United States
Experimental Investigation of Stress Corrosion on Supercritical CO2 Transportation Pipelines Against Leakage for CCUS Applications
Nov 2022
Publication
Carbon Capture Utilization and Storage (CCUS) is one of the key technologies that will determine how humans address global climate change. For captured CO2 in order to avoid the complications associated with two-phase flow most carbon steel pipelines are operated in the supercritical state on a large scale. A pipeline has clear Stress Corrosion Cracking (SCC) sensitivity under the action of stress and corrosion medium which will generally cause serious consequences. In this study X70 steel was selected to simulate an environment in the process of supercritical CO2 transportation by using high-temperature high-pressure Slow Strain Rate Tensile (SSRT) tests and high-temperature high-pressure electrochemical test devices with different O2 and SO2 contents. Studies have shown that 200 ppm SO2 shows a clear SCC sensitivity tendency which is obvious when the SO2 content reaches 600 ppm. The SCC sensitivity increases with the increase of SO2 concentration but the increase amplitude decreases. With the help of advanced microscopic characterization techniques such as scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) through the analysis of fracture and side morphology the stress corrosion mechanism of a supercritical CO2 pipeline containing SO2 and O2 impurities was obtained by hydrogen embrittlement fracture characteristics. With the increase of SO2 content the content of Fe element decreases and the corrosion increases demonstrating that SO2 plays a leading role in electrochemical corrosion. This study further strengthens the theoretical basis of stress corrosion of supercritical CO2 pipelines plays an important role in preventing leakage of supercritical CO2 pipelines and will provide guidance for the industrial application of CCUS.
Process of Transformation to Net Zero Steelmaking: Decarbonisation Scenarios Based on the Analysis of the Polish Steel Industry
Apr 2023
Publication
The European steel industry is experiencing new challenges related to the market situation and climate policy. Experience from the period of pandemic restrictions and the effects of Russia’s armed invasion of Ukraine has given many countries a basis for including steel along with raw materials (coke iron ore electricity) in economic security products (CRMA). Steel is needed for economic infrastructure and construction development as well as a material for other industries (without steel factories will not produce cars machinery ships washing machines etc.). In 2022 steelmakers faced a deepening energy crisis and economic slowdown. The market situation prompted steelmakers to impose restrictions on production volumes (worldwide production fell by 4% compared to the previous year). Despite the difficult economic situation of the steel industry (production in EU countries fell by 11% in 2022 compared to the previous year) the EU is strengthening its industrial decarbonisation policy (“Fit for 55”). The decarbonisation of steel production is set to accelerate by 2050. To sharply reduce carbon emissions steel mills need new steelmaking technologies. The largest global steelmakers are already investing in new technologies that will use green hydrogen (produced from renewable energy sources). Reducing iron ore with hydrogen plasma will drastically reduce CO2 emissions (steel production using hydrogen could emit up to 95% less CO2 than the current BF + BOF blast furnace + basic oxygen furnace integrated method). Investments in new technologies must be tailored to the steel industry. A net zero strategy (deep decarbonisation goal) may have different scenarios in different EU countries. The purpose of this paper was to introduce the conditions for investing in low-carbon steelmaking technologies in the Polish steel market and to develop (based on expert opinion) scenarios for the decarbonisation of the Polish steel industry.
Artificial Intelligence/Machine Learning in Energy Management Systems, Control, and Optimization of Hydrogen Fuel Cell Vehicles
Mar 2023
Publication
Environmental emissions global warming and energy-related concerns have accelerated the advancements in conventional vehicles that primarily use internal combustion engines. Among the existing technologies hydrogen fuel cell electric vehicles and fuel cell hybrid electric vehicles may have minimal contributions to greenhouse gas emissions and thus are the prime choices for environmental concerns. However energy management in fuel cell electric vehicles and fuel cell hybrid electric vehicles is a major challenge. Appropriate control strategies should be used for effective energy management in these vehicles. On the other hand there has been significant progress in artificial intelligence machine learning and designing data-driven intelligent controllers. These techniques have found much attention within the community and state-of-the-art energy management technologies have been developed based on them. This manuscript reviews the application of machine learning and intelligent controllers for prediction control energy management and vehicle to everything (V2X) in hydrogen fuel cell vehicles. The effectiveness of data-driven control and optimization systems are investigated to evolve classify and compare and future trends and directions for sustainability are discussed.
