Fuel Reduction Research Articles

Decadal Impacts of Wildfire Fuel Reduction Treatments on Ecosystem Structure and Fire Behavior in Alaskan Boreal Forests

Decadal Impacts of Wildfire Fuel Reduction Treatments on Ecosystem Structure and Fire Behavior in Alaskan Boreal Forests

Novel Mathematical Method to Obtain the Optimum Speed and Fuel Reduction in Heavy Diesel Trucks

In Mexico and many parts of the world, land cargo transport units (UTTC) operate at high speeds, causing accidents, increased fuel costs, and high levels of polluting emissions in the atmosphere. The speed in road driving, by the carriers, has been a factor little studied; however, it causes serious damage. This problem is reflected in accidents, road damage, low efficiency in the life of the engine and tires, low fuel efficiency, and high polluting emissions, among others. The official Mexican standard NOM-012-SCT-2-2017 on the weight and maximum dimensions with which motor transport vehicles can circulate, which travel through the general communication routes of the federal jurisdiction, establishes the speed limit at the one to be driven by an operator. Because of the new reality, the uses and customs of truck operators have been affected, mainly in their operating expenses. In this work, a mathematical model is presented with which the optimum driving speed of a UTTC is obtained. The speed is obtained employing the equality between the forces required to move the motor unit and the force that the tractor has available. The required forces considered are the force on the slope, the aerodynamic force, and the friction force, and the force available was considered the engine torque. This mathematical method was tested in seven routes in Mexico, obtaining significant savings of fuel above 10%. However, the best performance route possesses 65% flat terrain and 35% hillocks without mountainous terrain, regular type of highway, and a load of 20,000 kg, where the savings increase up to 16.44%.

Prescribed fire limits wildfire severity without altering ecological importance for birds

BackgroundFire suppression and anthropogenic land use have increased severity of wildfire in western U.S. dry conifer forests. Managers use fuels reduction methods (e.g., prescribed fire) to limit high-severity wildfire and restore ecological function to these fire-adapted forests. Many avian species that evolved in these forests, however, are adapted to conditions created by high-severity wildfire. To fully understand the ecological implications of fuels reduction treatments, we need to understand direct treatment effects and how treatments modulate subsequent wildfire effects on natural communities. We studied bird population and community patterns over nine years at six study units, including unburned (2002–2003), after prescribed fire (2004–2007), and after wildfire (2008–2010). We used a before-after, control-impact (BACI) approach to analyze shifts in species occupancy and richness in treated units following prescribed fire and again in relation to burn severity following wildfire.ResultsWe found examples of both positive and negative effects of wildfire and prescribed fire on bird species occupancy depending on and largely consistent with their life history traits; several woodpecker species, secondary cavity-nesting species, aerial insectivores, and understory species exhibited positive effects, whereas open cup canopy-nesting species and foliage- or bark-gleaning insectivores exhibited negative effects. Wildfire affected more species more consistently through time than did prescribed fire. Wildfire burned units initially treated with prescribed fire less severely than untreated units, but the slopes of wildfire effects on species occupancy were similar regardless of prior prescribed fire treatment.ConclusionsOur results suggest managers can employ prescribed fire to reduce wildfire severity without necessarily altering the ecological importance of wildfire to birds (i.e., the identity of species exhibiting negative versus positive responses). Additional study of the ecological implications of various fuels reduction practices, representing a range of intensities and fire regimes, would further inform forest management that includes biodiversity objectives.

The Role of BECCS in Achieving Climate Neutrality in the European Union

The achievement of climate neutrality in the European Union by 2050 will not be possible solely through a reduction in fossil fuels and the development of energy generation from renewable sources. Large-scale implementation of various technologies is necessary, including bioenergy with carbon capture and storage (BECCS), carbon capture and storage (CCS), and carbon capture and utilisation (CCU), as well as industrial electrification, the use of hydrogen, the expansion of electromobility, low-emission agricultural practices, and afforestation. This research is devoted to an analysis of BECCS as a negative emissions technology (NET) and the assessment of its implementation impact upon the possibility of achieving climate neutrality in the EU. The modelling approach utilises tools developed within the LIFE Climate CAKE PL project and includes the MEESA energy model and the d-PLACE CGE economic model. This article identifies the scope of the required investment in generation capacity and the amount of electricity production from BECCS necessary to meet the greenhouse gas (GHG) emission reduction targets in the EU, examining the technology’s impact on the overall system costs and marginal abatement costs (MACs). The modelling results confirm the key role of BECCS technology in achieving EU climate goals by 2050.

