of the ways to overcome it is to use a simulation model such as DNDC. However, using this model with a specific territory requires ground verification to confirm its effectiveness. Here, we tested the DNDC model on the largest pristine bog ecosystem of the world, the Great Vasyugan Mire (GVM). The GVM of western Siberia is virtually undisturbed by anthropogenic activity and is the largest bog of Northern Eurasia (53,000 km2). Based on various ground-based observations, the performance of the Wetland-DNDC model was demonstrated (Thale coefficient 0.085 and R2 = 0.675 for CO2). Model input parameters specific to the GVM were constrained and model sensitivity to a wide range of input parameters was analyzed. The estimated annual terrestrial carbon fluxes in 2019 from the GVM test site are mainly controlled by plant respiration (61%) and forest floor degradation (38%). The net CO2 emission flux was 8600 kg C ha−1 year−1, which is in line with estimates from other independent studies.

Techno-economic assessment of jet fuel production using the Fischer-Tropsch process from steel mill gas

In order to reduce human-made global warming, the aviation industry is under pressure to reduce greenhouse gas (GHG) emissions. Production of sustainable aviation fuel (SAF) from steel mill gases could help reduce the emissions intensity of jet fuel. This study presents a simulation, techno-economic assessment, and GHG emissions assessment of a Fischer-Tropsch (FT) process using two steel mill gases (coke oven gas and blast furnace gas) as feedstock. The process was analysed both with and without carbon capture and storage (CCS) to reduce process emissions. The minimum viable selling price (MVSP) was determined to be 1,046 €/tonne for the standard scenario and 1,150 €/tonne for the CCS scenario, which is higher than the fossil-fuel-based benchmark (325–1,087 €/tonne since 2020), although similar to the lowest costs found for other SAF benchmarks. The GHG emissions intensity was found to be 49 gCO2-eq./MJ for the standard scenario and 21 gCO2-eq./MJ with CCS, far lower than the 88 gCO2-eq./MJ average for the conventional benchmark and in the mid-lower range of found emissions intensities for other SAF benchmarks. When a CO2 tax of 130 €/tonne is considered, the MVSP for the standard scenario increases to 1,320 €/tonne while the CCS scenario increases to 1,269 €/tonne, making them cost-competitive with the fossil-fuel benchmark (797–1,604 €/tonne). The studied process offers economically viable small-to-medium scale SAF plants (up to 50 kt/y SAF) at a CO2 tax of 190 €/tonne or higher for the CCS scenario and 290 €/tonne or higher for the standard scenario.

Emissions of Greenhouse Gases in Yakutia: A Retrospective Analysis Based on the Fuel and Energy Balance

ABSTRACT The development of fuel and energy balances has been rather widely validated at the level of the constituent entities of the Russian Federation. These balances could become the basis for retrospective assessments of greenhouse gas emissions. The dynamics of emissions are to a significant degree determined by the structure of final internal consumption of fuel and energy resources. Aggregate data make it possible to assess changes in the energy and carbon intensities of the GRP [gross regional product]. They are also the prerequisite for the creation of regional inventories as part of the national system for monitoring, reporting, and verifying the volume of greenhouse gas emissions. A correlation and regression analysis of data for 1990–2015 established a direct correlation between anthropogenic emissions and economic growth and also the public’s quality and standard of living.

Life cycle assessment of shared electric bicycle on greenhouse gas emissions in China

Following the bike-sharing system, the shared electric bicycle (SEB) is experiencing explosive growth in China as an emerging shared transportation mode. While shared transportation has long been linked to energy conservation and reducing emissions, a major problem facing SEB is whether it can reach the goal of greenhouse gas (GHG) reduction. This paper aims to evaluate GHG emissions at each stage of production, operation, and disposal of the SEB using life cycle assessment of GHG emissions. We also compared the differences in GHG emissions between the recycling incineration scenario (H1) and the recycling degradation scenario (H2) in the disposal stage. The GHG emissions of SEB in the production and operation stages were found to be 379.6173 kg CO2-eq and 183.4663 kg CO2-eq, respectively. However, the GHG emission reduction in the use stage was 1049.8374 kg CO2-eq. Thus, the net GHG reduction in the life cycle of the SEB was 487.3923 kg CO2-eq. (H1) and 433.9215 kg CO2-eq. (H2), respectively, indicating that SEB had a green effect. Non-recyclable parts of SEB will take 48 years to degrade in landfills in the H2 scenario. The GHG emission thresholds for SEB were further discussed. When the average daily turnover rate of SEB was less than 4 and its operation day was less than 479, SEB would not be able to achieve the goal of GHG reduction in the whole life cycle, with the riding statistics remaining unchanged. Finally, some advice for practical issues of electric bicycle sharing in energy conservation and GHG reduction were presented in response to the results.

