Benefits Of Greenhouse Gas Emissions Research Articles

Greenhouse gas emissions benefits of the lightweight vehicle fleet in China: A dynamic fleet perspective

Lightweighting is believed to be a silver bullet to reduce greenhouse gas (GHG) emissions related to the road transportation. However, the fleet-scale and long-term GHG emissions estimation on the light-duty passenger vehicle (LDPV) fleet in China is still underexplored. A dynamic fleet-based life cycle assessment (LCA) model is developed to predict the annual GHG emissions attributable to the lightweight LDPV fleet in China at provincial level. With the most aggressive implementation of lightweighting, the cumulative mitigation potential of lightweight LDPV fleet from 2021 to 2050 is 0.72 Gt CO2 eq and 0.55 Gt CO2 eq using high-strength steel (AHSS) and aluminium (Al), respectively. Sooner implementation brings a higher cumulative reduction in GHG emissions. Delaying the implementation by five years would sacrifice 0.16 Gt CO2 eq ∼0.2 Gt CO2 eq cumulative reduction, and the loss would increase to 0.31 Gt CO2 eq ∼0.41 Gt CO2 eq when postpone the lightweighting by ten years.

Combined cooling, heat and power for commercial buildings: Optimization for hydrogen-methane blend fuels

Considering the rapid pace of global warming, it is crucial to decarbonize our energy supply to meet both electric power and thermal energy demands. This study evaluates the application of a combined cooling, heat, and power system for commercial applications in a maritime temperate climate to assess the feasibility of meeting thermal and electrical demand with medium-size commercial generators fueled with blends of hydrogen and natural gas. Demand load data analysis has been conducted using open-source datasets to identify building categories with representative thermal and electrical demands. A large hospital was chosen for a representative case study to define system component capacity and operation optimization to minimize estimated costs and greenhouse gas emissions. Along with the generator, the combined cooling, heat, and power system included thermal energy storage and an absorption cooler, supplemented with conventional boiler and an electric (vapor compression) cooling system. The optimized system was compared to a conventional combination of grid electrical supply for power; cooling from an electrical chiller; and heat load from a natural gas boiler. A hierarchical clustering algorithm was employed to identify five representative days to cover the entire year while keeping the optimization tractable. The system was sized using nested optimization, where operation over the year was optimized for a given system component sizing, then the sizing was adjusted, and the operation re-optimized in an iterative process. This ensured that the final system specification was optimized for both component size (capacity) and operation. The results show that a combined cooling, heat, and power system can provide economic and greenhouse gas emissions benefits for electricity grids with marginal CO2 intensities greater than 230–260 g/kWh. Adding up to 50% hydrogen to the natural gas can reduce this break-even intensity by up to 12%. Net cost savings on the order of 5% can also be achieved at the break-even greenhouse gases grid intensity. Depending on the grid CO2 intensity and fuel composition, combined cooling, heat, and power can save more than 14% compared to the conventional system in 20 years.

Uncertainty in life cycle greenhouse gas emissions of sustainable aviation fuels from vegetable oils

Sustainable aviation fuel (SAF) is one of the most promising short-to medium-term term options to mitigate greenhouse gas (GHG) emissions from aviation. Life cycle assessment (LCA) is commonly used to estimate GHG emissions from SAF in comparison to fossil kerosene. While there are several studies reporting the GHG emissions from SAF, uncertainty in the results is not always addressed in a comprehensive way.In this work, GHG emissions of hydroprocessed esters and fatty acids (HEFA) fuels derived from jatropha (Jatropha curcas), pennycress (Thlaspi arvense), castor (Ricinus communis), energy tobacco (Nicotiana tabacum, Solaris) and Salicornia (Salicornia bigelovii) oils were estimated. A stochastic methodology was employed where parametric uncertainty was propagated using Monte Carlo simulations. Uncertainty due to methodological choices was incorporated through scenario analyses. Emissions from direct land use change (DLUC) and the associated uncertainty were assessed under the IPCC Tier 1 approach by considering alternative land use transitions per feedstock.Analyzed HEFA pathways provide GHG emissions benefits (34–65%) in comparison to fossil kerosene when DLUC emissions are not considered. Parametric uncertainty yields up to 26% deviation from the median well-to-wake GHG emissions. Changing the allocation choice for the oil extraction step, from the base assumption of energy-based allocation to mass- or market-based, can impact the results by up to 46%. DLUC is a more significant source of uncertainty than both parametric uncertainty and allocation assumptions in the analysis. DLUC emissions negate any GHG savings from HEFA fuels if forests or natural shrublands are lost.

