Calculation Of Greenhouse Gas Emissions Research Articles

A quantitative assessment of greenhouse gas (GHG) emissions from conventional and modular construction: A case of developing country

Building construction serves a vital purpose from a social and economic perspective by meeting the housing needs of society and contributing to the economic growth of a country. However, from an environmental perspective, this sector contributes negatively by releasing tons of greenhouse gas emissions (GHG) in the atmosphere, which consequently gives rise to other environmental hazards such as global warming and ozone depletion. The use of off-site modular construction practices in developed countries is increasing due to its environmental benefits over conventional cast-in-situ method. However, the environmental performance of a construction method may vary across various geographical regions, which is why environmental assessment of construction methods specific to a region is required. This study provides a calculation of GHG emissions in modular and conventional construction methods utilized in Pakistan, considering two single-family single-storey buildings with similar characteristics. The study also provides recommendations to homebuilders for the improvements in low-performance areas in both modular and conventional building methods. The results of the study show that modular building accounts for a total of 3449.73 kgCO2-equivalent GHG emissions whereas conventional building resulted in a total of 6501.91 kgCO2-equivalent GHG emissions. Modular building results in a reduction of 3052.19 kgCO2-equivalent GHG emissions (46.9%) as compared to a conventional site-built building. This implies that the modular construction method is a more environmentally viable option than conventional construction, which needs to be adopted on a large scale to reduce GHG emissions.

Tillage systems as a function of greenhouse gas (GHG) emission and fuel consumption mitigation.

In order to investigate the possibility of reducing GHG in winter wheat production, field trial was set up in a 3-year experiment (VS) with four different tillage systems (TS) and three N fertilization norms (FN). The tillage systems were CT-conventional tillage, DT-disk harrowing, LT-soil loosening, and NT-no tillage system. N fertilization norms were set to 120, 150 and 180kgha-1. Fuel consumption was measured with three-channel valve, and total value of consumption was calculated on total machinery passes according to technological map. Calculation of greenhouse gas (GHG) emissions from winter wheat production were done by BioGrace model (version 4d 2015). GHG emission per ton of yearly raw material was calculated from fertilizers (production and field emissions), seed, plant protection and diesel usage, so the result was expressed in kg CO2eq ha-1 per year. The main properties of research (TS, FN and VS) are showing statistical significance on total GHG emission from winter wheat production. The largest GHG emission had LT tillage system with 261.89kg CO2eq ha-1 from fuel emission and 2919.22kg CO2eq ha-1 in total. This tillage system also had highest yield of 7.78tha-1. The lowest yield was observed at NT system (6.92tha-1), also with the lowest GHG emission from fuel consumption and total production (fuel 118.30 and total 2685.94kg CO2eq ha-1). Reduced tillage system such as DT can significantly reduce GHG emissions from diesel consumption without having an impact on wheat yield. This study suggests that DT, primarily, and NT can be recommended as convenient agricultural practices conducive to reconstruct an optimal balance between GHG emissions, yields, and N excesses.

Inventory of greenhouse gas emissions and removals in Kaluga region

Climate change, namely global warming, remains at the forefront of the global environmental debate. At present, the international Paris Agreement, which aims to maintain the average temperature of the planet, is in force. The Russian Federation develops, annually updates, publishes and provides a national inventory of anthropogenic emissions and removals by sinks of all greenhouse gases. Each region shall annually conduct an inventory of greenhouse gas emissions and removals on its territory. According to international recommendations and methods for estimating greenhouse gas emissions and removals, the base year should be 1990, because then it becomes possible to carry out an analysis for a multi-year period. Different methodological bases and instructions of the Russian Ministry of Natural Resources are used to estimate GHG emissions and removals. Inventory of greenhouse gas emissions and removals in Kaluga region for the period 1990, 2012-2017 was conducted by JSC "Research Institute of Atmosphere", and for 2018 – LLC Ecoanalitika. The amount of absorbed greenhouse gases was considered for such land categories as forest land, arable land, fodder land, lands of settlements and special purpose lands. GHG emissions were estimated by the sectors "Energy" (Section I), "Industrial Processes and Product Use" (PIP) (Section II), "Agriculture" (Section III) and "Waste" (Section IV). The calculation of greenhouse gas emissions may be of varying complexity. The higher the level of complexity, the more accurate the results. Presented data for 1990, 2012-2018 show that GHG emissions excluding absorption increased by 5 per cent, while emissions excluding absorption decreased by 38 per cent. The presented chart shows that the largest amount of emissions is in the Energy Sector. The results of the assessment of GHG emissions and removals should be used in planning the development of the annual inventory.

