Energy Allocation Approach Research Articles

Bioenergy with carbon capture and storage (BECCS) potential in jet fuel production from forestry residues: A combined Techno-Economic and Life Cycle Assessment approach

In this study, the economic and environmental feasibility of a process configuration based on the Bioenergy and Carbon Capture and Storage (BECCS) concept is assessed. The research analyses the production of jet fuel from forestry residues-derived syngas via the Fischer-Tropsch (FT) technology. Further, the CO2 removed in the syngas cleaning section is not released to the environment, instead it is permanently sequestrated. The produced Sustainable Aviation Fuel (SAF) has the potential to achieve negative emissions. The present research is a one-of-a-kind study for the jet fuel production within the BECCS concept. The process has been modelled within the Aspen Plus and Matlab software to obtain detailed and realistic mass and energy balances. Based on these balances, the technical, economic and environmental parameters have been calculated. Based on a plant that treats 20 dry-t/h of forest residues, 1.91 t/h of jet fuel are produced, while 11.26 t/h of CO2 are permanently stored. The inclusion of the CCS chain in the biorefinery increase the minimum jet fuel selling price from 3.03 £/kg to 3.27 £/kg. The LCA results for global warming show a favourable reduction in the BECCS case, in which negative emissions of −121.83 gCO2eq/MJ of jet fuel are achieved, while without CCS case exhibits GHG emissions equal to 15.51 gCO2eq/MJ; in both cases, the multi-functionality is faced with an energy allocation approach. It is, then, evident the significant environmental advantages of the BECCS process configuration. Nevertheless, financial feasibility can only be attained through the implementation of existing policy schemes and the formulation of new strategies that would reward negative emissions. The application of the UK’s policy “Renewable Transport Fuel Obligation” and a hypothetical scheme that rewards negative CO2 emissions, breaks-even the Minimum Jet fuel Selling Price (MJSP) at 1.49 £/kg for a certificate and carbon price of 0.20 £/certificate and 246.64 £/tonne of CO2.

The Effect of Microplastics on the Bioenergetics of the Mussel Mytilus coruscus Assessed by Cellular Energy Allocation Approach

Marine microplastics pollution is a major environmental concern in marine ecosystems worldwide, yet the biological impacts of microplastics on the coastal biota are not yet fully understood. We investigated the impact of suspended microplastics on the energy budget of the mussels Mytilus coruscus using the Cellular Energy Allocation (CEA) approach. The mussels were exposed to control conditions (no microplastics) or to one of the three concentrations of 2 μm polystyrene microspheres (10, 104, and 106 particles/L) for 14 days, followed by 7 days of recovery. Exposure to high concentrations of microplastics (104 or 106 particles/L) increased cellular energy demand (measured as the activity of the mitochondrial electron transport system, ETS) and depleted cellular energy stores (carbohydrates, lipids, and proteins) in the mussels whereas exposure to 10 particles/L had no effect. Carbohydrate levels decreased already after 7 days of microplastics exposure and were restored after 7 days of recovery. In contrast, the tissue levels of lipids and proteins declined more slowly (after 14 days of exposure) and did not fully recover after 7 days following the removal of microplastics. Therefore, the total energy content and the CEA declined after 7–14 days of exposure to high microplastics concentrations, and remained suppressed during 7 days of subsequent recovery. These findings demonstrate a negative impact of microplastics on energy metabolism at the cellular level that cannot be restored during a short time recovery. Given a close link of CEA with the organismal energy balance, suppression of CEA by microplastics exposure suggests that bioenergetics disturbances might lead to decreases in growth and productivity of mussels’ populations in environments with heavy microplastics loads.

Throughput-Conscious Energy Allocation and Reliability-Aware Task Assignment for Renewable Powered In-Situ Server Systems

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In-situ</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">InS</i> ) server systems are typically deployed in special environments to handle <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">InS</i> workloads which are generated from environmentally sensitive areas or remote places lacking modern power supply infrastructure. This special operating environment of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">InS</i> servers urges such systems to be powered by renewable energy. In addition, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">InS</i> systems are vulnerable to soft errors due to the harsh environments they deploy. This article tackles the problem of allocating harvested energy to renewable powered servers and assigning the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">InS</i> workloads to these servers for optimizing throughput of both the overall system and individual servers under energy and reliability constraints. We perform the energy allocation based on system state. In particular, for systems in low energy state, we propose a game theoretic approach that models the energy allocation as a cooperative game among multiple servers and derives a Nash bargaining solution. To meet the reliability constraint, we analyze the reliability optimality of assigning tasks to multiple servers and design a reliability-aware task assignment heuristic based on the analysis. Experimental results show that with a small time overhead, the proposed energy allocation approach achieves a high throughput from perspectives of both the overall system and individual servers, and the proposed task assignment approach ensures an increased system reliability.

