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The objectives for this project were:

To discharge the UK Participating Agency role in the first year of Task 18 of the IEA's Implementing Agreement on Hydrogen

To review and identify candidate UK hydrogen demonstration projects

To reach agreement in relation to one or more of these projects, in relation to their participation within the Task 18 project analysis framework

The conclusions from this project were:

The work has identified a range of hydrogen related demonstration activities in the UK, either already operational, under construction or planned

Compressed gaseous hydrogen fuelled fuel cell installations represent the majority of installations to date

The HARI project, at West Beacon Farm, Leics., represented the sole UK example of an integrated renewable energy/hydrogen system implemented to date

Anticipated developments , which are projected to be commissioned within the next six months, include the CUTE re-fuelling station in Essex and the PURE project, in Unst, Shetland

This summary provides information on:

Objectives

Summary

Contractor

Cost

Duration

Background

The Work Programme

Conclusions

Potential for Future Development

Green ammonia is produced from renewable hydrogen with no direct CO2 emissions when combusted, making it an important option to interrogate. This research uses a mixed methods approach, including analysing shipping stakeholders� perspectives, to consider the full range of factors relating to its deployment and use. The study emphasizes though that the on-ground realities of transitioning away from fossil fuels require significant developments across the entire fuel supply chain, which extends beyond considerations around ammonia�s technological viability and encompass changes needed to onboard and portside infrastructure, incentives to accelerate retrofit and fleet renewal, and recognition of risks posed by first-movers in the sector. This study states that with short timeliness associated with Paris targets, and anticipated rising costs of new fuel infrastructure, there is an imperative to implement mitigation policy that focuses on urgently reducing reliance on liquid fuels, while alternative fuel deployment is established at scale.

Hydrogen produced from natural gas with steam methane reforming coupled with carbon capture and sequestration (SMRCCS) is proposed as fuel for consumer heating and cooking systems. This paper presents estimates of the energy losses and methane and carbon dioxide emission and global warming across the whole gas to hydrogen heat supply chain - from production to consumer. Processed natural gas is typically about 95% methane which is a potent greenhouse gas with a global warming potential (GWP) such that, with 20 year and 100 year GWP horizons, about 4% and 8% leakage respectively will cause as much global warming as the carbon dioxide formed when burning the methane. Data on gas emissions and SMRCCS costs and performance are sparse and wide ranging and this presents a major problem in accurately appraising the possible role of hydrogen from methane. The survey indicates emissions between 50 and 200 gCO2eq per unit of heat (kWhth) for SMRCCS H2 heat depending on leakage and GWP time horizon assumed. The second part of the paper reviews gas supply pricing and security and presents a cost minimised configuration of a SMRCCS hydrogen heating system derived with a simple model. Uncertainty in SMRCCS greenhouse gas emissions coupled with a net zero emission target and the long term issue of the physical and economic security of natural gas supply, bear on the potential advantages of SMRCCS as compared to other options, such as heating with renewable electricity driving consumer or district heating heat pumps.

This document provides the rationale for the design and manufacture of the test rig forming Work Package 2 Task 2.3. This document is one of two for the HRSG experiments and provides the details of the test rig, what parameters it has been designed for to support the test program.

This document describes the design parameters for the second test rig to be constructed on the HSL Buxton site in order to complete the contracted work that HSL and ICL have undertaken to deliver under a consortium agreement with ETI. The project is being delivered in three phases.

Phase 1 was a literature review of current knowledge for the use of hydrogen and hydrogen blended fuels in the current electrical generation sectors, and concentrated on gas engines (turbine and reciprocating) utilising heat recovery steam generating (HRSG) boilers attached to their exhaust systems. There was also a series of laboratory experiments to determine, the turbulent flame velocities, pressure rises from ignition, and auto-ignition temperatures etc.

This deliverable is number 2 of 8 in the project. The current study investigates the impact of fuel reactivity changes caused by the gradual dilution of hydrogen with either methane or carbon monoxide. The impact of nitrogen dilution is also considered. The experimental configuration was chosen to investigate auto-ignition in a turbulent shear layer formed between the fuel jet and a stream of hot combustion products. The results obtained suggest that under the current condition the reactivity of CH₄,/H₂ blends become increasingly reduced by the CH₄ component beyond the 50/50 mixture. By contrast, CO mixtures remain much more reactive over the entire range of conditions. A strong impact of dilution has also been shown and the effect is consistent with a reduced ability of the H₂ component of the fuel blend to trigger auto-ignition of the carbon containing component

This document provides the rationale for, and a description of, the design process covering the design, manufacture and installation, commissioning and operating procedures for the test rig. The scenario of interest is one in which a CCGT/CCGE flames out for whatever reason and for the following few seconds unburnt fuel passes through the turbine (in the CCGT case) without re-igniting and into the exhaust system.

