Net Energy Benefit Research Articles

Measuring the effect of forced irrigation on the front surface of PV panels for warm tropical conditions

Irrigating the front surface of a PV panel is one method for reducing its operating temperature, thus increasing the output power. Several studies have investigated this method. Nevertheless, information on the thermal effects and energy benefits provided by irrigation over several operating cycles and water flow rates in warm-tropical conditions is lacking. Thus, this work presents the experimental characterization of the operating temperature and output power from irrigated 255 W PV panels. The experiment considered twelve irrigation regimens with four flow rates (1.75 l/min, 3.75 l/min, 4.75 l/min, and 9.50 l/min) and four operating cycles (1’:29’, 5’:25’, 15’:15’, and continuous). The study provides a description of transient cooling processes as functions of flow rate and solar irradiation, as well as heating of the PV panel. Such description is based on data analysis using two indices: relative temperature difference (RTD) and generated power increase (GPI), which quantifies the additional generated energy and estimates the net energy benefit considering the energy consumed by the irrigation system. Results indicate that irrigation can enhance daily energy production by 10%; a flow rate equal to or greater than 3.75 l/ min (2.34 l/min/m2) produces similar effects. The GPI caused by irrigation depends on the solar irradiation, where GPI is found to be 0.5% to 2.0% for 400 W/m2 or lower, 2% to 5% for values between 400 W/m2 and 800 W/m2, and 5% to 10% for 800 W/m2 or greater. The power consumed by the irrigation system significantly affects the net energy benefit.

Food waste treatment with a leachate bed reactor: Effects of inoculum to substrate ratio and reactor design

This study evaluated the effects of different inoculum to substrate ratios (ISRs) (5, 10, 15%) on hydrolysis and acidogenesis of food waste in a conventional leachate bed reactor (LBR-C) and a novel fractionalized LBR (LBR-F). At ISR of 10%, LBR-C experienced clogging and thus the solid removal and VFA production reduced significantly. Without any clogging events at high ISR of 10%, LBR-F achieved significantly higher (p < 0.05) VS removal of 91%, hydrolysis yield of 837 g cumulative sCOD/kg volatile solids (VS), and VFA yield of 669 g COD/kg VS. Hydrogen yield was as high as 20 m3/ton food waste in LBR-F. Energy balance indicated that the LBR-F can be energy-positive for food waste treatment with net energy benefit of ∼8 kWh/ton food waste treated. Considering the high VFA yield, the LBR-F can also be a promising food waste fermentation system for the biorefinery platform.

Implementation of Upscaled Microbial Fuel Cells for Optimized Net Energy Benefit in Wastewater Treatment Systems

AbstractMicrobial fuel cells are bioelectrochemical devices that use exoelectrogenic biofilms to convert organic matter into electric energy. Recent research of microbial fuel cells has occurred be...

Systematic application of a quantitative definition of marginal lands in estimating biomass energy potential in the Missouri/Mississippi River Corridor

Cultivation of cellulosic biomass on marginal lands in the Missouri/Mississippi River Corridor (MMRC) could improve environmental performance for the watershed, e.g. nutrient runoff interception, erosion stabilization, feedstock for bio-based energy, and barge shipments could have net energy benefits. This work reviewed marginal lands literature to reach a generic definition that could be linked with publicly available land and soil quality datasets to quantify marginal lands in the MMRC. The definition developed is: Marginal lands are non-croplands and/or lands not suitable for long-term food crop production because of high erodibility (K factor > 0.4) and/or being prone to flood. The MMRC extends 161 km from the banks of the Mississippi and Missouri rivers, totaling 2.5 million km2. Bioenergy production potential was estimated using scenarios to explore the inclusion and exclusion of croplands, forestland and Conservation Reserve Program lands. Among the plausible scenarios a maximum of 189.3 billion liters and a minimum of 1.85 billion liters of bioethanol can be produced in MMRC. The maximum jet fuel production could meet all US demand and the maximum electricity production could meet 23% of current US demand. This work highlights the trade-offs associated with competing demands on land in relation to achieving bioenergy goals.