Energy allocation for activity recognition in wearable devices with kinetic energy harvesting

AbstractHarvesting kinetic energy from body movement is regarded as a promising rechargeable energy source for wearable devices with low‐power. Energy allocation is essential for motion‐based rechargeable devices since the great variability of energy gained from movement. Based on the realistic characteristics of an ultra‐low‐power wearable devices and our measurement observations, we propose the optimization framework allocating energy to maximize the average accuracy of human activity recognition and provide an offline and online algorithm, respectively. We evaluate the proposed energy allocation approach with real‐world human activity and kinetic energy harvesting datasets. Experimental results validate that our proposed energy allocation approach can maximize the energy allocation utility and improve energy efficiency of wearable devices.

Environmental assessment of energy-driven biorefineries: the case of the coffee cut-stems (CCS) in Colombia

Coffee cut-stems (CCS) are typically left in the field after coffee harvesting as fertilizer or used partially for cooking and drying of coffee grains. However, the energy contained in this residue is not completely exploited. For this reason, different applications for CCS have been considered to obtain innovative products. This work aims to evaluate the environmental impact of energy generation through two biorefinery systems using CCS as feedstock. The life cycle assessment (LCA) considers a cradle-to-gate approach, beginning at the seed germination and ending at the production of ethanol, electricity, and low-pressure steam. Inventory data of the coffee production are collected from national reports. Mass and energy balances are calculated using an integrated methodological approach comprising the conceptual design and optimization of the CCS biorefineries. CCS production is one of the hotspots in both evaluated biorefineries due to the use of high amounts of fertilizers, contributing to most of the environmental impact categories. From the two assessed biorefinery configurations, the system with the lowest environmental benefits was the one that considered the generation of electricity and steam. Factors such as the high emissions of exhaust gases (mainly composed of CO2) and the use of water for steam generation were the main contributors. The alternative solution I (AS-I) has the lowest environmental impact in comparison with the base case. From the sensitivity analyses, the use of energy allocation approach provided better performance than the system expansion approach. However, the selection of one approach over the other highly depends on the evaluated impact category based on the uncertainty analysis. The production of CCS has the highest contribution to the overall environmental impact of the evaluated biorefineries, and thus, we need available information of the coffee crop production including the production of co-products, such as CCS. We present a detailed inventory of the production of CCS in Colombia as an important contribution for further research in the area of coffee-based biorefineries. Based on our inventory, the production of bioenergy (electricity and steam) for a coffee-based biorefinery seems to provide the best environmental performance in comparison to the production of biofuels (ethanol).

Novel Secure Validation Scheme to Assess Device Legitimacy in Internet of Things

The increasing security concerns in Internet-of-Things (IoT) have led the researchers to evolve up with multiple levels of the research-based solution towards identifying and protecting the lethal threats. After reviewing the existing literature, it is found that existing approaches are highly specific toward stopping threats via predefined threat information. Hence, the proposed system introduces a new computational model capable of building up a flexible validation model for evaluating the legitimacy of the IoT nodes. The proposed system develops an algorithm that uses a simplified generation of secret keys, performs encryption, and generates validation tokens to ensure a higher degree of privacy and data integrity. The proposed model also contributes towards a unique energy allocation approach to ensure better energy conservation while performing security operations. The simulated study outcome shows better security and data transmission performance compared to the existing scheme.