This document provides the rationale for the design and manufacture of the test rig forming Work Package 2 Task 2. This document is one of two for the circular duct experiments and provided the details of the test rig, what parameters it has been designed for to support the test program.

The rig will provide an experimental facility to investigate the flame out of CCGT/CCGE systems and the consequences of unburnt fuel passing through the turbine (in the CCGT case) and into the exhaust system. In such circumstances the maximum hydrogen concentration in the downstream mixture is not expected to exceed 10-12% v/v hydrogen (when fuelled with pure hydrogen), and be at temperatures of the order of 400–600°C, depending on the exhaust composition and the degree of compression achieved in the compressor. For CCGE applications the hydrogen concentration may be higher by up toa factor of two. If re-ignition in the exhaust system is then assumed to occur, the project seeks to assess the potential consequences, particularly with reference to the flame acceleration and the detonation propensity of the air/fuel mixtures. This rig provides a reduced scale model of an actual turbine exhaust system such that the appropriate scaling criteria can be identified to enable predictions to be made of the hazards at full scale.

The rig can also contain a simulated heat exchanger so that its effect on initiating detonations can be examined as a precursor to the definitive heat exchanger tests proposed for the WP2.3 test rig using an actual heat exchanger but scaled down to a representative size

This document provides the rationale for the design and manufacture of the test rig forming Work Package 2 Task 2.3. This document is one of two for the HRSG experiments and provides the details of the test rig, what parameters it has been designed for to support the test program

The High Hydrogen project seeks to identify the safe limits for use of higher levels of hydrogen in the feedstock to combustion plant utilising heat recovery plant and if necessary develop safety standards to support the findings of the project. This project has investigated the risk potential from use of high hydrogen fuels in conventional turbines or engines with exhaust ducting leading to heat recovery equipment. The fuel valves in these systems take seconds to close when the system detect a flame failure or in a fault situation so the volume of gas and any diluents passing into the hot ducting prior to full shut down and purge is of interest. Established laboratory test devices have be used to investigate the effects of differing fuel / diluent compositions in the ducting in terms of the potential for ignition, and the strength of the event. This allows for the definition safe levels of hydrogen in the fuel and avoid the potential for a catastrophic event. The first deliverable from this project comprises of a full literature review of data currently available, a fuel matrix identifying the current fuels containing hydrogen and a test plan to fill in the gaps of current knowledge regarding the energetic reaction of these fuel sources. The findings from these tests will be used to develop the tests planned on industrial scale test plant in the next phase of this project.

The report contains details for the complete project. This project commenced in 2011 and has completed works at the end of 2016. There have been three previous sections to this project: a literature review, laboratory scale experiments and a circular duct phase; this last phase incorporated a scale heat recovery steam generating boiler.

The project has been shown to be able to simulate several of the relevant features of a full scale HRSG system using the current scaled test rig and to demonstrate the development of flame through the system and the generation of pressures, which are believed to be relevant to the understanding of how these will develop at full scale. The commissioning tests carried out have given confidence in the overall operation of the test rig in terms of achieving appropriate gas temperatures, injected fuel mixtures and equivalence ratios; exhaust/injected fuel mixing and HRSG purging times ahead of actual ignition. Detailed flow measurements at selected positions within the system have confirmed the uniformity of the flow in these regions and have provided background turbulence data for future flow and combustion modelling.

This deliverable is number 2 of 8 in the project. The current study investigates the impact of fuel reactivity changes caused by the gradual dilution of hydrogen with either methane or carbon monoxide. The impact of nitrogen dilution is also considered. The experimental configuration was chosen to investigate auto-ignition in a turbulent shear layer formed between the fuel jet and a stream of hot combustion products. The results obtained suggest that under the current condition the reactivity of CH₄,/H₂ blends become increasingly reduced by the CH₄ component beyond the 50/50 mixture. By contrast, CO mixtures remain much more reactive over the entire range of conditions. A strong impact of dilution has also been shown and the effect is consistent with a reduced ability of the H₂ component of the fuel blend to trigger auto-ignition of the carboncontaining component.

