Publications

In any application involving the production storage or use of hydrogen sensors are important devices for alerting to the presence of leaked hydrogen. Hydrogen sensors should be accurate sensitive and specific as well as resistant to long term drift and varying environmental conditions. Furthermore as an integral element in a safety system sensor performance should not be compromised by operational parameters. For example safety sensors may be required to operate at reduced oxygen levels relative to air. In this work we evaluate and compare a number of sensor technologies in terms of their ability to detect hydrogen under conditions of varying oxygen concentration.

This report by the Committee on Climate Change (CCC) assesses the potential role of hydrogen in the UK’s low-carbon economy.

It finds that hydrogen:

• is a credible option to help decarbonise the UK energy system but its role depends on early Government commitment and improved support to develop the UK’s industrial capability
• can make an important contribution to long-term decarbonisation if combined with greater energy efficiency cheap low-carbon power generation electrified transport and new ‘hybrid’ heat pump systems which have been successfully trialled in the UK
• could replace natural gas in parts of the energy system where electrification is not feasible or is prohibitively expensive for example in providing heat on colder winter days industrial heat processes and back-up power generation
• is not a ‘silver bullet’ solution; the report explores some commonly-held misconceptions highlighting the need for careful planning

The report’s key recommendations are:

• Government must commit to developing a low-carbon heat strategy within the next three years
• Significant volumes of low-carbon hydrogen should be produced in a carbon capture and storage (CCS) ‘cluster’ by 2030 to help the industry grow
• Government must support the early demonstration of the everyday uses of hydrogen in order to establish the practicality of switching from natural gas to hydrogen
• There is low awareness amongst the general public of reasons to move away from natural gas heating to low-carbon alternatives
• A strategy should be developed for low-carbon heavy goods vehicles (HGVs) which encourages a move away from fossil fuels and biofuels to zero-emission solutions by 2050

In this report the Committee sets out how Northern Ireland can reduce its greenhouse gas emissions between now and 2030 in order to meet UK-wide climate change targets.

The report’s key findings are:

• Existing policies are not enough to deliver this reduction
• There are excellent opportunities to close this gap and go beyond 35%
• Meeting the cost-effective path to decarbonisation in Northern Ireland will require action across all sectors of the economy and a more joined-up approach

Overall Northern Ireland’s fair contribution to the UK’s fifth carbon budget requires emissions reductions of at least 35% against 1990 levels by 2030.

The Scottish Act sets a long-term target to reduce emissions of greenhouse gases (GHGs) by at least 80% in 2050 relative to 1990 with an interim target to reduce emissions by 42% in 2020. Secondary legislation passed in October 2010 and October 2011 also set a series of annual emission reduction targets for 2010 to 2022 and 2023 to 2027 respectively. We advised the Scottish Government on annual targets for the period 2028 to 2032 in March 2016 and July 2016.<br/>The report reveals that Scotland’s annual emissions reduction target for 2014 was met with gross Scottish greenhouse gas emissions including international aviation and shipping falling by 8.6% in 2014. This compares to a 7.3% fall for the UK as a whole. Since 1990 gross Scottish emissions have fallen nearly 40% compared to nearly 33% at a UK level.

This is the Committee’s seventh report on Scotland’s progress towards meetings emissions targets as requested by Scottish Ministers under the Climate Change (Scotland) Act 2009.

Overall Scotland continues to outperform the rest of the UK in reducing its greenhouse gas emissions but successful strategies for energy and waste mask a lack of progress in other parts of the Scottish economy.

The report shows that Scotland’s total emissions fell by 10% in 2016 compared to 2015. The lion’s share of this latest drop in emissions came from electricity generation.

The key findings are:

• Overall Scotland met its annual emissions targets in 2016. 
• Scotland’s progress in reducing emissions from the power sector masks a lack of action in other areas particularly transport agriculture forestry and land use.
• Low-carbon heat transport agriculture and forestry sector policies need to improve in order to hit 2032 emissions targets.
• The Scottish Government’s Climate Change Plan – published in February 2018 – now has sensible expectations across each sector to reduce emissions.

