Cumulative Greenhouse Gas Emissions Research Articles

Ozone Pollution Increases CO2 and N2O Emissions in Ozone‐sensitive Wheat System

Core Ideas Elevated O3 (EO3) effects on GHG flux and GWP from O3‐sensitivity wheat systems were studied.EO3 reduced belowground biomass of O3‐sensitive (SW) and O3‐tolerant (TW) wheat cultivars.O3‐sensitivty of wheat cultivar affected responses of gaseous C and N emission and GWP to EO3.SW wheat would release more freshly assimilated C, adding GHG emission and GWP under EO3. The effects of elevated O3 (EO3) on greenhouse gas (GHG) emissions and global warming potential (GWP) from wheat systems with differential O3 sensitivity are not well understood. The nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions from cropping (CP) and bare soil or root‐free (BS) plots, GWP, GWP per unit yield, and biomass and its allocation to belowground between O3‐sensitive (cultivar YN19) and tolerant (cultivar Y15) wheat (Triticum aestivum L.) systems were investigated at EO3 and ambient O3 (AO3) with an open‐air O3 fumigation system. Results indicated that a 50% elevation above AO3 significantly reduced belowground biomass of the two cultivars. The EO3 significantly increased the cumulative emissions of CO2 and N2O but did not change that of CH4 in YN19 CP. For BS, it significantly increased the emission of CO2 but decreased that of CH4 and N2O. The EO3 significantly increased the GWP and GWP per unit yield in YN19 CP but reduced the GWP in BS. The O3 sensitivity of wheat cultivar affected the responses of gaseous C and N emission, GWP and GWP per unit yield to EO3. The O3‐sensitive wheat cultivar would release more freshly assimilated C, increasing cumulative GHG emissions, GWP and GWP per unit yield in response to O3 stress, when compared to the O3 O3‐tolerant wheat cultivar. Our results suggest that EO3 may impair soil C and N sequestration in an O3 O3‐sensitive wheat–soil system in view of lower root biomass but higher CO2 and N2O emissions under EO3.

Life‐cycle assessment of torrefied coppice willow co‐firing with lignite coal in an existing pulverized coal boiler

AbstractCoal‐fired electricity generation is a major emitter of greenhouse gases (GHGs) in Canada and the Federal Government has taken steps toward mandated reduction in GHG emissions. One pathway to reduced emissions is via co‐firing of coal with short‐rotation coppice (SRC) willow grown on marginal land in Saskatchewan. This study uses a life‐cycle inventory model to investigate the GHG emissions from nine scenarios for electricity generation with willow pellets at a retrofitted generating station in Saskatchewan. Torrefied and non‐torrefied willow pellets from SRC plantations in the Prairie and Boreal Plains ecozones are considered. Direct co‐firing of pellets and indirect co‐firing via a circulating fluidized bed gasifier are modeled. The model output shows cumulative, levelized, and disaggregated GHG emissions. The scenarios account for the plantation establishment period required to reach a co‐firing ratio of 40% by energy input. Torrefied and non‐torrefied willow pellets grown in the Prairie ecozone indirectly co‐fired with lignite coal result in 43% and 47% net cumulative GHG emissions reduction compared to the existing coal fired pathway. Direct co‐firing of the same feedstocks results in a 34% and 31% reduction in GHG emissions, respectively. The biomass‐based portion of all scenarios was found to produce negative net cumulative GHG emissions on a life‐cycle basis with willow grown in the Prairies ecozone (i.e., GHG emissions from the willow plantation to the combustion of the pellet with coal). Co‐firing is therefore a viable option for reducing GHG emissions from electricity generation. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

Evaluation of fertilizer and water management effect on rice performance and greenhouse gas intensity in different seasonal weather of tropical climate