Assessment of Greenhouse Gas Emissions from Hydrogen Production Processes: Turquoise Hydrogen vs. Steam Methane Reforming

Hydrogen has received substantial attention because of its diverse application in the energy sector. Steam methane reforming (SMR) dominates the current hydrogen production and is the least expensive endothermic reaction to produce grey hydrogen. This technology provides the advantages of low cost and high energy efficiency; however, it emits an enormous amount of CO2. Carbon capture storage (CCS) technology helps reduce these emissions by 47% to 53%, producing blue hydrogen. Methane pyrolysis is an alternative to SMR that produces (ideally) CO2-free turquoise hydrogen. In practice, methane pyrolysis reduces CO2 emissions by 71% compared to grey hydrogen and 46% compared to blue hydrogen. While carbon dioxide emissions decrease with CCS, fugitive methane emissions (FMEs) for blue and turquoise hydrogen are higher than those for grey hydrogen because of the increased use of natural gas to power carbon capture. We undertake FMEs of 3.6% of natural gas consumption for individual processes. In this study, we also explore the utilization of biogas as a feedstock and additional Boudouard reactions for efficient utilization of solid carbon from methane pyrolysis and carbon dioxide from biogas. The present study focuses on possible ways to reduce overall emissions from turquoise hydrogen to provide solutions for a sustainable low-CO2 energy source.

Life cycle greenhouse gas emissions from five contrasting rice production systems in the tropics

Carbon Footprints (CFs) quantification of major rice production systems (RPSs) is a prerequisite for chalking out strategies for climate change mitigation in agriculture. Total life cycle greenhouse gas emissions (LC-GHGs) from production to consumption could provide precise CFs for RPSs. Therefore, to address this issue, we assessed all the three segments of LC-GHGs for five major contrasting RPSs in India, such as, aerobic rice (AR), shallow lowland rice (SLR), system of rice intensification (SRI), deep water rice (DWR), and zero-tilled direct-seeded rice (ZTR)) to determine the CFs. The CF was found to be lowest in ZTR but the LC-GHGs were found to be lowest in case of AR, which recorded higher CF than that of ZTR. So, for short-term reduction of greenhouse gas (GHG) emission, aerobic rice (AR) is a good option. However, ZTR with lowest CF among all, could be prompted with incentives for long-term strategy. Among the segmental LC-GHGs, the ‘on-farm’ emission contributed less compared to the other two segments. The post-harvest to consumption segment contributed the maximum (54%–69%) of total LC-GHGs, followed by ‘cradle-to-farm’ (21%–27%), and on-farm operations (11%–23%). These findings suggest that post-harvest components that contribute maximum GHG emissions must be tackled scientifically with proactive policy initiatives. However, the data on this segment is limited and scattered. Therefore, real-time assessment of GHG emissions during post-harvest activities and transportation of inputs from cradle to farm require more precise quantification. Although the CF in SRI was found to be more, yet this system has the potential to fetch higher yields and better soil carbon storage. So, SRI could be encouraged for food security and long-term sustainability perspectives by reducing greenhouse gas emissions by 3-to-4 times.

The Ethanol–Ethyl Acetate System as a Biogenic Hydrogen Carrier

Liquid organic hydrogen carriers will likely be a key element of a future hydrogen economy by enabling the storage and transport of large quantities of hydrogen. Ethanol is a liquid organic hydrogen carrier that is readily available from biological resources, which undergoes a reversible reaction to yield hydrogen and ethyl acetate. The objective of the present study is to obtain a better understanding of the thermodynamic and environmental suitability of the ethanol–ethyl acetate cycle for hydrogen storage applications. The analysis covers three aspects: thermodynamics of the chemical reaction, energy balance of the process, and a first‐order assessment of greenhouse gas emissions. Thermodynamics of the reaction are characterized by a standard Gibbs energy of reaction close to zero which allows the reaction to be shifted between hydrogenation and dehydrogenation within a moderate window of temperature and pressure conditions. The energy demand for dehydrogenation is comparatively small, resulting in an overall system efficiency of 88%. A life cycle greenhouse gas analysis over a 20‐year storage system lifetime gives a carbon intensity of 7.0 kg‐CO2eq/kg‐H2 delivered. These results indicate that the ethanol–ethyl acetate system has considerable promise as a hydrogen carrier and should be the subject of further research.

