Substitution Of Natural Gas Research Articles

Quantification and location of a renewable gas industry based on digestion of wastes in Ireland

Six EU gas grids have a target of 100% substitution of natural gas with renewable gas by 2050. This industry will start with biogas upgraded to biomethane. The biomethane resource and location of waste substrates (such as agricultural slurries, slaughterhouse waste, milk processing waste, and source separated household organic waste) were determined using the most recent spatially explicit data for Ireland. The total biomethane resource was estimated equivalent to: 7.6% of natural gas usage, 7% of energy in transport; 52% of the fuel usage in heavy goods vehicles in 2013. In terms of natural gas usage it corresponded to 26.5% of industrial gas use, and 52% of residential natural gas use. The resource as a source of thermal energy is equivalent to wood chips from 16.5% of arable land under short rotation coppice willow. Thematic maps illustrating the location of each resource were developed to highlight regions of significant biomethane production potential. The regions with the greatest resource of cattle slurry are located in the south and east of the country; sheep manure resources are concentrated on the western seaboard, while the largest biomethane resource from household organic waste is found in urban and city areas (63% of household organic waste biomethane resource).

Impact of biological treatments of bio-waste for nutrients, energy and bio-methane recovery in a life cycle perspective

Composting of the source-segregated organic fraction of municipal solid waste was compared in a life cycle perspective with conventional anaerobic digestion (AD), aimed at electricity substitution, and with AD aimed at biogas upgrading into bio-methane. Three different uses of the bio-methane were considered: injection in the natural gas grid for civil heating needs; use as fuel for high efficiency co-generation; use as fuel for vehicles. Scenarios with biogas upgrading showed quite similar impact values, generally higher than those of composting and conventional AD, for which there was a lower impact. A decisive contribution to the higher impact of the scenarios with bio-methane production was by the process for biogas upgrading. In any case the substitution of natural gas with bio-methane resulted in higher avoided impacts compared to electricity substitution by conventional AD. The uncertainty analysis confirmed the positive values for eutrophication, acidification and particulate matter. Large uncertainty was determined for global warming and photochemical ozone formation.

Greenhouse gas balance of cropland conversion to bioenergy poplar short-rotation coppice

Abstract. The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short-rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. This period corresponded to a single rotation of the SRC site. The REF site was a crop rotation between grassland and winter wheat, i.e. the same management of the SRC site before the conversion to short-rotation coppice. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (FCO2), whereas chambers were used to measure N2O and CH4 emissions from soil. The measurements began 2 years after the conversion of arable land to SRC so that an older poplar plantation was used to estimate the soil organic carbon (SOC) loss due to SRC establishment and to estimate SOC recovery over time. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled. A GHG emission offset, due to the substitution of natural gas with SRC biomass, was credited to the GHG budget of the SRC site. Emissions generated by the use of biomass (FEXP) were also considered. Suitability was finally assessed by comparing the GHG budgets of the two sites. CO2 uptake was 3512 ± 224 g CO2 m−2 at the SRC site in 2 years, and 1838 ± 107 g CO2 m−2 at the REF site. FEXP was equal to 1858 ± 240 g CO2 m−2 at the REF site, thus basically compensating for FCO2, while it was 1118 ± 521 g CO2 m−2 at the SRC site. The SRC site could offset 379.7 ± 175.1 g CO2eq m−2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN made up 2 and 4 % in the GHG budgets of SRC and REF sites respectively, while the SOC loss was 455 ± 524 g CO2 m−2 in 2 years. Overall, the REF site was close to neutrality from a GHG perspective (156 ± 264 g CO2eq m−2), while the SRC site was a net sink of 2202 ± 792 g CO2eq m−2. In conclusion the experiment led to a positive evaluation from a GHG viewpoint of the conversion of cropland to bioenergy SRC.

Natural gas as petroleum fuels substitution: Impact on economic performance in Indonesia

ABSTRACTThe lack of natural gas infrastructure is the main hurdle in maximizing natural gas usage in Indonesia. This study analyzes the substitution of natural gas for petroleum fuels and its investment impacts on Indonesian economic performances using econometrics. Five econometric models have been proposed which are capable of describing economic behavior. The policy simulations show that fuel substitution has a significant impact on Indonesian economic performance, particularly related to reducing unemployment.

