Emission Reduction Rate Research Articles

Analysis of lifecycle CO2reduction performance for long-life apartment house

Long-life apartment houses are sustainable buildings that use fewer resources and can reduce CO2 emission over the course of their life cycle. However, there have been few quantitative evaluations of the CO2 emission reduction effect when the life of apartment houses is increased. In this study, the CO2 emission reduction rate over the life cycle of long-life apartment houses (Types II and III) was evaluated using high durability and maintenance technologies from general apartment houses (Type I) as reference data. CO2 emissions over the life of the apartment houses were evaluated by dividing the life cycle into construction, operation, maintenance/management, and dismantlement/disposal phase. To achieve this goal, the life of apartment houses was calculated using the life calculation technique, and the CO2 emission amount over a 100-year evaluation period was compared. The life of general apartment houses was set to about 40 years, while that of long-life apartment houses, due to the application of long-life construction technologies, was set to more than 100 years. CO2 emissions of long-life apartment houses over their life cycle tended to decrease compared with that of general apartment houses. In particular, the maximum CO2 emission reduction rates of long-life apartment houses were 36.18% and 33.04%, respectively. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 555–566, 2015

A comparative assessment of economic-incentive and command-and-control instruments for air pollution and CO2 control in China's iron and steel sector

China's iron and steel sector is faced with increasing pressure to control both local air pollutants and CO2 simultaneously. Additional policy instruments are needed to co-control these emissions in this sector. This study quantitatively evaluates and compares two categories of emission reduction instruments, namely the economic-incentive (EI) instrument of a carbon tax, and the command-and-control (CAC) instrument of mandatory application of end-of-pipe emission control measures for CO2, SO2 and NOx. The comparative evaluation tool is an integrated assessment model, which combines a top-down computable general equilibrium sub-model and a bottom-up technology-based sub-model through a soft-linkage. The simulation results indicate that the carbon tax can co-control multiple pollutants, but the emission reduction rates are limited under the tax rates examined in this study. In comparison, the CAC instruments are found to have excellent effects on controlling different pollutants separately, but not jointly. Such results indicate that no single EI or CAC instrument is overwhelmingly superior. The environmental and economic effectiveness of an instrument highly depends on its specific attributes, and cannot be predicted by the general policy category. These findings highlight the necessity of clearer identification of policy target priorities, and detail-oriented and integrated policy-making among different governmental departments.

A projection of energy consumption and carbon dioxide emissions in the electricity sector for Saudi Arabia: The case for carbon capture and storage and solar photovoltaics

The paper examined the case study of the Saudi electricity sector and provided projections for energy use and respective carbon dioxide (CO2) emissions for the period 2010–2025 with and without cleaner energy technologies. Based on two sets of 20 life cycle assessment studies for carbon capture and storage and solar photovoltaic technologies, CO2 emission reduction rates were used for projecting future CO2 emissions. Results showed enormous savings in CO2 emissions, for the most likely case, year 2025 reported savings that range from 136 up to 235 MtCO2. Including low growth and high growth cases, these savings could range from 115 up to 468 MtCO2 presenting such an unrivalled opportunity for Saudi Arabia. These projections were developed as a way of translating the inherent advantages that cleaner energy technologies could provide for CO2 emissions savings. It is hoped that the results of this paper would inform energy policymaking in Saudi Arabia.

LCCP Evaluation on Environmental Impact of Air-Conditioning Cold and Heat Source

Several indexes for evaluating the global warming impact, including GWP (global warming potential), TEWI (total equivalent warming impact) and LCCP (life cycle climate performance), are analyzed and investigated from the concept, contents, difference and correlation among them. LCCP is a rigorous method to calculate the cradle-to-grave warming impact of different refrigeration and air conditioning systems. The LCCP index was therein used to analyze overall greenhouse effect of three air conditioning cold and heat source plans for a public building. The results show that the total amount of equivalent CO2 emission from air conditioning heat and cold sources is up to 50,000 tons throughout the life cycle. Indirect global warming impact dominated the LCCP values of cold and heat source systems, which accounts for >96% of overall impact and caused by energy consumption both for producing refrigerant and operating refrigeration and air conditioning equipment. Therefore, increasing the energy efficiency of air conditioning and refrigeration equipment to reduce indirect global warming impact is the key to lowering A/C’ total impact on climate change. The LCCP of water source heat pump is always lower than that of conventional electric water chillers plus gas direct-fired unit, and its carbon emission reduction rates up to 32.4% as compared to the latter. So the overall impact from air conditioning cold and heat source could be effectively reduced through using renewable energy technology.