Intensively double cropping rice increases greenhouse gas (GHG) emission in tropical countries, and hence, finding better management practices is imperative for reducing global warming potential (GWP), while sustaining rice yield. This study demonstrated an efficient fertilizer and water management practice targeting seasonal weather conditions effects on rice productivity, nitrogen use efficiency (NUE), GWP, and GHG intensity (GHGI). Two-season experiments were conducted with two pot-scale experiments using urea and urea+cattle manure (CM) under continuous flooding (CF) during the wet season (2013WS), and urea with/without CaSiO3 application under alternate wetting and drying (AWD) during the dry season (2014DS). In 2013WS, 120kgNha−1 of urea fertilizer resulted in lower CH4 emission and similar rice production compared to urea+CM. In 2014DS, CaSiO3 application showed no difference in yields and led to significant reduction of N2O emission, but increased CH4 emission and GWP. Due to significant increases in GHG emissions in urea+CM and CaSiO3 application, we compared a seasonal difference in a local rice cultivation to test two water management practices. CF was adopted during 2013WS while AWD was adopted during 2014DS. Greater grain yields and yield components and NUE were obtained in 2014DS than in 2013WS. Furthermore, higher grain yields contributed to similar values of GHGI although GWP of cumulative GHG emissions was increased in 2014DS. Thus, utilizing urea only application under AWD is a preferred practice to minimize GWP without yield decline for double cropping rice in tropical countries.

Greenhouse gas emissions from different land-use areas in the Littoral Zone of the Three Gorges Reservoir, China

A series of ecological projects, including forest and dike-pond projects, were constructed in the littoral zone of the Three Gorges Reservoir (TGR) to maintain the ecological safety of this area. Previous ecological designs mainly focused on the functions of ecological engineering for environmental purification, economic value and increased biodiversity. However, the variations in land-use may alter the emissions of greenhouse gases (GHGs), which were ignored in our previous design. In this paper, the carbon sequestration benefits of ecological engineering were evaluated after dynamically monitoring the GHG emissions from different land-use sites during the growing (April-September) and submerged (October-March) seasons. The results showed that CH4 fluxes in the dike-ponds (3.76 CH4-mgm−2h−1) and rice paddies (6.09±1.60mg-CH4m−2h−1) were significantly higher than those in the natural littoral zone (0.77±0.27 mg-CH4m−2mg-CH4·m−2h−1) and forest project (0.57±0.31mg-CH4m−2h−1) during the growing season. There were no significant differences in the CO2 fluxes from different land-use sites. The emission of N2O from different land-use sites was low and ranged from −0.02 to 0.07mg-N2Om−2h−1. The growing season contributed to more than 76% of the cumulative annual GHG emissions. Direct GHG emissions and the carbon sequestration ability of species determined the net carbon sinks in the littoral zone. Net carbon sinks in the forest projects with different understory plant communities showed a small variation, with a range of −2.58 to 3.40 t-CO2ha−1year−1, but the design of the dike-pond projects should favor species that are positive net carbon sinks, e.g., Sagittaria (19.76 t-CO2ha−1y−1) and Canna generalis (16.79 t-CO2ha−1y−1), rather than those that are negative net carbon sinks, e.g., Trapa natans (−11.79 t-CO2ha−1y−1).

Greenhouse gas emission effect of suspending slash pile burning in Ontario's managed forests

Ontario has made a commitment to reduce its greenhouse gas (GHG) emissions by 15, 37, and 80% below 1990 levels by 2020, 2030, and 2050, respectively. Ontario's forest managers can contribute to meeting these targets by implementing changes to forestry practices that either reduce emissions from operations or increase carbon sequestration in forest ecosystems and harvested wood products. We present an analysis of the effects on GHG emissions resulting from suspending the current management practice of slash pile burning (burning harvest residue in the forest without energy recovery). The analysis was performed for each of Ontario's forest management units (FMU) with assumed suspension of slash pile burning for four different periods: 2016–2025, 2016–2050, 2016–2075, and 2016–2100. Annual and cumulative avoided emissions from suspending slash pile burning that would have occurred with current practices were estimated from planned harvest volume and area adjusted to reflect harvesting levels from 1990 to 2009, data on slash pile burning from 2008 to 2013, and emission factors for combustion and decay of wood estimated from the literature. Suspending slash pile burning was estimated to reduce GHG emissions by year 2100 in all four no-burn scenarios, with cumulative GHG emission reductions estimated at -0.7, -4.5, -14.1, and -33.4 Mt CO2eq (million tonnes of CO2 equivalent), respectively. At the same time, suspending slash pile burning for the above-listed four periods resulted in losses of forest area by 2100 estimated at 7200, 24000, 40800, and 57800, respectively. The accuracy of these projections is affected by uncertainty in estimates of several components of the analysis, of which the primary one is the historical rate of slash pile burning. Improvement in measuring and reporting procedures is needed to obtain more reliable estimates of the amount of slash burned.

