Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

Primary energy and greenhouse gas implications of increasing biomass production through forest fertilization

As part of the Net Zero Carbon Water Cycle Program (NZCWCP) for Victoria state in Australia, we have sought to understand the potential to reduce household energy consumption and related Greenhouse Gas (GHG) emissions by influencing water use. Digital metering data disaggregated into 57 million discrete water usage events across 105 households at a resolution of 10 millilitres at 10 second intervals from June 2017 to March 2020, from a previous Yarra Valley Water (Melbourne, Australia) study, was analysed, together with the dynamic relationship between the multiple energy sources (natural gas, grid electricity, solar) used to heat water for showers in each hour of the day. Water-related energy (WRE) use, including water desalination and treatment, pumping, heating, wastewater collection and treatment, comprised 12.6% of Australia’s primary energy use in 2019. Water heating (by natural gas and electricity) comprised the largest component of WRE use for across residential, commercial, and industrial sectors. Furthermore, 69% of Victoria’s total water usage was by residential customers in 2020-2021. WRE GHG emissions were around 3.8% of Victoria’s total GHG emissions in 2018. Showers (~50% of residential WRE), system losses (~27% of residential WRE), and clothes washers (~9% of residential WRE) are the three largest components of WRE consumption. The main objective of this work is the creation of industry-accessible tools to improve knowledge and management options from the understanding of reductions in cost and GHG emissions from household showering WRE use. Potential options considered, to reduce water and energy use, as well as associated GHG emissions and customer utility bills, include (a) behaviour management such as water and energy pricing to change time of use behaviours, and (b) the adoption of efficient shower head improvements. Shower WRE and GHG emissions were found able to be strongly impacted by small changes in daily routines. GHG emissions reduction from showering could be reduced up to 20 (in summer) - 22% (in winter) by shifting demand time of showering or replacing residential showerheads. Extrapolated to state and Australian scales, reductions in water usage could be up to 14 GL (Victoria) and 144 GL (Australia), and reductions in GHG emissions 1,600 ktCO2eq (Victoria) and 17,300 ktCO2eq (Australia). It provides fundamental new information which could inform a suite of new management options to impact water-related energy from showers, and related GHG emissions and customer water and energy cost.

Mitigating Curtailment and Carbon Emissions through Load Migration between Data Centers

Energy-related activities are a major contributor of greenhouse gas (GHG) emissions. A growing body of knowledge clearly depicts the links between human activities and climate change. Over the last century the burning of fossil fuels such as coal and oil and other human activities has released carbon dioxide (CO2) emissions and other heat-trapping GHG emissions into the atmosphere and thus increased the concentration of atmospheric CO2 emissions. The main human activities that emit CO2 emissions are (1) the combustion of fossil fuels to generate electricity, accounting for about 37% of total U.S. CO2 emissions and 31% of total U.S. GHG emissions in 2013, (2) the combustion of fossil fuels such as gasoline and diesel to transport people and goods, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. GHG emissions in 2013, and (3) industrial processes such as the production and consumption of minerals and chemicals, accounting for about 15% of total U.S. CO2 emissions and 12% of total ...

Life-cycle energy use and greenhouse gas emissions of palm fatty acid distillate derived renewable diesel