Reduction in Greenhouse Gas and Other Emissions from Ship Engines: Current Trends and Future Options
Nov 2022
Publication
The impact of ship emission reductions can be maximised by considering climate health and environmental effects simultaneously and using solutions fitting into existing marine engines and infrastructure. Several options available enable selecting optimum solutions for different ships routes and regions. Carbon-neutral fuels including low-carbon and carbon-negative fuels from biogenic or non-biogenic origin (biomass waste renewable hydrogen) could resemble current marine fuels (diesel-type methane and methanol). The carbon-neutrality of fuels depends on their Well-to-Wake (WtW) emissions of greenhouse gases (GHG) including carbon dioxide (CO2) methane (CH4) and nitrous oxide emissions (N2O). Additionally non-gaseous black carbon (BC) emissions have high global warming potential (GWP). Exhaust emissions which are harmful to health or the environment need to be equally removed using emission control achieved by fuel engine or exhaust aftertreatment technologies. Harmful emission species include nitrogen oxides (NOx) sulphur oxides (SOx) ammonia (NH3) formaldehyde particle mass (PM) and number emissions (PN). Particles may carry polyaromatic hydrocarbons (PAHs) and heavy metals which cause serious adverse health issues. Carbon-neutral fuels are typically sulphur-free enabling negligible SOx emissions and efficient exhaust aftertreatment technologies such as particle filtration. The combinations of carbon-neutral drop-in fuels and efficient emission control technologies would enable (near-)zero-emission shipping and these could be adaptable in the short- to mid-term. Substantial savings in external costs on society caused by ship emissions give arguments for regulations policies and investments needed to support this development.
Everything About Hydrogen Podcast: Plotting the Course for a Decarbonized Global Maritime Industry
Jan 2023
Publication
On this episode of EAH we sat down with Dr. Bo Cerup-Simonsen Chief Executive Officer of the Maersk Mc-Kinney Møller Center for Zero Carbon Shipping. Bo holds a PHD in Naval Architecture and Mechanical Engineering and spent seven years as a research engineer at MIT.
Bo explains the Center's work and we discuss decarbonization of shipping using hydrogen derived green fuels.
The podcast can be found on their website.
Bo explains the Center's work and we discuss decarbonization of shipping using hydrogen derived green fuels.
The podcast can be found on their website.
Electric Aircraft Fueled by Liquid Hydrogen and Liquefied Natural Gas
Jul 2021
Publication
The paper is a review of the opportunities and challenges of cryogenic power devices of electric aircraft and the ongoing research and development efforts of the government agencies and the industry. Liquid Hydrogen (LH2) and Liquefied Natural Gas (LNG) are compared to support high temperature superconducting (HTS) and normal metal devices respectively. The power devices were assumed to operate at the normal boiling point of the fuel used. The efficiencies of the electrical devices are estimated based on state-of-the-art technology. The mass flow rates and total fuel requirements for both the cryogenic fuels required to maintain the operating temperatures of the devices were simulated using thermal network models. A twin-aisle 300 passenger aircraft with a 5.5 h flight duration was used for the models. The results show that the required masses of LH2 and LNG are 744 kg and 13638 kg respectively for the cooling requirement. The corresponding volumes of LH2 and LNG required are 9760 and 30300 L respectively. In both cases the estimated mass of the fuel needed for the aircraft is more than what is needed to maintain the cryogenic environment of the power devices. It was concluded that an electric aircraft with LNG cooled normal metal devices is feasible. However an aircraft with HTS devices and cooled with LH2 is more attractive if the ongoing R&D efforts on HTS devices and LH2 infrastructure are successful. The emission reductions would be substantially higher with LH2 particularly when H2 is produced using renewable energy sources.