Greenhouse gas emission benefits of adopting new energy vehicles in Suzhou City, China: A case study.

The promotion of new energy in light-duty vehicles (LDVs) is considered as an effective approach for achieving low-carbon road transport targets. In this study, life cycle assessment was performed for five typical vehicle models in Suzhou City (fourth largest LDV stock in China): internal combustion engine vehicle (ICEV), hybrid electric vehicle (HEV), plug-in electric vehicle (PHEV), battery electric vehicle (BEV) and hydrogen fuel cell vehicle (HFCV). Their energy consumption, and greenhouse gas (GHG) and air pollutant emissions during vehicle and fuel cycles in 2020 were examined using the Greenhouse gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. GHG emission reduction potential of LDV fleet was projected under various scenarios for 2021-2040. The results showed that BEVs exhibited advantages for replacing ICEVs over HEVs, PHEVs and HFCVs, taking into account China's road electrification policy. The GHG emission intensity of BEVs in 2040 was estimated to be 19-34% of ICEVs in 2020, with a deep decarbonized electricity mix and improved vehicle efficiency. For the aggressive Sustainable Development Scenario, the GHG emissions of LDVs would peak before 2026, ahead of China's target by 2030, and the ~ 100% share of EVs in 2040 would result in a lower GHG emissions, equivalent to the 2010 level. It highlights the importance of early action, green electricity mix, and public transport development in reducing GHG emissions of large LDV fleet.

Greenhouse gas mitigation potential of replacing diesel fuel with wood-based bioenergy in an arctic Indigenous community: A pilot study in Fort McPherson, Canada

Remote and northern communities surrounded by forested areas are well positioned to use wood-based bioenergy to meet their energy needs and thereby reduce their greenhouse gas (GHG) emissions. However major gaps remain regarding the GHG mitigation potential considering the challenges along the biomass supply chain. Using Fort McPherson, an Indigenous community located in the Northwest Territories (NWT), Canada, we developed a life cycle assessment based model to estimate the potential GHG emission reductions and timing. We also built two main bioenergy scenarios testing 1) wood chips made from locally harvested willow or 2) imported pellets made from sawmill residues including key parameters like transport distances, boiler efficiency, and emission factors. We found that replacing diesel fuel with bioenergy resulted in GHG savings as high as 32,166 t of CO2 eq over 100 years. GHG benefits can be achieved within 0–20 years for local wood chips or 2–37 years for imported sawmill residue pellets. Increases in transport distance and decreases in biomass boiler efficiency resulted in delays in GHG emissions benefits for both local chips and imported pellets. This study shows that the use of local or imported forest biomass to replace diesel in remote northern communities’ energy systems can generate GHG savings within a time-frame that is relevant to current climate change concerns. In addition to GHG mitigation potential, we discuss the socio-economic and environmental factors to take into consideration at the community level when deciding between local or imported biomass supply chains.

Life cycle assessment of mid-range passenger cars powered by liquid and gaseous biofuels: Comparison with greenhouse gas emissions of electric vehicles and forecast to 2030