Driven by the need to develop a wide variety of products with low environmental impact, biorefineries need to emerge as highly integrated facilities. This becomes effective when overall mass and energy integration through a centralised utility system design is undertaken. An approach combining process integration, energy and greenhouse gas (GHG) emission analyses is shown in this paper for Jatropha biorefinery design, primarily producing biodiesel using oil-based heterogeneously catalysed transesterification or green diesel using hydrotreatment. These processes are coupled with gasification of husk to produce syngas. Syngas is converted into end products, heat, power and methanol in the biodiesel case or hydrogen in the green diesel case. Anaerobic digestion of Jatropha by-products such as fruit shell, cake and/or glycerol has been considered to produce biogas for power generation. Combustion of fruit shell and cake is considered to provide heat. Heat recovery within biodiesel or green diesel production and the design of the utility (heat and power) system are also shown. The biorefinery systems wherein cake supplies heat for oil extraction and seed drying while fruit shells and glycerol provide power generation via anaerobic digestion into biogas achieve energy efficiency of 53 % in the biodiesel system and 57 % in the green diesel system. These values are based on high heating values (HHV) of Jatropha feedstocks, HHV of the corresponding products and excess power generated. Results showed that both systems exhibit an energy yield per unit of land of 83 GJ ha−1. The global warming potential from GHG emissions of the net energy produced (i.e. after covering energy requirements by the biorefinery systems) was 29 g CO2-eq MJ−1, before accounting credits from displacement of fossil-based energy by bioenergy exported from the biorefineries. Using a systematic integration approach for utilisation of whole Jatropha fruit, it is shown that global warming potential and fossil primary energy use can be reduced significantly if the integrated process schemes combined with optimised cultivation and process parameters are adopted in Jatropha-based biorefineries.

The economical and environmental performance of miscanthus and switchgrass production and supply chains in a European setting

Housing sector is one of the important greenhouse gases (GHGs) emissions which result global warming. In order to trace the energy use before and after primary energy factor of electricity adjustment, this paper analyzed the primary energy factor of electricity of the end user in Taiwan from 1982 to 2009 first. Then the compositions of the primary energy use and emissions in Taiwan housing sector were analyzed. The share of electricity use in total energy use of the housing sector was 64.2% at 2009 before primary energy factor of electricity adjustment. By using primary energy factor of the electricity demand of the year as adjustment, the share of the primary energy use of the electricity increased as 84.4%. Results of the research also showed that the annual log growth rate of the primary energy use induced by electricity use was 6.45% in Taiwan housing sector from 1982 to 2009. The total primary energy use of the housing sector in 2009 was about 5.7 times of which in 1982. Respect to emission factor of the housing sector, the research showed that the annual log growth rate of GHG Emissions of the housing sector was 7.81% from 1982 to 2009. The total GHG Emissions of the housing sector in 2009 was about 8.25 times of which in 1982. The shares of emissions from electricity in housing sector were 59.6% in 1982, and 86.6% in 2009. These results showed that the use of electricity was one of the major sources of the housing emissions growth this period.

Researchers at Argonne National Laboratory expanded the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model and incorporated the fuel economy and electricity use of alternative fuel/vehicle systems simulated by the Powertrain System Analysis Toolkit (PSAT) to conduct a well-to-wheels (WTW) analysis of energy use and greenhouse gas (GHG) emissions of plug-in hybrid electric vehicles (PHEVs). The WTW results were separately calculated for the blended charge-depleting (CD) and charge-sustaining (CS) modes of PHEV operation and then combined by using a weighting factor that represented the CD vehicle-miles-traveled (VMT) share. As indicated by PSAT simulations of the CD operation, grid electricity accounted for a share of the vehicle's total energy use, ranging from 6% for a PHEV 10 to 24% for a PHEV 40, based on CD VMT shares of 23% and 63%, respectively. In addition to the PHEV's fuel economy and type of on-board fuel, the marginal electricity generation mix used to charge the vehicle impacted the WTW results, especially GHG emissions. Three North American Electric Reliability Corporation regions (4, 6, and 13) were selected for this analysis, because they encompassed large metropolitan areas (Illinois, New York, and California, respectively) and provided a significant variation of marginal generation mixes. The WTW results were also reported for the U.S. generation mix and renewable electricity to examine cases of average and clean mixes, respectively. For an all-electric range (AER) between 10 mi and 40 mi, PHEVs that employed petroleum fuels (gasoline and diesel), a blend of 85% ethanol and 15% gasoline (E85), and hydrogen were shown to offer a 40-60%, 70-90%, and more than 90% reduction in petroleum energy use and a 30-60%, 40-80%, and 10-100% reduction in GHG emissions, respectively, relative to an internal combustion engine vehicle that used gasoline. The spread of WTW GHG emissions among the different fuel production technologies and grid generation mixes was wider than the spread of petroleum energy use, mainly due to the diverse fuel production technologies and feedstock sources for the fuels considered in this analysis. The PHEVs offered reductions in petroleum energy use as compared with regular hybrid electric vehicles (HEVs). More petroleum energy savings were realized as the AER increased, except when the marginal grid mix was dominated by oil-fired power generation. Similarly, more GHG emissions reductions were realized at higher AERs, except when the marginal grid generation mix was dominated by oil or coal. Electricity from renewable sources realized the largest reductions in petroleum energy use and GHG emissions for all PHEVs as the AER increased. The PHEVs that employ biomass-based fuels (e.g., biomass-E85 and -hydrogen) may not realize GHG emissions benefits over regular HEVs if the marginal generation mix is dominated by fossil sources. Uncertainties are associated with the adopted PHEV fuel consumption and marginal generation mix simulation results, which impact the WTW results and require further research. More disaggregate marginal generation data within control areas (where the actual dispatching occurs) and an improved dispatch modeling are needed to accurately assess the impact of PHEV electrification. The market penetration of the PHEVs, their total electric load, and their role as complements rather than replacements of regular HEVs are also uncertain. The effects of the number of daily charges, the time of charging, and the charging capacity have not been evaluated in this study. A more robust analysis of the VMT share of the CD operation is also needed.