Everything About Hydrogen Podcast: Manufacturing the Components of a Hydrogen Economy
Dec 2022
Publication
On today’s episode Alicia Chris and Patrick are chatting with Vonjy Rakajoba UK Managing Director at Robert Bosch. The Bosch Group is a leading global supplier of technology and services and employs roughly 402600 associates worldwide. Its operations are divided into four business sectors: Mobility Solutions Industrial Technology Consumer Goods and Energy and Building Technology. Bosch believes that hydrogen has a bright future as an energy carrier and is making considerable upfront investments in this area. From 2021 to 2024 the company plans to invest around 600 million euros in mobile fuel-cell applications and a further 400 million euros in stationary ones for the generation of electricity and heat. Vonjy is here with us to discuss more about what Bosch’s expansion into the hydrogen energy sector will look like and how the company expects the market to grow moving forward.
The podcast can be found on their website.
The podcast can be found on their website.
Deep Decarbonisation Pathways of the Energy System in Times of Unprecedented Uncertainty in the Energy Sector
May 2023
Publication
Unprecedented investments in clean energy technology are required for a net-zero carbon energy system before temperatures breach the Paris Agreement goals. By performing a Monte-Carlo Analysis with the detailed ETSAPTIAM Integrated Assessment Model and by generating 4000 scenarios of the world’s energy system climate and economy we find that the uncertainty surrounding technology costs resource potentials climate sensitivity and the level of decoupling between energy demands and economic growth influence the efficiency of climate policies and accentuate investment risks in clean energy technologies. Contrary to other studies relying on exploring the uncertainty space via model intercomparison we find that the CO2 emissions and CO2 prices vary convexly and nonlinearly with the discount rate and climate sensitivity over time. Accounting for this uncertainty is important for designing climate policies and carbon prices to accelerate the transition. In 70% of the scenarios a 1.5 ◦C temperature overshoot was within this decade calling for immediate policy action. Delaying this action by ten years may result in 2 ◦C mitigation costs being similar to those required to reach the 1.5 ◦C target if started today with an immediate peak in emissions a larger uncertainty in the medium-term horizon and a higher effort for net-zero emissions.
Risk of the Hydrogen Economy for Atmospheric Methane
Dec 2022
Publication
Hydrogen (H2) is expected to play a crucial role in reducing greenhouse gas emissions. However hydrogen losses to the atmosphere impact atmospheric chemistry including positive feedback on methane (CH4) the second most important greenhouse gas. Here we investigate through a minimalist model the response of atmospheric methane to fossil fuel displacement by hydrogen. We find that CH4 concentration may increase or decrease depending on the amount of hydrogen lost to the atmosphere and the methane emissions associated with hydrogen production. Green H2 can mitigate atmospheric methane if hydrogen losses throughout the value chain are below 9 ± 3%. Blue H2 can reduce methane emissions only if methane losses are below 1%. We address and discuss the main uncertainties in our results and the implications for the decarbonization of the energy sector.
Prediction of Transient Hydrogen Flow of Proton Exchange Membrane Electrolyzer Using Artificial Neural Network
Aug 2023
Publication
A proton exchange membrane (PEM) electrolyzer is fed with water and powered by electric power to electrochemically produce hydrogen at low operating temperatures and emits oxygen as a by-product. Due to the complex nature of the performance of PEM electrolyzers the application of an artificial neural network (ANN) is capable of predicting its dynamic characteristics. A handful of studies have examined and explored ANN in the prediction of the transient characteristics of PEM electrolyzers. This research explores the estimation of the transient behavior of a PEM electrolyzer stack under various operational conditions. Input variables in this study include stack current oxygen pressure hydrogen pressure and stack temperature. ANN models using three differing learning algorithms and time delay structures estimated the hydrogen mass flow rate which had transient behavior from 0 to 1 kg/h and forecasted better with a higher count (>5) of hidden layer neurons. A coefficient of determination of 0.84 and a mean squared error of less than 0.005 were recorded. The best-fitting model to predict the dynamic behavior of the hydrogen mass flow rate was an ANN model using the Levenberg–Marquardt algorithm with 40 neurons that had a coefficient of determination of 0.90 and a mean squared error of 0.00337. In conclusion optimally fit models of hydrogen flow from PEM electrolyzers utilizing artificial neural networks were developed. Such models are useful in establishing an agile flow control system for the electrolyzer system to help decrease power consumption and increase efficiency in hydrogen generation.