Is “Fuel Reduction” Justified as Fire Management in Spotted Owl Habitat?

The California Spotted Owl is an imperiled species that selects mature conifer forests for nesting and roosting while actively foraging in the “snag forest habitat” created when fire or drought kills most of the trees in patches. Federal agencies believe there are excess surface fuels in both of these habitat conditions in many of California’s forests due to fuel accumulation from decades of fire suppression and recent drought-related tree mortality. Accordingly, agencies such as the U.S. Forest Service are implementing widespread logging in Spotted Owl territories. While they acknowledge habitat degradation from such logging, and risks to the conservation of declining Spotted Owl populations, agencies hypothesize that such active forest management equates to effective fuel reduction that is needed to curb fire severity for the overall benefit of this at-risk species. In an initial investigation, I analyzed this issue in a large 2020 fire, the Creek Fire (153,738 ha), in the southern Sierra Nevada mountains of California. I found that pre-fire snag density was not correlated with burn severity. I also found that more intensive forest management was correlated to higher fire severity. My results suggest the fuel reduction approach is not justified and provide indirect evidence that such management represents a threat to Spotted Owls.

Modelling the impact of the energy transition on gas distribution networks in Germany

The energy transition is leading to profound changes in all parts of the energy system, but the reduction of fossil fuels in the heating sector is a major challenge for the energy sector. The changing heat-generating structure also affects its supply infrastructures. The impact on the existing electricity infrastructure is evident and subject to a lot of research, but gas distribution networks are not considered in most studies. The ongoing defossilization brings the need to assess the impact on gas distribution networks. The assumption of gas as a bridge technology might lead to potential lock-ins or sunk cost. The central question reads: how will gas distribution networks change by 2050 as we move towards a greenhouse gas neutral energy system?This question is answered by using a model network analysis called DINO to compute the infrastructure development and associated cost for existing greenhouse gas-neutral scenarios from present day until the year 2050. The supply task and the necessary network elements with their physical parameters are included in the model, and the cost-optimal gas distribution network infrastructure is calculated for each county in Germany.In short, the infrastructure analysis shows a declining need for gas distribution networks for all given greenhouse gas-neutral scenarios. In all-electric scenarios, the network length of the required grid infrastructure decreases to zero by 2050. Even in moderate scenarios with high shares of synthetic gas in the heating system, less gas distribution infrastructure is needed. The results of the research presented in this paper can be used to support the necessary measures to ensure a development of gas distribution networks that support greenhouse gas neutrality.

Effect of hybridization on mechanical, thermal and water absorption properties of biocomposite

Environmental concern over synthetic materials and sustainability issues due to the reduction of fossil fuels have given rise to remarkable progress in the development of green products like biocomposites. Natural fiber is used as reinforcement in biodegradable, ecofriendly and economic composites. However, they lack desired mechanical properties at highly humid or aqueous environment, which limits their application in many fields. Hybrid biocomposites with more than one type of natural fiber has recently drawn great research due to their improved properties. This paper focused on the studies of mechanical, thermal and water absorption properties of pure woven cotton fiber/ polystyrene (WCF/PS) and hybrid woven palm-cotton fiber/ polystyrene (WPCF/PS) biocomposite. The mechanical properties of the samples were evaluated by a Universal Testing machine (UTM) and thermal properties by Thermo Gravimetric analyzer (TGA). Water absorption properties were analyzed by % weight gain method. The mechanical properties including tensile strength, tensile modulus and impact strength were found to be higher in hybrid WPCF/PS biocomposite. Higher thermal stability and less water absorption property were observed in the hybrid sample. This study reveals that improvement in properties could be achieved in biocomposite through hybridisation of palm fiber with cotton fiber, which would help to widen their research scope and commercial acceptability.

