Institution of Gas Engineers & Managers

The decarbonisation of waterborne transport is arguably the biggest challenge faced by the maritime industry presently. By 2050 the International Maritime Organization (IMO) aims to reduce greenhouse gas emissions from the shipping industry by 50% compared to 2008 with a vision to phase out fossil fuels by the end of the century as a matter of urgency. To meet such targets action must be taken immediately to address the barriers to adopt the various clean shipping options currently at different technological maturity levels. Green hydrogen as an alternative fuel presents an attractive solution to meet future targets from international bodies and is seen as a viable contributor within a future clean shipping vision. The cost of hydrogen fuel—in the shortterm at least—is higher compared to conventional fuel; therefore energy-saving devices (ESDs) for ships are more important than ever as implementation of rules and regulations restrict the use of fossil fuels while promoting zero-emission technology. However existing and emerging ESDs in standalone/combination for traditional fossil fuel driven vessels have not been researched to assess their compatibility for hydrogen-powered ships which present new challenges and considerations within their design and operation. Therefore this review aims to bridge that gap by firstly identifying the new challenges that a hydrogen-powered propulsion system brings forth and then reviewing the quantitative energy saving capability and qualitive additional benefits of individual existing and emerging ESDs in standalone and combination with recommendations for the most applicable ESD combinations with hydrogen-powered waterborne transport presented to maximise energy saving and minimise the negative impact on the propulsion system components. In summary the most compatible combination ESDs for hydrogen will depend largely on factors such as vessel types routes propulsion operation etc. However the mitigation of load fluctuations commonly encountered during a vessels operation was viewed to be a primary area of interest as it can have a negative impact on hydrogen propulsion system components such as the fuel cell; therefore the ESD combination that can maximise energy savings as well as minimise the fluctuating loads experienced would be viewed as the most compatible with hydrogen-powered waterborne transport.

We analyze the use of hydrogen as a fuel for the automotive industry with the aim of decarbonizing the economy. Hydrogen is a suitable option for avoiding pollutant gas emissions developing environmentally friendly technologies replacing fossil fuels with clean renewable energies and complying with the Paris Agreement and Glasgow resolutions. In this sense renewable energies such as wind solar photovoltaic geothermal biomass etc. can be used to produce the necessary hydrogen to power vehicles. In this way the entire process from hydrogen production to its consumption as fuel will be 100% clean. If we are to meet future energy demands it is necessary to forecast the amount of hydrogen needed taking into account the facilities currently available and new ones that will be required for its generation storage and distribution. This paper presents a process for optimizing hydrogen production for the automotive industry that considers the amount of hydrogen needed the type of facilities from which it will be produced how the different sources of production are to be combined to achieve a competitive product and the potential environmental impacts of each energy source. It can serve as a frame of reference for the various actors in the hydropower and automotive industries so that more efficient designs can be planned for the gradual introduction of hydrogen fuel cell vehicles (HFCVs). The methodology implemented in this paper sets an optimization problem for minimizing energy production costs and reducing environmental impacts according to the source of energy production. The EU framework with respect to the decarbonization of the economy the percentages of the different types of energy sources used and the non-polluting vehicle fleet in the automotive sector will be considered.

Now it is time to set up reliable water electrolysis stacks with active and robust electro‐ catalysts to produce green hydrogen. Compared with catalytic kinetics much less attention has been paid to catalyst stability and the weak understanding of the catalyst deactivation mechanism restricts the design of robust electrocatalysts. Herein we discuss the issues of catalysts’ stability evaluation and characterization and the degradation mechanism. The systematic understanding of the degradation mechanism would help us to formulate principles for the design of stable catalysts. Particularly we found that the dissolution rate for different 3d transition metals differed greatly: Fe dissolves 114 and 84 times faster than Co and Ni. Based on this trend we designed Fe@Ni and FeNi@Ni core‐shell structures to achieve excellent stability in a 1 A cm−2 current density as well as good catalytic activity at the same time

This study provides H2 gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So this study has a dual benefit for hydrogen generation; at the same time it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min respectively. The complete analyses confirm the chemical structure such as XRD FTIR HNMR SEM and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na2S2O3 or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm) and the number of H2 moles increases from 8.4 to 33.1 mmol h−1 cm−2 for using Na2S2O3 and sewage water as electrolyte respectively. Moreover all the thermodynamic parameters such as activation energy (Ea) enthalpy (∆H*) and entropy (∆S*) were calculated; additionally a simple mechanism is mentioned for the water-splitting reaction.