Assessment of greenhouse gases emissions, global warming potential and net ecosystem economic benefits from wheat field with reduced irrigation and nitrogen management in an arid region of China

In the context of global warming, water scarcity, and high fertilizer costs, identifying proper irrigation and nitrogen (N) management is essential for balancing emissions of greenhouse gases (GHGs), crop production, and economic benefits in arid regions. A two-year field study was conducted to determine the interactive effects of irrigation regimes (I100, 750 mm; I80, 600 mm and I60, 450 mm) and N application rates (N100, 300 kg ha−1; N75, 225 kg ha−1; and N50, 150 kg ha−1) on GHGs emissions, global warming potential (GWP), greenhouse gas intensity (GHGI), and net ecosystem economic benefits (NEEB) from spring wheat field in Northwest China. Our results depicted the lowest cumulative GHGs emissions and GWP with low irrigation and low N application rates but at the cost of a significant decrease in grain yield and NEEB compared to full irrigation and N application. Instead, moderate irrigation and N application (I80N75) showed the most promising effects by significantly reducing GHGs emissions while improving the NEEB and yield benefits. Compared to I100N100, the I80N75 treatment decreased cumulative N2O emissions by 43.2 % and 33.1 %, CO2 by 28.8 % and 26.2 %, GWP by 46.8 % and 35.6 %, and GHGI by 55.0 % and 43.5 % in 2015 and 2016, respectively. In addition, the I80N75 treatment improved the NEEB by 79.3 % and 78.6 % and grain yield by 15.2 % and 16.1 % in 2015 and 2016 compared to I100N100, respectively. The wheat field acted as a CH4 sink regardless of all the treatments. Soil moisture and inorganic N contents were the primary driving factors that influenced the GHGs emissions from the wheat field, manifested by their significant correlations. Overall, 600 mm irrigation and 225 kg N ha−1 fertilization is an effective strategy with a good trade-off between economic benefits and environmental performance from spring wheat fields in the arid region of Northwest China.

Systemic measures on reduction of greenhouse gas emissions in animal husbandry enterprises. A review

The paper presents a review of different approaches to solving problems arising upon greenhouse gas emission from activities of animal husbandry enterprises. The sector of ruminant animal production is under close attention for ecological reasons due to its significant contribution to emission of enteric methane (CH4) and an effect on global climate change. Moreover, analysis of the main sources of methane emission in the agricultural sector of the agro-industrial complex, including by species of livestock and poultry, is given. An impact of a feeding system, feeds and feed additives in use and manure storage on nitrogen losses is estimated. In this connection, the authors examine several promising scientific and practical development results that are aimed to reducing emissions and formulating a strategy for controlling direct emissions of greenhouse gases in animal husbandry that do not jeopardize animal productivity, especially in the context of sustainability. Practical activities that envisage the development of the complex of measures for reduction of greenhouse gas emissions are examined. Potential strategies for mitigating their consequences were divided into the following main categories: animal raising, changes in animal diets and manipulations with rumen. Furthermore, several other measures facilitating an increase in livestock productivity and reduction of the negative effect on the environment were taken. Eco-economic methods for assessing emissions of harmful gases in production of animal husbandry products are considered and the necessity of developing simpler cost-effective technologies for quantitative assessment of greenhouse gas emissions and a search for solutions to preserve favorable climate is emphasized. When assessing greenhouse gas emissions, the loss sizes and cumulative ecological damage are taken into account. Realization of strategies for emission reduction should lead to an increase in animal productivity and a decrease in the negative effect of animal husbandry on the environment.