Методичний підхід до визначення прогнозної структури споживання первинного палива

We have proposed a methodical approach to determining the predictive levels of the consumption of primary fuel with using parameters of the energy intensity of gross added value of the kinds of primary fuel by the types of economic activity and specific fuel consumption per person for population. This approach enables one to determine the predictive structure of fuel consumption for separate types of economic activity, sectors of economy, and the county. We have estimated the predictive amounts of primary fuel for the future up to 2030. We have determined the predictive fuel saving for the optimistic and pessimistic scenarios and the amount of possible substitution of natural gas in the energy sector of the country. We present the predictive calculated amounts of final fuel consumption bu aggregated types of economic activity and population for two scenarios and the amounts of predictive fuel consumption in the energy sector by the types of electricity- and heat-generating sources.

Drivers of the US CO2 emissions 1997-2013.

Fossil fuel CO2 emissions in the United States decreased by ∼11% between 2007 and 2013, from 6,023 to 5,377 Mt. This decline has been widely attributed to a shift from the use of coal to natural gas in US electricity production. However, the factors driving the decline have not been quantitatively evaluated; the role of natural gas in the decline therefore remains speculative. Here we analyse the factors affecting US emissions from 1997 to 2013. Before 2007, rising emissions were primarily driven by economic growth. After 2007, decreasing emissions were largely a result of economic recession with changes in fuel mix (for example, substitution of natural gas for coal) playing a comparatively minor role. Energy–climate policies may, therefore, be necessary to lock-in the recent emissions reductions and drive further decarbonization of the energy system as the US economy recovers and grows.

Life cycle assessment of medium-density fiberboard manufacturing process in Islamic Republic of Iran

This study deals with the interface between energy consumption and its related emissions in the manufacturing of one cubic meter medium density fiberboard (MDF) in Iran and provides a comprehensive life cycle inventory (LCI) data for production process. The study was developed following the methodological guidelines of ISO 14040. Inventories data for a gate-to-gate assessment of MDF manufacturing were collected by on-site surveys. Ten impact categories including of: Abiotic depletion (AD), Acidification (AC), Eutrophication (EP), Global warming (GW), Ozone layer depletion (OLD), Fresh water aquatic ecotoxicity (FE), Marine aquatic ecotoxicity (ME), Human toxicity (HT), Terrestrial ecotoxicity (TE) and Photochemical oxidation (PO) in three subsystem of manufacturing process were assessed. The subsystem of fiber preparation was the major contributor to the environmental impacts. Urea-formaldehyde (UF) resin production was identified as the main hotspot, except in AD, AC, OLD and PO impacts that natural gas, electricity, transport and production process were the main hotspots, respectively. Moreover, Tube dryer, MDF saw and hogger were the most effective sectors in the emissions of production process. Results for substitution of natural gas showed that except in some impacts categories, use of alternative source of thermal energy such as wood residue could improve emissions from manufacturing.

Gate to gate life cycle assessment of flat pressed particleboard production in Islamic Republic of Iran

Particleboard is one of the non-structural wood-based composites developed in the late 1950s in Iran to utilize agricultural and industrial wood residues. Since there was no published document about its Life Cycle Inventory in Iran, the aim of this study was to document the life cycle inventory data from the particleboard manufacturing in the second hand lines in Iran. The study covers the energy consumption and environmental impacts of raw materials and processes during particleboard production. In order to identify the main hotspots and characterize the production process, impact categories were considered using CML methodology and cumulative exergy demand (CExD) indicator. The results revealed that the board shaping subsystem was the main contributor to the most of impact categories.The main hotspot for resin production was known as Urea-formaldehyde (UF). Electricity was the main hotspot in acidification (AC) and ozone layer depletion (OLD) impact categories, while transportation and production process were the main hotspots in marine aquatic ecotoxicity (ME) and photochemical oxidation (PO) impact categories, respectively. Moreover, rotary dryer, hot press, flaker and hammer mill, vacuum pump and diesel fuel were the most effective sectors in the emissions of the production process. Results for substitution of natural gas showed that, except some impact categories, the use of alternative source of thermal energy such as wood residues could improve emissions from the manufacturing process.

