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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Photon to plate: A holistic view of photosynthetic and anthropogenic energy fluxes

Modern agriculture couples photosynthetic energy with human-applied energy supplements (e.g., fertilizers, labor, cultivation) to feed a growing population. These energy supplements usually come from fossil fuels, presenting an opportunity to decrease fossil fuel required per calorie by improving photosynthetic efficiency. To quantify how improving photosynthetic efficiency would decrease the supplemental energy needed per calorie, we present a “photon to plate” life cycle analysis of energy flows (photosynthetic and human-applied) needed to produce fresh-cut fries. Our results show that photosynthetic inefficiencies require ~80 times the energy used to cultivate, harvest, transport and prepare fries for consumption and that improvements to photosynthesis could reduce the energy applied by humans per calorie by almost 40%. This study highlights the magnitude of energy used during photosynthesis and the potential for photosynthetic improvements to increase agricultural sustainability.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Hybrid-energy approach enabled by heat storage and oxy-combustion to generate electricity with near-zero or negative CO 2 emissions

We assess a hybrid-energy approach that modifies a steam-turbine power plant to use renewable energy sources (electricity, plus options for geothermal and solar heat), plus fossil fuel (natural gas and coal) and/or waste biomass (e.g., Douglas fir woodchips). Heat storage allows heat to be created during periods of excess energy supply and for that heat to be converted to electricity when demanded. Excess electricity, such as from variable renewable energy (VRE), is used to generate oxygen for oxy-combustion furnaces that create very-hot, high-purity CO 2 that heats granular rock beds in insulated vessels. Cool CO 2 leaving the beds is dried, sent to compressors powered by excess VRE electricity, before being sent by pipeline to geologic CO 2 storage. Very-hot CO 2 transfers high-grade heat from storage to the power plant in a closed loop that returns medium-grade heat back to storage, allowing low- and medium-grade renewable-heat sources to be stacked beneath combustion heat, with all heat sources being converted to electricity at the same (high) thermal efficiency. Reliable, on-demand power may be generated with near-zero CO 2 emissions with fossil fuel and with negative CO 2 emissions with waste biomass. Our analyses show that with fossil fuel, up to 35% of gross power can be derived from renewable sources, while for waste biomass, it can be entirely derived from renewable sources. Because our approach has the potential to ensure that grids have a continuous supply of clean energy and because electricity is only generated once, when demanded, it could serve as an efficient alternative to bulk energy storage.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2015

Impact of solar panels on global climate

Regardless of the harmful effects of burning fossil fuels on global climate1,2, other energy sources will become more important in the future because fossil fuels could run out by the early twenty-second century3 given the present rate of consumption4. This implies that sooner or later humanity will rely heavily on renewable energy sources. Here we model the effects of an idealized large-scale application of renewable energy on global and regional climate relative to a background climate of the representative concentration pathway 2.6 scenario (RCP2.6; ref. 5). We find that solar panels alone induce regional cooling by converting incoming solar energy to electricity in comparison to the climate without solar panels. The conversion of this electricity to heat, primarily in urban areas, increases regional and global temperatures which compensate the cooling effect. However, there are consequences involved with these processes that modulate the global atmospheric circulation, resulting in changes in regional precipitation.

Environmental Sciences & Ecology↗
DOE OSTI2015

Southward shift of the northern tropical belt from 1945 to 1980

Regardless of the harmful effects of burning fossil fuels on global climate1,2, other energy sources will become more important in the future because fossil fuels could run out by the early twenty-second century3 given the present rate of consumption4. This implies that sooner or later humanity will rely heavily on renewable energy sources. Here we model the effects of an idealized large-scale application of renewable energy on global and regional climate relative to a background climate of the representative concentration pathway 2.6 scenario (RCP2.6; ref. 5). We find that solar panels alone induce regional cooling by converting incoming solar energy to electricity in comparison to the climate without solar panels. The conversion of this electricity to heat, primarily in urban areas, increases regional and global temperatures which compensate the cooling effect. However, there are consequences involved with these processes that modulate the global atmospheric circulation, resulting in changes in regional precipitation.