Modeling the impact of food wastes on wastewater treatment plants

Food waste (FW) enriched with readily biodegradable organics can enhance biological nutrient removal (BNR), and biogas production. This study conducted extensive wastewater treatment simulations using BioWin software to predict the impact of food waste on nutrient removal, biogas generation, and energy balance. A total of 114 scenarios were tested to simulate different treatment technologies i.e. conventional activated sludge, Modified Ludzack-Ettinger (MLE), anaerobic-anoxic-aerobic (A2O), Bardenpho, and 2nd generation BNR technologies. The simulations also included sidestream treatment for nitrogen removal, as well as mainstream partial nitrification based on BNR. The results showed that FW addition enhanced nitrogen removal and decreased effluent nitrogen for BNR processes by 3.6–7.9 mg/L for MLE, 0.6–1.3 mg/L for A2O, and 1–2.3 mg/L for Bardenpho. In addition, FW addition decreased net operational cost by 26%–63% for BNR processes operating at mainstream conventional dissolved oxygen (DO) of 2 mg/L, 24%–78% for partial nitrification system, 29%–54% for sidestream, and 23%–76% for sidestream with mainstream partial nitrification process. The total net energy benefit considering both the net change in aeration energy and methane energy for a typical 37,854 m3/d or 10 MGD plant increased with FW addition by 3300–7900 kWh/d with a variation between BNR types, due to a substantial increase in methane production. Carbon diversion scenarios showed that the higher primary treatment efficiencies decreased the net operational cost and increased net energy gain.

Energy and greenhouse gas life cycle assessment and cost analysis of aerobic and anaerobic membrane bioreactor systems: Influence of scale, population density, climate, and methane recovery

This study calculated the energy and greenhouse gas life cycle and cost profiles of transitional aerobic membrane bioreactors (AeMBR) and anaerobic membrane bioreactors (AnMBR). Membrane bioreactors (MBR) represent a promising technology for decentralized wastewater treatment and can produce recycled water to displace potable water. Energy recovery is possible with methane generated from AnMBRs. Scenarios for these technologies were investigated for different scale systems serving various population densities under a number of climate conditions with multiple methane recovery options. When incorporating the displacement of drinking water, AeMBRs started to realize net energy benefits at the 1 million gallons per day (MGD) scale and mesophilic AnMBRs at the 5 MGD scale. For all scales, the psychrophilic AnMBR resulted in net energy benefits. This study provides insights into key performance characteristics needed before an informed decision can be made for a community to transition towards the adoption of MBR technologies.

A comprehensive evaluation of Daphnia pulex foraging energetics and the influence of spatially heterogeneous food

Aquatic organisms are distributed in a heterogeneous, nonrandom manner, and zooplankton are known to seek out and orient themselves within regions of high food concentration. Yet, the energetics associated with this foraging behavior are unknown. We hypothesized that zooplankton foraging behavior increases foraging efficiency measured as food consumption per unit effort. In this study, we measured the energetic costs and benefits for the zooplankton Daphnia pulex foraging in a range of algal concentrations to determine the net energetic benefit of foraging in algal patches. The net energy benefit of foraging increased significantly with increases in algal concentration; this trend was driven by significant increases in prey ingestion with algal concentration, whereas foraging costs did not change. Even considering corrections for changes in assimilation efficiency, foraging in algal patches greatly increases net foraging benefit compared to foraging in low concentrations of algae and thus has the potential for higher reproduction and greater growth in filter-feeding zooplankton.

Performance Analysis of Nanoelectromechanical Relay-Based Field-Programmable Gate Arrays

The energy consumption of field-programmable gate arrays (FPGA) is dominated by leakage currents and dynamic energy associated with programmable interconnect. An FPGA built entirely from nanoelectromechanical (NEM) relays can effectively eliminate leakage energy losses, reduce the interconnect dynamic energy, operate at temperatures >225 °C and tolerate radiation doses in excess of 100 Mrad, while hybrid FPGAs comprising both complementary metal-oxide-semiconductor (CMOS) transistors and NEM relays (NEM-CMOS) have the potential to realize improvements in performance and energy efficiency. Large-scale integration of NEM relays, however, poses a significant engineering challenge due to the presence of moving parts. We discuss the design of FPGAs utilizing NEM relays based on a heterogeneous 3-D integration scheme, and carry out a scaling study to quantify key metrics related to performance and energy efficiency in both NEM-only and NEM-CMOS FPGAs. We show how the integration scheme has a profound effect on these metrics by changing the length of global wires. The scaling regime beyond which net performance and energy benefits is seen in NEM-CMOS over a baseline 90 nm CMOS technology is defined by an effective relay beam length of 0.5 $\mu \text{m}$ , on-resistance of 200 $\text{k}\Omega$ , and a via pitch of 0.4 $\mu \text{m}$ , all achievable with existing process technology. For ultra-low energy applications that are not performance critical, NEM-only FPGAs can provide close to $15\times$ improvement in energy efficiency.