Forest fires and carbon emission release in semi-arid regions of Indonesia: the evidence from medium resolution of satellite imagery

Forest fires are one of the causes of forest degradation and deforestation in Indonesia. Tropical savanna forests are one of the forest ecosystems found in the Indonesian region with a semi-arid climate type prone to drought and fire. Forest fires contribute to the release of greenhouse gas emissions into the atmosphere. The calculation method to estimate the burnt area is still an obstacle in calculating greenhouse gas emissions due to forest fires. This research aims to assess the burnt area in tropical savanna forest cover type using medium resolution satellite imagery data by utilizing the Normalized Burn Ratio index in four villages in East Sumba Regency and estimating greenhouse gas emissions these activities. The results showed that the NBR method does not produce an estimate of the burned area with a fair degree of accuracy because the characteristic of channel 7 (SWIR) is sensitive to vegetation moisture content. The savanna forest cover type is the type of land cover identified as the most dominant burned area. It produces the highest greenhouse gas emissions compared to other land cover types.

Environmental impacts assessment for Australian buildings: thermal resistance and environmental impacts relationship

Selecting suitable construction designs for efficient energy management and moderating greenhouse gas emissions regarding to a construction project's life-cycle of are typically demanding to designers in the fight with climate change across the global. Scientists are striving to develop building optimization models so that strategies are ably devised to moderate energy consumption and greenhouse gas emissions simultaneously. An inclusive greenhouse gas emissions valuation model is established to utilise several types of buildings envelop, which is adhered to the National Construction Building Code of Australia - energy efficiency requirement. The extracted results are exported from GaBi version 8.1 and consolidated by Visual Basic in Microsoft Excel to calculate greenhouse gas emissions amount in regard to building's energy consumption in 50 years. Accordingly, Credit 15A which is one of five pathways in the category: Green-Star's greenhouse gas emissions reduction (Green-Star is the rating tool to enhance a project's sustainability during its life-cycle) will be used to assess by selecting the wall structures following the guidance in the Insulation Council of Australia and New Zealand (2014) handbook. With the model, designers and planners probably apply the optimum envelope structure types with the relevant R-value options for their design.

Comparison of methods for vehicle emissions calculation and their sensitivity to fleet structuring

Introduction. The study presents the results of the calculation of greenhouse gas emissions and polluting solids by vehicles fleet on the basis of three independent estimates of the set of initial data on the breakdown of the fleet by technological classes (the number and types of vehicles of different ecological classes, annual mileage, etc.). Such data is not provided in the forms of state statistical reports and is generated by the researchers. The article solves the problem of determining their significance for calculating the total emissions in the context of a large data array for the territory of Russia.Materials and methods. Three different versions to the calculation of greenhouse gas emissions (basic version, equalization of transport work and new approach - equalization of fuel consumption) are proposed in order to identify differences in the obtained emissions in different conditions (i.e., to determine quantitative characteristics of the accuracy of the final values). A new method has been developed for assessing the effect of average mileage and vehicle distribution on classes on the total emissions values, implemented within each proposed version. In addition, two types of sensitivity formulas are formed by the authors to assess the impact of vehicle distribution on classes and average mileage to final emission calculations. The use of these formulas provides scientific analysis and interpretation of the influence of the factors in expert review on the final values of the emissions of each type.Results. The differences in sorting cars into classes in expert evaluations were revealed and the closest ones are determined. It was found that the most sensitive to changes in mileage and class of cars, on which fuel consumption depends, are CO2 emissions.Conclusion. The scientific sensitivity analysis of both types showed the importance of maintaining the principles underlying expert evaluation from year to year in order to ensure that the results obtained are consistent.

