Applications & Pathways

Limiting global warming and the pursuit of a net-zero global society by 2050 emphasizes the need to transform the hard-to-abate industrial sectors. The cement sector is the second-largest source of global industrial emissions accounting for 8% of worldwide greenhouse gas emissions. Fuel switching in the cement sector is a decarbonization pathway that has not been explored in detail; previous studies involving fuel switching in the sector either view it from an energy efficiency lens or focus on a single technology. In this study a framework is developed to evaluate and directly compare six fuel switching options (including hydrogen biomass municipal solid waste and natural gas) from 2020 to 2050. Capital costs non-energy operating costs energy costs and carbon costs are used to calculate marginal abatement costs and emulate cost based-market decisions. The developed framework is used to conduct a case study for Canada using the LEAP-Canada model. This study shows that cumulative energy-related greenhouse gas emissions can be reduced by up to 21% between 2020 and 2050 with negative marginal abatement costs. Multiple fuel switching decarbonization pathways were established reducing the likelihood that locality prevents meaningful emissions reduction and suggesting that with low-carbon fuel and electricity policies the sector can take significant steps towards emissions reduction. The developed framework can be applied to jurisdictions around the world for decision making as nations move towards eliminating emissions from cement production.

Fuel cell electric vehicles (FCEVs) provide a viable answer to transportation issues caused by fossil fuel limitations and environmental concerns. This review presents a thorough evaluation of the most recent advances in FCEV durability research. It addresses 4 major topics: component upgrades technical control techniques test optimization and durability prediction. Upgrades to components include improved catalysts bipolar plates gas diffusion layers proton exchange membranes and plant balancing. Technical control solutions include power energy temperature ventilation and control management. Stress acceleration and cold start tests are examples of test optimization whereas durability prediction requires parameter selection real-time monitoring dynamic modeling and lifespan prediction. This review also makes some novel recommendations targeted at improving the endurance of FCEVs. These include measures for raising public awareness lowering prices while increasing performance improving subsystems for greater durability updating health diagnostics to prevent performance deterioration and implementing supporting regulations to encourage industry upgrading. These findings are expected to accelerate the adoption of FCEVs and the transition to a more sustainable transportation system.

Desulphurization of oil-based fuels is common practice to mitigate the ecological burden to ecosystems and human health of SOx emissions. In many countries fuels for vehicles are restricted to 10 ppm sulphur. For marine fuels low sulphur contents are under discussion. The environmental impact of desulphurization processes is however quite high: (1) The main current source for industrial hydrogen is Steam Methane Reforming (SMR) with a rather high level of CO2 emissions (2) the hydrotreating process especially below 150 ppm needs a lot of energy. These two issues lead to three research questions: (a) What is the overall net ecological benefit of the current desulphurization practice? (b) At which sulfphur ppm level in the fuel is the additional ecological burden of desulphurization higher than the additional ecological benefit of less SOx pollution from combustion? (c) To what extent can cleaner hydrogen processes improve the ecological benefit of diesel desulphurization? In this paper we use LCA to analyze the processes of hydrotreatment the recovery of sulphur via amine treating of H2S and three processes of hydrogen production: SMR without Carbon Capture and Sequestration (CCS) SMR with 53% and 90% CCS and water electrolysis with two types of renewable energy. The prevention-based eco-costs system is used for the overall comparison of the ecological burden and the ecological benefit. The ReCiPe system was applied as well but appeared not suitable for such a comparison (other damage-based indicators cannot be applied either). The overall conclusion is that (1) the overall net ecological benefit of hydrogen-based Ultra Low Sulphur Diesel is dependent of local conditions but is remarkably high (2) desulphurization below 10 ppm is beneficial for big cities and (3) cleaner production of hydrogen reduces eco-cost by a factor 1.8–3.4.