Geology↗
DOE OSTI2016

Investigation of the Effects of Hydrogen Atoms Concentration on the Tungsten Sigma 5 (310) Symmetric Tilt Grain Boundary Strength

Recently, strict policies are being made by several government agencies, environmentalists, and some people against the usage of fossil fuels as the source of energy generation. Not only because its supply does not meet the booming human population all around the world but also it is not pollution-free; just to mention a few. These setbacks attached to fossil fuels make nuclear fusion energy an important means of energy generation; it is characterized with clean and easy means of energy generation compared to other methods of power production such as hydropower and solar power. The success of fusion power depends on the design of modern fusion materials and the selection of the plasma facing materials (PFMs). ITER and Demonstration Power plant (DEMO) considered Tungsten (W) as part of their PFMs. W is the most preferred plasma facing material (PFM) for the future nuclear fusion reactors such as in the proposed DEMO and ITER- which is at the moment the largest Tokamak nuclear fusion reactor under construction in the world. Tungsten has excellent thermal properties, low-sputtering yield, and high melting point. Hydrogen (H) atoms have an affinity for tungsten grain boundary, and are trapped there permanently. In addition, it makes W prone to failure. In a fusion environment, W is exposed to extremely high fluences of H isotopes and irradiation. The low-energy H isotopes will be retained in the tungsten material leading to the formation of blisters in W and cause degradation of the mechanical and thermal properties of W. For safety reason, the effect of hydrogen atoms concentration at the tungsten S5 (310) grain boundary (GB) needs to be investigated and it will aid in better designing of fusion wall materials. Σ5 (310) is considered in this work because it is one of the most important and dominant GBs in the atomic distribution of materials. GBs affect the strength of W as well. The GBs with superior properties can be increased in the atomic distribution of W relative to others in order to achieve high overall material properties. GBs play a role in determining the properties of materials such as the thermal and electrical conductivity of a material. The crystallography description of the Σ5 (310) grain boundary comprises of Σ, tilt type- symmetric, crystallographic direction [001] and the GB plane. The Σ is related to the coincidence site lattice (CSL) model, which denotes that in a certain orientation between two grains, there are numbers of points where the atoms coincide. For the case of Σ5 (310), the misorientation between the two crystals is 36.9 degree along [001] direction and the GB plane is (310). GB properties differ as result of different sigma values and Σ is the reciprocal of CSL. Thus, Σ5 GB has 1/5 of the atoms in coincident sites. For the case of a tilt boundary, the lattice vector is embedded in the GB plane. Also for a tilt-symmetric GB, the grains directions are mirrored against the GB plane. The classic molecular dynamics method (MD) is an accurate numerical approach that adopts Newton's equation of motion to get atoms trajectories.Studies have been carried out on atomistic simulation of tungsten.The effect of H on GB migration in W was studied by using molecular dynamics simulation and it was discovered that H prevents the GB migration at different H concentrations and temperatures. Others investigated the migration, dissolution and trapping of H in W using MD and first principles method. Atomistic simulations have been used to predict the GB energy in Fe and Mo using embedded atom method (EAM) and it was concluded that the GB energies in the metals are affected more by the orientation of the GB plane than by the misorientation of the lattice. Study was done on symmetric and asymmetric tilt grain boundaries in Cu and Al using MD method and the GB structures and energies were established; EAM was adopted as well. The formation of hydrogen blisters and cracking processes for various tungsten materials were investigated and it was observed that, dopants increase the number of blisters and exfoliations for both stress relieved and recrystallized W. Investigation was carried out on the surface morphology changes in W caused by plasmas heat and particle loadings and their effects on material degradation in ITER. In addition, the study of interactions between low energetic hydrogen and tungsten surface was carried out using molecular dynamics simulations with analytical bond order potential (ABOP) and the results addressed irradiation damage in tungsten. Mechanism of blister formation on W surface was studied using experimental approach and it was observed that the amount of blisters formed depends on the beam fluence. This work investigates the effect of hydrogen atom concentrations at the W Σ5 (310) tilt-symmetric GB on the grain boundary energy and the GB pulling force. (authors)

36 MATERIALS SCIENCE↗
DOE OSTI2015

A space-based, high-resolution view of notable changes in urban NO x pollution around the world (2005-2014)

Nitrogen oxides (NO x = NO + NO 2 ) are produced during combustion processes and, thus may serve as a proxy for fossil fuel-based energy usage and coemitted greenhouse gases and other pollutants. We use high-resolution nitrogen dioxide (NO 2 ) data from the Ozone Monitoring Instrument (OMI) to analyze changes in urban NO 2 levels around the world from 2005 to 2014, finding complex heterogeneity in the changes. We discuss several potential factors that seem to determine these NO x changes. First, environmental regulations resulted in large decreases. The only large increases in the United States may be associated with three areas of intensive energy activity. Second, elevated NO 2 levels were observed over many Asian, tropical, and subtropical cities that experienced rapid economic growth. Two of the largest increases occurred over recently expanded petrochemical complexes in Jamnagar (India) and Daesan (Korea). Third, pollution transport from China possibly influenced the Republic of Korea and Japan, diminishing the impact of local pollution controls. However, in China, there were large decreases over Beijing, Shanghai, and the Pearl River Delta, which were likely associated with local emission control efforts. Fourth, civil unrest and its effect on energy usage may have resulted in lower NO 2 levels in Libya, Iraq, and Syria. Fifth, spatial heterogeneity within several megacities may reflect mixed efforts to cope with air quality degradation. We also show the potential of high-resolution data for identifying NO x emission sources in regions with a complex mix of sources. Lastly, intensive monitoring of the world's tropical/subtropical megacities will remain a priority, as their populations and emissions of pollutants and greenhouse gases are expected to increase significantly.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Bringing research findings to the real world is an essential and rewarding experience