Numerical Simulation of Hydrogen Diffusion in Cement Sheath of Wells Used for Underground Hydrogen Storage
Jul 2023
Publication
The negative environmental impact of carbon emissions from fossil fuels has promoted hydrogen utilization and storage in underground structures. Hydrogen leakage from storage structures through wells is a major concern due to the small hydrogen molecules that diffuse fast in the porous well cement sheath. The second-order parabolic partial differential equation describing the hydrogen diffusion in well cement was solved numerically using the finite difference method (FDM). The numerical model was verified with an analytical solution for an ideal case where the matrix and fluid have invariant properties. Sensitivity analyses with the model revealed several possibilities. Based on simulation studies and underlying assumptions such as non-dissolvable hydrogen gas in water present in the cement pore spaces constant hydrogen diffusion coefficient cement properties such as porosity and saturation etc. hydrogen should take about 7.5 days to fully penetrate a 35 cm cement sheath under expected well conditions. The relatively short duration for hydrogen breakthrough in the cement sheath is mainly due to the small molecule size and high hydrogen diffusivity. If the hydrogen reaches a vertical channel behind the casing a hydrogen leak from the well is soon expected. Also the simulation result reveals that hydrogen migration along the axial direction of the cement column from a storage reservoir to the top of a 50 m caprock is likely to occur in 500 years. Hydrogen diffusion into cement sheaths increases with increased cement porosity and diffusion coefficient and decreases with water saturation (and increases with hydrogen saturation). Hence cement with a low water-to-cement ratio to reduce water content and low cement porosity is desirable for completing hydrogen storage wells.
Solar Water Splitting by Photovoltaic-electrolysis with a Solar-to-hydrogen Efficiency over 30%
Oct 2016
Publication
Hydrogen production via electrochemical water splitting is a promising approach for storing solar energy. For this technology to be economically competitive it is critical to develop water splitting systems with high solar-to-hydrogen (STH) efficiencies. Here we report a photovoltaic-electrolysis system with the highest STH efficiency for any water splitting technology to date to the best of our knowledge. Our system consists of two polymer electrolyte membrane electrolysers in series with one InGaP/GaAs/GaInNAsSb triple-junction solar cell which produces a large-enough voltage to drive both electrolysers with no additional energy input. The solar concentration is adjusted such that the maximum power point of the photovoltaic is well matched to the operating capacity of the electrolysers to optimize the system efficiency. The system achieves a 48-h average STH efficiency of 30%. These results demonstrate the potential of photovoltaic-electrolysis systems for cost-effective solar energy storage.
Techno-economic Feasibility of Hybrid PV/wind/battery/thermal Storage Trigeneration System: Toward 100% Energy Independency and Green Hydrogen Production
Dec 2022
Publication
With the clear adverse impacts of fossil fuel-based energy systems on the climate and environment ever-growing interest and rapid developments are taking place toward full or nearly full dependence on renewable energies in the next few decades. Estonia is a European country with large demands for electricity and thermal energy for district heating. Considering it as the case study this work explores the feasibility and full potential of optimally sized photovoltaic (PV) wind and PV/wind systems equipped with electric and thermal storage to fulfill those demands. Given the large excess energy from 100% renewable energy systems for an entire country this excess is utilized to first meet the district heating demand and then to produce hydrogen fuel. Using simplified models for PV and wind systems and considering polymer electrolyte membrane (PEM) electrolysis a genetic optimizer is employed for scanning Estonia for optimal installation sites of the three systems that maximize the fulfillment of the demand and the supply–demand matching while minimizing the cost of energy. The results demonstrate the feasibility of all systems fully covering the two demands while making a profit compared to selling the excess produced electricity directly. However the PV-driven system showed enormous required system capacity and amounts of excess energy with the limited solar resources in Estonia. The wind system showed relatively closer characteristics to the hybrid system but required a higher storage capacity by 75.77%. The hybrid PV/wind-driven system required a total capacity of 194 GW most of which belong to the wind system. It was also superior concerning the amount (15.05 × 109 tons) and cost (1.42 USD/kg) of the produced green hydrogen. With such full mapping of the installation capacities and techno-economic parameters of the three systems across the country this study can assist policymakers when planning different country-scale cogeneration systems.