A Comparative Study of Free Formaldehyde Control Technology in Wood-Based Panels

Adopted the treatment methods of ultrasonic dispersion on nano-TiO2/Al2O3, of sustained-releasing ClO2 and of post-heating way. The results show that the reduction rate of formaldehyde emission treated by nano-TiO2/Al2O3 is 22.2%, the average reduction rate of particleboard free formaldehyde in nine days is 64.7%, and the post-heating- treatment can reduce the plywood formaldehyde by 34.5%.

고순도 수소함량에 따른 HCNG 연소특성 및 배출가스 영향 평가

This investigation decribes the effect of the combustion and emission characteristics of HCNG engine according to the high purity hydrogen contents. The HCNG fuel was made by the mixture with a high purity hydrogen () and a natural gas. The test vehicle was applied to the bi-fuel (Gasoline and CNG) system and this system was modified from the fuel supply and fuel tank. In addition, the three premixed HCNG fuels with mixed rate of 10, 20 and 30% of hydrogen were used to maintain the safety. In order to analyze the combustion characteristics of HCNG and CNG, the fuel was injected in the combustor with constant volume. The exhaust emission from light duty vehicle with bi-fuel system was analyzed by a chassis dynamometer and emission analyzer. From these results, the reduction rate of NOx emission increased in the HCNG fuel and emission amount of THC and CO shows a similar level with CNG fuel. This study can be utilized the basic data for the development of a new business plans related with HCNG engines.

Assessment of CO2 reduction of alkali-activated concrete

Although alkali-activated (AA) concrete is generally regarded as one of the most effective concrete technologies for reducing CO2 emissions, very few investigations have been carried out on the assessment of the CO2 reduction of such concrete. The present paper reports an evaluation procedure for the CO2 reduction of AA concrete. The studied system considers all of the steps from the cradle to pre-construction. CO2 reduction for secondary precast concrete products is also evaluated with reference to practical examples wherein ground granulated blast-furnace slag (GGBS) cement is replaced with AA GGBS binder. Comparisons of the performance efficiency indicators, binder and CO2 intensities, reveal that the contribution of the binder to the total CO2 emission is more significant in ordinary Portland cement (OPC)-based concrete than in AA concrete, whereas the contribution of aggregate transportation becomes more critical in AA concrete than in OPC-based concrete. The reduction rate of CO2 emission of AA concrete relative to OPC concrete commonly ranges between 55 and 75%. In addition, the CO2 reduction rate in secondary precast concrete products that use AA GGBS binder instead of GGBS cement can be evaluated as approximately 20% when the total aggregate-to-binder ratio ranges between 3.0 and 4.0. On the other hand, Ca(OH)2-based AA GGBS concrete shows a CO2 intensity that is approximately 2.4 times lower than that of OPC concrete. Overall, the slope of the increasing rate of the CO2 intensity against the binder intensity is lower in Ca(OH)2-based AA GGBS concrete than in OPC-based concrete.

National GHG emissions reduction pledges and 2°C: comparison of studies

This article provides further detail on expected global GHG emission levels in 2020, based on the Emissions Gap Report (United Nations Environment Programme, December 2010), assuming the emission reduction proposals in the Copenhagen Accord and Cancun Agreements are met. Large differences are found in the results of individual groups owing to uncertainties in current and projected emission estimates and in the interpretation of the reduction proposals. Regardless of these uncertainties, the pledges for 2020 are expected to deliver emission levels above those that are consistent with a 2°C limit. This emissions gap could be narrowed through implementing the more stringent conditional pledges, minimizing the use of ‘lenient’ credits from forests and surplus emission units, avoiding double-counting of offsets and implementing measures beyond current pledges. Conversely, emission reduction gains from countries moving from their low to high ambition pledges could be more than offset by the use of ‘lenient’ land use, land-use change and forestry (LULUCF) credits and surplus emissions units, if these were used to the maximum. Laying the groundwork for faster emission reduction rates after 2020 appears to be crucial in any case.