Reducing greenhouse gas emissions of New Zealand beef through better integration of dairy and beef production

Integrating dairy and beef production offers opportunities to reduce greenhouse gas (GHG) emissions of beef production, which is dominated by emissions related to maintenance of the breeding cow. This study aims to quantify the GHG reduction potential of the New Zealand (NZ) beef sector when replacing beef breeding cows and their calves with dairy beef animals. To this end, we combined a cattle herd model of NZ beef and dairy production with GHG emission calculations of beef production. We computed GHG emissions (to farm-gate stage) of the current amount of beef produced, while increasing the number of dairy beef calves at the expense of the number of suckler-beef calves. GHG emissions were 29% lower per kg carcass weight for dairy beef animals compared to suckler-beef animals. The average emission intensity decreased from 21.3 to 16.7 kg CO2e per kg carcass weight (−22%) as the number of suckler-beef animals declined to zero and dairy beef animals increased. Integrating dairy and beef production would enable the NZ beef sector to reduce annual GHG emissions by nearly 2000 kt CO2e (i.e. 22% of the total sector's emissions), while the dairy sector would improve their social licence to operate by reducing the number of surplus dairy calves slaughtered from 4-days old.

GHG emission requirements and benchmark values for Norwegian buildings

As a response to the Paris agreement, Norway is committed to reducing greenhouse gas (GHG) emissions by 50 percent by 2030. Highly energy-efficient buildings have a greater proportion of embodied GHG emissions from material use (55-87%) compared to operational emissions. A new national standard, NS3720:2018 a methodology for greenhouse gas emission calculations for buildings, has harmonised the life cycle assessment (LCA) calculation of environmental impacts arising from Norwegian buildings and has led to an increase in LCAs. This paper aims to collect life cycle GHG emission data on Norwegian building case studies to help form recommendations for national GHG emission requirements and benchmark values that can be used by the Research centre for zero emission neighbourhoods in smart cities (FME ZEN), Futurebuilt and in Norwegian building codes (TEK). To do this, a statistical analysis of a reference sample is carried out to provide bottom-up derived reference values. Empirical life cycle GHG emission data results are collected from Norwegian building case studies in the reference, design and as-built project phases, sampled from Norwegian programmes and research centres such as Futurebuilt, Framtidens Byer, ZEB and ZEN. Altogether 133 Norwegian building cases have been gathered from 2009-2020, covering 1,023,738m2 of heated floor area for 49,360 building users. A functional unit of ‘1m2 of heated floor area over a building lifetime of 60 years is used. The results show an interquartile range of 240-492 kgCO2eq/m2 or 4-8.2 kgCO2eq/m2/yr, a median of 396 kgCO2eq/m2 or 6.6 kgCO2eq/m2/yr and a mean of 324 kgCO2eq/m2 or 5,4 kgCO2eq/m2/yr for all building typologies in the as-built phase. These results can be used to form initial indications for GHG emission requirements and benchmark values in Norway.

Research on the relationship between China's greenhouse gas emissions and industrial structure and economic growth from the perspective of energy consumption.

A comprehensive understanding of the relationships between greenhouse gas (GHG) emissions and industrial structure and economic growth holds great significance for China to realize the development of a green economy. This paper calculates GHG emissions based on China's energy consumption, divides the industrial structure in detail, and uses the extended Stochastic Impacts by Regression on Population, Affluence, and Technology model that is realized by PLS method and Tapio decoupling model to study the relationship of GHG emissions to industrial structure and economic growth. The results show that (1) China's total GHG emissions showed a year-on-year growth trend from 2000 to 2017. For CO2, CH4, and N2O, only N2O emission showed a significant downward trend, while CO2 and CH4 emissions showed a slow growth trend. (2) The proportions of added value of industry and construction are positively correlated with GHG emissions, while those of farming, forestry, animal husbandry, and fishery; wholesale and retail trade; transport; and accommodation and catering are negatively correlated with GHG emissions. (3) China's GHG emissions and overall economic growth are in a decoupling state, but in the energy field, N2O emission reduction control has the best effect. Additionally, the overall economic growth of China's industrial sector and GHG emissions have experienced the process of decoupling-link-negative decoupling-link-decoupling. Graphical abstract.