Resource depletion impact assessment: Impacts of a natural gas scarcity in Australia

Natural gas is an important fuel and feedstock for many sectors of the Australian economy and is vital in Australia’s plan to become one of the world’s largest liquefied natural gas (LNG) exporters. Recent work aims to analyse the consequences of a natural gas scarcity in Australia using a resource depletion indicator that measures the environmental and economic impacts resulting from substitution of natural gas with black coal, diesel and coal seam gas (CSG) alternatives. The impacts are assessed for sectors which consume the bulk of Australia’s natural gas, namely baseload and peaking grid electricity, off-grid electricity and heating in mining, ammonia production, alumina and nickel refining, and residential heating. From these results, the implications of a natural gas scarcity in Australia can be drawn. In the cases where black coal was chosen as the alternative and diesel is the alternative substitute where black coal was inappropriate such as in peaking power generation and remote mine applications, substitution of natural gas resulted in an overall increase in emissions and cost. Substitution of natural gas with CSG resulted in an apparent decrease in most environmental and economic impacts, but posed environmental concerns regarding underground water extraction and downstream saline water treatment; there are also potential conflicts between landowners and miners, and the use of land for agriculture or mining. Based on these results, sectors can be arranged according to priority of substitution and assessed according to the change in environmental and economic impacts. This makes the methodology a useful companion to existing LCA methodologies by providing additional depth to the impact assessment of resource depletion.

Investigation of thermal and environmental characteristics of combustion of gaseous fuels

Numerical investigations are fulfilled for some thermal and environmental characteristics of combustion of gaseous fuels used at present in tube furnaces of petroleum refineries. The effect of the fuel composition on these characteristics is shown and probable consequences of the substitution of natural gas to other types of fuels. Methane, ethane, propane, butane, propylene, and hydrogen are considered for comparison, which in most cases are constituents of the composition of the fuel burnt in furnaces. The effect of the fuel type, its associated combustion temperature, combustion product emissivity, temperature of combustion chamber walls, mean beam length, and heat release on the variation in the radiant heat flux within the radiant chamber of furnaces is investigated. The effect of flame characteristics, which are determined by the presence of diffusion combustion zones formed by burners used at present in furnaces for reducing nitrogen oxides emission, is analyzed. The effect of the fuel type on the equilibrium NO concentration is also investigated. The investigations were carried out both at arbitrary given gas temperatures and at effective temperatures dependent on the adiabatic combustion temperature and the temperature at the chamber output and determined based on solving a set of equations at various heat-release rates of the combustion chamber.

Upgraded biogas from municipal solid waste for natural gas substitution and CO2 reduction – A case study of Austria, Italy, and Spain

Biogas is rich in methane and can be further purified through biogas upgrading technologies, presenting a viable alternative to natural gas. Landfills and anaerobic digestors treating municipal solid waste are a large source of such biogas. They therefore offer an attractive opportunity to tap into this potential source of natural gas while at the same time minimizing the global warming impact resulting from methane emissions in waste management schemes (WMS) and fossil fuel consumption reduction. This study looks at the current municipal solid waste flows of Spain, Italy, and Austria over one year (2009), in order to determine how much biogas is generated. Then it examines how much natural gas could be substituted by using four different biogas upgrading technologies. Based on current waste generation rates, exploratory but realistic WMS were created for each country in order to maximize biogas production and potential for natural gas substitution. It was found that the potential substitution of natural gas by biogas resulting from the current WMS seems rather insignificant: 0.2% for Austria, 0.6% for Italy and 0.3% for Spain. However, if the WMS is redesigned to maximize biogas production, these figures can increase to 0.7% for Austria, 1% for Italy and 2% for Spain. Furthermore, the potential CO2 reduction as a consequence of capturing the biogas and replacing fossil fuel can result in up to a 93% reduction of the annual national waste greenhouse gas emissions of Spain and Italy.