The pending changes in the U.S. presidential administration and Congress threaten the ongoing progress being made in lowering U.S. greenhouse gas (GHG) emissions. Yet the need for reducing emissions and directly addressing the energy-climate crisis has never been greater. The energy-climate crisis is defined as the situation created by reliance on fossil fuels for 80% of global energy supply, the combustion of which releases CO 2 , the main greenhouse gas causing global warming. Instead of allowing the U.S. national political situation to be a distraction, scientists, engineers, and policy experts need to push even harder to turn research findings into practical applications so those findings can contribute to actually reducing emissions. In addition, scientists and engineers need to communicate research results to lawmakers and the public to reinforce the urgency of directly addressing the energy-climate crisis. Without giving away still-developing conclusions of the ongoing project, this paper describes that facilitating practical application of research results can be a very rewarding and satisfying experience.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Energy Transition: Challenges and Opportunities for the Oil & Gas Industry

The energy sector has been experiencing a massive but gradual shift in recent years toward renewable and low-carbon energy sources. The future of fossil fuels lies in the ability of the industry to adapt to the market, environment, and social trends within the energy transition framework. In this chapter, we review the challenges that the oil and gas industry will be facing in the coming years. We then explore opportunities and growth areas that this transition provides to the industry. This chapter focuses on three areas of digitization and modernization, developing innovative low-carbon fuels, and harnessing underground and offshore facilities and expertise.

blockchain technology↗
DOE OSTI2019

Computational study of full-scale VHTR lower plenum for turbulent mixing assessment

Next-generation nuclear reactors are poised to efficiently provide reliable power at enhanced safety levels for many years to come. Among the fundamental designs for these reactors is the very-hightemperature reactor (VHTR), which employs helium as the primary coolant and has the potential of reaching elevated temperatures such that chemical processing (e.g., electrolysis for hydrogen production) is viable alongside traditional electricity generation. This and other next-generation reactors also represent a strategic bridge for ultimately transitioning from fossil fuel-dominated energy portfolios to one where renewable options abound. For the VHTR, the ultimate goal of constructing a new plant will be preceded by additional fundamental research aimed at generating trusted models for behavior prediction under normal and accident scenarios. This paper presents a detailed computational fluid dynamics simulation of the lower plenum, where hot coolant from the core mixes together in a turbulent fashion before traveling to power conversion equipment. Because the flow is expected to enter the lower plenum across a wide range of temperatures and velocities, concerns exist when the mixing is incomplete. The potential hot spots on cylindrical support pedestals and the uniformity of the main outlet are the primary metrics of interest in this study, along with flow velocities and temperatures at different locations within the lower plenum. Three locations are probed in detail and suggest a large range exists for approach velocities and temperatures. A large degree of stratification is also seen on the surfaces of the support pedestals, suggesting a facility should accommodate testing for such behavior. The characterizations presented provide the valuable data needed in order to design appropriate experimental testbeds, where scaled modeling can be carried out in a manner meaningful in predicting the full-scale behavior.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Graphene nanoplatelets reinforced cement as a solution to leaky wellbores reinforcing weak points in hydrated Portland cement with graphene nanoparticles improves mechanical and chemical durability of wellbore cements

In this work, to improve the performance of wellbore cement under subsurface environments, graphene nanoplatelets (GNPs) were added in various percentages to Class-H cement slurry. Microstructural characterization of cement slurries cured at 90 °C and 95% RH indicates that GNP modifies the microstructure of hydrated cement by reinforcing pore spaces. As a result, the mechanical properties, such as Young's modulus and axial peak stress, obtained from high temperature triaxial compression tests are significantly improved based on different percentages of added GNPs. Furthermore, the hydrated 1 × 2 inch GNP- Portland cement cores tested under simulated deep wellbore conditions of high-temperature and high pressure (HTHP), appear to have a ductile-like behavior, when compared to a typical brittle nature of Portland cement pastes. From our observations and published data on graphene resistance to fracture, GNP addition to cement is evidently enhancing the flexibility of cement. These improvements would reduce the risks associated with wellbore cement deterioration and a consequent leakage in fossil fuel production, geothermal energy production, CO 2 storage as well as long-term sealing materials in plugging and abandonment of all wellbores at the end of their service life.