This paper proposes and assesses three different control approaches for the hydrocarbon natural gas (HCNG) penetrated integrated energy system (IES). The three control approaches adopt mixed integer linear programing conditional value at risk (CVaR) and robust optimization (RO) respectively aiming to mitigate the renewable generation uncertainties. By comparing the performance and efficiency the most appropriate control approach for the HCNG penetrated IES is identified. The numerical analysis is conducted to evaluate the three control approaches in different scenarios where the uncertainty level of renewable energy (within the HCNG penetrated IES) varies. The numerical results show that the CVaR-based approach outperforms the other two approaches when renewable uncertainty is high (approximately 30%). In terms of the cost to satisfy the energy demand the operational cost of the CVaR-based method is 8.29% lower than the RO one while the RO-based approach has a better performance when the renewable uncertainty is medium (approximately 5%) and it is operational is 0.62% lower than that of the CVaR model. In both evaluation cases mixed integer linear programing approach cannot meet the energy demand. This paper also compares the operational performance of the IES with and without HCNG. It is shown that the IES with HCNG can significantly improve the capability to accommodate renewable energy with low upgrading cost.

Green hydrogen (H2) produced from renewable energy sources (RES) through electrolysis offers a promising solution to decarbonize hard-to-abate sectors paving the way for H2 hubs. The agility of electrolyzers especially proton-exchange membrane (PEM) technology can be leveraged to provide flexibility to future integrated electricity and H2 systems. More flexibility can be unlocked by optimizing the designs of H2 hubs which generally consist of electrolyzers H2 storage tanks H2 liquefiers and battery energy storage systems (BESSs). This paper introduces a generic optimization framework for finding the least-cost designs of H2 hubs that also minimizes system operating costs under arbitrary H2 demand profiles. The proposed electrolyzer model incorporates a variable efficiency to avoid overestimating the power consumption and the true size of electrolyzers. In RES-rich countries like Australia envisaged H2 export demand may constitute a significant source of demand flexibility. The proposed framework is therefore demonstrated on a case study involving the Australian National Electricity Market (NEM) under a future large-scale green H2 export scenario assessing the impact of three different H2 export profile assumptions on H2 hub investment costs system operating costs and system flexibility. These profiles include: (a) a realistic one based on historical liquefied natural gas (LNG) ship schedules and a pilot H2 export project (b) an inflexible constant demand across the year and (c) a flexible monthly target without intraday and interday restrictions. Numerical analysis demonstrates that the optimal H2 hub designs obtained under the more realistic H2 export profile assumptions enjoy the lowest system operating costs and the highest flexibility the latter of which is evidenced by a substantial increase in availability of reserves.

On the path towards decarbonisation of the steel industry the use of H2 /NG blends in furnaces where high temperatures are needed is one of the alternatives that needs to be carefully studied. The present paper shows the CFD study carried out for a full-scale reheating furnace burner case. The real operating conditions as well as experimental measurements provided by the furnace operator were used to validate the results and reduce simulation uncertainties. The burner under consideration (2.5 MW) works in flameless mode with natural gas and preheated air (813 K). Starting from this point another three fuel blends with volumetric percentages of 23% (also known as G222) 50% and 75% of H2 in natural gas were considered. For this purpose the open source CFD code OpenFOAM was used where the novel NE-EDC turbulence-chemistry interaction model was implemented which has already been successfully validated specifically for flameless combustion in a furnace. The implementation incorporated an enhanced approach for calculating the chemical time-scale coupled with a specific post-processing solver to predict NO emissions. The study analyses the relative impact of the considered fuel blends on NO formation and flameless regime. The modelling results demonstrated the burner’s capability to operate efficiently with high concentrations of hydrogen maintaining flameless regime in all cases. This condition ensured uniform temperature distributions and low levels of NO emissions reaching a maximum value of 86 mg/m3 . These results indicated the proper functionality of the existing natural gas-based burner with H2 /NG blends which was the primary requirement for the conversion process.