Substitution of Natural Gas by Biomass

The task of investigation was development of main approaches for biomass preparing and processing for use it in industrial furnaces and boilers instead of natural gas. The direct combustion of sawdust and sunflower husks and gasification of different kinds of biomass were studied. The burnout time of sawdust and sunflower husks particles was defined and demands for fuel preparing for use it in rotary kilns were elaborated. Special burners and heat regimes for sunflower husks combustion in rotary kilns were developed and implemented. Original technology of biomass air gasification was proposed and studied. It was shown, that producer gas has low calorific value sufficient for use it in boilers and engines. Industrial gas generator of 1,8 MW capacity and dual fuel burners for joint or separate combustion of producer and natural gas were developed and implemented at steam boiler. Technical solutions piloted in industrial scale could be efficiently applied in manufacturing sectors and energy sector.

Complex analysis of energy production technologies from solid biomass in the Ukraine

The results of the energetic, economic, and environmental analyses of technologies of energy production from solid biomass are considered. Examples of the introduction of the technology of the direct combustion of biomass (straw and wood) in a boiler installation, a domestic boiler, and a combined heat and power plant (CHPP) are considered. The results indicate the energetic and environmental reasonability of implementation of such projects. From the economic viewpoint, the introduction of the boilers that use the biomass is profitable with the substitution of natural gas for the state-financed and industrial consumers, and the CHPP operation with the use of biomass is profitable with selling the electrical energy by the “feed-in” tariff.

Environmental consequence analysis for resource depletion

Resource depletion is of concern to both present and future generations in terms of access to resources. It is a prominent impact category within life cycle assessment (LCA) and sustainability assessment. This paper examines existing resource depletion approaches and indicators in the context of natural gas depletion, and their limitations in modelling the wider environmental consequences of resource consumption. Some existing models assume substitution of scarce fossil fuels with an alternative fossil fuel or mix, but do not consider all of the subsequent change in impacts. An additional methodology is proposed to measure the impact changes when fossil fuel substitution occurs as a result of scarcity. The methodology will demonstrate the effect of resource scarcity for individual processes but also multiple processes which operate at different levels of resource consumption with varying degrees of impacts. The methodology is applied to a scarcity situation of natural gas in Australia, where black coal is substituted for gas. It is first applied to natural gas consumed for electricity generation only. In the second case, the methodology is applied to the substitution of natural gas for both electricity generation and hydrogen production. The varying impacts on emissions to air and water, together with solid waste generation and water depletion, as a result of the substitution are used to reflect the consequences of fossil fuel depletion. The indicators also provide information on the impacts of substitution in each product, thus enabling users to prioritise products based on the impacts produced during natural gas allocation.

Experimental and numerical study of hydrogen addition in a natural gas heavy duty engine for a bus vehicle

Hydrogen added to natural gas improves the process of combustion with the possibility to develop engines with higher performance and lower environmental impact. In this paper experimental and numerical analyses on a multi cylinder stoichiometric heavy duty engine, fuelled with natural gas–hydrogen blends, are reported. Some constrains on hydrogen content and maximum load achievable have limited the scope of investigation. A specific modelling of the reference engine was developed to extend the study at full load condition and at higher hydrogen content. The results showed a higher combustion speed when hydrogen content in the fuel is increased. However, the positive effect of shorter combustion duration on thermal efficiency is mitigated by higher wall heat loss, due to higher combustion temperatures. Therefore lower CO2 emissions are due only to the substitution of natural gas with hydrogen, making crucial the way of hydrogen producing to have a benefit on well-to-wheel CO2 emissions.