• Biofuels can provide significant GHG emissions benefits in a short period of time. • The current trend to increase the size of batteries is detrimental to GHG impacts. • With an adapted battery size, PHEVs seem to be another relevant solution. • Electrification and biofuels can together reach the European Green Deal targets. Electrification of the transport sector is a relevant measure to decarbonize, but the massive electrification approach can be questioned since another interesting low-carbon solutions are available. Current and future forecast comparative analysis of the greenhouse gas emissions of mid-range passenger cars, obtained using life cycle assessment (LCA) methodology, are presented. Two important factors are addressed by assessing the use of biofuels suitable for internal combustion engines (including bio natural gas vehicles) and forecasting the LCA results in 2030 with updated vehicle weight, battery technology, and CO 2 electricity content. The synthesis shows that conventional engines powered with biofuels complement electrified powertrains. Plug-in hybrid electric vehicles seem to be the ideal solution owing to the limited size of their batteries. The current trend of expanding the battery size to improve the range of electric vehicles is detrimental to greenhouse gas (GHG) impacts. Biofuels can provide significant GHG emission benefits in a short time as vehicle powertrains can already accommodate up to 85% ethanol or 100% biodiesel without engine changes.

Life-Cycle Greenhouse Gas Emission Benefits of Natural Gas Vehicles

Abundant supply, low prices, and low carbon content may result in an increased use of natural gas (NG) as an alternative transportation fuel. Assessments of the associated climate benefits are sensitive to the climate metric and time horizon selected to equate methane to equivalent CO2 emissions and to the assumptions of methane emissions during NG production, distribution, and use. We report life-cycle greenhouse gas (GHG) emissions from cars, light-duty trucks (LDTs), and heavy-duty trucks (HDTs) that are powered directly or indirectly using NG as a function of methane emission rates. We show that whether internal combustion engine vehicles (ICEVs) powered by fossil compressed natural gas (CNG) have GHG benefits over their gasoline and diesel counterparts depends on a value judgment of using either an integrated or end-point climate metric (e.g., global warming potential [GWP] or global temperature change potential [GTP]) and a short or long time horizon (e.g., 20 or 100 years). Conversion of NG into electricity or hydrogen for use in battery electric vehicles (BEVs) or fuel-cell vehicles (FCVs) has clear GHG benefits for cars and LDTs. Benefits are less clear for HDTs where heavy batteries and CNG tanks lead to a relatively poor GHG performance of BEVs and CNG_ICEVs compared to the incumbent diesel technology.

Quantification of sustainable animal manure utilization strategies in Hangzhou, China

ContextChina's livestock and poultry industries have been experiencing a transformation over recent decades, transitioning from family-size farms to larger, confined animal feeding operations. This development has significantly improved animal production capacity and reduced costs but has also created new challenges to manure management. One important concern is the conflicting interests of environmental protection and economic welfare between policymakers and manure utilization practitioners. ObjectiveIn this study, a regional manure utilization chain (RMUC) model was developed by recognizing optimal logistic configurations for manure and manure-based products between animal feeding operations, centralized processing facilities, and crop farms. We then use RMUC model to quantify the impact of management practices to the animal manure utilization chain of Hangzhou, China in the context of sustainable development. MethodThe RMUC model implemented an analytical target cascading structure with a multi-objective optimization algorithm to generate a set of Pareto-optimal configurations for discussing the regional economic costs and greenhouse gas (GHG) emission considering the practitioners' operational decisions to the designated manure management practices. Results and conclusionA comparative analysis quantified and prioritized the manure management practices (solid/liquid separation, manure reduction strategies); estimated economic and GHG emission credits of manure composition measurements; and indicated economic and GHG emission benefits of electric vehicles and the secondary infrastructures on manure distribution. The results showed sustainable metrics of the manure utilization improvement, including private costs, regional benefits, and the global impact of GHG emissions. SignificanceThe RMUC model demonstrated the compromise between practitioners' interests and public sustainability benefits given a certain level of constraints in decision process. Our analysis is an example of implementing computational models to deal with agricultural systematic problems with social, environmental, and economic concerns.

Life Cycle Primary Energy Demand and Greenhouse Gas Emission benefits of vehicle lightweighting with recycled carbon fibre

Recycled carbon fibre (rCF) is a potential material for sustainable vehicle lightweighting but its realistic environmental impacts are still unclear. In this study, a Life Cycle Assessment (LCA) investigates the primary energy demand (PED) and global warming potential (GWP) of using rCF reinforced Polyamide 66 (PA66) for a side-view mirror bracket, in comparison with its conventional cast aluminium counterpart. Results indicate that using rCF+PA66 with 40wt% rCF in the US can achieve around 13% and 34% reduction in the PED/GWP of the cradle-to-gate phases and the use phase, respectively. Scenario analysis is also carried out to understand the impact of geographical setting and fibre content in rCF+PA66. It shows that replacing aluminium with 40wt% rCF+PA66 in the EU saves 31.5% and 29.7% more cradle-to-gate PED and GWP, respectively, than in the US. A higher reduction of 43.4% and 41.2% in the cradle-to-grave PED and GWP compared to aluminium can be achieved by increasing fibre mass fraction.