The document contains a series of reports:-

• Report 1: CTO’s Overview of Work Package 2, Task 1. Prof H.J. Michels, Imperial College London.
• Report 2a: Ignition, turbulent deflagration and DDT potential of hydrogen / methane and hydrogen / carbon monoxide mixtures with air. Prof P.R. Lindstedt, Imperial College London
• Report 2b: Shock Tube Studies of the Ignition Delay Times of Syn-Gases. Prof. R. K. Hanson, Dr. D. F. Davidson, Stanford University.
• Report 3: Modelling of blast in hydrogen power generation systems. Dr R.Rosario, BAE Systems.
• Report 4: One-Dimesional model predictions of test rigs pressure distributions (deliverable One). Dr G. Munday, Information Search and Analysis Consultants.

This is the last interim report for the High Hydrogen project. It describes and discusses the work performed to date at Buxton, the process used to design commission and operate the circular duct test rig for exploring the operational capability of plant using hydrogen-based fuels with heat recovery systems on their exhaust systems. There will be one further deliverable from this project which will provide results for the HRSG model tests and draw the full programme of works together from the literature review, through the laboratory experiments and the two scale experimental rigs. The executive summary on page 9 provides a good insight into the report and its objectives. The key insights from Prof Hans Michels, whilst on a limited number of tests, provide some key information that begins to link the project phases).

The objectives of the tests were to model at reduced scale,the consequences of a flameout in a full-size combined cycle gas turbine (CCGT) when running on high hydrogen fuel mixtures. The test parameters varied were the fuel mixture composition, the equivalence ratio and the exhaust gas temperature. The heat recovery steam generator (HRSG) was modelled by a series of tubes giving a blockage ratio of 40% per tube row. The numbers of tube rows tested were 0, 8 and 15.

This report presents the results obtained without analysis; it does however comment upon the consistency of the data sets in respect of the parameters tested.

This deliverable is number 1 of 8 in the project and forms the basis of the project direction. It provides information on the current gaps in knowledge of plants operating on High Hydrogen fuels. The report provides an in depth review of the current literature landscape relating to the use of hydrogen rich fuels for both reciprocating engines and gas turbines. All current fuels containing hydrogen are detailed with their other constituent parts. The report identifies the scaling principles to determine how the results from the laboratory can be applied to the plant being constructed for the next phase and real world applications. Appendix A3 Analysis of HSE gas turbine and gas engine incidents database has been removed for confidentiality reasons.

A brief summary report supporting Stage Gate 1 for discussions to identify the fuel mixtures we should utilize in the test program.

Three representative fuel systems are suggested, based on future potential fuel sources, which can also be tested generically in the laboratory such that their properties can be readily assessed in respect of their DDT potential, and the needs of the project. The issue of the selection process is also reviewed in the light of real gas turbine systems. This provides additional information, which shows that certain high hydrogen fuels could potentially result in fuel mixtures exceeding the LFL in the exhaust stream following a flameout. The three fuel systems are:-

• Refinery Fuel Gas
• Syngas
• Producer Gas from Biomass

The purpose and focus of the Hydrogen Turbines project is to improve the ETI's understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines, and to provide data on the potential economics and technical requirements of such technology to refine overall energy system modelling inputs. The final deliverable (D2) comprises eight separate components. This document is D2 WP1 Report - providing results of a techno-economic assessment of options for hydrogen power production from coal, coal/biomass and gas. It covers:

• Options for hydrogen production
• Techno-economic definition of the selected hydrogen production options
• Characterisation of basic design requirements for a cost effective hydrogen store
• Requirements / options for hydrogen turbines
• Economics of hydrogen pipelines
• Effects of hydrogen purity

The purpose and focus of the Hydrogen Turbines project is to improve the ETI’s understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines, and to provide data on the potential economics and technical requirements of such technology to refine overall energy system modelling inputs. The final deliverable (D2) comprises eight separate components. This document is D2 WP3 Report – providing a series of supporting studies:

• Identification of potential salt cavern locationswithin UK and first 25 miles of UK Continental Shelf;
• Salt cavern cost structure;
• HSE challenges of cavern construction and operation;
• Managing loss of containment;
• Licensing and build timeline;
• Alternative cavern use; and
• Landscapingstudy of alternatives to salt caverns.