At present transportation energy comes primarily from fossil fuels. In order to mitigate the effects of greenhouse gas emissions it is necessary to transition to low-carbon transportation technologies. These technologies can include battery electric vehicles fuel cell vehicles and biofuel vehicles. This transition includes not only the development and production of suitable vehicles but also the development of appropriate infrastructure. For example in the case of battery electric vehicles this infrastructure would include additional grid capacity for battery charging. For fuel cell vehicles infrastructure could include facilities for the production of suitable electrofuels which again would require additional grid capacity. In the present paper we look at some specific examples of infrastructure requirements for battery electric vehicles and vehicles using hydrogen and other electrofuels in either internal combustion engines or fuel cells. Analysis includes the necessary additional grid capacity energy storage requirements and land area associated with renewable energy generation by solar photovoltaics and wind. The present analysis shows that the best-case scenario corresponds to the use of battery electric vehicles powered by electricity from solar photovoltaics. This situation corresponds to a 47% increase in grid electricity generation and the utilization of 1.7% of current crop land.

The current literature on solid oxide fuel cell and internal combustion engine (SOFC-ICE) integration is focused on the application of advanced combustion technologies operating as bottoming cycles to generate a small load share. This integration approach can pose challenges for ships such as restricted dynamic capabilities and large space and weight requirements. Furthermore the potential of SOFC-ICE integration for marine power generation has not been explored. Consequently the current work proposes a novel approach of SOFC-ICE integration for maritime applications which allows for high-efficiency power generation while the SOFC anode-off gas (AOG) is blended with natural gas (NG) and combusted in a marine spark-ignited (SI) engine for combined power generation. The objective of this paper is to investigate the potential of the proposed SOFC-ICE integration approach with respect to system efficiency emissions load sharing space and weight considerations and load response. In this work a verified zero-dimensional (0-D) SOFC model engine experiments and a validated AOG-NG mean value engine model is used. The study found that the SOFC-ICE integration with a 67–33 power split at 750 kWe power output yielded the highest efficiency improvement of 8.3% over a conventional marine natural gas engine. Simulation results showed that promising improvements in efficiency of 5.2% UHC and NOx reductions of about 30% and CO2 reductions of about 12% can be achieved from a 33–67 SOFC-ICE power split with comparatively much smaller increments in size and weight of 1.7 times. Furthermore the study concluded that in the proposed SOFC-ICE system for maritime applications a power split that favours the ICE would significantly improve the dynamic capabilities of the combined system and that the possible sudden and large load changes can be met by the ICE.

To reduce hydrogen consumption by hydrogen fuel cell vehicles (HFCVs) an adaptive power-following control strategy based on gated recurrent unit (GRU) neural network operating condition recognition was proposed. The future vehicle speed was predicted based on a GRU neural network and a driving cycle condition recognition model was established based on k-means cluster analysis. By predicting the speed over a specific time horizon feature parameters were extracted and compared with those of typical operating conditions to determine the categories of the parameters thus the adjustment of the power-following control strategy was realized. The simulation results indicate that the proposed control strategy reduces hydrogen consumption by hydrogen fuel cell vehicles (HFCVs) by 16.6% with the CLTC-P driving cycle and by 4.7% with the NEDC driving cycle compared to the conventional power-following control strategy. Additionally the proposed strategy effectively stabilizes the battery’s state of charge (SOC).

The continuous increase of energy demand with the subsequent huge fossil fuel consumption is provoking dramatic environmental consequences. The main challenge of this century is to develop and promote alternative more eco-friendly energy production routes. In this framework Solid Oxide Cells (SOCs) are a quite attractive technology which could satisfy the users’ energy request working in reversible operation. Two operating modes are alternated: from “Gas to Power” when SOCs work as fuel cells fed with hydrogen-rich mixture to provide both electricity and heat to “Power to Gas” when SOCs work as electrolysers and energy is supplied to produce hydrogen. If solid oxide fuel cells are an already mature technology with several stationary and mobile applications the use of solid oxide electrolyser cells and even more reversible cells are still under investigation due to their insufficient lifetime. Aiming at providing a better understanding of this new technological approach the study presents a detailed description of cell operation in terms of electrochemical behaviour and possible degradation highlighting which are the most commonly used performance indicators. A thermodynamic analysis of system efficiency is proposed followed by a comparison with other available electrochemical devices in order to underline specific solid oxide cell advantages and limitations.