Power Quality Improvement Using Dynamic Voltage Restorer on Grid-Connected Wind Energy System

Reduction of fossil fuels and increasing technology made importance of wind generation as renewable energy sources. With increasing number of wind farms fed to grid increases grid fault issues due to various wind systems disconnected from grid during grid faults. To get better grid operation, wind farms are probable to be carried during disturbance related to grid faults extensively known as fault ride through capability. In proposed system a fault ride through method in wind farm management system connected to grid is investigated in term of critical clearing time. This paper examines the use of dynamic voltage restorer on the enhancement of fixed-speed wind generator systems. The controller capability performance, drive performance, and cost factor are considered. Simulation is performed using MATLAB Simulink for constant speed wind generators with closed-loop controller-based DVR are tested. The constant speed drive called synchronous generator-based wind system feed to an infinite bus system. Simulation results show the wind system with DVR has better fault ride-through capability other compensated voltages and is more efficient in minimizing voltage fluctuations called sag/swell and wind generator’s speed. Additionally, DVR aids wind generators to maintain voltage sag/swell with the grid limits requirements with economical as compared to other voltage compensating systems.

Effects of fuel reduction treatments on the sporocarp production and richness of a Quercus/Cistus mixed system

Wildfire is a recurrent factor that shapes and influences Mediterranean ecosystems where mixed oak (Quercus) forests with a rockrose (Cistus) understory are broadly represented. These ecosystems are also associated with large and diverse fungal communities. These fungal communities play essential ecological roles for the survival of vascular plant, such as the mineral and water uptaking or resistance against pathogens carried out by mycorrhizal fungi, as the saprotrophic fungi are a key factor for the recycling of the dead matter. In addition, edible fungi, such as Boletus edulis, provide a source of income for the nearby rural population. Fuel reduction treatments are applied to reduce the risk of wildfire; however, their potential impact on fungal communities is unclear. Thus, the aim of this work was to investigate the effect of different fuel reduction treatments on fungi associated with Quercus and Cistus. This aim is accompanied by the management-driven objective to obtain data from fuel reduction treatments that will enable managers to find solutions with a balanced approach to maintaining productive areas of edible mushroom production while reducing fire risks across the landscape. Sporocarps were sampled over a five-year period in stands dominated by mature or coppiced Quercus pyrenaica and accompanied by Cistus ladanifer understory. These stands had been subjected to different fuel reduction treatment levels involving moderate- or high-intensity thinning, for Q. pyrenaica, or clearing, for C. ladanifer. The goal was to determine sporocarp production, species richness, and taxonomic composition. Sporocarp production and fungal richness were drastically affected by the fuel reduction treatments but only when C. ladanifer is included in the treatment. Taxa composition was strongly correlated with the treatments applied to the rockrose understory. This was probably due to the large range of associated ectomycorrhizal fungi of C. ladanifer and their high capacity to recolonize an area after disturbances. Based on our results, we conclude that the implementation of moderate-/high-intensity fuel reduction treatments is compatible with the conservation of the fungal community present in these systems. In addition, the creation of a multi-stage mosaic of stands through mechanical management could enable fire prevention to be managed in an effective way while maintaining fungal diversity and sporocarp production, favoring the use of non-wood resources in rural areas and conserving a healthier forest ecosystem.

Long-Term Effects of Fuel Reduction Treatments on Surface Fuel Loading in the Blue Mountains of Oregon

Fire exclusion and a lengthening fire season has resulted in an era of megafires. Fuel reduction treatments in forested ecosystems are designed to guard against future extreme wildfire behavior. Treatments create a heterogenous landscape and facilitate ecosystem function and resilience in fire-adapted forests of the western United States. Despite widespread recognition that repeated fuel treatments are needed to maintain desired stand characteristics over time, few field studies have evaluated treatment longevity. The Blue Mountains Fire and Fire Surrogate site in northeastern Oregon presented an opportunity to investigate woody fuel loading 15–17 years after four treatments: mechanical thin, prescribed burn, both thin and burn, and no treatment control. The principal findings were: (1) fine fuel load 15 years post-burn remained slightly below pre-treatment values; (2) rotten coarse fuel load was reduced post-burn, but sound coarse fuel was not altered by any active treatment; and (3) total woody fuel load 15–17 years post-treatment was similar to pre-treatment values. Understanding surface fuel loading is essential for predicting fire behavior. Overall, the effects of fuel reduction treatments on woody surface fuels were transitory in dry mixed conifer forests. Frequent maintenance treatments are recommended to protect values at risk in areas with high fire hazards. Quantifying the persistence of changes in forest conditions aids in the planning and analysis of future fuel treatments, along with scheduling maintenance of existing treated areas.