A comparative study of floor construction on sloping sites: an analysis of cumulative energy demand and greenhouse gas emissions

In order to make environmentally aware decisions, there is growing interest in the comparative energy and greenhouse gas (GHG) performance of competing construction methods. Little research has been done concerning competing ground floor construction methods, especially given different site variables, such as slope and soil type. A life cycle assessment approach was adopted to analyse environmental impacts, including cumulative energy demand and GHG emissions for detached housing construction in Australia. Data was drawn from 24 case study housing projects, including 12 reinforced concrete and 12 suspended timber floor projects. The data presented in the paper compares cumulative energy demand, GHG and the constituent parts of competing construction methods. The findings indicate that the timber floors use/create significantly less cumulative energy demand and GHG emissions than concrete floors—approximately 2.1 to 2.7 times less energy and 2.3 to 2.9 times less GHG. These findings are limited to the site slope and foundation soil types identified in the paper. The main application of the work is in guidance concerning the lowest environmental impact options for detached housing construction.

Greenhouse Gas Emissions from Excavation on Residential Construction Sites

Despite considerable research concerning the manifestation of greenhouse gases in the usage of buildings, little has been done concerning emissions arising from the construction process itself. This paper specifically examines emissions arising from cut and fill excavation on residential construction sites. Even though such excavation is often seen as being economical in terms of providing a flat base for concrete raft slab construction, the environmental consequences of this approach need to be considered more fully in terms of impact on the environment. This is particularly important when steeply sloping sites are involved and for different soil types. The paper undertakes a study that quantitatively assesses the cumulative greenhouse gas emissions caused by cut and fill excavation on 52 residential projects in Australia for a range of slope and soil types. The paper presents results from the study and concludes that greenhouse gas emissions increase as site slope increases; the building footprint area (as distinct from Gross Floor Area), exposes the need to reduce the area of the building to reduce greenhouse gas emissions; excavation of rock soils creates higher emissions than other soil types; and cut and fill excavation on steeply slope sites increase emissions. Potential alternative construction includes suspended floor construction systems which involve less excavation.

Mitigation of greenhouse gas emissions from reed canary grass in paludiculture: effect of groundwater level

Combination of rewetting and wetland crop cultivation (paludiculture) is pursued as a wider carbon dioxide (CO2) mitigation option in drained peatland. However, information on the overall greenhouse gas (GHG) balance for paludiculture is lacking. We investigated the GHG balance of peatlands grown with reed canary grass (RCG) and rewetted to various extents. Gas fluxes of CO2, methane (CH4) and nitrous oxide (N2O) were measured with a static chamber technique for 10 months from mesocosms sown with RCG and manipulated to ground water levels (GWL) of 0, −10, −20, −30 and −40 cm below the soil surface. Gross primary production (GPP) was estimated from the above ground biomass yield. The mean dry biomass yield across all water table treatments was 6 Mg ha−1 with no significant differences between the treatments. Raising the GWL to the surface decreased both the net ecosystem exchange (NEE) of CO2 and N2O emissions whereas CH4 emissions increased. Total cumulative GHG emissions (for 10 months) corresponded to 0.08, 0.13, 0.61, 0.68 and 0.98 kg CO2 equivalents m−2 from the GWL treatments at 0, −10, −20, −30 and −40 cm below the soil surface, respectively. The results showed that a reduction in total GHG emission can be achieved without losing the productivity of newly established RCG when GWL is maintained close to the surface. Further studies should address the practical constrains and long-term productivity of RCG cultivation in rewetted peatlands.

