Institution of Gas Engineers & Managers

Photocatalytic hydrogen generation is one of the most promising solutions to convert solar power into green chemical energy. In this work a multi-component TiO₂–Ag–Cu₂O composite was obtained through simple impregnation-calcination of Cu₂O and subsequent photodeposition of Ag onto electrospun TiO₂ nanotubes. The resulting TiO₂–Ag–Cu₂O photocatalyst exhibits excellent photocatalytic H₂ evolution activity due to the synergetic effect of Ag and Cu₂O on electrospun TiO₂nanotubes. A dual Z-scheme charge transfer pathway for photocatalytic reactions over TiO₂–Ag–Cu₂O composite was proposed and discussed. This work provides a prototype for designing Z-scheme photocatalyst with Ag as an electron mediator.

Ni₃S₂ and NiS supported on carbon spheres are successfully synthesized by a facile hydrothermal method. And then a series of physical characterizations included XRD (X-ray diffraction) EDS (energy dispersive spectroscopy) FESEM (field emission scanning electron microscopy) and XPS (X-ray photo-electron spectroscopy) were used to analyze the samples. XRD was used to confirm that NiNi₃S₂ S2 and NiS were successfully fabricated. FESEM indicated that Ni₃S₂ and NiS disperse well on carbon spheres. Electrochemical tests showed that nickel sulfides supported by carbon spheres exhibited excellent hydrogen evolution performance. The excellent catalytic activity is attributed to the synergistic effect of carbon spheres and transition metal sulfides of which the carbon spheres act to enhance the electrical conductivity and the dispersion of Ni₃S₂ and NiS thus providing more active sites for the hydrogen evolution reaction.

Nowadays decarbonization of energy economy is a topical theme and several pathways are under discussion. Gaseous fuels will play a primary role during this transition and the production of renewable or low carbon-impact gaseous fuels is necessary to deal with this challenge. Decarbonization will be sustained by an increasing share of renewables which production intermittency can be critical for the energy system. Renewable hydrogen generation is a viable solution since this energy vector can be produced from electricity with a fast response and injected in the existing natural gas infrastructures granting storage capacity and easy transport. Parallelly to the renewable-based energy production fossil-based energy can be exploited with a low carbon impact using methane from reservoirs to produce hydrogen capturing CO2. The mentioned scenarios will lead to hydrogen enrichment of natural gas which impact on the infrastructures is being actively studied. The effect on end-user devices instead is poorly analysed but is fundamental to be assessed. This paper highlights the impact on the widely used premixed condensing boilers which will be fired with hydrogen enriched natural gas in the near future and the changes required to components.

Hydrogen separation through oxygen transport membranes (OTMs) has attracted much attention. Asymmetric membranes with thin dense layers provide low bulk diffusion resistances and high overall hydrogen separation performances. However the resistance in the porous support layer (PSL) limits the overall separation performance significantly. Engineering the structure of the PSL is an appropriate way to enable fast gas transport and increase the separation performance. There is no relevant research on studying the influence of the PSL on hydrogen separation performance so far. Herein we prepared Ce_0.85Sm_0.15O_1.925 – Sm_0.6Sr_0.4Cr_0.3Fe_0.7O_3-δ (SDC-SSCF) asymmetric membranes with straight grooves in PSL by tape-casting and laser grooving. A ~30% improvement in the hydrogen separation rate was achieved by grooving in the PSLs. It indicates that the grooves may reduce the concentration polarization resistance in PSL for the hydrogen separation process. This work provides a straight evidence on optimizing the structures of PSL for improving the hydrogen separation performance of the membrane reactors.

Clean hydrogen:

• What's driving the excitement?
• Will hydrogen stay on the main stage of the energy transition?
• What is the market for clean hydrogen today?

Download the full white paper from the Delta EE website here

Heating and hot water within buildings account for almost a quarter of global energy consumption. Approximately 90% of this heat is derived directly from the combustion of fossil fuels primarily natural gas leading to the unabated emission of carbon dioxide. This paper assesses the environmental sustainability of a range of heating technologies and scenarios on a life cycle basis. The major technologies considered are natural gas boilers air source heat pumps hydrogen boilers and direct electric heaters. The scenarios use the UK as an example due to its status as a major economy with a legally-binding net-zero carbon target for 2050; they consider plausible future electricity and natural gas mixes including the potential growth of domestic shale gas. The environmental impacts are estimated using ReCiPe 2016. Current gas boilers have a climate change impact of 220 g CO₂ eq./kWh of heat which could fall to 64 g CO₂ eq./kWh for boilers fuelled by hydrogen derived from natural gas with carbon capture. Heat from electric air source heat pumps or hydrogen from electrolysis can achieve net zero with a decarbonised electricity mix but electrolysis has the highest energy demand of all options which leads to the highest impacts across 17 of the 19 categories. Despite their high carbon emissions gas boilers remain the lowest impact option across 12 categories as they avoid the impacts related to electricity generation including metal depletion toxicities and eutrophication. By 2050 the best performing scenario sees the climate change impact of the heating mix fall by 95%; this is achieved by prioritising electric air source heat pumps without hydrofluorocarbon refrigerants alongside demand reduction. The results show that if infrastructure and financial challenges can be overcome there are several viable decarbonisation strategies for heating with heat pumps offering the most environmentally sustainable option of those considered here. However increased renewable electricity demand may worsen some environmental impacts compared to natural gas boilers.