A numerical study on methanol steam reforming reactor utilizing engine exhaust heat for hydrogen generation

Internal combustion engines are used in most vehicles around the world to power the transport sector. Efficiency improvement, emission reduction, and utilization of alternative fuels are the main aspects of current IC engine research. Hydrogen-enhanced combustion proved to be one of the efficient ways to achieve such goals. But the problem lies in the storage of hydrogen for the transportation sector, and on-board fuel reforming is a promising option for solving this issue. It deals with transforming a suitable liquid fuel (methanol) into an H2-rich gas using a catalytic conversion process. For sustaining the reforming reaction, the required heat energy is taken from engine exhaust waste heat, this process is known as thermochemical recuperation. Number of studies on the reformers utilized for on-board hydrogen generation using engine exhaust heat are limited in the literature. The present study investigates the performance of a reactor that uses the exhaust gas heat energy for sustaining the reforming reaction. A numerical analysis was performed over a selected reactor where exhaust gases were flowing at one side, while on the other, the reforming reaction was taking place with the help of heat provided by high-temperature exhaust gases. A packed bed-type reactor was chosen for the current study and a parametric study was conducted where the effects of various operating parameters on both reacting and heating sides on the reactor's performance were investigated. It was found that temperature was the most influential inlet parameter among others. Steam/Carbon ratio and flow configuration had a negligible effect on the hydrogen yield as well as methanol conversion. Reactant inlet velocity increment revealed a significant drop in methanol conversion as it reduces the residence time for reforming reaction in the catalyst zone.

Effects of large herbivores on fire regimes and wildfire mitigation

Abstract Abandonment of agricultural land is widespread in many parts of the world, leading to shrub and tree encroachment. The increase of flammable plant biomass, that is, fuel load, increases the risk and intensity of wildfires. Fuel reduction by herbivores is a promising management strategy to avoid fuel build‐up and mitigate wildfires. However, their effectiveness in mitigating wildfire damage may depend on a range of factors, including herbivore type, population density and feeding patterns. Here, we review the evidence on whether management with herbivores can reduce fuel load and mitigate wildfires, and if so, how to identify suitable management that can achieve fire mitigation objectives while providing other ecosystem services. We systematically reviewed studies that investigated links between herbivores, fire hazard, fire frequency and fire damage. We found that, in general, herbivores reduce fuel load most effectively when they are mixed feeders, when grazing and browsing herbivores are combined and when herbivore food preferences match the local vegetation. In some cases, the combination of herbivory with other management strategies, such as mechanical clearing, is necessary to reduce wildfire damage. Synthesis and Applications. We conclude that herbivores have the capacity to mitigate wildfire damage, and we provide guidance for grazing management for wildfire mitigation strategies. As areas undergoing land abandonment are particularly prone to wildfires, the maintenance or promotion of grazing by domestic or wild herbivores is a promising tool to reduce wildfire risk in a cost‐effective way, while also providing other ecosystem services. Relevant land‐use policies, including fire suppression policies, agricultural and forest(ry) policies could incentivise the use of herbivores for better wildfire prevention.