36 MATERIALS SCIENCE↗
DOE OSTI2020

The reservoir network: A new network topology for district heating and cooling

Thermal district networks are effective solutions to substitute fossil fuels with renewable energy sources for heating and cooling. Moreover, thermal networking of buildings allows energy efficiency to be further increased. The waste heat from cooling can be reused for heating in thermal district systems. Because of bidirectional energy flows between prosumers, thermal networks require new hydraulic concepts. In this work, we present a novel network topology for simultaneous heating and cooling: the reservoir network. The reservoir network is robust in operation due to hydraulic decoupling of transfer stations, integrates heat sources and heat sinks at various temperature levels and is flexible in terms of network expansion. Furthermore, we used Modelica simulations to compare the new single-pipe reservoir network to a basecase double-pipe network, taking yearly demand profiles of different building types for heating and cooling. The electric energy consumed by the heat pumps and circulations pumps differs between the reservoir and base case networks by less than 1%. However, if the reservoir network is operated with constant instead of variable mass flow rate, the total electrical consumption can increase by 48% compared to the base case. As with any other network topology, the design and control of such networks is crucial to achieving energy efficient operation. Investment costs for piping and trenching depend on the district layout and dimensioning of the network. If a ring layout is applied in a district, the reservoir network with its single-pipe configuration is more economical than other topologies. For a linear layout, the piping costs are slightly higher for the reservoir network than for the base case because of larger pipe diameters.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Role of pH and Eh in geothermal systems: Thermodynamic examples and impacts on scaling and corrosion

The global demand for sustainable and clean renewable energy sources is rapidly increasing to meet growing energy demands while curtailing the CO2 emissions from fossil fuels. Harnessing the natural heat or geothermal energy of the Earth's interior can simultaneously address both issues by offering a clean and renewable energy source. Enhanced geothermal systems require the movement and cycling of fluid through a porous rock media. Further, this process requires understanding the chemistry occurring at the fluid-rock and fluid-metal interfaces both in the deep subsurface and surface, where fluid is circulated for energy transfer or storage. In this review paper, we evaluate the current state of research on how two key variables, pH and Eh, control the fluid-rock reactions controlling mineral scaling and the steel corrosion reactions associated with geothermal systems. These variables are frequently used in geochemical modeling to predict chemical reactions in geothermal systems. Prediction of the fluid-rock behavior can be utilized to formulate new strategies for extending the lifespan and efficiency of heat extraction and utilization and maximizing the safety of geothermal systems.

15 GEOTHERMAL ENERGY↗
DOE OSTI2019

Operation of a 50-kW th chemical looping combustion test facility under autothermal conditions

The United States Department of Energy is developing transformational fossil fuel combustion technologies that result in more efficient power cycles and/or substantial reductions in GHG emissions. Chemical Looping Combustion (CLC) has the potential to achieve a lower cost of electricity than a supercritical pulverized coal power plant with an amine absorption system. Although the concept and research on chemical looping has a long history, CLC has numerous technical issues that must be addressed prior to a commercial debut. This effort is directed toward the following major issues for CLC: (1) demonstrating continuous solids handling, operability, and reactor performance at autothermal conditions and (2) preliminary assessments of oxygen carrier attrition and relative material make-up costs. These are critical issues that should be addressed under realistic conditions prior to directing resources toward larger scale demonstrations. This paper will also describe NETL’s small 50-kWth natural gas circulating CLC test facility located in Morgantown, WV. Despite its small size, this experimental test unit has operated at autothermal conditions for 11 h using a copper-iron-alumina oxygen carrier developed at NETL. Here, this paper will describe the test facility and operating experiences using NETL’s “Gen 2.0” oxygen carrier material. Natural gas conversion to CO2 ranged from 70 to 90% over approximately 75 oxidation-reduction cycles during the autothermal operating period. Estimates for the process specific attrition rate during autothermal operation are also presented. Finally, estimates for the oxygen carrier makeup cost, specific to the NETL process configuration, are several orders of magnitude greater than the NETL target. Future work should focus on reducing the oxygen carrier material cost and improving the attrition resistance of the oxygen carrier material under autothermal test conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Microwave-assisted ammonia decomposition over metal nitride catalysts at low temperatures