This is the Committee’s fifth report on Scotland’s progress towards meeting emission reduction targets as requested by Scottish Ministers under the Climate Change (Scotland) Act 2009.<br/>The Scottish Act sets a long-term target to reduce emissions of greenhouse gases (GHGs) by at least 80% in 2050 relative to 1990 with an interim target to reduce emissions by 42% in 2020. Secondary legislation passed in October 2010 and October 2011 also set a series of annual emission reduction targets for 2010 to 2022 and 2023 to 2027 respectively. We advised the Scottish Government on annual targets for the period 2028 to 2032 in March 2016 and July 2016.<br/>The report reveals that Scotland’s annual emissions reduction target for 2014 was met with gross Scottish greenhouse gas emissions including international aviation and shipping falling by 8.6% in 2014. This compares to a 7.3% fall for the UK as a whole. Since 1990 gross Scottish emissions have fallen nearly 40% compared to nearly 33% at a UK level.

Hydrogen jet flames resulting from ignition of unintended releases can be extensive in length and pose significant radiation and impingement hazards. One possible mitigation strategy to reduce exposure to jet flames is to incorporate barriers around hydrogen storage and delivery equipment. While reducing the extent of unacceptable consequences the walls may introduce other hazards if not properly configured. This paper describes experiments carried out to characterize the effectiveness of different barrier wall configurations at reducing the hazards created by jet fires. The hazards that are evaluated are the generation of overpressure during ignition the thermal radiation produced by the jet flame and the effectiveness of the wall at deflecting the flame.<br/>The tests were conducted against a vertical wall (1-wall configuration) and two “3-wall” configurations that consisted of the same vertical wall with two side walls of the same dimensions angled at 135° and 90°. The hydrogen jet impinged on the center of the central wall in all cases. In terms of reducing the radiation heat flux behind the wall the 1-wall configuration performed best followed by the 3-wall 135° configuration and the 3-wall 90°. The reduced shielding efficiency of the three-wall configurations was probably due to the additional confinement created by the side walls that limited the escape of hot gases to the sides of the wall and forced the hot gases to travel over the top of the wall.<br/>The 3-wall barrier with 135° side walls exhibited the best overall performance. Overpressures produced on the release side of the wall were similar to those produced in the 1-wall configuration. The attenuation of overpressure and impulse behind the wall was comparable to that of the three-wall configuration with 90° side walls. The 3-wall 135° configuration’s ability to shield the back side of the wall from the heat flux emitted from the jet flame was comparable to the 1-wall and better than the 3-wall 90° configuration. The ratio of peak overpressure (from in front of the wall and from behind the wall) showed that the 3-wall 135° configuration and the 3-wall 90° configuration had a similar effectiveness. In terms of the pressure mitigation the 3-wall configurations performed significantly better than the 1-wall configuration

Clarification of questions of safety represents a decisive contribution to the successful introduction of vehicles fuelled by hydrogen. At the moment the safety of hydrogen is being discussed and investigated by various bodies. The primary focus is on fuel-cell vehicles with hydrogen stored in gaseous form. This paper looks at the safety of hydrogen-fuelled vehicles with an internal combustion engine and liquefied hydrogen storage. The safety concept of BMW’s hydrogen vehicles is described and the specific aspects of the propulsion and storage concepts discussed. The main discussion emphasis is on the utilization of boil-off parking of the vehicles in an enclosed space and their crash behaviour. Theoretical safety observations are complemented by the latest experimental and test results. Finally reference is made to the topic-areas in the field of hydrogen safety in which cooperative research work could make a valuable contribution to the future of the hydrogen-powered vehicle.

This report responds to a request from the Governments of the UK Wales and Scotland asking the Committee to reassess the UK’s long-term emissions targets. Our new emissions scenarios draw on ten new research projects three expert advisory groups and reviews of the work of the IPCC and others.<br/>The conclusions are supported by detailed analysis published in the Net Zero Technical Report that has been carried out for each sector of the economy plus consideration of F-gas emissions and greenhouse gas removals.

This is the first document of a two-part review of the Fourth Carbon Budget which covers 2023 to 2027. The Fourth Carbon Budget agreed by the Government in June 2011 was scheduled to be reviewed in 2014. The second part of the review is available here: The Fourth Carbon Budget Review – part 2: the cost effective path to the 2050 target (December 2013).<br/>According to the Climate Change Act 2008 carbon budgets can only be altered if there is a significant change in circumstances upon which the budget was set. Any such change in circumstances must be demonstrated through evidence and analysis.<br/>The Fourth Carbon Budget Review – part 1 focuses on developments in three categories of circumstance on which the budget was set: climate science international circumstances and European Union pathways. The report also looks at findings by the Intergovernmental Panel on Climate Change and assesses the implications for carbon budgets.