The purpose and focus of the Hydrogen Turbines project is to improve the ETI’s understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines, and to provide data on the potential economics and technical requirements of such technology to refine overall energy system modelling inputs. The final deliverable (D2) comprises eight separate components. This document is D2 WP3 Report – providing a series of supporting studies, including alternative methods of hydrogen production and hydrogen-based power generation, alternatives to salt cavern storage and broader issues around hydrogen use in the UK energy system.

The purpose and focus of the Hydrogen Turbines project is to improve the ETI’s understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines, and to provide data on the potential economics and technical requirements of such technology to refine overall energy system modelling inputs. The final deliverable (D2) comprises eight separate components. This document is D2 WP5 Report – identifying a representative hydrogen storage and flexible turbine system and providing a comparison to a baseline of a CCGT with post combustion carbon capture, either with or without CO₂ storage buffering

The purpose and focus of the Hydrogen Turbines project is to improve the ETI’s understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines, and to provide data on the potential economics and technical requirements of such technology to refine overall energy system modelling inputs. The final deliverable (D2) comprises eight separate components. This document is D2 – Summary Report, providing an Overview of the project.

The ETI’s energy system modelling shows that flexible power generation systems comprising hydrogen generation with CCS, intermediate storage (particularly using salt caverns) and flexible turbines are attractive options for the UK. In the model described here, hydrogen is supplied from coal and biomass fired gasifiers and steam methane reformers, with CO₂ captured for storage. This permits the use at high load of capital intensive and relatively inflexible conversion and CCS equipment, filling hydrogen storage when power is not needed, and releasing hydrogen at short notice through turbines when power is at a premium

This report reviews the performance and costs of existing commercial gas turbines and the capability of gas turbines to operate using hydrogen-containing fuel gases. The report was commissioned by ETI to provide background information for a project they will undertake on salt caverns for storage of hydrogen for use in gas turbine power plants.

A wide range of gas turbines are reported by manufacturers to be suitable for fuel gases that contain hydrogen. There is significant experience of using gases that contain mixtures of mainly hydrogen,methane and other hydrocarbon gases, especially refinery off-gases and coke oven gas, which typically contains 50-60%vol H₂. Gases with H₂ concentrations of up to 95% are reported to be used. There is also experience of using syngas from gasification which typically contains 25-50%vol H₂ but the other main constituent is CO, which has substantially different properties to methane.

Use of fuel gas containing H₂ presents some significant technical challenges for gas turbines but also some potential benefits.

The biggest technical challenge is reported to be the high flame speed of H₂, which can result in flashback, although it reduces the risk of blowout. The properties of hydrogen-methane mixtures in gas turbines combustors vary non-linearly with concentration. It is reported that only when hydrogen becomes the main constituent is there a large variation in the laminar flame speed.

Development aspects and assessments of Gas Turbines (fired by methane and/or H₂) are provided, including contemporary OCGT GTs from GE. Additionally, potentially synergistic capture technologies are described

With the growth of renewables a clean, dispatchable power source will be required in the 2030s. One scheme for providing this involves storing large quantities of H₂ in salt caverns, and to use the inventory to produce power or heat during peak hours. Although H₂ is stored already in caverns in the UK, there has been little work on the effect of rapid repetitive cycling on cavern integrity. The suitability of UK salt caverns for use in storing H₂ in rapid cycle mode is examined, based on detailed geotechnical analysis of saltfields in Yorkshire, Teesside and Cheshire. A detailed analysis is carried out by Atkins on a Cheshire cavern, using a combination of superimposed seasonal and daily demand patterns .The limitations of today’s market offering for firing H₂ in gas turbines is described. Outline costing for schemes taking H₂from salt caverns and producing power are presented.

ETI modelling, using its Energy System Modelling Environment (ESME), shows that flexible power generation systems comprising hydrogen generation with CCS, intermediate hydrogen storage (particularly using salt caverns) and flexible turbines are attractive components in a future UK energy system. In such a system, hydrogen is supplied from coal and biomass fired gasifiers and steam methane reformers, with CO₂ captured for storage - see Figure 1 below for hypothetical layouts. This permits the use at high load of capital intensive and relatively inflexible conversion and CCS equipment, filling hydrogen storage when power is not needed, and releasing hydrogen at short notice through turbines when power is at a premium. Superficially there are no barriers to using salt caverns as stores, as such stores are in use in the USA. However these are for high value added applications andnot for use in power where loss of efficiency is a more serious drawback. The ETI currently lacks sufficient data and knowledge to build a good representation of costs or efficiency (particularly relating to hydrogen storage) in ESME.