Estimasi Emisi Gas Rumah Kaca pada Pengelolaan Sampah Domestik dengan Metode IPCC 2006 di TPA Talang Gulo Kota Jambi

The waste that loaded to the Talang Gulo Landfill in 2018 is 1,012.234 m3/day and is predicted to produce Greenhouse Gas (GHG) emissions such as CH4 and N2O. The purpose of this study was to create a waste management layout, to determine the generation data and composition of waste in Jambi city and calculate the estimated amount of Greenhouse Gas (GHG). The calculation of Greenhouse Gas (GHG) emissions in this study used from Intergovernmental Panel On Climate Change (IPCC) 2006 method. Sampling results show that the average waste generation in Jambi City is 0.207 kg/person/day. Food waste, plastics, and paper were the dominant components from the composition of waste in landfill by 47,381%, 20.565%, and 13.096%. CH4 emissions generated from landfill zone VI in 2019 amounted to 4,695×10-2 Gg and would increase to 16,608×10-2 Gg in 2030. Greenhouse gas emissions generated from the composting zone consisted of 8,6×10-4 Gg CH4 and 5,16×10-5 Gg N2O in 2019 and 9,5×10-4 Gg CH4 and 5,7×10-5 Gg N2O in 2030. Emissions from heavy equipment activity in 2019 amounted to 1,065 Gg CO2. Estimates of greenhouse gas emissions are useful for taking steps to mitigate greenhouse gas emissions.

Calculating the Carbon Footprint in ports by using a standardized tool

One of the significant environmental threats in ports in recent years are carbon dioxide emissions generated by different activities carried out in these areas, which lead to Climate Change. In the maritime industry, this topic is getting more critical every day. The main cause of Climate Change is the emission of Greenhouse Gases (GHG). The total amount of GHG that are emitted both directly and indirectly by an activity are calculated by the following indicator: the Carbon Footprint.The review of different case studies shows while in recent years many ports calculate their Carbon Footprint and report it, each port uses its own method and there is not any unified and complete method to calculate Carbon Footprint. This makes comparing results among different ports a difficult task and proves the need for such a method. Therefore, it has been developed a standardized tool to calculate GHG emissions in ports. The tool has been developed by using Excel and Visual Basic software and it is based on the WPCI (World Ports Climate Initiative) and IPCC (Intergovernmental Panel on Climate Change) guidelines and the GHG Protocol. Such tool is specifically designed so that port authorities can calculate their Carbon Footprint and report it accordingly.The tool has different steps taking into account the three scopes of emissions defined by the WPCI guideline for ports. Once developed, it was validated by a set of selected ports and environmental experts. The final aim is to distribute this tool to all ports and make it freely available.

Frameworks for reducing greenhouse gas (GHG) emissions from municipal solid waste in Oman