Technological feasibility and costs of achieving a 50 % reduction of global GHG emissions by 2050: mid- and long-term perspectives

In this article we examine the technological feasibility of the global target of reducing GHG emissions to 50 % of the 1990 level by the year 2050. We also perform a detailed analysis of the contribution of low-carbon technologies to GHG emission reduction over mid- and long-term timeframes, and evaluate the required technological cost. For the analysis we use AIM/Enduse[Global], a techno-economic model for climate change mitigation policy assessment. The results show that a 50 % GHG emission reduction target is technically achievable. Yet achieving the target will require substantial emission mitigation efforts. The GHG emission reduction rate from the reference scenario stands at 23 % in 2020 and 73 % in 2050. The marginal abatement cost to achieve these emission reductions reaches $150/tCO2-eq in 2020 and $600/tCO2-eq in 2050. Renewable energy, fuel switching, and efficiency improvement in power generation account for 45 % of the total GHG emission reduction in 2020. Non-energy sectors, namely, fugitive emission, waste management, agriculture, and F-gases, account for 25 % of the total GHG emission reduction in 2020. CCS, solar power generation, wind power generation, biomass power generation, and biofuel together account for 64 % of the total GHG emission reduction in 2050. Additional investment in GHG abatement technologies for achieving the target reaches US$ 6.0 trillion by 2020 and US$ 73 trillion by 2050. This corresponds to 0.7 and 1.8 % of the world GDP, respectively, in the same periods. Non-Annex I regions account for 55 % of the total additional investment by 2050. In a sectoral breakdown, the power generation and transport sectors account for 56 and 30 % of the total additional investment by 2050, respectively.

RCP2.6: exploring the possibility to keep global mean temperature increase below 2°C

The RCP2.6 emission and concentration pathway is representative of the literature on mitigation scenarios aiming to limit the increase of global mean temperature to 2°C. These scenarios form the low end of the scenario literature in terms of emissions and radiative forcing. They often show negative emissions from energy use in the second half of the 21st century. The RCP2.6 scenario is shown to be technically feasible in the IMAGE integrated assessment modeling framework from a medium emission baseline scenario, assuming full participation of all countries. Cumulative emissions of greenhouse gases from 2010 to 2100 need to be reduced by 70% compared to a baseline scenario, requiring substantial changes in energy use and emissions of non-CO2 gases. These measures (specifically the use of bio-energy and reforestation measures) also have clear consequences for global land use. Based on the RCP2.6 scenario, recommendations for further research on low emission scenarios have been formulated. These include the response of the climate system to a radiative forcing peak, the ability of society to achieve the required emission reduction rates given political and social inertia and the possibilities to further reduce emissions of non-CO2 gases.

Implications of Biodiesel-Induced Land-Use Changes for CO2 Emissions: Case Studies in Tropical America, Africa, and Southeast Asia

Biofuels are receiving growing negative attention. Direct and/or indirect land-use changes that result from their cultivation can cause emissions due to carbon losses in soils and biomass and could negate any eventual greenhouse gas (GHG) reduction benefit. This paper evaluates the implications of land-use change emission on the climate-change mitigation potential of different biofuel production systems in 12 case studies in six countries. We calculated carbon debts created by conversion of different land-use types, ranging from annual cropland to primary forest. We evaluated case studies using three different biofuel crops: oil palm, Jatropha, and soybean. The time needed for each biofuel production system to pay back its carbon debt was calculated based on a life-cycle assessment of the GHG reduction potentials of the system. Carbon debts range from 39 to 1743.7 Mg C0 2 ha -1. The oil palm case studies created the largest carbon debts (472.8-1743.7 t C0 2 ha -1) because most of the area expansion came at the expense of dense tropical forest. The highest debt was associated with plantation on peatland. For all cases evaluated, only soybean in GuarantA£ do Norte and Alta Floresta, Brazil needed less than one human generation (30 years) to repay the initial carbon debt. Highest repayment times were found for Jatropha (76-310 years) and oil palm (59-220 years) case studies. Oil palm established in peatlands had the greatest repayment times (206-220 years). High repayment times for Jatropha resulted from the combined effects of land-cover change and low CO 2 emission reduction rate. These outcomes raise serious questions about the sustainability of biofuel production. The carbon implications of conversion of (semi-)natural systems with medium to high biomass indicate that, in order to generate climate benefits, cultivation of biofuel feedstocks should be restricted to areas that already have low carbon content. © 2011 by the author(s).