Contribution of offshore wind to the power grid: U.S. air quality implications

Offshore wind is an established technology in Europe and Asia, but it has not yet gained market share in the United States. There is, however, increasing interest in offshore wind development in many coastal regions of the United States. As offshore wind grows in those regions it will displace existing and future electric generation assets, which will lead to changes in the emissions from the electric power sector. This research explores combinations of two electric sector drivers, offshore wind capital costs and carbon dioxide (CO2) caps, to measure the changes in the energy mix and quantify offshore wind’s impact on electric sector emissions. An energy system modeling approach is applied, using a nested parametric sensitivity analysis, to generate and explore potential energy futures and analyze the air quality and greenhouse gas emissions benefits of offshore wind as an energy source. The analysis shows that offshore wind capacity was added due to cost reductions more than CO2 cap stringency, though both increased capacity additions. Capacity varied more by CO2 cap stringency at higher prices and less at lower prices. CO2 mitigation led to reductions in all five emissions investigated, regardless of offshore wind cost. Offshore wind-specific reductions were only consistent across all CO2 caps for CO2 and methane (CH4), though offshore wind-specific reductions were found for all emissions in the absence of CO2 caps. Results are presented nationally, analyzing the differences in adoption of offshore wind and how this technology provides a broader range of emission reduction options for the power sector.

Life cycle cost and GHG emission benefits of electric vehicles in China

The penetration rate of Electric Vehicles (EVs) is continuously growing in China. Since EV is considered as an environment-friendly vehicle with lower cost of operation, many studies have paid attention to the Life Cycle Cost (LCC) and Greenhouse Gas (GHG) emission evaluation on EVs. This study aims to expand the scope and provide comprehensive results for LCC and GHG emission comparison between ICEV and EV under different driving cycles, which refer to the driving patterns and parameters such as velocity and acceleration changed by years. The charging infrastructure and battery pilot use have also been involved in the evaluation. Results show that the LCC of an EV is about 9% higher than that of an ICEV under the driving cycle in Beijing in 2020. At the same time, the life cycle GHG emissions of an EV are about 29% lower than those of an ICEV. If the lifetime mileage is not as long as expected, the gap of LCC would be larger and the gap of GHG emissions would be smaller. Recycling is very effective in reducing the GHG emissions but does not work for LCC reduction. Battery pilot use has large potentials on LCC reduction but it still needs time to realize. In this scenario without battery pilot use, the cost effectiveness of an EV is about 4 kg CO2eq/$.

Confronting, collaborating, withdrawing? A psychiatric evaluation of three strategies to promote political climate action

This qualitative study analyzes the lack of political action to address climate change using a psychiatric lens, and frames that ambivalence lies at the core of inaction. While most politicians understand that climate action is absolutely necessary, any significant action is stalled by a number of important barriers they have to overcome. Using clinical analogies from eating disorders and the scientific literature on motivational change, this paper analyzes three current strategies that push for political action. First, using force and emotions (like confronting activists) is equivalent to playing a power struggle, which risks increasing politicians' resistance to change. Second, collaborative discussions in multilateral conferences and debates risk feeding verbal manifestos without enacting behavioural change. Withdrawal from the manifestos of politicians is a third strategy to push for change discussed in this paper. However, even after bypassing manifestos, this strategy is unlikely to succeed because the benefits of greenhouse gas emissions, linked to our current social norms, seriously outweigh the benefits of climate action. Overall, all three methods present severe flaws and are not viable solutions to help politicians implement climate action. Other enhanced options are likely to be necessary.