Cropping system diversification can reduce the negative environmental impacts of agricultural production, including soil erosion and nutrient discharge. Less is known about how diversification affects energy use, climate change, and air quality, when considering farm operations and supply chain activities. We conducted a life cycle study using measurements from a nine-year Iowa field experiment to estimate fossil energy (FE) use, greenhouse gas (GHG) emissions, PM2.5-related emissions, human health impacts, and other agronomic and economic metrics of contrasting crop rotation systems and herbicide regimes. Rotation systems consisted of 2-year corn-soybean, 3-year corn-soybean-oat/clover, and 4-year corn-soybean-oat/alfalfa-alfalfa systems. Each was managed with conventional and low-herbicide treatments. FE consumption was 56% and 64% lower in the 3-year and 4-year rotations than in the 2-year rotation, and GHG emissions were 54% and 64% lower. Diversification reduced combined monetized damages from GHG and PM2.5-related emissions by 42% and 57%. Herbicide treatment had no significant impact on environmental outcomes, while corn and soybean yields and whole-rotation economic returns improved significantly under diversification. Results suggest that diversification via shifting from conventional corn-soybean rotations to longer rotations with small grain and forage crops substantially reduced FE use, GHG emissions, and air quality damages, without compromising economic or agronomic performance.

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.

A fuel cycle model—called the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model—has been developed to evaluate well-to-wheels (WTW) energy and emission impacts of motor vehicle technologies fueled with various transportation fuels. The GREET model contains various hydrogen (H2) production pathways for fuel cell vehicle (FCV) applications. In this study, the GREET model was expanded to include four nuclear H2 production pathways: (a) H2 production at refueling stations via electrolysis using light water reactor–generated electricity, (b) H2 production in central plants via thermochemical water cracking using heat from a high-temperature gas-cooled reactor (HTGR), (c) H2 production in central plants via high-temperature electrolysis using HTGR-generated electricity and steam, and (d) H2 production at refueling stations via electrolysis using HTGR-generated electricity. The WTW analyses of these four options include these stages: uranium ore mining and milling, uranium yellowcake transportation, uranium conversion, uranium enrichment, uranium fuel fabrication, uranium fuel transportation, electricity or H2 production in nuclear power plants, H2 transportation, H2 compression, and H2 FCV operation. Our well-to-pump results show that significant reductions in fossil energy use and greenhouse gas (GHG) emissions are achieved by nuclear-based H2 compared to natural gas–based H2 production via steam methane reforming for a unit of H2 delivered at refueling stations. When H2 is applied to FCVs, the WTW results also show large benefits in reducing fossil energy use and GHG emissions.