Postponing emission reductions from 2020 to 2030 increases climate risks and long-term costs

Substantially postponing the emission reductions, compared to the ranges indicated in IPCC’s recent assessment for 2020 as required for meeting the longterm 2°C target, increases the risk of exceeding this target. The costs of a delay strategy are lower in the short term, but leads to higher costs in the longer term. The analysis shows if the emission reductions are postponed to 2030 it is not likely that higher emissions from the earlier years can be fully compensated in future decades in a so-called ‘delayed action scenario’. A full compensation would require emission reduction rates in the coming decades that are much higher than those found in the scenario literature. Without compensation, the risk of exceeding the global temperature rise target of 2°C will increase. This confirms that it is not only the reduction commitments for 2050 that determine the risk of exceeding the 2°C target, but also the path between now and 2050. To meet this 2°C target, more ambitious 2020 reduction targets are needed for the developed and developing countries than those that have been pledged so far.

STUDY ON ENERGY CONSERVATION EFFECTS OF HOUSING ELECTRICITY AND HEAT SOURCE EQUIPMENTS

This paper presents effects of housing electricity and heat source equipments. We studied about energy saving effects of 4 equipments, CO2 Heat Pump water heater (CO2-HP), Micro Gas Engine Co-Generation System (GE-μCGS), Polymer Electrolyte Fuel Cell Co-Generation System (PEFC-CGS), and Solid Oxide Fuel Cell Co-Generation System (SOFC-CGS). As the result, we have found that energy consumption and CO2 emission reduction rate is the highest in case of SOFC-CGS. Energy consumption is reduced by 17-20% using SOFC-CGS on Electric Power Load Tracking Operation, and 44-47% on Rated Operation. And CO2 emission is reduced by 5-20% on Electric Power Load Tracking Operation and 22-46% on Rated Operation.

Research on Reduction Rate of CO and Smoke Criterion Emission in Road Tunnel Ventilation

It is known that calculating the required amount of air is the rationale of the whole design of road tunnel ventilation and defining the reduction rate of CO and smoke criterion emission also generates a great effect on the long-term required amount of air. In terms of this, through listing and analyzing the components of vehicle pollutant discharge, emission standards of pollutants from cars in the European Union (EU), and discharge standards prescribed by PIARC, it is apparent that the emission standards of vehicle pollutants in China should follow that of the EU and should be divided into 4 stages. By analyzing the annual reduction coefficient values and the criterion emission reduction of CO and smoke, with consideration of the legal provisions in China for strict limitation of CO and smoke emission from vehicles, development of automotive technology and domestic and overseas environmental requirements, it is suggested that at present the 1-2% reduction rate set according to China's Specifications for Design of Ventilation and Lighting of Highway Tunnels is conservative. Therefore, a synthetic analysis should be made in actual tunnel ventilation design and confining the required amount of air within a rational scope to ascertain the tunnel operation safety.

Mercury in Arctic air: The long-term trend

The long-term (1974–2000) time trend of total filterable mercury (TFM) in the air in the Canadian Arctic is reported. The concentration of TFM had declined by (3.0 ± 0.8) % and (3.1 ± 0.9) % per year in the summer and fall, respectively, over the 27 years, which coincided with the calculated reduction rate of world-wide mercury emission (~ 3.3% per year) from human activities between 1983 and 1995. The time trend for winter and early spring was not statistically significant as the variability of TFM was very large, partly due to Arctic Mercury Depletion Events and partly due to Arctic haze.

C212 CO_2排出削減に有効な燃料電池コージェネレーションシステムの運用方法の検討(OS4 省エネルギー・小型分散電源・コジェネ技術)

As the effective operational methods of Fuel Cell Co-Generation System (FC-CGS) to curtail thermal power generation, Daily Start and Stop operation during the peak time of power demand is proposed. To evaluate effectiveness of those proposed operational methods, the model of daily load curve in each season is made. Then, CO_2 emission reduction rates, utilized capacity of FC-CGS, and improvement effect on daily load curve by adopting proposed operational methods to FC-CGS are assessed quantitatively. In the result, by adopting 9 to 22 operation to FC-CGS, the highest CO_2 emission reduction rates and improvement effect on daily load curve are obtained.