Energetic, economic, and greenhouse gas emissions assessment of biomass and solar photovoltaic systems for an industrial facility

The industrial sector is responsible for nearly 25% of direct and more than 35% of cumulative global energy-related greenhouse gas (GHG) emissions. This study evaluates the feasibility and comparative analysis of on-site solar photovoltaic (PV) and biomass-fed boilers based on historical energy consumption and demand to reduce dependence on grid-supplied electricity and coal-fired boiler for a rice processing industrial plant. The analysis includes energetic, economic, and GHG emissions assessments and covers (a) Solar PV systems, (b) Biomass fuels, and (c) Co-firing scenarios. Financial analysis of solar PV considers both company-owned and bank-financed systems of fixed and double axis tracking technologies. Biomass fuels include 100% wood, 100% rice husk, and a 50%–50% wood-rice husk mix. Historical energy consumption shows that annual electricity demand is 4,479 MWh, costing $537,480 and producing 2,307 tCO 2 emissions. Feasibility of 1MW, company-owned fixed axis solar PV plant shows a yearly electricity production of 1,544 MWh with 0.031 $/kWh levelized cost and reducing 733 tCO 2 with a payback period of 2.8 years. The base case scenario for boiler operations consists of 3,746 tons of coal burning, costing $427,075 and producing 11,840 tCO 2 emissions. Rice husk fuel study shows a 19% fuel cost savings, a 1.7-year payback period, and 11,612 tCO 2 GHG emission reductions. It is concluded that biomass-based rice husk fuel feedstock is the most suitable renewable energy source (RES) for this industrial facility and can reduce 82% of cumulative annual GHG emissions. Furthermore, energy efficiency improvements and off-site carbon credits provide additional opportunities to achieve net-zero GHG emissions for plant operations.

Breeding progress reduces carbon footprints of wheat and rye

Crop breeding has boosted global agricultural productivity over recent decades, but little is known about its contribution to climate change mitigation. Here we assess greenhouse gas emissions per unit land (GHGL) and greenhouse gas emissions per unit harvest product, i.e. carbon footprint (CFP) of winter wheat (Triticum aestivum) and winter rye (Secale cereale) from official German variety trials in the period 1983 to 2019. We assess the life cycle greenhouse gas (GHG) emissions and analyze the data using mixed effects models. We find that breeding progress led to slightly increased GHGL, amounting to ∼4–10%, but to strongly decreasing CFP, amounting to ∼13–23% in wheat and rye since 1983. With a ∼20% lower GHGL and ∼8% lower CFP in rye compared to wheat, the extension of rye production offers viable climate change mitigation potential. Finally, we find that lower CFP are associated with hybrid breeding, chemical plant protection and larger farms. We conclude that with increasing global food demand and limited cropland, breeding progress contributes considerably to climate change mitigation through reduced CFP.

Implementing an appropriate metric for the assessment of greenhouse gas emissions from livestock production: A national case study

Livestock farming is of major economic relevance but also severely contributes to environmental impacts, especially greenhouse gas (GHG) emissions such as methane (CH4; particularly from ruminant production) and nitrous oxide (N2O; mainly from manure management and soil cultivated for feed production). In this study, we analyse the impact of GHG emissions from Austrian livestock production, using two metrics: a) the commonly used global warming potential (GWP) over 100 years (GWP100 in CO2-equivalents, CO2-e), and b) the recently introduced metric GWP*, which describes additional warming as a function of the timeline of short-lived GHG emissions (unit CO2 warming equivalents, CO2-we). We first compiled the sectoral (i.e. only direct emissions without upstream processes) GWP100 for different livestock categories with a focus on dairy cattle, beef cattle and pigs in Austria between 1990 and 2019. We also estimated product-related (i.e. per kg carcass weight or per litre of milk) GWP100 values, including upstream processes. We then calculated the corresponding GWP* metrics, both sectoral and product-related, and compared them with the GWP100 values. Decreasing livestock numbers and improved production efficiency were found to result in strong sectoral emission reductions from dairy production (–32 % of GWP100 from 1990 to 2019) and from pigs (–32 % CO2-e). This contrasts with low reductions from other livestock categories and even increases for cattle other than dairy cows (+3 % CO2-e), mainly due to rising suckler cow numbers. Allocated results per kg milk and kg body mass show quite similar results. Using the GWP* metric, the climate impacts of Austrian livestock production are less severe. When assuming constant management and emission intensity over a period of at least 20 years, the CO2-we (GWP*) is almost 50 % less than CO2-e (GWP100) per kg Austrian raw milk due to the different impacts of the short-lived CH4. A similar trend applies to an average cattle carcass (-40 % warming impact). The emission reductions of the shrinking Austrian livestock population represent an important contribution to a climate-neutral agriculture: The CH4 reductions of livestock production during the past 20 years reduce the current total Austrian CO2-we by 16 %. Continuous CH4 reduction, as we show it here for Austrian livestock, is an effective option to tackle the climate crisis in the short term. It shall be stressed that a relatively low GWP* should not be interpreted as a concession for further CH4 emissions but as an actual reduction of (additional) warming.

