An assessment of greenhouse gas emissions and material flows caused by the Finnish economy using the ENVIMAT model

Aluminum production is a major energy consumer and important source of greenhouse gas (GHG) emissions globally. Estimation of the energy consumption and GHG emissions caused by aluminum production in China has attracted widespread attention because China produces more than half of the global aluminum. This paper conducted life cycle (LC) energy consumption and GHG emissions analysis of primary and recycled aluminum in China for the year 2020, considering the provincial differences on both the scale of self-generated electricity consumed in primary aluminum production and the generation source of grid electricity. Potentials for energy saving and GHG emissions reductions were also investigated. The results indicate that there are 157,207 MJ of primary fossil energy (PE) consumption and 15,947 kg CO2-eq of GHG emissions per ton of primary aluminum ingot production in China, with the LC GHG emissions as high as 1.5–3.5 times that of developed economies. The LC PE consumption and GHG emissions of recycled aluminum are very low, only 7.5% and 5.3% that of primary aluminum, respectively. Provincial-level results indicate that the LC PE and GHG emissions intensities of primary aluminum in the main production areas are generally higher while those of recycled aluminum are lower in the main production areas. LC PE consumption and GHG emissions can be significantly reduced by decreasing electricity consumption, self-generated electricity management, low-carbon grid electricity development, and industrial relocation. Based on this study, policy suggestions for China’s aluminum industry are proposed. Recycled aluminum industry development, restriction of self-generated electricity, low-carbon electricity utilization, and industrial relocation should be promoted as they are highly helpful for reducing the LC PE consumption and GHG emissions of the aluminum industry. In addition, it is recommended that the central government considers the differences among provinces when designing and implementing policies.

Life cycle assessment of primary energy demand and greenhouse gas (GHG) emissions of four propylene production pathways in China

The European Commission has published a framework on the environmental sustainability of buildings, called Level(s), a set of indicators addressing the resource efficiency and environmental impact of buildings. This framework is now a key element of European initiatives to develop a circular economy and aims to address whole life cycle greenhouse gas (GHG) emissions and to drive a renovation wave for existing buildings. Analysis of the whole life cycle environmental impact of buildings, with an emphasis on GHG emissions, is also the focus of initiatives in several EU Member States. To support users, Level(s) was accompanied by a list of Life Cycle Assessment (LCA) software tools and databases for calculating such indicators. A need was identified for practical, user-orientated information about the scope, consistency, cost, and accessibility of LCA software tools and databases. Therefore, a list of LCA tools and databases used in Europe for the assessment of the whole life cycle environmental impacts of buildings was compiled in 2017–2020 and their characteristics analysed based on a set of criteria. This paper describes the policy context of Level(s) and discusses criteria that can be used for the characterisation of LCA software tools and databases from the list compiled for Level(s). The methods included a literature review, surveys/interviews, and the co-creation of criteria for the categorization of tools and databases. The results are criteria including construction-specificity, system boundaries & scope, indicators, modelling granularity, methodological adherence to Level(s) and EN standards, data quality, transparency and verification, accessibility, data exchange and interoperability, cost, training and support, as well as additional information. By providing greater visibility regarding the features of tools and databases, this paper contributes to the mainstream use of Level(s) and also to the implementation of key EU policy initiatives aimed at enhancing the environmental sustainability of the built environment, such as the EU Renovation Wave, the New European Bauhaus, and the EU taxonomy for sustainable activities.