Energetic cost derived of short-term starvation on marine crustacean Palaemon elegans

Event Abstract Back to Event Energetic cost derived of short-term starvation on marine crustacean Palaemon elegans Ico Martinez1*, Alicia Herrera1, Inmaculada Herrera1, Daniel R. Bondyale-Juez1, Vanesa Romero-Kutzner1, Mayte Tames-Espinosa1, Theodore T. Packard1 and May Gómez Cabrera1 1 University of Las Palmas de Gran Canaria, Spain Starvation has a major impact on physiological processes in marine plankton and these processes have a major impact on the energy transfer through marine ecosystems. However, quantifying and understanding how starvation changes different aspects of the energy transfer has been retarded because planktologists have largely relied on biomass fractionation to shed light on it. Here, we experiment with the cellular energy allocation approach (CEA index), the respiratory electron transport system activity (ETS), and organic analysis of lipids (Lip), carbohydrates (Carb) and proteins (Prot) to help further our understanding of the energy transfer in the caridean shrimp, Palaemon elegans. We analyzed the effect of 72 hours of starvation using the CEA index that is calculated as the ratio between energy available to energy consumption. It allows us to evaluate the net energy budget (Verslycke and Janssen, 2002). The energy available (Ea) was determined from Lip, Carb, and Prot content, where Ea = Lip + Carb + Prot. Energy consumption (Ec) was calculated from the activity of ETS. All the parameters were transformed into energy equivalents using their respective energy of combustion (Gnaiger, 1983). Proteins were the main energy source (1450.8±355.7 mJ•mgWW-1), followed by lipids (727.2±124.4 mJ•mgWW-1) and carbohydrates (82.1±17.9 mJ•mgWW-1). After 24 hours of starvation, the carbohydrates dropped by 38.2%, a significant decrease. After 48 hours, the proteins had decreased by 36.0%. The lipids were the last to decrease. After 72 hours they had dropped by 42.3%. Adding these organic constituents to calculate the Ea revealed a significant decreasing trend of 34.42% at 72 hours (from 2260.1±485.5 to 1482.3±120.9 mJ•mgWW-1). In contrast, the Ec, as ETS activity, showed a significant increase at 24 hours (from 85.2±16.6 to 158.0±40.4 mJ•h-1•mgWW-1) that stabilized after 72 hours. Overall, the energy balance (Ea/Ec) showed that the energy available was higher than the energy consumption during the experiment. Ea/Ec ratio decreased for the first 24 hours, then remained stable for the next 48 hours. This portrait of energy regulation shows a rapid shift mechanism of P. elegans under sudden adverse conditions. References Gnaiger, E. (1983). ‘Calculation of energetic and biochemical equivalents of respiratory oxygen consumption’, in Polarographic oxygen sensors (Springer), 337–345. Verslycke, T., and Janssen, C. R. (2002). Effects of a changing abiotic environment on the energy metabolism in the estuarine mysid shrimp Neomysis integer (Crustacea: Mysidacea). J. Exp. Mar. Bio. Ecol. 279, 61–72. Keywords: CEA index, Energy available, energy consumption, Palaemon elegans, Starvation Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Poster Presentation Topic: Ecology, Biodiversity and Vulnerable Ecosystems Citation: Martinez I, Herrera A, Herrera I, Bondyale-Juez DR, Romero-Kutzner V, Tames-Espinosa M, Packard TT and Gómez Cabrera M (2019). Energetic cost derived of short-term starvation on marine crustacean Palaemon elegans. Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00191 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 14 May 2019; Published Online: 27 Sep 2019. * Correspondence: Mrs. Ico Martinez, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain, ico.martinez@ulpgc.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ico Martinez Alicia Herrera Inmaculada Herrera Daniel R Bondyale-Juez Vanesa Romero-Kutzner Mayte Tames-Espinosa Theodore T Packard May Gómez Cabrera Google Ico Martinez Alicia Herrera Inmaculada Herrera Daniel R Bondyale-Juez Vanesa Romero-Kutzner Mayte Tames-Espinosa Theodore T Packard May Gómez Cabrera Google Scholar Ico Martinez Alicia Herrera Inmaculada Herrera Daniel R Bondyale-Juez Vanesa Romero-Kutzner Mayte Tames-Espinosa Theodore T Packard May Gómez Cabrera PubMed Ico Martinez Alicia Herrera Inmaculada Herrera Daniel R Bondyale-Juez Vanesa Romero-Kutzner Mayte Tames-Espinosa Theodore T Packard May Gómez Cabrera Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Estimation of U.S. refinery water consumption and allocation to refinery products