‘A System For All Seasons’ analyses Britain’s electricity generation and consumption trends concluding that the country’s wind and solar farms will have enough spare electricity generated in spring and summer when demand is lower to produce green hydrogen to the equivalent capacity of 25 Hinkley Point C nuclear power plants.

The hydrogen stored would provide the same amount of energy needed for every person in the UK to charge a Tesla Model S electric vehicle more than 21 times in the autumn and winter months when energy demand is highest creating a clean energy buffer that avoids having to manage limited energy supplies on the international markets.

Crucially the research finds that the UK has enough capacity to store the hydrogen in a combination of salt caverns and disused oil and gas fields in the North Sea as well other locations to meet this demand.

The research also finds that using renewable hydrogen will help reduce the total number of wind farms needed in 2050 by more than 75% because it will ensure electricity generated by Britain’s wind farms is used as efficiently as possible by avoiding surplus electricity going to waste.

‘A System For All Seasons’ finds that:

• Britain’s wind and solar farms could generate between 60-80GW of renewable hydrogen - the equivalent capacity of 25 Hinkley Point C nuclear power plants - from spare renewable electricity generated in the spring and summer months between May and October each year.
• Running the energy system this way will reduce the need for the total electricity generating capacity of UK wind farms from 500-600GW by 2050 down to 140-190GW – a reduction of up to 76%.
• It would mean Great Britain would be using spare renewable electricity that would otherwise go to waste to produce green hydrogen. Under the alternative scenario additional wind farms would need to be built to accommodate for autumn and wind energy demand peaks but be left unused during other times of the year.
• With 140-190GW of wind generation capacity 115 to 140TWh of green hydrogen would be stored – enough energy for every person in the UK to charge a Tesla Model S more than 21 times.
• The potential storage volume from Britain’s salt fields ranges from >1TWh up to 30TWh. For disused oil and gas fields the potential storage volume for individual sites ranges from ~1TWh up to 330TWh.

The APPG on Hydrogen has published its report urging the Government to deliver beyond its existing net zero commitments and set ambitious hydrogen targets in forthcoming strategies to reach net zero by 2050.

The All-Party Parliamentary Group (APPG) on Hydrogen’s report on the role of ‘Hydrogen in powering industry’ sets out 10 recommendations to support and accelerate the growth of the UK’s hydrogen sector and enable a sustainable energy transition.

• The Government must continue to expand beyond its existing commitments of 5GW production in the forthcoming Hydrogen Strategy.
• Any forthcoming Government and devolved policies must be complementary of the wider UK low-carbon commitments.
• Industrial clusters should be prioritised for hydrogen use and will be the key catalyst for driving forward the UK’s decarbonisation of industry.
• The Government must commit to incentivising hydrogen production within the UK as opposed to importing this.
• The Government must align hydrogen production pathways with nuclear technology to enhance hydrogen production.
• The Government must develop a UK wide hydrogen network to support the transport sector including a larger-scale implementation of hydrogen refuelling stations.
• Regulators must act quickly to update energy regulations and guidance to support hydrogen’s role in powering industry.
• For hydrogen to expand in the UK a technology neutral approach is required for all types of energy systems.
• Significant and long-term financial support is required for the development deployment and operation of hydrogen technologies.
• Ofgem must ensure the hydrogen market is subject to effective competition to drive down prices for consumers.

In this study four energy storage systems (Power-to-Gas-to-Power) were analysed that allow electrolysis products to be fully utilized immediately after they are produced. For each option the electrolysis process was supplied with electricity from a wind farm during the off-peak demand periods. In the first two variants the produced hydrogen was directed to a natural gas pipeline while the third and fourth options assumed the use of hydrogen for synthetic natural gas production. All four variants assumed the use of a gas expander powered by high-temperature exhaust gases generated during gas combustion. In the first two options gas was supplied from a natural gas network while synthetic natural gas produced during methanation was used in the other two options. A characteristic feature of all systems was the combustion of gaseous fuels within a ballast-free oxidant atmosphere without nitrogen which is the fundamental component of air in conventional systems. The fifth variant was a reference for the systems equipped with gas expanders and assumed the use of fuel cells for power generation. To evaluate the individual variants the energy storage efficiency was defined and determined and the calculated overall efficiency ranged from 17.08 to 23.79% which may be comparable to fuel cells.