PurposeThe Gulf Cooperation Council member countries not only generate the highest quantity of municipal solid waste (MSW) per capita when compared globally, but also in most of these countries, such waste is just dumped at different landfill stations. In Oman, the total quantity of MSW stood at 2.0 million tons per year. The emission from this waste is estimated at 2,181,034 tons/year (carbon dioxide equivalent). This article attempts to develop frameworks that considered landfilling, composting and recycling of MSW.Design/methodology/approachTo know the composition of the municipal solid waste in Oman, a quantitative research method was employed. The greenhouse gas (GHG) emissions from MSWM in this study focus on three major gases, CO2, CH4 and N2O. The Intergovernmental Panel on Climate Change (IPCC) 2006 model is used to calculate GHG emissions from landfills and composting (IPCC, 2006). Four frameworks – baseline F0, framework F1, framework F2 and framework F3 – are outlined in this paper. The F0 represents the current situation of the MSW in which most of the waste goes to landfills and dumpsites. In F1, improved MSW collection service and landfilling are incorporated and open burning is restricted. The F2 considered landfilling and composting, while F3 is based on landfilling, composting and recycling.FindingsThe framework F2, which proposes the composting process for the organic waste which normally goes to landfills, results in the reduction of emissions by 40% as compared to landfill practice. Similarly, the samples of MSW collected in Oman show a good amount of recycling waste. The framework F3, which considers the landfill, composting and recycling, reduced the total GHG emissions from 2,181,034 tons/year to 1,427,998 tons/year (carbon dioxide equivalent), representing a total reduction of 35% in emissions.Research limitations/implicationsDifferent values such as CH4 correction factor, the fraction of degradable organic carbon and the fraction of DOC used to determine the GHG emissions from MSW considering landfilling, composting and recycling based on the IPPC model and existing literature review. The actual determination of these values based on the Oman conditions may result in more accurate emissions from MSW in Oman.Practical implicationsDifferent frameworks suggested in this research have different practical implications; however, the final framework F3, which produces fewer emissions, required a material recovery facility to recycle the MSW in Oman. For framework F3, it is important that the residents in Oman have enough knowledge and willingness to do the waste segregation at the household level. Apparently, such knowledge and willingness need to be determined through a separate study.Originality/valueThe frameworks F2 and F3 are considered to be more suitable solutions compared to the current practices for Oman and other gulf countries to reduce its per capita emissions from MSW and protect its local environment. There is a potential for further work that needs to explore the possible solutions to implement the suggested frameworks.

Alternative study of reducing Carbon Dioxide (CO2) from the transportation sector in Medan city

Increase of amount greenhouse gas (GHG) emissions from human activities in the form of an increase the number of vehicles indirectly impacting climate change. The purpose of this study is to calculate GHG emissions, namely carbon dioxide (CO2) generated from the transportation sector and determine the scenario of reducing CO2 emissions from the sector transportation in Medan City. The method of calculating GHG emissions in this study uses TIER II from IPCC. The study was conducted in 12 locations of sampling points with a traffic counting time of 12 hours per each point with variations in the time of workdays and weekdays. The results showed that CO2 emissions generated at the twelve sampling locations amounted to 484.41 - 561.16 tons CO2 / year. The scenario of reducing CO2 emissions in this study is the application of Bus Rapid Transit (BRT), parking management systems and fuel substitution. Comparison of the average of the three scenarios in reducing CO2 namely; the application of BRT ± 24.28% with the number of BRT units needed per road segment ranging from 11 - 57 units; fuel substitution of ± 9.16% and parking management system ± 12.08%.

Analysis of Sources and Trends in Agricultural GHG Emissions from Annex I Countries

The vast majority of the scientific community believe that anthropogenic greenhouse gas (GHG) emissions are the predominant cause of climate change. One of the GHG emission sources is agriculture. Following the International Panel on Climate Change (IPCC) guidelines regarding GHG emission calculation, agriculture is responsible for around 10% of the overall global emissions. Agricultural GHG emissions consist of several emission source categories and several GHGs. In this article were described the results of multivariate statistical analyses performed on data gathered during the period 1990–2017 from the inventories of 43 Annex I countries (parties to the United Nations Framework Convention on Climate Change, UNFCCC, listed in Annex I of the Convention). Trends in the agricultural GHG emissions were analyzed. Generally, the global agricultural GHG emissions are increasing, while the emissions from Annex I countries are decreasing. Apart from the application of urea, emissions from all other sources, such as enteric fermentation, manure management, rice cultivation, agricultural soils, field burning of agricultural residues, and liming are decreasing. Based on multivariate analysis, the most different countries, in terms of GHG emission sources composition in agriculture and emission trends, are Australia, Japan, New Zealand and USA. The rest of the Annex I countries are mostly from Europe and their shares and trends are similar, with slight differences between countries depending, among others, on the date of joining the European Union.