BackgroundThe availability of feedstock options is a key to meeting the volumetric requirement of 136.3 billion liters of renewable fuels per year beginning in 2022, as required in the US 2007 Energy Independence and Security Act. Life-cycle greenhouse gas (GHG) emissions of sorghum-based ethanol need to be assessed for sorghum to play a role in meeting that requirement.ResultsMultiple sorghum-based ethanol production pathways show diverse well-to-wheels (WTW) energy use and GHG emissions due to differences in energy use and fertilizer use intensity associated with sorghum growth and differences in the ethanol conversion processes. All sorghum-based ethanol pathways can achieve significant fossil energy savings. Relative to GHG emissions from conventional gasoline, grain sorghum-based ethanol can reduce WTW GHG emissions by 35% or 23%, respectively, when wet or dried distillers grains with solubles (DGS) is the co-product and fossil natural gas (FNG) is consumed as the process fuel. The reduction increased to 56% or 55%, respectively, for wet or dried DGS co-production when renewable natural gas (RNG) from anaerobic digestion of animal waste is used as the process fuel. These results do not include land-use change (LUC) GHG emissions, which we take as negligible. If LUC GHG emissions for grain sorghum ethanol as estimated by the US Environmental Protection Agency (EPA) are included (26 g CO2e/MJ), these reductions when wet DGS is co-produced decrease to 7% or 29% when FNG or RNG is used as the process fuel. Sweet sorghum-based ethanol can reduce GHG emissions by 71% or 72% without or with use of co-produced vinasse as farm fertilizer, respectively, in ethanol plants using only sugar juice to produce ethanol. If both sugar and cellulosic bagasse were used in the future for ethanol production, an ethanol plant with a combined heat and power (CHP) system that supplies all process energy can achieve a GHG emission reduction of 70% or 72%, respectively, without or with vinasse fertigation. Forage sorghum-based ethanol can achieve a 49% WTW GHG emission reduction when ethanol plants meet process energy demands with CHP. In the case of forage sorghum and an integrated sweet sorghum pathway, the use of a portion of feedstock to fuel CHP systems significantly reduces fossil fuel consumption and GHG emissions.ConclusionsThis study provides new insight into life-cycle energy use and GHG emissions of multiple sorghum-based ethanol production pathways in the US. Our results show that adding sorghum feedstocks to the existing options for ethanol production could help in meeting the requirements for volumes of renewable, advanced and cellulosic bioethanol production in the US required by the EPA’s Renewable Fuel Standard program.

Impacts of alternative fuel combustion in cement manufacturing: Life cycle greenhouse gas, biogenic carbon, and criteria air contaminant emissions

Introducing demand to supply ratio as a new metric for understanding life cycle greenhouse gas (GHG) emissions from rainwater harvesting systems

A probabilistic fleet analysis for energy consumption, life cycle cost and greenhouse gas emissions modelling of bus technologies

Life cycle greenhouse gas (GHG) emissions from the production of nuclear power (in g CO2e/kWh) are uncertain due partly to a paucity of data on emissions from individual phases of the nuclear fuel cycle. Here, we present the first comprehensive life cycle assessment of GHG emissions produced from the mining and milling of uranium in Canada. The study includes data from 2006-2013 for two uranium mine-mill operations in northern Saskatchewan (SK) and data from 1995-2010 for a third SK mine-mill operation. The mine-mill operations were determined to have GHG emissions intensities of 81, 64, and 34 kg CO2e/kg U3O8 at average ore grades of 0.74%, 1.54%, and 4.53% U3O8, respectively. The production-weighted average GHG emission intensity is 42 kg CO2e/kg U3O8 at an average ore grade of 3.81% U3O8. The production-weighted average GHG emission intensity drops to 24 kg CO2e/kg U3O8 when the local hydroelectric GHG emission factor (7.2 g CO2e/kWh) is substituted for the SK grid-average electricity GHG emission factor (768 g CO2e/kWh). This results in Canadian uranium mining-milling contributing only 1.1 g CO2e/kWh to total life cycle GHG emissions from the nuclear fuel cycle (0.7 g CO2e/kWh using the local hydroelectric emission factor).

Plug-in hybrid electric vehicle (PHEV) technology has the potential to reduce operating cost, greenhouse gas (GHG) emissions, and petroleum consumption in the transportation sector. However, the net effects of PHEVs depend critically on vehicle design, battery technology, and charging frequency. To examine these implications, we develop an optimization model integrating vehicle physics simulation, battery degradation data, and U.S. driving data. The model identifies optimal vehicle designs and allocation of vehicles to drivers for minimum net life cycle cost, GHG emissions, and petroleum consumption under a range of scenarios. We compare conventional and hybrid electric vehicles (HEVs) to PHEVs with equivalent size and performance (similar to a Toyota Prius) under urban driving conditions. We find that while PHEVs with large battery packs minimize petroleum consumption, a mix of PHEVs with packs sized for ∼25–50 miles of electric travel under the average U.S. grid mix (or ∼35–60 miles under decarbonized grid scenarios) produces the greatest reduction in life cycle GHG emissions. Life cycle cost and GHG emissions are minimized using high battery swing and replacing batteries as needed, rather than designing underutilized capacity into the vehicle with corresponding production, weight, and cost implications. At 2008 average U.S. energy prices, Li-ion battery pack costs must fall below $590/kW h at a 5% discount rate or below $410/kW h at a 10% rate for PHEVs to be cost competitive with HEVs. Carbon allowance prices offer little leverage for improving cost competitiveness of PHEVs. PHEV life cycle costs must fall to within a few percent of HEVs in order to offer a cost-effective approach to GHG reduction.