Human health impacts in the life cycle of future European electricity generation

This paper presents Life Cycle Assessment (LCA) based quantification of the potential human health impacts (HHI) of base-load power generation technologies for the year 2030. Cumulative Greenhouse Gas (GHG) emissions per kWh electricity produced are shown in order to provide the basis for comparison with existing literature. Minimising negative impacts on human health is one of the key elements of policy making towards sustainable development: besides their direct impacts on quality of life, HHI also trigger other impacts, e.g. external costs in the health care system. These HHI are measured using the Life Cycle Impact Assessment (LCIA) methods “ReCiPe” with its three different perspectives and “IMPACT2002+”. Total HHI as well as the shares of the contributing damage categories vary largely between these perspectives and methods. Impacts due to climate change, human toxicity, and particulate matter formation are the main contributors to total HHI. Independently of the perspective chosen, the overall impacts on human health from nuclear power and renewables are substantially lower than those caused by coal power, while natural gas can have lower HHI than nuclear and some renewables. Fossil fuel combustion as well as coal, uranium and metal mining are the life cycle stages generating the highest HHI.

Integrated spatiotemporal modelling of bioenergy production potentials, agricultural land use, and related GHG balances; demonstrated for Ukraine

AbstractThis study shows how bioenergy potential and total greenhouse gas (GHG) balances of land‐use change and agricultural intensification can be modeled in an integrated way. The modeling framework is demonstrated for first‐ and second‐generation ethanol production in Ukraine for the timeframe 2010–2030 for two scenarios: a business as usual (BAU) scenario in which current trends in agricultural productivity are continued; and a progressive scenario, which projects a convergence of yield levels in Ukraine with Western Europe. The spatiotemporal development in land for food production is analyzed making use of the PCRaster Land Use Change (PLUC) model. The land‐use projections serve as input for the analysis of the CO2, N2O, and CH4 emissions related to changes in land use and agricultural management, as well as the abatement of GHG emissions by replacing fossil fuels with bioethanol production from wheat and switchgrass. This results in annual maps (1 km2 resolution) of the different GHG emissions for the modeled timeframe. In the BAU scenario, the GHG emissions increase over time, whereas in the progressive scenario, a total cumulative GHG emission reduction of 0.8 Gt CO2‐eq for wheat and 3.8 Gt CO2‐eq for switchgrass could be achieved in 2030. When the available land is used for the re‐growth of natural vegetation, 3.5 Gt CO2‐eq could be accumulated. These emission reductions could increase when appropriate measures are taken. The spatiotemporal PLUC model + GHG module allows for spatiotemporal and integrated modeling of total GHG emissions of bioenergy production and intensification of the agricultural sector. © 2014 Society of Chemical Industry and John Wiley & Sons, Ltd

Greenhouse gas emissions from landfill leachate treatment plants: A comparison of young and aged landfill

With limited assessment, leachate treatment of a specified landfill is considered to be a significant source of greenhouse gas (GHG) emissions. In our study, the cumulative GHG emitted from the storage ponds and process configurations that manage fresh or aged landfill leachate were investigated. Our results showed that strong CH4 emissions were observed from the fresh leachate storage pond, with the fluxes values (2219–26,489mgCm−2h−1) extremely higher than those of N2O (0.028–0.41mgNm−2h−1). In contrast, the emission values for both CH4 and N2O were low for the aged leachate tank. N2O emissions became dominant once the leachate entered the treatment plants of both systems, accounting for 8–12% of the removal of N-species gases. Per capita, the N2O emission based on both leachate treatment systems was estimated to be 7.99gN2O–Ncapita−1yr−1. An increase of 80% in N2O emissions was observed when the bioreactor pH decreased by approximately 1 pH unit. The vast majority of carbon was removed in the form of CO2, with a small portion as CH4 (<0.3%) during both treatment processes. The cumulative GHG emissions for fresh leachate storage ponds, fresh leachate treatment system and aged leachate treatment system were 19.10, 10.62 and 3.63GgCO2eqyr−1, respectively, for a total that could be transformed to 9.09kgCO2eqcapita−1yr−1.