The purpose and focus of the proposed project is:

• To improve the ETI’s understanding of the economics of flexible power generation systems comprising hydrogen production (with CCS), intermediate hydrogen storage (e.g. in salt caverns) and flexible turbines;
• To focus on the potential, economics and technical requirements for salt cavern storage and flexible turbines, to enable refinement of the ESME model in order to confirm or adjust ESME findings.

The first activity in the project (WP1 – see below for further details) is to characterise the requirements for storage for “power scale” use, in termsof offering tactical (diurnal) or strategic levels of storage (and what that means in terms of a delivery pattern of hydrogen) and to estimate what storage pressures are of interest.

The second exercise (WP2) is to find out where in the UK suitable salt structures exist, and how much storage there might be. “Suitability” will not just depend on rock quality, but on depth (pressure) and location. This will enable calculation of scalable costs for UK design types. This data will be of general use, to potentially examine the economics of different configurations around a store. It will be necessary to check, for example, whether or not use of a cavern as a hydrogen store represents better value than, say, a natural gas store or a CO₂ buffer store (which would also stabilise CCS flows).

The project will include a number of supporting studies (WP3) to provide context on the main thrust of the project: these will be brief and based on existing studies.

The outputs from WP1 - 3 will then be used to confirm the most favourable configuration (WP4) and/or identify any new ones. Provided these initial studies confirm the anticipated benefits of using hydrogen storage, the project will proceed via a Stage Gate following WP4 to model a representative system at high level and stress test the application in WP5.

The ETI’s energy system modelling shows that flexible power generation systems comprising hydrogen generation with CCS, intermediate storage (particularly using salt caverns) and flexible turbines are attractive options for the UK. In the model described here, hydrogen is supplied from coal and biomass fired gasifiers and steam methane reformers, with CO₂ captured for storage. This permits the use at high load of capital intensive and relatively inflexible conversion and CCS equipment, filling hydrogen storage when power is not needed, and releasing hydrogen at short notice through turbines when power is at a premium.

This executive summary covers the objectives and main findings of the five work packages, and suggests the next steps.

Reducing CO₂ emissions from UK transport is likely to require a combination of measures, including increased energy efficiency, new technology introduction, and fuel switching. Apart from demand-side management, the most important technologies can be divided into (a) vehicles and (b) fuels.

Key vehicle technologies are:

Battery electric vehicles, for niche markets including urban journeys

Hybrid-electric vehicles, replacing conventional gasoline and diesel vehicles

Fuel cell vehicles, potentially able to replace all conventional vehicles

Different fuels can be used in these different vehicles:

Electricity will be required for battery vehicles, and for some hybrids, known as plug-in hybrids

Biofuels can be introduced either as blends in current fuels, and used in current vehicles and hybrids, or potentially at levels of 100% with some engine modifications

Hydrogen is probably required for fuel cell vehicles, and could be also used in internal combustion engines

Each of these technologies and fuels faces technical, cost and policy challenges before it can compete commercially. However, these do not appear insurmountable. Each also offers benefits other than simply possible reductions in CO₂ emissions from transport. In the near term, hybrid vehicles and biofuels are expected to be the main contributors to reductions in emissions. The environmental impact of biofuels is complex and care should be taken in evaluating and monitoring their real-world effects, especially if either raw materials or finished fuels are imported. In the longer term, but only if technical development is successful, fuel cell vehicles using hydrogen offer the potential for major emissions reductions.

The table below gives indicative figures, and ranges, of costs of carbon reduction from different fuels and routes. It is extremely important to note the uncertainty inherent in all of the cost and price assumptions made here, especially as the timescales increase. Robust policy must be based not only on these numbers, but also on other factors that have not been examined under the analysis conducted for this report.

This report contains an executive summary, and is divided into the following sections:

1. Introduction
2. Important Issues and Caveats
3. Vehicle Technologies
4. Fuels
5. Technology and Cost Issues and Other Barriers
6. Costs of Energy Use and CO₂ Emission Reduction
7. Policy
8. Summary