Method for Calculating Greenhouse Gas Emissions from the Operation of Engineering Systems of Buildings

Method for Calculating Greenhouse Gas Emissions from the Operation of Engineering Systems of Buildings

ВЛИЯНИЕ ЭЛЕКТРОМОБИЛЕЙ НА ЭКОЛОГИЮ

Часто считается, что электромобили являются важным средством сокращения выбросов парниковых газов и энергопотребления в глобальном транспорте, особенно для автомобильного пассажирского транспорта.Целью данной статьи является изучение относительного использования энергии и выбросов парниковых газов электромобилей по сравнению с автомобилями с двигателем внутреннего сгорания. Сравнение энергоэффективности, а также сравнение выбросов парниковых газов были использованы в качестве методов в данной статье. Cравнения энергоэффективности осложняются противоречивыми методами, используемыми для первичных источников электроэнергии, таких как гидро, солнечная энергия или энергия ветра.В этой статье пересматривается степень, в которой электромобили могут эффективно решать проблемы глобального изменения климата и истощения запасов ископаемого топлива.Более того, в статье утверждается, что сравнение электромобилей и транспортных средств с двигателем внутреннего сгорания намного сложнее, чем общепризнанно. Неопределенности возникают как при использовании первичной энергии, так и при расчете выбросов парниковых газов.В целом, должен быть сделан вывод о том, что выгоды от использования электромобилей для энергии и парниковых газов меньше, чем обычно предполагается.Только когда во взаимосвязанных энергосистемах преобладают возобновляемые источники энергии, будет безопасно заявлять о превосходстве электромобилей.

Lifecycle Assessment of Biomass Supply Chain with the Assistance of Agent-Based Modelling

Even though biomass is characterised as renewable energy, it produces anthropogenic greenhouse gas (GHG) emissions, especially from biomass logistics. Lifecycle assessment (LCA) is used as a tool to quantify the GHG emissions from logistics but in the past the majority of LCAs have been steady-state and linear, when in reality, non-linear and temporal aspects (such as weather conditions, seasonal biomass demand, storage capacity, etc.) also have an important role to play. Thus, the objective of this paper was to optimise the environmental sustainability of forest biomass logistics (in terms of GHG emissions) by introducing the dynamic aspects of the supply chain and using the geographical information system (GIS) and agent-based modelling (ABM). The use of the GIS and ABM adds local conditions to the assessment in order to make the study more relevant. In this study, GIS was used to investigate biomass availability, biomass supply points and the road network around a large-scale combined heat and power plant in Naantali, Finland. Furthermore, the temporal aspects of the supply chain (e.g., seasonal biomass demand and storage capacity) were added using ABM to make the assessment dynamic. Based on the outcomes of the GIS and ABM, a gate-to-gate LCA of the forest biomass supply chain was conducted in order to calculate GHG emissions. In addition to the domestic biomass, we added imported biomass from Riga, Latvia to the fuel mixture in order to investigate the effect of sea transportation on overall GHG emissions. Finally, as a sensitivity check, we studied the real-time measurement of biomass quality and its potential impact on overall logistical GHG emissions. According to the results, biomass logistics incurred GHG emissions ranging from 2.72 to 3.46 kg CO2-eq per MWh, depending on the type of biomass and its origin. On the other hand, having 7% imported biomass in the fuel mixture resulted in a 13% increase in GHG emissions. Finally, the real-time monitoring of biomass quality helped save 2% of the GHG emissions from the overall supply chain. The incorporation of the GIS and ABM helped in assessing the environmental impacts of the forest biomass supply chain in local conditions, and the combined approach looks promising for developing LCAs that are inclusive of the temporal aspects of the supply chain for any specific location.