The life cycle greenhouse gas emission benefits from alternative uses of biofuel coproducts

Coproducts from bioenergy processing have potential as alternative products in the market, thereby reducing greenhouse gas (GHG) emissions. Thus far, the environmental benefits from coproduct use have been overlooked in most studies because of the lack of knowledge on their effective use and the limited commercialization. The objective of this study is to investigate the energy and GHG emissions savings by using biofuel coproducts. The effects of coproduct use on the overall life cycle GHG emissions performance of biofuels were evaluated. Dry distiller grains in the wheat to ethanol pathway, and crude glycerine and canola meal from biodiesel, are assumed to replace animal feed, fossil fuel, fertilizer, synthetic glycerine. A system expansion approach was implemented to estimate GHG emissions savings. The results show that the overall life cycle GHG emissions from the wheat to ethanol pathway can be reduced by 2–34% when dry distiller grains displace fertilizer, fossil fuel, or animal feed. In the canola to biodiesel pathway, GHG emissions can be reduced by 5–26% and 8–41% when canola meal replaces animal feed and crude glycerine replaces synthetic glycerine. The study highlights the potential role of the coproducts from biofuel production in additional GHG emissions reduction over the life cycle.

Modeling the GHG emissions intensity of plug-in electric vehicles using short-term and long-term perspectives

Plug-in electric vehicles (PEVs) can contribute to deep greenhouse gas (GHG) reduction targets but their efficacy depends on the sources of electricity. PEV GHG intensity can vary over time (and regionally), making it unclear how policymakers should regulate PEVs in the short and long-term. To explore this uncertainty, we model the short-term (Study 1) and long-term (Study 2) well-to-wheels GHG intensity of PEVs in three regions with very different electricity grid profiles: the Canadian provinces of British Columbia, Alberta, and Ontario. Study 1 uses empirical data on vehicle preferences, driving patterns, and recharge access from a representative survey of new vehicle buyers in Canada (n = 1754) to construct a temporally-explicit model of PEV usage in 2015. Fleet-wide emissions intensity of PEVs varies substantially between regions, with the greatest reduction potential relative to conventional gasoline vehicles seen in British Columbia (78–98%), followed by Ontario (58–92%) and Alberta (34–41%). Study 2 simulates the potential long-term dynamics of technology, behavior, and emissions with the CIMS energy-economy model. With the emissions intensity of electricity decreasing by at least one-third by 2050 and vehicle energy efficiency improving over time, simulation results find that, compared to 2015, 2050 fleet average PEV emissions are 40–52% lower in British Columbia, 57–74% lower in Alberta, and 36–46% lower in Ontario. Overall, we find that PEVs offer substantial GHG emissions benefits compared to conventional vehicles in all scenarios explored. Policy makers seeking deep GHG cuts may want to support PEV adoption, even in jurisdictions that presently use relatively carbon-intensive electricity.

Evaluation of Greenhouse Gas Emission Benefits of Vehicle Speed Limiters on On-Road Heavy-Duty Line-Haul Vehicles

Vehicle speed limiters (VSLs) are one of the strategies for reducing greenhouse gas (GHG) emissions from heavy-duty vehicles; they work by limiting peak vehicle speed. In the Federal Phase 2 Rule—GHG Emissions and Fuel Efficiency Standards for Medium- and Heavy-duty Engines and Vehicles, the greenhouse gas emission model (GEM) includes emission reduction credits for vehicles equipped with tamper-proof VSLs set at 55 to 65 miles per hour (mph). In this study, on-road testing of three class 8 combination tractor-trailers was conducted at various cruising speeds between 45 and 78 mph under steady conditions to evaluate the emission impacts of VSLs on heavy-duty vehicles. The three tested trucks were equipped with model year (MY) 2007 and newer engines and low-rolling-resistance tires on both the tractors and trailers. One truck was tested with a combined test weight of 35,000 lb and each of the other two trucks was tested with a combined test weight of 76,000 lb. A portable emission measurement system (PEMS) was used to measure carbon dioxide (CO2) emissions, and results showed that distance-based CO2 emission rates were dependent on both vehicle speed and engine revolutions per minute (rpm). Compared to average CO2 emission rates of approximately 1524 grams per mile (g/mile) at 78 mph for these test trucks, average CO2 emission rates at 51 mph were ~ 36% lower (approximately 978 g/mile) and represented the minimum distance-based (i.e., in g/mile) CO2 emission rates within the speed range evaluated for the three test trucks. Specifically, when decreasing speeds from 78 to 55 mph, CO2 emissions were between 0.7 and 2.6% lower per mph reduced. The emission benefits of using VSLs estimated from data in this study agree with the emission credits in the federal GEM. In addition, the quadratic relationship between CO2 emissions and vehicle speed measured for the three test trucks was used to corroborate updates to CARB’s EMission FACtor (EMFAC) 2017 model that were based on dynamometer testing; the measured trends from this VSL study support the predictions in that model.