The hydrogen economy will play a key role in future energy systems. Several thermal and catalytic methods for hydrogen production have been presented. In this review methane thermocatalytic and thermal decomposition into hydrogen gas and solid carbon are considered. These processes known as the thermal decomposition of methane (TDM) and thermocatalytic decomposition (TCD) of methane respectively appear to have the greatest potential for hydrogen production. In particular the focus is on the different types and properties of carbons formed during the decomposition processes. The applications for carbons are also investigated.

Development of probabilistic modelling tools to perform Bayesian inference and uncertainty quantification (UQ) is a challenging task for practical hydrogen-enriched and low-emission combustion systems due to the need to take into account simultaneously simulated fluid dynamics and detailed combustion chemistry. A large number of evaluations is required to calibrate models and estimate parameters using experimental data within the framework of Bayesian inference. This task is computationally prohibitive in high-fidelity and deterministic approaches such as large eddy simulation (LES) to design and optimize combustion systems. Therefore there is a need to develop methods that: (a) are suitable for Bayesian inference studies and (b) characterize a range of solutions based on the uncertainty of modelling parameters and input conditions. This paper aims to develop a computationally-efficient toolchain to address these issues for probabilistic modelling of NOx emission in hydrogen-enriched and lean-premixed combustion systems. A novel method is implemented into the toolchain using a chemical reactor network (CRN) model non-intrusive polynomial chaos expansion based on the point collocation method (NIPCE-PCM) and the Markov Chain Monte Carlo (MCMC) method. First a CRN model is generated for a combustion system burning hydrogen-enriched methane/air mixtures at high-pressure lean-premixed conditions to compute NOx emission. A set of metamodels is then developed using NIPCE-PCM as a computationally efficient alternative to the physics-based CRN model. These surrogate models and experimental data are then implemented in the MCMC method to perform a two-step Bayesian calibration to maximize the agreement between model predictions and measurements. The average standard deviations for the prediction of exit temperature and NOx emission are reduced by almost 90% using this method. The calibrated model then used with confidence for global sensitivity and reliability analysis studies which show that the volume of the main-flame zone is the most important parameter for NOx emission. The results show satisfactory performance for the developed toolchain to perform Bayesian inference and UQ studies enabling a robust and consistent process for designing and optimising low-emission combustion systems.

The Flexibility in Great Britain project analysed the system-level value of deploying flexibility across the heat transport industry and power sectors in Great Britain to provide a robust evidence-base on the role and value of flexibility in a net zero system.

Overview

Findings from this groundbreaking analysis of the future net zero energy system in Great Britain are expected to have profound implications for policymakers households and the wider energy sector across Great Britain.

Key findings include:

• Embedding greater flexibility across the entire energy system will reduce the cost of achieving net zero for all consumers while assuring energy security.
• Investing in flexibility is a no-regrets decision as it has the potential to deliver material net savings of up to £16.7bn per annum across all scenarios analysed in 2050.
• A more flexible system will accelerate the benefits of decarbonisation supported by decentralisation and digitalisation.
• To maximise the benefits of flexibility households and businesses should play an active role in the development and operation of the country’s future energy system as energy use for transport heat and appliances becomes more integrated.
• Policymakers should preserve existing flexibility options and act now to maximise future flexibility such as by building it into ‘smart’ appliances or building standards.

Read the Full Report here on the Carbon Trust Website

View the interactive analysis here at the Carbon Trust Website

Watch an accompanying video here at the Carbon Trust Youtube channel

The transition to low carbon energy and transport systems requires an unprecedented roll-out of new infrastructure technologies containing significant quantities of critical raw materials. Many of these technologies are based on general purpose technologies such as permanent magnets and electric motors that are common across different infrastructure systems. Circular economy initiatives that aim to institute better resource management practices could exploit these technological commonalities through the reuse and remanufacturing of technology components across infrastructure systems. In this paper we analyze the implementation of such processes in the transition to low carbon electricity generation and transport on the Isle of Wight UK. We model two scenarios relying on different renewable energy technologies with the reuse of Lithium-ion batteries from electric vehicles for grid-attached storage. A whole-system analysis that considers both electricity and transport infrastructure demonstrates that the optimal choice of renewable technology can be dependent on opportunities for component reuse and material recycling between the different infrastructure systems. Hydrogen fuel cell based transport makes use of platinum from obsolete catalytic converters whereas lithium-ion batteries can be reused for grid-attached storage when they are no longer useful in vehicles. Trade-offs exist between the efficiency of technology reuse which eliminates the need for new technologies for grid attached storage completely by 2033 and the higher flexibility afforded by recycling at the material level; reducing primary material demand for Lithium by 51% in 2033 compared to 30% achieved by battery reuse. This analysis demonstrates the value of a methodology that combines detailed representations of technologies and components with a systemic approach that includes multiple interconnected infrastructure systems.