The GHG emissions and economic performance of the Colombian palm oil sector; current status and long-term perspectives

Increasing oil palm plantations, both for obtaining crude palm oil (CPO) and for the production of biobased products, have generated growing concern about the impact of greenhouse gas (GHG) emissions on the environment. Colombia has the potential to produce sustainable biobased products from oil palm. Nevertheless, national GHG emissions have not yet been reported by this sector. Achieving the collection of the total primary data from the oil palm sector, in Colombia, entails a tremendous challenge. Notwithstanding, for this study, the data collection of 70% of the production of fresh fruit bunches (FFB) was achieved. Therefore, current situation of CPO production in Colombia is analyzed, including 1) GHG emissions calculation, 2) net energy ratio (NER), and 3) economic performance. Moreover, the analysis includes two future scenarios, where the CPO production chain is optimized to reduce GHG emissions. Future scenario A produces biodiesel (BD), biogas, cogeneration, and compost; while future scenario B produces BD, biogas, cogeneration, and pellets. The methodology, for all the scenarios, includes life-cycle assessment and economic analysis evaluation. The results show a significant potential for improving the current palm oil production, including a 55% reduction in GHG emissions. The impact of land-use change must be mitigated to reduce GHG emissions. Therefore, a sustainable oil palm expansion should be in areas with low carbon stock or areas suitable/available to the crop (e.g., cropland, pastureland). Avoiding the deforestation of natural forests is required. Besides, crop yield should be increased to minimize the land use, using biomass to produce biobased products, and capture biogas to reduce methane emissions. In the biodiesel production life-cycle, the NER analysis shows the fossil energy consumed is lower than the renewable energy produced. Regarding the economic performance, it shows that in an optimized production chain, the capital expenditure and operational expenditure will decrease by approximately 20%.

The effect of digestate and mineral fertilisation of cocksfoot grass on greenhouse gas emissions in a cocksfoot-based biogas production system

BackgroundClimate mitigation is a major consideration when choosing bioenergy systems. Anaerobic digestion of biomass is a bioenergy system, which is normally used for the treatment of manure or other residues, but cultivated energy crops may also provide a potential feedstock. One of the main crops for biogas production is still maize, but it may be desirable to replace it by perennial grasses, which also have high yields, but do not require as much management. The aim of this study was to analyse greenhouse gas (GHG) emissions in a biogas production system based on a perennial grass, cocksfoot, grown under different fertiliser application systems.MethodsField and laboratory experiments were carried out over a 7-year period to evaluate the influence of mineral nitrogen and digestate fertiliser application on cocksfoot biomass and biogas productivity. The obtained data were used to calculate GHG emissions and emission savings for the whole biogas production cycle, by use of the SimaPro v.8 software with the IMPACT 2002+ model, based on the climate change environmental impact category.ResultsProductivity of cocksfoot (Dactylis glomerata L.) was influenced by the annual rate of nitrogen applied as fertiliser, the fertiliser type and year, as influenced by the weather conditions. The biomass yield of cocksfoot fertilised with 180 kg nitrogen ha−1 year−1 was similar regardless if the nitrogen was applied as digestate or mineral fertiliser. At higher rates of nitrogen application (360–450 kg ha−1 year−1), higher yields and lower net GHG emissions could be obtained from the biogas production cycle when the nitrogen was applied as digestate compared to mineral fertiliser, especially in dry years. Energy input over the whole cycle was mainly influenced by the type of fertiliser and the biomass yield. Mineral fertiliser generally caused higher levels of GHG emissions than organic digestate fertiliser, when the same amount of energy is produced.ConclusionsThe cocksfoot grass-based biogas production system showed that a significant GHG emission saving potential exists, if nitrogen is added as digestate instead of mineral fertiliser, for similar yields of biomass and energy from biogas. Cocksfoot grass fertilised with digestate is thus a promising feedstock for biogas production.

Calculation of greenhouse gas emissions in Canary Islands wastewater treatment plants

Calculation of greenhouse gas emissions in Canary Islands wastewater treatment plants