Valorization of an untapped resource: Energy and greenhouse gas emissions benefits of converting manure to biogas through anaerobic digestion

Livestock farming generates animal manure as a by-product. In comparison to in some countries, manure is hardly used for energy production in Switzerland. A growing awareness of renewable energy needs, resource depletion, and climate challenges make the huge untapped potential of livestock manure very attractive, particularly regarding biogas technology. Here, we assessed the energy and greenhouse gas (GHG) emissions benefits of using manure for biogas, considering its spatial distribution in Switzerland. First, laboratory measurements were conducted to compare the composition of fresh manure with values from literature. Then, detailed assessments of manure availability for biogas production were performed. Finally, the mitigation potential regarding GHG emissions was estimated for three scenarios. The new lab-scale values confirmed early storage as an important phase that is still not considered in practice. Under current farming practice, Swiss manure could produce 430 million m3 biogas or 15 PJ gross biogas yearly, mostly from cattle. However, only 6% of this manure is currently being used for anaerobic digestion. The manure is widely spread across the country in relatively small farms. Considering the spatial distribution of manure and Swiss agricultural structures, there is considerable potential for small-scale individual installations, with a peak of approximately 250 GJ gross biogas yearly, as well as for joint-farm installations. If the currently exploitable amount of manure were used for energy, the emission of 159 kt of CO2 equivalent could be prevented compared to emissions under current management practices. Thus, manure digestion could be promoted for its wide environmental and energetic benefits.

Greenhouse gas emission benefits of vehicle lightweighting: Monte Carlo probabalistic analysis of the multi material lightweight vehicle glider

Vehicle lightweighting reduces fuel cycle greenhouse gas (GHG) emissions but may increase vehicle cycle (production) GHG emissions because of the GHG intensity of lightweight material production. Life cycle GHG emissions are estimated and sensitivity and Monte Carlo analyses conducted to systematically examine the variables that affect the impact of lightweighting on life cycle GHG emissions. The study uses two real world gliders (vehicles without powertrain or battery) to provide a realistic basis for the analysis. The conventional and lightweight gliders are based on the Ford Fusion and Multi Material Lightweight Vehicle, respectively. These gliders were modelled with internal combustion engine vehicle (ICEV), hybrid electric vehicle (HEV), and battery electric vehicle (BEV) powertrains. The probability that using the lightweight glider in place of the conventional (steel-intensive) glider reduces life cycle GHG emissions are: ICEV, 100%; HEV, 100%, and BEV, 74%.The extent to which life cycle GHG emissions are reduced depends on the powertrain, which affects fuel cycle GHG emissions. Lightweighting an ICEV results in greater base case GHG emissions mitigation (10 t CO2eq.) than lightweighting a more efficient HEV (6 t CO2eq.). BEV lightweighting can result in higher or lower GHG mitigation than gasoline vehicles, depending largely on the source of electricity.