Greenhouse gas mitigation effects of integrating biomass production into European agriculture

AbstractAs energy crop production on European croplands expands, driven by accelerating consumption of bioenergy, there is a pressing need to evaluate the environmental impacts associated with this production. The present study considers on‐going yield increases as a means of boosting agricultural output which results in a limited need to convert nature areas and grasslands to additional cropland. For nine land‐use variants, the study evaluates cumulative greenhouse gas emissions, net organic carbon fluxes from the soil, and abated emissions achieved by replacing fossil fuels for transport with biofuels. The main finding is that, in European agriculture, it is possible to combine large‐scale biomass production with food production sustained at current levels, with limited direct or indirect land‐use changes and while accomplishing significant net greenhouse gas mitigation. Maintaining the current (business as usual) agricultural system results in 4.9 GtCO2‐eq. of cumulative emissions by 2030. Intensified food production and energy crop production on freed cropland combined with mitigation measure implementation significantly reduces cumulative emissions for the annual crop groups of oil, starch and sugarbeet to 1.9, 1.5 and 2.1 GtCO2‐eq., respectively. By 2030, perennial energy crop production can mitigate cumulative emissions to a large extent, reaching negative emissions (i.e. net sequestration) for grass and wood crops of –3.3 and –4.5 GtCO2‐eq., respectively. For the variants compared to the baseline, nitrous oxide emissions will increase modestly due to higher fertilizer‐application rates, though at improved efficiencies per unit crop quantity produced. Emission mitigation results partly from the temporary increase in SOC sequestration though mainly from replacement of fossil resources by biomass resources. The results indicate that research and policy efforts aimed at further increasing productivity can raise the output from existing European croplands while being able to reduce or mitigate emissions significantly.

Soil Greenhouse Gas Emissions in Response to Corn Stover Removal and Tillage Management Across the US Corn Belt

In-field measurements of direct soil greenhouse gas (GHG) emissions provide critical data for quantifying the net energy efficiency and economic feasibility of crop residue-based bioenergy production systems. A major challenge to such assessments has been the paucity of field studies addressing the effects of crop residue removal and associated best practices for soil management (i.e., conservation tillage) on soil emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). This regional survey summarizes soil GHG emissions from nine maize production systems evaluating different levels of corn stover removal under conventional or conservation tillage management across the US Corn Belt. Cumulative growing season soil emissions of CO2, N2O, and/or CH4 were measured for 2–5 years (2008–2012) at these various sites using a standardized static vented chamber technique as part of the USDA-ARS’s Resilient Economic Agricultural Practices (REAP) regional partnership. Cumulative soil GHG emissions during the growing season varied widely across sites, by management, and by year. Overall, corn stover removal decreased soil total CO2 and N2O emissions by -4 and -7 %, respectively, relative to no removal. No management treatments affected soil CH4 fluxes. When aggregated to total GHG emissions (Mg CO2 eq ha−1) across all sites and years, corn stover removal decreased growing season soil emissions by −5 ± 1 % (mean ± se) and ranged from -36 % to 54 % (n = 50). Lower GHG emissions in stover removal treatments were attributed to decreased C and N inputs into soils, as well as possible microclimatic differences associated with changes in soil cover. High levels of spatial and temporal variabilities in direct GHG emissions highlighted the importance of site-specific management and environmental conditions on the dynamics of GHG emissions from agricultural soils.

Implications of the international reduction pledges on long-term energy system changes and costs in China and India

This paper analyses the impact of postponing global mitigation action on abatement costs and energy systems changes in China and India. It compares energy-system changes and mitigation costs from a global and two national energy-system models under two global emission pathways with medium likelihood of meeting the 2°C target: a least-cost pathway and a pathway that postpones ambitious mitigation action, starting from the Copenhagen Accord pledges. Both pathways have similar 2010–2050 cumulative greenhouse gas emissions. The analysis shows that postponing mitigation action increases the lock-in in less energy efficient technologies and results in much higher cumulative mitigation costs. The models agree that carbon capture and storage (CCS) and nuclear energy are important mitigation technologies, while the shares of biofuels and other renewables vary largely over the models. Differences between India and China with respect to the timing of emission reductions and the choice of mitigation measures relate to differences in projections of rapid economic change, capital stock turnover and technological development. Furthermore, depending on the way it is implemented, climate policy could increase indoor air pollution, but it is likely to provide synergies for energy security. These relations should be taken into account when designing national climate policies.