Increasing stress on the global water supply necessitates the measurement of water consumption as a sustainability metric to evaluate energy production, including the production of transportation fuels (gasoline, diesel, jet fuel) at petroleum refineries. This study estimated refinery water consumption for petroleum fuels by considering three typical refinery configurations (cracking, light coking, and heavy coking) that process different crude qualities (e.g., American Petroleum Institute Gravity (API) gravity and sulfur content). The results showed that refinery water consumption was 0.34, 0.44, and 0.47 bbl water/bbl crude (L water/L crude) for cracking, light coking, and heavy coking configurations, respectively. The water consumption for a specific refinery product was estimated using an energy allocation approach at the process unit level. The results indicated that gasoline production consumes the largest amount of water, 0.60–0.71gal water/gal gasoline (0.60–0.71L water/L gasoline), due to the energy-intensive (and thus water-intensive) processing of gasoline components (mainly sourced from alkylation, reformer, and fluid catalytic cracking units). In contrast, jet fuel production consumes the least water, 0.09gal water/gal jet fuel, for all three refinery configurations, because it is sourced directly from the crude distillation unit with minimal post-treating. The consumption of diesel is most sensitive to refinery configuration with 0.20, 0.30, and 0.40gal water/gal diesel (L water/L diesel) for cracking, light coking and heavy coking configurations, respectively. This is mainly because as configuration complexity increases to process heavier and sourer crudes, a sizable burden of hydrogen production from steam methane reforming unit is allocated to diesel fuel production (including diesel sulfur removal). The trend of water consumption associated with these refinery products is consistent with the energy consumption for their production.

Production of Hydrocarbon Fuel Using Two-Step Torrefaction and Fast Pyrolysis of Pine. Part 2: Life-Cycle Carbon Footprint

This study, as part II of two companion papers, investigated the environmental performance of liquid hydrocarbon biofuel production via fast pyrolysis of pine through two pathways: a one-step pathway via fast pyrolysis only, and a two-step pathway that includes a torrefaction step prior to fast pyrolysis. Fast pyrolysis in all cases took place at a temperature of 530 °C whereas for the two-step pathways, torrefaction was investigated at temperatures of 290, 310, and 330 °C. Bio-oil produced was then catalytically upgraded to hydrocarbon biofuel. Different scenarios for providing the required process heat either by using fossil energy or renewable energy, as well as the effect of heat integration, were also investigated. Our life cycle analysis indicated that using the energy allocation approach, a two-step heat integrated pathway with torrefaction taking place at 330 °C had the lowest global warming potential among all scenarios of about 29.0 g CO2 equiv/MJ biofuel. Using the system expansion approach, significantly higher reductions in GHG emissions of about 56 to 265% relative to conventional gasoline were observed for the heat integrated processes. More modest percentage reduction in emissions of about 34 to 67% was observed across all scenarios using the energy allocation approach.

Effect of Cu and Ni on cellular energy allocation in Enchytraeus albidus.

Effects of nickel and copper on Enchytraeus albidus (Oligochaeta) were investigated using the cellular energy allocation approach. This methodology is used to evaluate the energetic status of an organism and is indicative of its overall condition. Enchytraeids were exposed to the reproduction Effect Concentrations (EC50 and EC90), and the parameters measured were the total energy reserves available (protein, carbohydrate and lipid budgets) and the energy consumption [based on electron transport system activity] which were further integrated to obtain the cellular energy allocation over different periods of exposure (0-2, 2-4 and 4-8 days). Carbohydrates (in comparison to lipids and proteins) were the only energy source mobilized in the case of nickel within 8 days of exposure. For copper exposure, protein budgets were also strongly reduced. Energy consumption increased in a time and dose-dependent way for copper and in the longer exposure period (4-8 days) at the EC90 for Ni exposure, indicating that this is a good biomarker for effects of short-time metal exposure, while cellular energy allocation was only significantly reduced for the EC90 of copper (4-8 days) and EC50 of nickel (2-4 days). The effects of nickel at concentrations causing 50 and 90 % decrease in reproduction were likely not due to the changes in cellular energy allocation within 8 days of exposure.