Research on Control System of 5-DOF Magnetic Suspension Flywheel Battery

With the continuous reduction of fossil fuels, pure gasoline vehicles and diesel vehicles will inevitably withdraw from the stage of history. In contrast, new energy vehicles have huge room for development. However, the battery life and charging time of new energy vehicles are two important factors restricting their development. Therefore, more efficient energy storage methods need to be studied. Compared with traditional batteries, the new flywheel battery has attracted more scholars' attention due to its advantages of high charge and discharge efficiency, large stored energy, and long life cycle. In order to improve the performance of the flywheel battery and reduce the loss, a five-degree-of-freedom magnetic levitation flywheel battery is proposed in the paper to replace the traditional bearing-supported flywheel battery. Usually, the research on flywheel battery only focuses on a single aspect, and there are few literature to analyze the entire flywheel battery control system. Hence, the structure and principle of the five-degree-of-freedom flywheel battery are first introduced in the paper to design the control system for the five-degree-of-freedom flywheel battery and build a simulation model with the help of the Matlab/Simulink software. Finally, an experimental platform for the five-degree-of-freedom flywheel battery is established to conduct the experimental study to verify the reliability of the control system. The experimental results show that the five-degree-of-freedom flywheel battery control system proposed in the paper has good performance and stability.

Geometrical inlet effects on the behavior of a non-premixed fully turbulent syngas combustion; a numerical study

This study numerically evaluates a three-dimensional, turbulent, non-premixed syngas (a mixture of H2 and CO) flame issued from a round nozzle. The flow Reynolds number on the basis of the inlet velocity and the nozzle diameter is 16,700 and the flame is shrouded by a coflow under atmospheric conditions. A computational tool with a modified k-omega turbulence model and eddy dissipation model is used for simulating the reacting flow and its immediate surroundings. The outcomes are first compared against the existing experimental data. This reveals that when β*, as a constant coefficient in the k-omega turbulence model, is 0.073, the numerical results match the experimental data with high accuracy. Subsequently, the effects of variations in the diameter of the inlet nozzle and its geometry are investigated. This shows that an increase in the inlet nozzle diameter leads to the downstream movement of the high-temperature region diminishing combustion efficiency. Importantly, it is shown that using the elliptical inlet nozzle with the large diameter of 1.2 based nozzle diameter (4.48 mm) assists the combustion performance and increases the maximum combustion temperature by up to 9.6%. It also results in a considerable reduction of the unburned fuels and enhances the flow residence time significantly.

Mechanochemical Approach for Oxide Reduction of Spent Nuclear Fuels for Pyroprocessing

Solid-state mechanochemical reduction combined with subsequent melting consolidation was suggested as a technical option for the oxide reduction in pyroprocessing. Ni ingot was produced from NiO as a starting material through this technique while Li metal was used as a reducing agent. To determine the technical feasibility of this approach for pyroprocessing, which handles spent nuclear fuels, thermodynamic calculations of the phase stabilities of various metal oxides of U and other fission elements were made when several alkaline and alkali-earth metals were used as reducing agents. This technique is expected to be beneficial, not only for oxide reduction but also for other unit processes involved in pyroprocessing.

AEMFC Exploiting a Pd/CeO2-Based Anode Compared to Classic PEMFC via LCA Analysis

The hydrogen economy relies on effective and environmentally friendly processes for energy conversion and storage. To this end, hydrogen is progressively holding the role of preferred energy vector. Within this frame, electrochemical science and technology is actively contributing in developing advanced fuel cells and water electrolyzers to be integrated in (i) energy parks to decouple production and consumption; (ii) exploit renewable sources; (iii) favour the progressive reduction of fossil fuels and reduce the greenhouse effect via decarbonization. The exploitation of the relevant processes and devices call for the sound control over the environmental impact from production to end-of-life steps. Here, life-cycle analyses were performed and discussed focusing on both acid and alkaline fuel cells, i.e., proton exchange membrane fuel cells (PEMFC) and anion-exchange membrane fuel cells (AEMFC), and assessing their contribution to key environmental impact categories such as, for example, global warming and ozone layer depletion. Within these premises, the study points to the benefits of replacing platinum by low load Pd/CeO2 bifunctional electrocatalyst on electrochemical hydrogen production and usage.