Large-scale long-distance land-based hydrogen transportation systems: A comparative techno-economic and greenhouse gas emission assessment

Interest in hydrogen as an energy carrier is growing as countries look to reduce greenhouse gas (GHG) emissions in hard-to-abate sectors. Previous works have focused on hydrogen production, well-to-wheel analysis of fuel cell vehicles, and vehicle refuelling costs and emissions. These studies use high-level estimates for the hydrogen transportation systems that lack sufficient granularity for techno-economic and GHG emissions analysis. In this work, we assess and compare the unit costs and emission footprints (direct and indirect) of 32 systems for hydrogen transportation. Process-based models were used to examine the transportation of pure hydrogen (hydrogen pipeline and truck transport of gaseous and liquified hydrogen), hydrogen-natural gas blends (pipeline), ammonia (pipeline), and liquid organic hydrogen carriers (pipeline and rail). We used sensitivity and uncertainty analyses to determine the parameters impacting the cost and emission estimates. At 1000 km, the pure hydrogen pipelines have a levelized cost of $0.66/kg H2 and a GHG footprint of 595 gCO2eq/kg H2. At 1000 km, ammonia, liquid organic hydrogen carrier, and truck transport scenarios are more than twice as expensive as pure hydrogen pipeline and hythane, and more than 1.5 times as expensive at 3000 km. The GHG emission footprints of pure hydrogen pipeline transport and ammonia transport are comparable, whereas all other transport systems are more than twice as high. These results may be informative for government agencies developing policies around clean hydrogen internationally.

Next generation of life cycle related benchmarks for low carbon residential buildings in Germany

Germany’s national climate targets are in line with the Paris Climate Agreement and set the ambitious goal of becoming net zero emissions by 2045. The construction and real estate sector play an important role for sustainable development. In a cross-sectoral approach operational and embodied emissions of buildings account for 40% of GHG emissions in Germany. In order to contribute to climate protection, it is necessary to both pursue a strategy for decarbonizing the national building stock and to develop benchmarks for assessing greenhouse gas emissions in the life cycle of individual buildings. In Germany, benchmarks are used in sustainability assessment systems for more than 10 years to assess primary energy non-renewable (PENRT) and global warming potential (GWP) in the life cycle of buildings. Therefore, these need to be regularly reviewed and further developed in order to (1) adapt them to more ambitious reduction targets, (2) consider the current database, (3) include the state of standardization, and (4) follow the state of scientific discussion on methodological issues. This paper identifies new benchmarks for PENRT and GWP and shows the scale of current levels of performance. These can form the basis for funding programs and contribute to the discussion on the introduction of binding legal requirements.

Grazing amplifies the stimulating effects of N addition on N2O emissions in a temperate meadow steppe

Nitrogen (N) addition typically increases nitrous oxide (N2O) emissions, but the magnitude of this effect depends on land use type and intensity. Grazing has an important influence on grassland N dynamics, but it is not clear to what extent grazing may interact with N addition in affecting grassland N2O emissions. We investigated the mechanisms underlying the individual and interactive effects of N addition and cattle grazing (control (CK), N addition (N), grazing (G), and N addition plus grazing (N + G) treatments) on N2O emissions in a temperate meadow steppe by measuring N2O fluxes, weather factors, vegetation parameters and soil properties from October 2017 to September 2018. The studied temperate meadow steppe was a source of N2O emissions during the experimental period. Approximately 80 % of the annual N2O emissions were released during the plant growing season. The highest N2O emission was detected in the N + G plots, which indicated the grazing treatment amplified the stimulating effects of N addition on N2O emissions. The results from structural equation model (SEM) suggested that N addition enhanced N2O emission through increases in NH4+-N concentration and soil potential net nitrification rate (Nnitri); grazing promoted N2O emissions by increasing substrate availability directly via excreta or indirectly through trampling-associated soil aggregate disruption and substrate release. N2O emissions increased most strongly with N addition and grazing due to the synergetic effects between animal trampling, animal excreta and available N on the processes of nitrification and denitrification. Overall, our results suggest that the interactive effects of grassland management and global change factors on N2O emissions need to be considered for the accurate assessment of grassland greenhouse gas emissions.