Assessing the greenhouse impact of natural gas

The global warming impact of substituting natural gas for coal and oil is currently in debate. We address this question here by comparing the reduction of greenhouse warming that would result from substituting gas for coal and some oil to the reduction which could be achieved by instead substituting zero carbon energy sources. We show that substitution of natural gas reduces global warming by 40% of that which could be attained by the substitution of zero carbon energy sources. At methane leakage rates that are ∼1% of production, which is similar to today's probable leakage rate of ∼1.5% of production, the 40% benefit is realized as gas substitution occurs. For short transitions the leakage rate must be more than 10 to 15% of production for gas substitution not to reduce warming, and for longer transitions the leakage must be much greater. But even if the leakage was so high that the substitution was not of immediate benefit, the 40%‐of‐zero‐carbon benefit would be realized shortly after methane emissions ceased because methane is removed quickly from the atmosphere whereas CO2 is not. The benefits of substitution are unaffected by heat exchange to the ocean. CO2 emissions are the key to anthropogenic climate change, and substituting gas reduces them by 40% of that possible by conversion to zero carbon energy sources. Gas substitution also reduces the rate at which zero carbon energy sources must eventually be introduced.

A simple gas turbine system and co-generation power plant improvement based on endogenous and exogenous exergy destruction

Exergy analysis provides useful information about system optimization. An exergy analysis identifies the sources of thermodynamic inefficiencies by evaluating the exergy destruction within each system component. Splitting the exergy destruction into endogenous/exogenous parts represents a new development in the exergy analysis of energy conversion systems. The present work is an attempt to investigate the combustion process in a simple gas turbine (GT) and a cogeneration power plant based on the general concept of endogenous and exogenous exergy destruction. Therefore, using a graphical approach, an advanced exergy analysis is applied to both cycles with different fuels such as natural gas (NG) and diesel. Also, dual-fueling of the combustion chamber (CC) is investigated based on the aforementioned approach in which different substitutions of NG fuel with diesel fuel are considered. It is found that in both cycles, the CC has the largest value of the endogenous exergy destruction. The exergetic efficiency of the CC is the least value of the three components of the GT system and increases by about 1.76 per cent, when NG fuel is substituted for diesel fuel. Also, for the cogeneration power plant, it can be seen that the exergetic efficiency of CC increases by about 1.87 per cent, when NG fuel is substituted for diesel fuel. As a result, the total system exergetic efficiency for simple GT and co-generation power plants increases by 1.05 per cent and 1.6 per cent, respectively. Therefore, cycles have been improved by increasing the substitution of NG fuel with diesel fuel. The results obtained here may provide some useful information on the optimal design and performance improvement of these cycles.

Carbon charges and natural gas use in China

Substitution of natural gas for coal in China's power sector could significantly reduce emissions of carbon dioxide, but gas-fired power is generally more costly than coal-fired power in China today. This paper explores how carbon charges and carbon sequestration technology might tip the balance in favour of gas. The costs of electricity from new coal-fired and gas-fired power plants in China are compared under various assumptions about fuel costs, exchange rates, carbon dioxide charges, and application of carbon sequestration technology. Under average cost conditions today, gas-fired power is roughly two-thirds more costly than coal-fired power. But with a charge of $20/tonne of carbon dioxide, the costs of gas- and coal-fired power would typically be about equal. Over the longer term, carbon sequestration technology could be economical with a carbon dioxide charge of $22/tonne or more under typical cost conditions, but gas with sequestration would not have a clear cost advantage over coal with sequestration unless the charge exceeded $35/tonne.

03/02024 Substitution of natural gas for coal: climatic effects of utility sector emissions: Hayhoe, K. et al. Climatic Change, 2002, 54, (1–2), 107–139

03/02024 Substitution of natural gas for coal: climatic effects of utility sector emissions: Hayhoe, K. et al. Climatic Change, 2002, 54, (1–2), 107–139

Performance and heat release analysis of a pilot-ignited natural gas engine

The influence of engine operating variables on the performance, emissions and heat release in a compression ignition engine operating in normal diesel and dual-fuel modes (with natural gas fuelling) was investigated. Substantial reductions in NOx emissions were obtained with dual-fuel engine operation. There was a corresponding increase in unburned hydrocarbon emissions as the substitution of natural gas was increased. Brake specific energy consumption decreased with natural gas substitution at high loads but increased at low loads. Experimental results at fixed pilot injection timing have also established the importance of intake manifold pressure and temperature in improving dual-fuel performance and emissions at part load.