The Effect of Repeated Prescribed Burning on Soil Properties: A Review

Prescribed burning is a tool that is frequently used for various land management objectives, mainly related to reduction of hazardous forest fuels, habitat management and ecological restoration. Given the crucial role of soil in forest ecosystem processes and functions, assessing the effects of prescribed burning on soil is particularly relevant. This study reviews research on the impacts of repeated prescribed burning on the physical, chemical and biological properties of soil. The available information shows that the effects are highly variable, rather inconsistent and generally minor for most of the soil characteristics studied, while a number of soil properties show contrasting responses. On the other hand, ecosystem characteristics, differences in fire severity, frequency of application and the cumulative effect of treatment repetition over time, have possibly made it more difficult to find a more common response in soil attributes. Our study has also revealed some limitations of previous research that may have contributed to this result, including a limited number of long-term studies, conducted at a few experimental sites, and in a limited number of forest ecosystems. Research issues concerning the effects of prescribed fire on soil are presented. The need to integrate such research into a broader interdisciplinary framework, encompassing the role of the fire regime on ecosystem functions and processes, is also highlighted.

Experts’ multiple criteria evaluations of fuel management options to reduce wildfire susceptibility. The role of closer knowledge of the local socioeconomic context

Expert opinion can be a valuable tool for informed decision making. Concerning wildfire susceptibility reduction at the landscape scale, forest ecosystem experts play a key role in offering advice about appropriate fuel management practices to be applied by forest owners or their organizations, and in shaping public policies. A literature review aimed at identifying fuel management interventions and techniques found multiple and even opposing strategies. Recognizing the interdisciplinary and multi-dimensional nature of fuel management, we go beyond existing studies on forest experts’ opinions by comparing evaluations across forest experts with diverse training and experience, and by considering different evaluation criteria such as technical effectiveness, impact on soil or biodiversity, socioeconomic impact, and preference. Following an online survey to a sample of Portuguese experts, distinct socio-professional clusters were established and experts’ evaluations associated with their views on fire, forests, owners’ coordination, and rural development. Results show that experts rank their preferences by weighing effectiveness and impacts in different ways. Closer knowledge of the local context distinguishes expert preference, favouring more active fuels reduction strategies. Since experts with a closer knowledge of socioeconomic context tend to be further from policy-making processes, we urge their more balanced participation in those processes.

Fuel load, stand structure, and understory species composition following prescribed fire in an old-growth coast redwood (Sequoia sempervirens) forest

BackgroundWith the prevalence of catastrophic wildfire increasing in response to widespread fire suppression and climate change, land managers have sought methods to increase the resiliency of landscapes to fire. The application of prescribed burning in ecosystems adapted to fire can reduce fuel load and fire potential while minimizing impacts to the ecosystem as a whole. Coast redwood forests have historically experienced fire from both natural and anthropogenic sources, and are likely to respond favorably to its reintroduction.ResultsRandom sampling was conducted in three burned sites and in three unburned sites, in an old-growth coast redwood (Sequoia sempervirens [D. Don] Endl.) forest. Data were collected on fuel, forest structure, and understory species composition and compared between treatments. Downed woody fuel, duff depth, litter depth, and density of live woody fuels were found to be significantly lower on sites treated with fire compared to unburned sites. Density of the dominant overstory canopy species, coast redwood and Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco), remained consistent between treatments, and the abundance of herbaceous understory plant species was not significantly altered by burning. In addition, both downed woody fuel and live fuel measures were positively correlated with time since last burn, with the lowest measures on the most recently burned sites.ConclusionsOur results indicated that the use of prescribed burning in old-growth redwood forests can provide beneficial reductions in live and dead surface fuels with minimal impacts to overstory trees and understory herbaceous species.

Coupling Strategy for CO2Valorization Integrated with Organic Synthesis by Heterogeneous Photocatalysis

AbstractPhotocatalytic reduction of CO2to solar fuels and/or fine chemicals is a promising way to increase the energy supply and reduce greenhouse gas emissions. However, the conventional reaction system for CO2photoreduction with pure H2O or sacrificial agents usually suffers from low catalytic efficiency, poor stability, or cost‐ineffective atom economy. A recent surge of developments, in which photocatalytic CO2valorization is integrated with selective organic synthesis into one reaction system, indicates an efficient modus operandi that enables sufficient utilization of photogenerated electrons and holes to achieve the goals for sustainable economic and social development. In this Review we discuss current advances in cooperative photoredox reaction systems that integrate CO2valorization with organics upgrading based on heterogeneous photocatalysis. The applications and virtues of this strategy and the underlying reaction mechanisms are discussed. The ongoing challenges and prospects in this area are critically discussed.