The negative environmental impact of fossil fuel-based energy systems has unveiled the need to develop a CO x -free sustainable hydrogen (H 2 ) economy. Employing a microwave-assisted route, a ternary metal nitride catalyst (i.e., Co 2 Mo 3 N), and a low-temperature-pressure NH 3 decomposition process, this study investigated the possibility of developing a distributed H 2 production process. Here, this study not only explored lower cost-based catalyst systems but also the use of a microwave reactor to increase the energy efficiency of the process. Results from catalytic NH 3 decomposition experiments, performed in microwave reactors on Co 2 Mo 3 N catalyst, demonstrated the peak energy efficiency (of ~0.006 kgH 2 /kWh) at 400 °C in ambient pressure (with an NH 3 conversion >90%) which was around ninety times (~90 x) more efficient than a conventional system. Activation energy calculation also displayed a 20% less energy requirement for the microwave-based process (~31 kJ mol -1 ) than the conventional system (~37 kJ mol -1 ), indicating the advantage of the microwave-based process. Further microwave-assisted catalytic measurements and characterization of the Co 2 Mo 3 N catalyst, using x-ray diffraction (XRD) technique and scanning electron microscopic (SEM) images, revealed the excellent stability of this material at its peak performance (at 400 °C) and illustrated the potential of using this catalyst for a sustainable, economic, and energy-efficient approach for producing CO x -free H 2 .

08 HYDROGEN↗
DOE OSTI2023

To what extent can decommissioning options for marine artificial structures move us toward environmental targets?

Switching from fossil fuels to renewable energy is key to international energy transition efforts and the move toward net zero. For many nations, this requires decommissioning of hundreds of oil and gas infrastructure in the marine environment. Current international, regional and national legislation largely dictates that structures must be completely removed at end-of-life although, increasingly, alternative decommissioning options are being promoted and implemented. Yet, a paucity of real-world case studies describing the impacts of decommissioning on the environment make decision-making with respect to which option(s) might be optimal for meeting international and regional strategic environmental targets challenging. To address this gap, we draw together international expertise and judgment from marine environmental scientists on marine artificial structures as an alternative source of evidence that explores how different decommissioning options might ameliorate pressures that drive environmental status toward (or away) from environmental objectives. Synthesis reveals that for 37 United Nations and Oslo-Paris Commissions (OSPAR) global and regional environmental targets, experts consider repurposing or abandoning individual structures, or abandoning multiple structures across a region, as the options that would most strongly contribute toward targets. This collective view suggests complete removal may not be best for the environment or society. However, different decommissioning options act in different ways and make variable contributions toward environmental targets, such that policy makers and managers would likely need to prioritise some targets over others considering political, social, economic, and ecological contexts. Current policy may not result in optimal outcomes for the environment or society.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Nepal Himalaya offers considerable potential for pumped storage hydropower

There is a pressing need for a transition from fossil fuel to renewable energy to meet the increasing energy demands and reduce greenhouse gas emissions. The Himalayan region, with its unique topography and abundant water resources, offers substantial renewable energy potential, particularly through hydropower generation. However, the current exploitation rate is low owing to the predominance of run-of-river hydropower systems to support the power system. The utility-scale storage facility is crucial in the load scenario of an integrated power system to manage diurnal variation, peak demand, and penetration of intermittent energy sources. In this study, we assess the potential of pumped storage hydropower across Nepal, a central Himalayan country, under multiple configurations by pairing lakes, rivers, and available flat terrains. We then identify technically feasible pairs from those of potential locations. Infrastructural, environmental, operational, and other technical constraints govern the choice of feasible locations. Here, we show that 42% of the theoretical potential of 3000 GWh is technically feasible. We find the flat land-to-river configuration more promising than other configurations. Our findings provide insight into the potential of pumped storage hydropower and are of practical importance in planning sustainable power systems in the Himalayas and beyond.

13 HYDRO ENERGY↗
DOE OSTI2022

Electronic Structure-Based Descriptors for Oxide Properties and Functions

The transition from fossil fuels to renewable energy requires the development of efficient and cost-effective energy storage technologies. A promising way forward is to harness the energy of intermittent renewable sources, such as solar and wind, to perform (electro)catalytic reactions to generate fuels, thus storing energy in the form of chemical bonds. Furthermore, current catalysts rely on the use of expensive, rare, or geographically localized elements, such as platinum. Widespread adoption of new (electro)catalytic technologies hinges on the discovery and development of materials containing earth-abundant elements, which can efficiently catalyze an array of (electro)chemical reactions.

Adsorption↗