Energy-saving optimization of coking wastewater treated by aerobic bio-treatment integrating two-stage activated carbon adsorption

Contaminants removal efficiency and energy consumption are of practical importance in wastewater treatment. Herein, an energy saving system including aerobic bio-treatment combined with a two-stage adsorption (AB-2A) was proposed and applied to the treatment of coking wastewater. The adsorption before bio-treatment partially extracts energy and organic constituents from the wastewater, making the subsequent bio-treatment more effective. The adsorption after bio-treatment brings the effluent to the discharge requirements. In comparison with the biological treatment combined with subsequent ozonation (M0 mode), the proposed system rationalizes the material flows in the wastewater treatment by optimized activated carbon utilization targeting higher adsorption and energy extraction efficiencies. The combined system AB-2A aimed at reducing the chemical oxygen demand (COD) to the national discharge standard at maximized net energy benefit (NEB) and benefit cost ratio (BCR). The modified cost benefit analysis was applied to energy balance evaluation of the system. Two combustible adsorbents, a commercial activated carbon (CAC) and a sludge-derived activated carbon (SAC), were used for pollutants adsorption. The results showed that the average effluent COD of the combined system AB-2A reached 78.8 mg/L when subjected to the activated carbon adsorption after biodegradation, with 7.0 g/L CAC added sequentially to the biologically treated and then to the raw coking wastewater (M2(CAC) mode). COD removal efficiency of M2(CAC) mode exceeded 96% being equal to the reference result of M0 mode. Additionally, the NEB and BCR reached −11.81 kWh/m3 and 0.80 in M2(CAC) mode, respectively. Moreover, the M2 mode applying SAC (M2(SAC) mode) in amount of 7.0 g/L demonstrated the highest energy recovery compared to M0 and the separate adsorbent application to the raw influent and the bio-treated effluent (M1 mode). The difference values of NEB and BCR in M2(SAC) compared to M0 were shown as big as 28.87 kWh/m3 and 0.07, respectively. The excess sludge recycling in the wastewater treatment resulted in the positive benefit in energy saving. Summarizing, the AB-2A system using SAC appears to be high COD removal efficiency and energy saving in the future sustainable wastewater treatment.

Impact of improved production technologies on chickpea yields, economics and energy use in rainfed Vertisols

A field study was conducted during rabi season of 2013–14 in ten farmers’ fields of Joladarasi, K. Veerapur and Chellagurki villages of Bellary district in Karnataka, India to evaluate the improved chickpea variety JG11 with micronutrients application on yield, economics and energy flow in Vertisols. Adopting JG11 chickpea variety and application of micronutrient mixture at 5 kg ha-1 during winter season increased the grain and straw yields by 26% and 31%, respectively over A1variety cultivated by farmers without application of micronutrients. Application of micronutrients alone produced 9% higher yields in JG11 and A1. Greater gross and net returns with higher B:C ratio was observed with cultivation of JG11chickpea variety and application of micronutrients. Energy flow results revealed that smaller input energy through micronutrients application and cultivation of JG11variety produced higher total output energy and net energy benefit (NEB). The NEB per ha varied from 15966 MJ in control plots to as high as 22546 MJ in micronutrients applied plots with JG11 cultivation. Greater average energy use efficiency (EUE) of 3.57, energy productivity (EP) of 0.106 and lesser specific energy (SE) of 9.62 were observed with JG11 cultivation and applied with micronutrients compared to the control plots. Correlation studies indicated the positive and significant correlation of grain yield with net returns, B:C ratio, NEB, EUE and EP. In conclusion higher chickpea yields, profit and energy gains can be achieved by cultivating JG11 variety with micronutrients application at 5 kg ha-1 in the Vertisols of Bellary region during winter season.