Rewetting Drained Peat Meadows: Risks and Benefits in Terms of Nutrient Release and Greenhouse Gas Exchange

Rewetting of agriculturally used peatlands has been proposed as a measure to stop soil subsidence, conserve peat and rehabilitate ecosystem functioning. Unintended consequences might involve nutrient release and changes in the greenhouse gas (GHG) balance towards CH4-dominated emission. To investigate the risks and benefits of rewetting, we subjected soil columns from drained peat- and clay-covered peatlands to different water level treatments: permanently low, permanently inundated and fluctuating (first inundated, then drained). Surface water and soil pore water chemistry, soil-extractable nutrients and greenhouse gas fluxes were measured throughout the experiment. Permanent inundation released large amounts of nutrients into pore water, especially phosphorus (up to 11.7 mg P-PO4 l−1) and ammonium (4.8 mg N-NH4 l−1). Phosphorus release was larger in peat than in clay soil, presumably due to the larger pool of iron-bound phosphorus in peat. Furthermore, substantial amounts of phosphorus and potassium were exported from the soil matrix to the surface water, risking the pollution of local species-rich (semi-)aquatic ecosystems. Rewetting of both clay and peat soil reduced CO2 emissions. CH4 emissions increased, but, in contrast to the expectations, the fluxes were relatively low. Calculations showed that rewetting reduced net cumulative GHG emissions expressed as CO2 equivalents.

Greenhouse gas emission in relation to labile soil C, N pools and functional microbial diversity as influenced by 39 years long-term fertilizer management in tropical rice

Impacts of 39-years of fertilizer and manure application on greenhouse gas (GHG) emissions viz. methane, carbon dioxide and nitrous oxide, soil labile carbon (C) and nitrogen (N) pools, functional microbial diversity were investigated in a tropical flooded rice (Oryza sativa L.). The treatments included non-fertilized control, N, farmyard manure (FYM), FYM+N, NPK and FYM+NPK. Annual cumulative GHGs emissions after 39 years of intensive rice–rice cultivation were significantly higher in FYM+NPK treatments than other treatments. The global warming potential (GWP) in 100 years time scale and carbon equivalent emission (CEE) were increased significantly under the combined application of FYM+NPK by 88.4% over control. The carbon efficiency ratio (CER) was significantly higher (p≤0.05) in NPK as compared to others. The annual emissions of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2-C) in FYM+NPK were 177.6, 1.28, 1407kgha−1, respectively, in tropical rice–rice system (wet season rice-fallow–dry season rice-fallow) which were significantly higher (p≤0.05) than other treatments. Although the GHGs emissions were more under FYM+NPK treatment, it helps to maintain soil fertility and supported sustainable rice yield. The soil labile C, N pools, soil enzymatic activities and microbial populations were significantly higher under this treatment which is the indicators of improved soil fertility. Stepwise regression analysis of GHGs emission with related soil parameters was performed to predict seasonal fluxes from tropical rice.

Biofuels and Climate Change Mitigation: A CGE Analysis Incorporating Land-Use Change

The question of whether biofuels help mitigate climate change has attracted much debate in the literature. Using a global computable general equilibrium model that explicitly represents land-use change impacts due to the expansion of biofuels, this study attempts to shed some light on this question. The study shows that if biofuel mandates and targets currently announced by more than 40 countries around the world are implemented by 2020 using crop feedstocks, and if both forests and pasture lands are used to meet the new land demands for biofuel expansion, this would cause a net increase of greenhouse gas emissions released to the atmosphere until 2043, since the cumulative greenhouse gas emissions released through land-use change would exceed the reduction of emissions due to replacement of gasoline and diesel until then. However, if the use of forest lands is avoided by channeling only pasture lands to meet the demand for new lands, a net increase of cumulative greenhouse gas emissions would occur but would cease by 2021, only a year after the assumed full implementation of the mandates and targets. The study also shows, contrary to common perceptions, that the rate of deforestation does not increase with the rate of biofuel expansion; instead, the marginal rate of deforestation and corresponding land-use emissions decrease even if the production of biofuels increases.