The use of hydrogen as a non-emission energy carrier is important for the innovative development of the power-generation industry. Transmission pipelines are the most efficient and economic method of transporting large quantities of hydrogen in a number of variants. A comprehensive hydraulic analysis of hydrogen transmission at a mass flow rate of 0.3 to 3.0 kg/s (volume flow rates from 12000 Nm3/h to 120000 Nm3/h) was performed. The methodology was based on flow simulation in a pipeline for assumed boundary conditions as well as modeling of fluid thermodynamic parameters for pure hydrogen and its mixtures with methane. The assumed outlet pressure was 24 bar (g). The pipeline diameter and required inlet pressure were calculated for these parameters. The change in temperature was analyzed as a function of the pipeline length for a given real heat transfer model; the assumed temperatures were 5 and 25 ◦C. The impact of hydrogen on natural gas transmission is another important issue. The performed analysis revealed that the maximum participation of hydrogen in natural gas should not exceed 15%–20% or it has a negative impact on natural gas quality. In the case of a mixture of 85% methane and 15% hydrogen the required outlet pressure is 10% lower than for pure methane. The obtained results present various possibilities of pipeline transmission of hydrogen at large distances. Moreover the changes in basic thermodynamic parameters have been presented as a function of pipeline length for the adopted assumptions.

New energy vehicles (NEVs) especially electric vehicles (EVs) address the important task of reducing the greenhouse effect. It is particularly important to measure the environmental efficiency of new energy vehicles and the life cycle analysis (LCA) model provides a comprehensive evaluation method of environmental efficiency. To provide researchers with knowledge regarding the research trends of LCA in NEVs a total of 282 related studies were counted from the Web of Science database and analyzed regarding their research contents research preferences and research trends. The conclusion drawn from this research is that the stages of energy resource extraction and collection carrier production and energy transportation maintenance and replacement are not considered to be research links. The stages of material equipment and car transportation and operation equipment settling and forms of use need to be considered in future research. Hydrogen fuel cell electric vehicles (HFCEVs) vehicle type classification the water footprint battery recovery and reuse and battery aging are the focus of further research and comprehensive evaluation combined with more evaluation methods is the direction needed for the optimization of LCA. According to the results of this study regarding EV and hybrid power vehicles (including plug-in hybrid electric vehicles (PHEV) fuel-cell electric vehicles (FCEV) hybrid electric vehicles (HEV) and extended range electric vehicles (EREV)) well-to-wheel (WTW) average carbon dioxide (CO2 ) emissions have been less than those in the same period of gasoline internal combustion engine vehicles (GICEV). However EV and hybrid electric vehicle production CO2 emissions have been greater than those during the same period of GICEV and the total CO2 emissions of EV have been less than during the same period of GICEV.

An existing diesel engine was fitted with a common rail direct injection (CRDi) facility to inject fuel at higher pressure in CRDi mode. In the current work rotating blades were incorporated in the piston cavity to enhance turbulence. Pilot fuels used are diesel and biodiesel of Ceiba pentandra oil (BCPO) with hydrogen supply during the suction stroke. Performance evaluation and emission tests for CRDi mode were carried out under different loading conditions. In the first part of the work maximum possible hydrogen substitution without knocking was reported at an injection timing of 15◦ before top dead center (bTDC). In the second part of the work fuel injection pressure (IP) was varied with maximum hydrogen fuel substitution. Then in the third part of the work exhaust gas recirculation (EGR) was varied to study the nitrogen oxides (NOx) generated. At 900 bar HC emissions in the CRDi engine were reduced by 18.5% and CO emissions were reduced by 17% relative to the CI mode. NOx emissions from the CRDi engine were decreased by 28% relative to the CI engine mode. At 20% EGR lowered the BTE by 14.2% and reduced hydrocarbons nitrogen oxide and carbon monoxide by 6.3% 30.5% and 9% respectively compared to the CI mode of operation.