A life cycle energy use and greenhouse gas emissions analysis of the corn stover feedstock supply system for cellulosic biorefineries

Impacts of pre-treatment technologies and co-products on greenhouse gas emissions and energy use of lignocellulosic ethanol production

In this paper, a comprehensive study on corn-based ethanol in a Canadian context is conducted, which uses the most reliable and up to date data, considers realistic assumptions, and applies sound methodology to provide a basis for developing future scenarios for corn-based ethanol and compared the results with the conventional fuel, such as gasoline. It is estimated that the net energy value (NEV), defined as the energy content of a liter of ethanol minus the total energy use to produce a liter of ethanol, is 9.6 MJ L−1 (LHV), when co-products energy credits are not considered. In addition, a comparison of life cycle energy use for corn-based ethanol and gasoline reveals that the life cycle energy use to produce a liter of ethanol is considerably less than the life cycle energy use to produce a liter of gasoline. Furthermore, a comparison of life cycle greenhouse gas (GHG) emissions for corn-based ethanol and gasoline reveals that the life cycle GHG emissions released per liter of ethanol produced is an order of magnitude lesser than the life cycle GHG emissions released per liter of gasoline produced, when GHG emissions displaced by ethanol co-products are considered in the estimation. Finally, a comparison of our results in terms of net fossil fuel input, net fossil fuel ratio and GHG emissions is carried out with the results obtained from the ERG biofuel analysis meta-model (EBAMM) to reflect both Canadian and US perspectives. Copyright © 2010 John Wiley & Sons, Ltd.

A feasibility study of microgrids for reducing energy use and GHG emissions in an industrial application

This paper quantifies life cycle energy use and greenhouse gas (GHG) emissions associated with water resource recovery facilities (WRRFs) in India versus water quality improvements achieved from infrastructure investments. A first such analysis is conducted using operating data for a WRRF, which employs upflow anaerobic sludge blanket (UASB) reactors and oxidation. On-site operations energy use, process GHG emissions, and embodied energy in infrastructure were quantified. The analysis showed energy use and GHG emissions of 0.2 watt-hours (Wh) and 0.3 gram carbon dioxide (CO2) equivalents per liter (gCO2e/L) wastewater treated, and 1.3 Wh and 2.1 gCO2e/gBOD removed, achieving 81% biochemical oxygen demand (BOD) and 999% fecal coliform removal annually. Process emissions of WRRFs contributed 44% of life cycle GHG emissions, similar in magnitude to those from electricity (46%), whereas infrastructure contributed 10%. Average WRRF-associated GHG emissions (0.9gCO2e/L) were lower than those expected if untreated wastewater was released to the river. Investments made by WRRFs in developing world cities improve water quality and may mitigate overall GHG emissions.

Optimization of a residential solar combisystem for minimum life cycle cost, energy use and exergy destroyed

Life cycle energy and greenhouse gas assessment of the co-production of biosolids and biochar for land application

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

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.

Uncertainties in corn stover feedstock supply logistics cost and life-cycle greenhouse gas emissions for butanol production

Life cycle energy use and GHG emission assessment of coal-based SNG and power cogeneration technology in China

Realizing low life cycle energy use and GHG emissions in coal based polygeneration with CO2 capture

Replacing conventional materials (steel and iron) with lighter alternatives (e.g., aluminum, magnesium, and composites) decreases energy consumption and greenhouse gas (GHG) emissions during vehicle use but may increase energy consumption and GHG emissions during vehicle production. There have been many life cycle assessment (LCA) studies on the benefits of vehicle lightweighting, but the wide variety of assumptions used makes it difficult to compare results from the studies. To clarify the benefits of vehicle lightweighting we have reviewed the available literature (43 studies). The GHG emissions and primary energy results from 33 studies that passed a screening process were harmonized using a common set of assumptions (lifetime distance traveled, fuel-mass coefficient, secondary weight reduction factor, fuel consumption allocation, recycling rate, and energy intensity of materials). After harmonization, all studies indicate that using aluminum, glass-fiber reinforced plastic, and high strength steel to replace conventional steel decreases the vehicle life cycle energy use and GHG emissions. Given the flexibility in options implied by the variety of materials available and consensus that these materials have substantial energy and emissions benefits, it seems likely that lightweighting will be used increasingly to improve fuel economy and reduce life cycle GHG emissions from vehicles.

This paper examines the effectiveness of several important enterprise strategies for reducing the life-cycle energy use and greenhouse gas (GHG) emissions of office computers. A modeling framework is presented, which quantifies the annual primary energy use and GHG emissions necessary to maintain and operate an enterprise personal computer (PC) stock. The case of a California-based enterprise with 5,000 desktop PCs is considered as a baseline scenario. The model is applied to estimate technically-achievable reductions in life-cycle energy use and GHG emissions associated with six common enterprise PC management strategies, as compared to the baseline scenario. The total technical potential for primary energy savings is estimated at roughly 60%; the total technical potential for GHG savings is estimated at roughly 35%.

In this study the life cycle emissions and energy use are estimated for two types of energy technologies. The first technology evaluated is the sulfur lamp, a high-efficiency lighting system under development by the US Department of Energy (DOE) and Fusion Lighting, the inventor of the technology. The sulfur lamp is compared with conventional metal halide high-intensity discharge lighting systems. The second technology comparison is between standard-efficiency and high-efficiency gas and electric water heaters. In both cases the life cycle energy use and emissions are presented for the production of an equivalent level of service by each of the technologies. For both analyses, the energy use and emissions from the operation of the equipment are found to dominate the life cycle profile. The life cycle emissions for the water heating systems are much more complicated. The four systems compared include standard- and high-efficiency gas water heaters, standard electric resistance water heaters, and heat pump water heaters.

In order to achieve sustainable development in agriculture, it is necessary to quantify and compare the energy, economic, and environmental aspects of products. This paper studied the energy, economic, and greenhouse gas (GHG) emission patterns in broiler chicken farms in the Alborz province of Iran. We studied the effect of the broiler farm size as different production systems on the energy, economic, and environmental indices. Energy use efficiency (EUE) and benefit-cost ratio (BCR) were 0.16 and 1.11, respectively. Diesel fuel and feed contributed the most in total energy inputs, while feed and chicks were the most important inputs in economic analysis. GHG emission calculations showed that production of 1000 birds produces 19.13t CO2-eq and feed had the highest share in total GHG emission. Total GHG emissions based on different functional units were 8.5t CO2-eq per t of carcass and 6.83kg CO2-eq per kg live weight. Results of farm size effect on EUE revealed that large farms had better energy management. For BCR, there was no significant difference between farms. Lower total GHG emissions were reported for large farms, caused by better management of inputs and fewer bird losses. Large farms with more investment had more efficient equipment, resulting in a decrease of the input consumption. In view of our study, it is recommended to support the small-scale broiler industry by providing subsidies to promote the use of high-efficiency equipment. To decrease the amount of energy usage and GHG emissions, replacing heaters (which use diesel fuel) with natural gas heaters can be considered. In addition to the above recommendations, the use of energy saving light bulbs may reduce broiler farm electricity consumption.