Long-Term Energy and Climate Implications of Carbon Capture and Storage Deployment Strategies in the US Coal-Fired Electricity Fleet

To understand the long-term energy and climate implications of different implementation strategies for carbon capture and storage (CCS) in the US coal-fired electricity fleet, we integrate three analytical elements: scenario projection of energy supply systems, temporally explicit life cycle modeling, and time-dependent calculation of radiative forcing. Assuming continued large-scale use of coal for electricity generation, we find that aggressive implementation of CCS could reduce cumulative greenhouse gas emissions (CO(2), CH(4), and N(2)O) from the US coal-fired power fleet through 2100 by 37-58%. Cumulative radiative forcing through 2100 would be reduced by only 24-46%, due to the front-loaded time profile of the emissions and the long atmospheric residence time of CO(2). The efficiency of energy conversion and carbon capture technologies strongly affects the amount of primary energy used but has little effect on greenhouse gas emissions or radiative forcing. Delaying implementation of CCS deployment significantly increases long-term radiative forcing. This study highlights the time-dynamic nature of potential climate benefits and energy costs of different CCS deployment pathways and identifies opportunities and constraints of successful CCS implementation.

Life cycle approach for energy and environmental analysis of biomass and coal co-firing in CHP plant with backpressure turbine

Generation of near CO2 free energy (electricity and heat) in existing large co-generation technologies can be achieved by partial substitution of fossil fuels with biomass commonly regarded as CO2-neutral fuel. Co-firing of biomass with fossil fuels aims at reduction of greenhouse gases (GHG) emissions and non-renewable fuel resources depletion. Life cycle analysis was carried out for hard coal and two biomass sorts of different origin (willow chips and residual wood chips) requiring a diverse approach for their upstream inventory of non-renewable energy resources depletion and GHG emission. These fuels are co-combusted in a combined heat and power plant (CHP plant) for generation of electricity and heat. As in the case of cogeneration process, it was necessary to allocate the harmful effects between both energy carriers. Allocation of the burdens basing on the principle of the avoided process has been proposed. The empirical correlations concerning the electricity consumption of boiler auxiliaries' and boiler energy efficiency along with the increasing share of biomass in the fuel blend were applied in the calculations. The functional unit chosen to compare the results was 1 TJ of heat. Sensitivity analysis was carried out to bring the final conclusions and recommendations. Both environmental burdens (non-renewable resources depletion and the greenhouse effect) are dependant on the share of biomass in the combusted blend. It was proved, that the partial substitution of coal with biomass (in the considered range of 0–20% on the thermal basis) leads to the decrease of the total life-cycle non-renewable energy resources depletion and cumulative GHG emissions for generation and supply of 1 MJ of heat (functional unit) and 1 MWh of electricity generated during multifunctional process of combined heat and power generation. Residual biomass shows its advantages over dedicated energy crops (on the example of willow biomass). Additionally, it has been proved, that the share of operational component dominates in the total system burdens concerning the regarded life cycle.

Greenhouse gas emissions from a wastewater sludge-amended soil cultivated with wheat (Triticum spp. L.) as affected by different application rates of charcoal

Applying biochar to soil is an easy way to sequester carbon in soil, while it might reduce greenhouse gas (GHG) emissions and stimulate plant growth. The effect of charcoal application (0, 1.5, 3.0 and 4.5%) on GHG emission was studied in a wastewater sludge-amended arable soil (Typic Fragiudepts) cultivated with wheat (Triticum spp. L.) in a greenhouse. The application of charcoal at ≥1.5% reduced the CO2 emission rate significantly ≥37% compared to unamended soil (135.3 g CO2 ha−1 day−1) in the first two weeks, while the N2O emission rate decreased 44% when 4.5% charcoal was added (0.72 g N2O ha−1 day−1). The cumulative GHG emission over 45 days was 2% lower when 1.5% charcoal, 34% lower when 3.0% charcoal and 39% lower when 4.5% charcoal was applied to the sludge-amended soil cultivated with wheat. Wheat growth was inhibited in the charcoal-amended soil compared to the unamended soil, but not yields after 135 days. It was found that charcoal addition reduced the emissions of N2O and CO2, and the cumulative GHG emissions over 45 days, without altering wheat yield.