Wireless Power Meets Energy Harvesting: A Joint Energy Allocation Approach in OFDM-Based System

This paper investigates an orthogonal frequency division multiplexing (OFDM)-based wireless powered communication system, where one user harvests energy from an energy access point (EAP) to power its information transmission to a data access point (DAP). The channels from the EAP to the user, i.e., the wireless energy transfer (WET) link, and from the user to the DAP, i.e., the wireless information transfer (WIT) link, vary over both time slots and sub-channels (SCs) in general. To avoid interference at DAP, WET and WIT are scheduled over orthogonal SCs at any slot. Our objective is to maximize the achievable rate at the DAP by jointly optimizing the SC allocation over time and the power allocation over time and SCs for both WET and WIT links. Assuming availability of full channel state information (CSI), the structural results for the optimal SC/power allocation are obtained and an offline algorithm is proposed to solve the problem. Furthermore, we propose a low-complexity online algorithm when causal CSI is available.

Compilation of an Embodied CO2 Emission Inventory for China Using 135-Sector Input-Output Tables

A high-quality carbon dioxide (CO2) inventory is the cornerstone of climate change mitigation. Most of the previously reported embodied CO2 inventories in China have no more than 42 sectors, and this limitation may introduce apparent inaccuracy into the analysis at the sector level. To improve the quality of input-output (IO)-based CO2 inventories for China, we propose a practical energy allocation approach to link the energy statistics to the 135-sector IO tables for China and compiled a detailed embodied CO2 intensity and inventory for 2007 using a single-region IO model. Interpretation of embodied CO2 intensities by fuel category, direct requirement, and total requirement in the sectors were conducted to identify, from different perspectives, the significant contributors. The total embodied CO2 emissions in 2007 was estimated to be 7.1 Gt and was separated into the industrial sector and final demand sector. Although the total CO2 estimations by the 42-sector and 135-sector analyses are equivalent, the allocations in certain groups of sectors differ significantly. Our compilation methodologies address indirect environmental impacts from industrial sectors, including the public utility and tertiary sectors. This method of interpretation could be utilized for better communication with stakeholders.

Development of leakage energy allocation approach for time‐varying interharmonics tracking

Recently, an increasing use of power electronic facilities in industry has produced considerable harmonics and interharmonics in power systems. The power supply quality is therefore seriously threatened. The discrete Fourier transform (DFT) is currently the most important tool in signal analysis. However, a misapplication of DFT may result in incorrect outcome because of some inherent limitations such as spectral leakage or aliasing effect etc. The existing interharmonics even raise more difficulty in signal analysis than harmonics. To overcome this dilemma, this study develops a strategy of leakage energy allocation method for both stationary and non-stationary interharmonics identification. The proposed algorithm can regain its original interharmonics amplitude by restoring all spilled leakage energy, and also finds its individual frequency component according to the distribution of spilled leakage energy. The performance effectiveness of the proposed approach is verified using the numerical examples in terms of reliability, rapid response and high-precision performance.

Greenhouse Gas Emission Evaluation of the GTL Pathway

Gas to liquids (GTL) products have the potential to replace petroleum-derived products, but the efficacy with which any sustainability goals can be achieved is dependent on the lifecycle impacts of the GTL pathway. Life cycle assessment (LCA) is an internationally established tool (with GHG emissions as a subset) to estimate these impacts. Although the International Standard Organization's ISO 14040 standard advocates the system boundary expansion method (also known as the "displacement method" or the "substitution method") for life-cycle analyses, application of this method for the GTL pathway has been limited until now because of the difficulty in quantifying potential products to be displaced by GTL coproducts. In this paper, we use LCA methodology to establish the most comprehensive GHG emissions evaluation to date of the GTL pathway. The influence of coproduct credit methods on the GTL GHG emissions results using substitution methodology is estimated to afford the Well-to-Wheels (WTW) greenhouse gas (GHG) intensity of GTL Diesel. These results are compared to results using energy-based allocation methods of reference GTL diesel and petroleum-diesel pathways. When substitution methodology is used, the resulting WTW GHG emissions of the GTL pathway are lower than petroleum diesel references. In terms of net GHGs, an interesting way to further reduce GHG emissions is to blend GTL diesel in refineries with heavy crudes that require severe hydrotreating, such as Venezuelan heavy crude oil or bitumen derived from Canadian oil sands and in jurisdictions with tight aromatic specifications for diesel, such as California. These results highlight the limitation of using the energy allocation approach for situations where coproduct GHG emissions reductions are downstream from the production phase.