This study assessed the techno-economic performance and life cycle greenhouse gas (GHG) emissions for various liquefied natural gas (LNG) supply chains in China in order to find the most efficient way to supply and use LNG. This study improves current literature by adding supply chain optimization options (cold energy recovery and hydrogen production) and by analyzing the entire supply chain of four different LNG end-users (power generation, industrial heating, residential heating, and truck usage). This resulted in 33 LNG pathways for which the energy efficiency, life cycle GHG emissions, and life cycle costs were determined by process-based material and energy flow analysis, life cycle assessment, and production cost calculation, respectively. The LNG and hydrogen supply chains were compared with a reference chain (coal or diesel) to determine avoided GHG emissions and GHG avoidance costs. Results show that NG with full cryogenic carbon dioxide capture (FCCC) is most beneficial pathway for both avoided GHG emissions and GHG avoidance costs (70.5–112.4 g CO2-e/MJLNG and 66.0–95.9 $/t CO2-e). The best case was obtained when NG with FCCC replaces coal-fired power plants. Results also indicate that hydrogen pathways requires maturation of new technology options and significant capital cost reductions to become attractive.

Biomaterials and raw earth have demonstrated a promising potential for improving various thermal properties of plastering mortars used in buildings. The objective of this research was the evaluation of the thermal-energy performances and life cycle greenhouse gas (GHG) emissions of different mixtures of engineered, bio-based earth mortars composed of bamboo particles, earth, and different cementitious materials. Four mixtures were assessed: mortars without bamboo particles (matrix), and mortars containing 3%, 6%, or 9% of bamboo particles by volume. The bulk density and thermal conductivity values obtained for the matrix and mortars with the highest percentage of bamboo particles (9%) were 1704.13 and 1471.80 kg/m3, and 0.62 and 0.43 W/M·K, respectively. Based on experimental results, thermal-energy simulations were carried out using a social housing project as a case study. The simulations evaluated different climate conditions and applied life cycle GHG emissions assessment methodology. Compared with typical cement and lime plastering mortars, the proposed bio-based earth mortars presented a superior thermal-energy performance and lower GHG emissions, particularly the 9% bamboo particles mixture. GHG emissions reached a maximum decrease of 28%. The main scientific contribution of this research is the presentation of an engineered, bio-based earth mortar that can be manufactured using local raw materials available in most developing countries with significant housing demands. The method used, based on experimental research, thermal-energy analysis, and life cycle GHG emissions, may be used for evaluating other innovative materials. It was verified that even with thin plastering in buildings, it is possible to achieve energy efficiency gains and to reduce GHG emissions.

Life cycle greenhouse gas emissions and freshwater consumption of liquefied Marcellus shale gas used for international power generation

Life cycle assessment of greenhouse gas emissions for various feedstocks-based biochars as soil amendment

The literature analyzing the fuel saving, life cycle greenhouse gas (GHG) emission, and ownership cost impacts of lightweighting vehicles with different powertrains is reviewed. Vehicles with lower powertrain efficiencies have higher fuel consumption. Thus, fuel savings from lightweighting internal combustion engine vehicles can be higher than those of hybrid electric and battery electric vehicles. However, the impact of fuel savings on life cycle costs and GHG emissions depends on fuel prices, fuel carbon intensities and fuel storage requirements. Battery electric vehicle fuel savings enable reduction of battery size without sacrificing driving range. This reduces the battery production cost and mass, the latter results in further fuel savings. The carbon intensity of electricity varies widely and is a major source of uncertainty when evaluating the benefits of fuel savings. Hybrid electric vehicles use gasoline more efficiently than internal combustion engine vehicles and do not require large plug-in batteries. Therefore, the benefits of lightweighting depend on the vehicle powertrain. We discuss the value proposition of the use of lightweight materials and alternative powertrains. Future assessments of the benefits of vehicle lightweighting should capture the unique characteristics of emerging vehicle powertrains.

Assessment of greenhouse gas emissions of ventilated timber wall constructions based on parametric LCA