Studying the potential of energy saving through vertical greenery systems: Using EnergyPlus simulation program

Vertical Greenery Systems (VGS) are upcoming facade cladding fixtures which restore the connection between the city and nature. They are capable of providing thermal benefits to the building. The objective of this study is to explore the impact of VGS on building energy performance. This study simulates thermal effect of VGS using a mathematical model based on heat balance principle of the foliage layer and soil later, which is then integrated into one of the widely accepted building simulation program, EnergyPlus. The integrated VGS model is validated against two reported experimental studies, and show good agreement. Validation results show that integrated VGS model satisfactorily predict the effect of VGS on indoor air temperature and exterior and interior surface temperature of facades with VGS. The integrated VGS model is then used to assess the impact of VGS on building energy performance in warm temperature climates. Simulations have shown that in hot summer days, VGS leads to reduce exterior surface temperature of building facades, maximum of 26°C. The annual cooling energy consumption is reduced by 3% for warm temperature climates. However, during the winter season insulation effect of VGS cause increase in heating demand of the building. Simulations suggest that, passive energy benefits of VGS are promising during summer periods, whereas it may disadvantageous during winter periods. However, in warm temperature climates, VGS still able to provide net passive energy benefits to the building.

Energy Consumption and Sensitivity Analysis of Rainfed Chickpea Production in Vertisols of Semi-arid Karnataka

In-situ rainwater conservation improves chickpea productivity in Vertisols. This hypothesis was tested by layout of compartmental bunds (CB) during rainy season and evaluating the performance of chickpea varieties during winter season. Grain yield of JG11 chickpea variety was 43.9 % higher in CB plots as compared to farmers’ practice. Further, results revealed that smaller energy input through CB and cultivation of JG11 produced higher energy output of 40,183 MJ ha−1 and net energy benefit of 30,553 MJ ha−1. Higher average energy use efficiency of 4.15, energy productivity of 0.126 and lesser specific energy of 8.22 were observed in CB plots cultivated with JG11. Econometric model estimation emphasized that human labour was significantly positive on yield. Thus sensitivity analysis also indicated marginal physical productivity of 3.29 for man labour. The impact of direct, renewable and non-renewable energies on yield was significant. Higher net returns of Rs. 23,722 per ha and B:C ratio of 1.83 was observed with cultivation of JG11 in CB plots. The authors concluded that adoption of CB and cultivation of JG11 variety ensured greater chickpea productivity even during drought years with higher energy efficiency and returns in Vertisols of Karnataka, India.

Energy-positive food wastewater treatment using an anaerobic membrane bioreactor (AnMBR)

An immersed-membrane anaerobic membrane bioreactor (AnMBR) achieved 88–95% of COD removal for meat-processing wastewater at organic loading rate (OLR) of 0.4–3.2 kgCOD m−3 d−1. Membrane flux was stable for low OLR (0.4 and 1.3 kgCOD m−3 d−1), but irrecoverable fouling occurred at high OLR of 3.2 kgCOD m−3 d−1. Methane gas yield of 0.13–0.18 LCH4 g−1CODremoved was obtained, which accounted for 33–38% of input COD, the most significant electron sink. Dissolved methane was only 3.4–11% of input COD and consistently over-saturated at all OLR conditions. The least accumulation of dissolved methane (25 mg L−1 and saturation index 1.3) was found for the highest OLR of 3.2 kgCOD m−3 d−1 where biogas production rate was the highest. Energy balances showed that AnMBR produced net energy benefit of 0.16–1.82 kWh m−3, indicating the possibility of energy-positive food wastewater treatment using AnMBRs.

Net Energy Analysis of Gas Production from the Marcellus Shale

Total production of dry natural gas in the USA increased to 24.4 Tcf in 2013, a 35 % increase from 2005 levels. This increase was largely a result of the rapid development of shale resources in the lower 48 states. The Marcellus play alone accounted for nearly 15 % of the total dry gas produced in 2013. In this study, we calculate the energy return on investment (EROI) using a hybrid life-cycle analysis approach bounded by three process stages: (1) EROIPP (2) EROIP,PT and (3) EROIGRID, which includes the energetic costs associated with electricity generation. Most significantly, the inclusion of electricity generation within the EROI analysis makes possible a functional unit comparison to alternative sources of energy into the power grid. Well pad preparation and well drilling had the largest energy costs of all the upstream process stages, accounting for nearly 75 % of production and processing costs. However, the largest energy consumer among the process stages is the cost associated with electricity production, and our model assumes 43 % power plant efficiency, accounting for nearly 94 % of the total energy costs of producing electricity from natural gas. Defined by process stage, our analysis calculated an EROIP&P of 39.7, a EROIP,P&T of 24.9, and an EROIGRID of 10.7. The EROIGRID value of 10 is the same as that calculated for photovoltaic systems, indicating that shale gas, when burned for electricity, provides similar net energy benefits to society as an average PV system.