Repurposing Pipelines for Hydrogen: Legal and Policy Considerations
Nov 2022
Publication
As the world looks to implement the Energy Transition repurposing existing fossil fuel infrastructure to produce or distribute “clean” energy will be critical. The most promising is using natural gas pipelines for moving hydrogen. This is the cheapest and fastest method of transport and reducing the cost of transporting hydrogen is a key step in making it economically viable. However while there are technical challenges the greater challenge is in the legal arena. This paper seeks to outline the numerous legal — treaty statutory and contractual — and regulatory obstacles to repurposing natural gas pipelines for hydrogen transport. Gas pipelines exist in a complex microclimate of international public and private law and domestic law and contracts. Ownership is often layered and tangled; financing doubly so; and myriad state interests compound the private interests including national security concerns energy supply imperatives and geopolitical balance. State aid — investment subsidies and tax breaks — may encumber the project with additional legal obligations. And the contracts that control the development of a pipeline project may inject further legal complexity such as dispute mediation procedures and fora and applicable law. This paper seeks to map all the likely areas of future conflict or difficulty so that work on developing the requisite legal regime and remedies to permit use of natural gas pipelines for hydrogen transport can begin now. For policy and lawmakers as well as the private sector evaluating these known unknowns is a good starting point for reconsidering legislation regulation contracts and project risk in preparation for the future probability of hydrogen pipelines.
Grid Ancillary Services using Electrolyzer-based Power-to-Gas Systems with Increasing Renewable Penetration
Nov 2023
Publication
Increasing penetrations of renewable-based generation have led to a decrease in the bulk power system inertia and an increase in intermittency and uncertainty in generation. Energy storage is considered to be an important factor to help manage renewable energy generation at greater penetrations. Hydrogen is a viable long-term storage alternative. This paper analyzes and presents use cases for leveraging electrolyzer-based power-to-gas systems for electric grid support. The paper also discusses some grid services that may favor the use of hydrogenbased storage over other forms such as battery energy storage. Real-time controls are developed implemented and demonstrated using a power-hardware-in-the-loop(PHIL) setup with a 225-kW proton-exchange-membrane electrolyzer stack. These controls demonstrate frequency and voltage support for the grid for different levels of renewable penetration (0% 25% and 50%). A comparison of the results shows the changes in respective frequencies and voltages as seen as different buses as a result of support from the electrolyzers and notes the impact on hydrogen production as a result of grid support. Finally the paper discusses the practical nuances of implementing the tests with physical hardware such as inverter/electrolyzer efficiency as well as the related constraints and opportunities.
Cost of Long-Distance Energy Transmission by Different Carriers
Nov 2021
Publication
This paper compares the relative cost of long-distance large-scale energy transmission by electricity and by gaseous and liquid carriers (e-fuels). The results indicate that the cost of electrical transmission per delivered MWh can be up to eight times higher than for hydrogen pipelines about eleven times higher than for natural gas pipelines and twenty to fifty times higher than for liquid fuels pipelines. These differences generally hold for shorter distances as well. The higher cost of electrical transmission is primarily due to lower carrying capacity (MW per line) of electrical transmission lines compared to the energy carrying capacity of the pipelines for gaseous and liquid fuels. The differences in the cost of transmission are important but often unrecognized and should be considered as a significant cost component in the analysis of various renewable energy production distribution and utilization scenarios.
Numerical Predictions of a Swirl Combustor Using Complex Chemistry Fueled with Ammonia/Hydrogen Blends
Jan 2020
Publication
Ammonia a chemical that contains high hydrogen quantities has been presented as a candidate for the production of clean power generation and aerospace propulsion. Although ammonia can deliver more hydrogen per unit volume than liquid hydrogen itself the use of ammonia in combustion systems comes with the detrimental production of nitrogen oxides which are emissions that have up to 300 times the greenhouse potential of carbon dioxide. This factor combined with the lower energy density of ammonia makes new studies crucial to enable the use of the molecule through methods that reduce emissions whilst ensuring that enough power is produced to support high-energy intensive applications. Thus this paper presents a numerical study based on the use of novel reaction models employed to characterize ammonia combustion systems. The models are used to obtain Reynolds Averaged Navier-Stokes (RANS) simulations via Star-CCM+ with complex chemistry of a 70%–30% (mol) ammonia–hydrogen blend that is currently under investigations elsewhere. A fixed equivalence ratio (1.2) medium swirl (0.8) and confined conditions are employed to determine the flame and species propagation at various operating atmospheres and temperature inlet values. The study is then expanded to high inlet temperatures high pressures and high flowrates at different confinement boundary conditions. The results denote how the production of NOx emissions remains stable and under 400 ppm whilst higher concentrations of both hydrogen and unreacted ammonia are found in the flue gases under high power conditions. The reduction of heat losses (thus higher temperature boundary conditions) has a crucial impact on further destruction of ammonia post-flame with a raise in hydrogen water and nitrogen through the system thus presenting an opportunity of combustion efficiency improvement of this blend by reducing heat losses. Final discussions are presented as a method to raise power whilst employing ammonia for gas turbine systems.