Reducing the risk of Atlantic thermohaline circulation collapse: sensitivity analysis of emissions corridors

We present emissions corridors for the 21 st century reducing the risk of collapse of the Atlantic thermohaline circulation (THC) while considering ex- pectations about the socio-economically acceptable pace of emissions reductions. Emissions corridors embrace the range of CO2 emissions that are compatible with normatively defined policy goals or 'guardrails'. They are calculated along the conceptual and methodological lines of the tolerable windows approach. We inves- tigate the sensitivity of the emissions corridors to key uncertain physical quantities (i.e. climate sensitivity and North Atlantic hydrological sensitivity, emissions of non- CO2 greenhouse gases and sulfate aerosols) as well as to the guardrails. Results indicate a large dependency of the width of the emissions corridor on climate and hydrological sensitivity: for low values of the climate and/or hydrological sensitivity, the corridor boundaries are far from being transgressed by business-as-usual emis- sions scenarios for the 21 st century. In contrast, for high values of both quantities already low non-intervention scenarios leave the corridor in the early decades of this century. The width of the CO2 emissions corridor is also affected by the emissions pathway of non-CO2 greenhouse gases and sulfate aerosols, but to a lesser extent. We further find that the choice of the policy goal strongly influences the shape of the emissions corridor. Pursuit of a more ambitious THC target, for instance, tightens the corridor considerably. More strict expectations concerning the socio-economically admissible pace of emissions reduction (expressed in terms of a maximum emissions reduction rate and a transition time towards a de-carbonizing economy) act in the

Reframing the climate change challenge in light of post-2000 emission trends

The 2007 Bali conference heard repeated calls for reductions in global greenhouse gas emissions of 50 per cent by 2050 to avoid exceeding the 2 degrees C threshold. While such endpoint targets dominate the policy agenda, they do not, in isolation, have a scientific basis and are likely to lead to dangerously misguided policies. To be scientifically credible, policy must be informed by an understanding of cumulative emissions and associated emission pathways. This analysis considers the implications of the 2 degrees C threshold and a range of post-peak emission reduction rates for global emission pathways and cumulative emission budgets. The paper examines whether empirical estimates of greenhouse gas emissions between 2000 and 2008, a period typically modelled within scenario studies, combined with short-term extrapolations of current emissions trends, significantly constrains the 2000-2100 emission pathways. The paper concludes that it is increasingly unlikely any global agreement will deliver the radical reversal in emission trends required for stabilization at 450 ppmv carbon dioxide equivalent (CO2e). Similarly, the current framing of climate change cannot be reconciled with the rates of mitigation necessary to stabilize at 550 ppmv CO2e and even an optimistic interpretation suggests stabilization much below 650 ppmv CO2e is improbable.

風力エネルギーを利用した有孔管方式によるサンドバイパスシステムの試設計

This paper introduces a new concept of coastal management system in order to protect beaches against erosion, by transporting sand materials from the near-by deposition area to the eroded beach using wind power energy without CO2 emission. A new Sand Bypass system using pipes with holes was developed and the field tests were conducted at the Northern Kanto area beach faced to the Pacific Ocean. Results of the tests showed that 100kW electric power supply was necessary in the system, and 300kW-typed offshore wind generator was recommended with the system. Estimated CO2 emission reduction rate was also discussed.

Observation of confinement degradation of energetic ions due to Alfvén eigenmodes in JT-60U weak shear plasmas

Confinement degradation of energetic ions due to Alfvén eigenmodes (AEs) has been investigated with negative ion based neutral beam injection at ∼370 keV into JT-60U weak shear plasmas. AEs with a rapid frequency sweeping and then saturation as the minimum value of the safety factor decreases have been observed. This frequency behaviour can be explained by the reversed-shear induced AE (RSAE) and the transition from RSAEs to the toroidicity-induced AEs (TAEs). The associated change in the charge exchange neutral particle flux suggests energetic ion transport due to these AEs. The total neutron emission reduction rate in the presence of these AEs is evaluated by calculation using the orbit following Monte-Carlo code taking into account the change in bulk plasmas. The evaluation indicates confinement of energetic ions is degraded due to these AEs. In particular, it is found that the confinement degradation of energetic ions is maximum during the transition from RSAEs to TAEs and the maximum reduction rate (ΔSn/Sn)MAX is estimated to be ∼45%.