Application of experimental design techniques in the optimization of the ultrasonic pretreatment time and enhancement of methane production in anaerobic co-digestion

In this study, wheat straw (WS) and dairy manure (DM) were ultrasonically pretreated to optimize the time for ultrasonic pretreatment (UP), identify the most appropriate optimization method, clarify whether UP is a high efficiency method for application, and explain why UP improves total methane production (TMP). The pretreatment conditions were designed using orthogonal experiment design (OED) and central composite design (CCD) and were optimized using the direct measurement method and response surface method, the relationships among the initial digestion characteristics and TMP were subsequently analyzed, the net energy, and energy benefit were calculated. The OEM results showed that mixed DM pretreated for 30minutes (min) and WS pretreated for 20min (DM30WS20) produced the maximum TMP, net energy, and energy benefit of 186mL/g TS (total solid), 6.04kJ/g TS, and 2.88kJ/g TS, respectively. For CCD, the maximum TMP, net energy, and energy benefit were 146.61mL/g TS, 4.91kJ/g TS, and 1.75kJ/g TS, respectively, and were obtained with DM9WS25. The maximum TMP, net energy, and energy benefit of OED were greater than those of CCD, indicating that OED is more suitable for UP in anaerobic digestion (AD). When pretreated with UP, the surface of DM showed an increasingly uniform distribution and WS became increasingly rough and displayed fractures of different degrees. Cellulose activity contributed the maximum (0.3856) direct decision influence to TMP, and the comprehensive decision influence at a pH of 0.328 was the highest in TMP. This study concluded that the direct measurementmethod in OED was best suited for the design and optimization of pretreatment conditions by UP in AD. UP improved TMP, net energy, and energy benefit by changing the initial environment of AD. Therefore, UP is a high-energy benefit method and worth popularizing for AD.

Effect on battery life of vehicle-to-home electric power provision under Canadian residential electrical demand

Vehicle-to-Home (V2H) is a support activity using electric vehicles where the electric power stored in their batteries is supplied in response to residential electrical demand. It is understood that supplementary battery use such as V2H will reduce the battery service life. Judicious V2H activity can provide energy benefits at acceptable levels of battery life reduction. The present study employs a fundamentals based battery simulation to explore a range of V2H scenarios to assess the net energy benefits, and weigh these against associated battery life reduction attributable to V2H. The frequency (daily, weekly, monthly), duration and time-of-day of the V2H event were test parameters. Long term (i.e. given roughly 16year battery calendar life) detailed simulations which included a daily driving regime together with V2H activity based on detailed residential electricity use data were used to determine battery lifetimes. Apart from aggressive driving and fast charging which greatly impact electric vehicle (EV) battery life, the largest contributions to battery degradation were for intense participation in V2H services, such as handling the household electrical load for 8h daily. A 10.6year battery life with no V2H, was lowered to about 10.2years with 1h daily V2H, and to about 8.5years with 8h daily V2H. However, lower intensity, and especially lower frequency use of the EV battery can still provide useful V2H services with acceptable battery degradation.

Generating a positive energy balance from using rice straw for anaerobic digestion

Abstract About 150 million metric tons of rice straw is produced in Southeast Asian countries every year. Several barriers impeding the collection of rice straw from the fields as well as the lack of knowledge on alternative uses of rice straw led to the practice of burning which causes air pollution and greenhouse gas emissions. To identify the benefits and uses of rice straw for energy generation is the main objective of this research. The study evaluated the energy balance of the rice straw supply chain and energy conversion through anaerobic digestion (AD). The input energy was categorized either as direct and indirect energy. Direct energy included agricultural inputs, fuel consumption and manpower. Fuel consumption was measured directly from the vehicles and equipment used in the experiment while manpower was measured using the metabolic equivalent of task (MET) based on labor time per ton of straw. Indirect energy was calculated based on the energy for the manufacture, lubrication, and maintenance of machines and equipment. The net energy of the rice straw supply chain for biogas generation through AD is 3,500 MJ per ton of straw. This rice straw management option can provide a 70% net output energy benefit. The research highlighted the potential of rice straw as a clean fuel source with a positive energy balance, helping to reduce greenhouse gas emissions compared with the existing practice of burning it in the field.