Examination of the optimal operation of building scale combined heat and power systems under disparate climate and GHG emissions rates

This work aims to elucidate notions concerning the ideal operation and greenhouse gas (GHG) emissions benefits of combined heat and power (CHP) systems by investigating how various metrics change as a function of the GHG emissions from the underlying electricity source, building use type and climate. Additionally, a new term entitled “CHP Attributable” reductions is introduced to quantify the benefits from the simultaneous use of thermal and electric energy, removing benefits achieved solely from fuel switching and generating electricity more efficiently.The GHG emission benefits from implementing internal combustion engine, microturbines, and phosphoric acid (PA) fuel cell based CHP systems were evaluated through an optimization approach considering energy demands of prototypical hospital, office, and residential buildings in varied climates. To explore the effect of electric GHG emissions rates, the ideal operation of the CHP systems was evaluated under three scenarios: “High” GHG emissions rates, “Low” GHG emissions rates, and “Current” GHG emissions rate for a specific location.The analysis finds that PA fuel cells achieve the highest GHG emission reductions in most cases considered, though there are exceptions. Common heuristics, such as electric load following and thermal load following, are the optimal operating strategy under specific conditions. The optimal CHP capacity and operating hours both vary as a function of building type, climate and GHG emissions rates from grid electricity. GHG emissions reductions can be as high as 49% considering a PA fuel cell for a prototypical hospital in Boulder, Colorado however, the “CHP attributable reductions are less than 10%.

Cost–benefit analysis of GHG emission reduction in waste to energy projects of China under clean development mechanism

Energy recovery is widely considered an important part of hierarchy of waste management. Previously, researchers have primarily focused on cost-effectiveness analysis of solid waste management, ignoring the global warming potential (GWP) impacts. By integrating greenhouse gas (GHG) emissions and the cost–benefit analysis, we analyzed the cost–benefit of GHG emissions for two waste to energy (WtE) methods: incineration with combined heat and power (ICHP) which produces electricity and heat, and landfill disposal with landfill gas utilization (LGU). We calculated both costs and benefits per ton certified GHG emission reductions (CER) for 20 clean development mechanism (CDM) projects with WtE technology in typical northern and southern cities in China. Furthermore, benefits were analyzed under two different scenarios: benefit only from recovery energy revenues; benefit from recovery energy revenues plus gate fee revenues. The results show that: (1) ICHP projects are beneficial from the GHG reduction standpoint; (2) The ratio of CER revenues to benefit is very high during 2008–2011. However, the decrease of CER price in CDM projects causes the disposal gate fee from local government to become more and more important for these two WtE technologies, especially for LGU. However, with or without the CDM, there is still a huge GHG reduction potential in solid waste management in China. Policies should be developed to facilitate and encourage WtE, and the selection of WtE method depends on geographical region and economics.

Greenhouse Gas Emission Benefits of Sodium Bisulfate used in Poultry Litter Treatment

This study evaluated the life cycle greenhouse gas emissions (in units of carbon dioxide-equivalent, CO2- equivalent) from the production and distribution of sodium bisulfate, used in poultry litter treatment to control ammonia levels. The study also evaluated the comparative life cycle greenhouse gas emissions and benefits from sodium bisulfate application in poultry houses in reducing ventilation energy requirements, both heating fuel and cooling electricity, from reduced ammonia levels. The method involved modeling the production and transportation of raw materials needed per ton (907 kg) of sodium bisulfate, modeling the final product sodium bisulfate, allocating emission results for co-product in the production process, and modeling the usage reduction in propane (for heating) and electricity (for ventilation) in poultry houses from the application of sodium bisulfate during an entire operating year (spring/summer and winter). This was applied to a poultry house that was 1,858 square meters and housed 25,000 birds for the 907 kg of sodium bisulfate required per year. The life cycle greenhouse gas emission was found to be about 318 kg of CO2-equivalent for the production and distribution of sodium bisulfate per 907 kg. The avoided life cycle greenhouse gas emission from the energy usage reductions in field studies conducted during winter in eastern and south-eastern U.S. kg regions was estimated to be approximately 735 kg of CO2-equivalent from the use of 907 of sodium bisulfate and approximately 1,410 kg during summer and spring. This equates to a CO2- equivalent savings of 0.0294 kg per bird in winter and 0.0564 kg per bird in summer and spring. The results show a significant environmental benefit in reducing greenhouse gas emissions and energy conservation from poultry farming with the use of sodium bisulfate.