Analysis to Support Revised Distances between Bulk Liquid Hydrogen Systems and Exposures
Sep 2021
Publication
The minimum distances between exposures and bulk liquid hydrogen listed in the National Fire Protection Agency’s Hydrogen Technology Code NFPA 2 are based on historical consensus without a documented scientific analysis. This work follows a similar analysis as the scientific justification provided in NFPA 2 for exposure distances from bulk gaseous hydrogen storage systems but for liquid hydrogen. Validated physical models from Sandia’s HyRAM software are used to calculate distances to a flammable concentration for an unignited release the distance to critical heat flux values and the visible flame length for an ignited release and the overpressure that would occur for a delayed ignition of a liquid hydrogen leak. Revised exposure distances for bulk liquid hydrogen systems are calculated. These distances are related to the maximum allowable working pressure of the tank and the line size as compared to the current exposure distances which are based on system volume. For most systems the exposure distances calculated are smaller than the current distances for Group 1 they are similar for Group 2 while they increase for some Group 3 exposures. These distances could enable smaller footprints for infrastructure that includes bulk liquid hydrogen storage tanks especially when using firewalls to mitigate Group 3 hazards and exposure distances. This analysis is being refined as additional information on leak frequencies is incorporated and changes have been proposed to the 2023 edition of NFPA 2.
The NREL Sensor Laboratory: Status and Future Directions for Hydrogen Detection
Sep 2021
Publication
The NREL Hydrogen Sensor Laboratory was commissioned in 2010 as a resource for the national and international hydrogen community to ensure the availability and proper use of hydrogen sensors. Since then the Sensor Laboratory has provided unbiased verification of hydrogen sensor performance for sensor developers end-users and regulatory agencies and has also provided active support for numerous code and standards development organizations. Although sensor performance assessment remains a core capability the mission of the NREL Sensor Laboratory has expanded toward a more holistic approach regarding the role of hydrogen detection and its implementation strategy for both assurance of facility safety and for process control applications. Active monitoring for detection of unintended releases has been identified as a viable approach for improving facility safety and lowering setbacks. The current research program for the Sensor Laboratory addresses both conventional and advanced developing detection strategies in response to the emerging large-scale hydrogen markets such as those envisioned by H2@Scale. These emerging hydrogen applications may require alternative detection strategies that supplement and may ultimately supplant the use of traditional sensors for monitoring hydrogen releases. Research focus areas for the NREL Sensor Laboratory now encompass the characterization of released hydrogen behavior to optimize detection strategies for both indoor and outdoor applications assess advanced methods of hydrogen leak detection such as hydrogen wide area monitoring for large scale applications implement active monitoring as a risk reduction strategy to improve safety at hydrogen facilities and to provide continuing support of hydrogen safety codes and standards. In addition to assurance of safety detection will be critical for process control applications such as hydrogen fuel quality verification for fuel cell vehicle applications and for monitoring and controlling of hydrogen-natural gas blend composition.
Everything About Hydrogen Podcast: Catching up on the State of Scale in PEM Electrolysis
Feb 2022
Publication
This episode of EAH is a chance for the team to catch up with one of our early guests on the show Graham Cooley - CEO of ITM Power. For the past twenty years ITM Power PLC has been designing and manufacturing electrolyser systems that generate hydrogen based on proton exchange membrane (PEM) technology. As the first hydrogen related company to be listed on the London Stock Exchange ITM are globally recognised experts in the field of electrolysis. In 2021 the company opened its first Gigafactory in Bessemer Park Sheffield: the world’s largest electrolyser production factory.
The podcast can be found on their website
The podcast can be found on their website
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