Net energy benefits of carbon nanotube applications

Implementation of carbon nanotubes (CNTs) in various applications can reduce material and energy requirements of products, resulting in energy savings. However, processes for the production of carbon nanotubes (CNTs) are energy-intensive and can require extensive purification. In this study, we investigate the net energy benefits of three CNT-enabled technologies: multi-walled CNT (MWCNT) reinforced cement used as highway construction material, single-walled CNT (SWCNT) flash memory switches used in cell phones and CNT anodes and cathodes used in lithium-ion batteries used in electric vehicles. We explore the avoided or additional energy requirement in the manufacturing and use phases and estimate the life cycle net energy benefits for each application. Additional scenario analysis and Monte Carlo simulation of parameter uncertainties resulted in probability distributions of net energy benefits, indicating that net energy benefits are dependent on the application with confidence intervals straddling the breakeven line in some cases. Analysis of simulation results reveals that SWCNT switch flash memory and MWCNT Li-ion battery cathodes have statistically significant positive net energy benefits (α=0.05) and SWCNT Li-ion battery anodes tend to have negative net energy benefits, while positive results for MWCNT-reinforced cement were significant only under an efficient CNT production scenario and a lower confidence level (α=0.1).

Reduced-order modelling of flexible CCS and assessment using short-term resource scheduling approach

CCS (Carbon Capture and Storage) can allow conventional fuels for electricity generation to be used while achieving deep reductions in GHG (Greenhouse Gas) emissions at the cost, though, of reduced efficiency and capacity relative to an electricity system without CCS. It has been proposed that the deployment of generating units with CCS that are flexible—in particular, that can moderate their CO2 recovery in response to market conditions—would mitigate some of the disbenefit associated with the technology. This paper uses the short-term resource scheduling approach to assess the value of flexible generating units with CCS (Carbon Capture and Storage); generating unit part-load performance, variability of CO2 recovery, and detailed operation of an electricity system including transmission and reliability constraints are considered simultaneously. A parametric study of the performance of a coal-fired generating unit with CCS is undertaken using an Aspen Plus® steady-state model and a reduced-order model representing the Pareto optimal frontier of the unit is developed using regression analysis. The base economic dispatch underlying the electricity system simulator is extended to accommodate flexible generating units with CCS. The flexible generating unit with CCS is added to the IEEE RTS’96 (Institute of Electrical and Electronics Engineers One-Area Reliability Test System—1996) and the operation of the modified IEEE RTS’96 is simulated for one week. The results are contrasted with results taken from Alie et al. (2015) for the base IEEE RTS’96 and an IEEE RTS’96 with “fixed” CCS. “Flexible” CCS is effective at reducing GHG emissions, though to a slightly lesser extent than was observed via “fixed” CCS. However, with GHG regulation in place, flexibility markedly increases the net energy benefit of the generating unit with CCS and this was achieved not through adjustment of CO2 recovery in order to moderate output but, rather, by increasing the generating unit's ability to successfully compete to provide reserve power. Performance metrics that do not consider the impact of GHG mitigation options on energy benefit may not correctly rank GHG mitigation options.

Life Cycle Energy and Greenhouse Gas Emissions of Automobiles Using Aluminum in China

SummaryTransportation is a major part of energy consumption and greenhouse gas (GHG) emissions. Aluminum (Al) as a light metal can reduce vehicle weight, energy consumption, and pollutant emissions, but Al production is energy intensive. The main contents of this study are the following: (1) create the life cycle inventory of Al parts based on the energy background in China and (2) evaluate the energy savings and GHG reduction for the vehicle when steel parts are replaced by Al parts. Although there is a considerable reduction in energy consumption of per tonne Al in China owing to continuing development of process technology in recent years, energy consumption is higher than the world average level and European level. Over the vehicle's life cycle driving of 200,000 kilometers, the vehicle was found to avoid 1,447 to 1,590 liters of gasoline consumption when six typical steel parts were replaced by Al parts. Based on the current technology, the breakeven distance was calculated, resulting in a net energy benefit to use the lightweight Al parts compared with steel parts. A sensitivity analysis was conducted to show different energy savings by considering secondary weight reduction and different driving distance. The results indicate that weight reduction by using Al is quite effective to reduce the energy consumption and GHG of transportation.