The pyrolysis of biomass can help produce liquid transportation fuels with properties similar to those of petroleum gasoline and diesel fuel. Argonne National Laboratory conducted a life-cycle (i.e., well-to-wheels [WTW]) analysis of various pyrolysis pathways by expanding and employing the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The WTW energy use and greenhouse gas (GHG) emissions from the pyrolysis pathways were compared with those from the baseline petroleum gasoline and diesel pathways. Various pyrolysis pathway scenarios with a wide variety of possible hydrogen sources, liquid fuel yields, and co-product application and treatment methods were considered. At one extreme, when hydrogen is produced from natural gas and when bio-char is used for process energy needs, the pyrolysis-based liquid fuel yield is high (32% of the dry mass of biomass input). The reductions in WTW fossil energy use and GHG emissions relative to those that occur when baseline petroleum fuels are used, however, is modest, at 50% and 51%, respectively, on a per unit of fuel energy basis. At the other extreme, when hydrogen is produced internally via reforming of pyrolysis oil and when bio-char is sequestered in soil applications, the pyrolysis-based liquid fuel yield is low (15% of the dry mass of biomass input), but the reductions in WTW fossil energy use and GHG emissions are large, at 79% and 96%, respectively, relative to those that occur when baseline petroleum fuels are used. The petroleum energy use in all scenarios was restricted to biomass collection and transportation activities, which resulted in a reduction in WTW petroleum energy use of 92-95% relative to that found when baseline petroleum fuels are used. Internal hydrogen production (i.e., via reforming of pyrolysis oil) significantly reduces fossil fuel use and GHG emissions because the hydrogen from fuel gas or pyrolysis oil (renewable sources) displaces that from fossil fuel natural gas and the amount of fossil natural gas used for hydrogen production is reduced; however, internal hydrogen production also reduces the potential petroleum energy savings (per unit of biomass input basis) because the fuel yield declines dramatically. Typically, a process that has a greater liquid fuel yield results in larger petroleum savings per unit of biomass input but a smaller reduction in life-cycle GHG emissions. Sequestration of the large amount of bio-char co-product (e.g., in soil applications) provides a significant carbon dioxide credit, while electricity generation from bio-char combustion provides a large energy credit. The WTW energy and GHG emissions benefits observed when a pyrolysis oil refinery was integrated with a pyrolysis reactor were small when compared with those that occur when pyrolysis oil is distributed to a distant refinery, since the activities associated with transporting the oil between the pyrolysis reactors and refineries have a smaller energy and emissions footprint than do other activities in the pyrolysis pathway.

Effect of different frame materials on the primary energy use of a multi storey residential building in a life cycle perspective

Throughout the past two decades, numerous studies characterized the greenhouse gas (GHG) emissions and net energy balance of corn ethanol production in the USA. A wide range of reported values resulted from differences in the vintage of the data used to evaluate the ethanol conversion technology and the agricultural practices of corn production, which evolved substantially during the rapid growth phase of the industry. Methodological differences in life cycle assessments also caused the reported values to vary widely. With corn dry mills growing from 30% of total installed ethanol production capacity in 1990 to 80–90% from 2006 to 2011, we document the evolution of this industry using vintage‐specific data to analyze selected energy and environmental metrics, including GHG emissions, fossil energy use, direct land use, and GHG emissions reduction per hectare of land harvested for ethanol production. Our estimates indicate that production and use of corn ethanol emitted 44% fewer GHG emissions, consumed 54% less fossil energy and required 44% less land in 2010 compared to 1990 (on a life cycle basis). Our review and analysis point to strategies for reducing the carbon footprint of the corn dry mill industry by building on the progress already achieved. Using biomass (e.g. residues from corn production) for process heat or combined heat and power is one such strategy. Additional environmental benefits are projected from the adoption of integrated gasification combined cycle technology (using corn residues), which leads to energy‐self‐sufficient mills or net electricity producers depending on the power system configuration. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd