ExpectedOutcome:
The growing attention on methane emissions is also triggering a debate around the safety of hydrogen. Although different in nature, the two issues are frequently associated with each other in the public debate. During a recent event organised by the US-based Environmental Defence Fund, the topic of hydrogen leakage and related GHG emissions took up a prominent place in the discussion with members of the European Parliament and Commission officials. According to the participants, the discussion and the lessons learned about methane emission can be applied to the subject of hydrogen leakage. Even though hydrogen in itself is not a GHG, by depleting hydroxyl radicals (OH), thus increasing the atmospheric lifetime of methane as well as by influencing tropospheric ozone formation, the total GWP of hydrogen over 100 years can be estimated at 5.8[1]. As hydrogen leakage, during storage and transportation, is potentially the largest source of anthropogenic hydrogen emissions, minimising hydrogen leakage rates is therefore key to ensure climate sustainability of the developing hydrogen economy. Furthermore, as around 60% of hydrogen’s global warming potential results from changes in methane concentration, tackling hydrogen leakage would be complementary to the EU Methane Strategy[2] and the Proposal for a Regulation to reduce Methane emissions of December 2021[3] as well as to the recent Global Methane Pledge[4]. As hydrogen has a very broad flammability range - a 4 percent to 74 percent concentration in air – leakage detection and prevention is also crucial from safety point of view, especially inside confined spaces.
Safety requirements of natural gas (NG), mixed NG/H2 and pure hydrogen transport require robust yet innovative solutions for sensor-based leak detection monitoring throughout Europe. In addition, leaks at HRS level became one the main concerns to operate safely and economically the retail business.
The sensor technology development in this field should address the development, testing and validation of new detection techniques and tools for measurement by continuous monitoring of pure hydrogen and mixed methane-hydrogen emissions.
This will enable safer storage, transport (in NG Grid or trailers) and distribution of gaseous hydrogen. The approach to solve these safety issues may vary due to different demands at different sites, both enclosed and open air, and will depend on variable configuration of the network / distribution, different gas pressure ranges and hydrogen concentration, and possible interference from other components like the NG/H2 mixture.
Current technologies for continuous leak detection monitoring are not satisfactory and should meet the industry & public area requirements.
Project results are expected to contribute to all of the following expected outcomes:
- The development of leak detection system that can classify leak types and leak sources according to risk, location, impact, consideration of severity, probability and predictability arising from sensors for leak detection and system integrity including predictive maintenance, odorised molecules and airborne technologies which will detect hydrogen leakage remotely (such as Raman LiDAR for hydrogen pipelines).
- To ensure safe operation of hydrogen infrastructure (e.g. HRS, filling centres, gas grids, compressor housings)
- Improvement of Leak detection time/rate and detection accuracy of the system
- Improvement in the productivity and cost effectiveness of the sensor device. While some leak categories may require continuous monitoring, for other leaks periodic measurements by mobile sensors or multiplexed arrangements may be more cost-effective. Continuous monitoring solutions can detect and report leaks in real-time and trigger early warning systems which helps to reduce risk for both humans and materials, especially in densely populated areas or densely built industry parks and refineries.
Project results are expected to contribute to all of the following objectives of the JU as reflected in the SRIA of the Clean Hydrogen JU:
- Increase the level of safety of hydrogen technologies and applications
- Enable through research and demonstration activities the transportation of hydrogen through the natural gas grid either by blending or via repurposing to 100% hydrogen.
The project is also expected to achieve the following technical KPIs:
- Concentration measurement accuracy for safe operation in terms of explosion limit, 1% lower explosive limit (LEL). This means that the sensor should be able to detect 0.04% of H2 in air;
- A minimum detection sensitivity of ± 0.18% by volume of hydrogen in air (a good practice is to set the detectors to alarm at 0.4% hydrogen by volume in air, which is 10% of the lower flammability limit (LFL);
- A maximum. response time of 1 sec at a concentration of 0.4% by volume (more than 10% LFL), while keeping in mind that sensor performance can vary from one application to another, this is extremely important for system designed to monitor hydrogen concentrations in rooms or areas (e.g. turbomachinery package enclosure) with high temperature environments in presence of hot surfaces with temperatures above auto-ignition (AIT).
Scope:
The proposed research is expected to focus on developing and validating reliable leak sensing services and leak detection sensor technologies for hydrogen and NG/H2 mixtures. The proposed research work should start at TRL 3 and end at TRL 5 or higher.
New and optimised leak detection sensors and tools should be developed in order to enable safer storage, transport and distribution of hydrogen. Leak detection technologies may include the development of new or optimisation of existing portable and fixed sensors (ideally with remote access) with various technical approaches (e.g. acoustic, laser scanning, optical fibre sensors, infrared if NG/H2 mix considered, odorised molecules, strain gauge). Optimisation of existing hydrogen emission detection systems in terms of measuring range, tolerance, temperature measuring range, pressure range, response and recovery time[5], and to lower the costs for investments, compression/operations and maintenance should also be considered.
Besides the technical KPIs that were already mentioned in the expected outcome section other key elements for leak detection monitoring are outlined below:
- Leak detection devices should identify the origin or the leak (e.g acoustic detection) to allow the commissioning & operating team to fix the issue;
- The leak detection system should warn personnel with visual and audible warnings when the environment is becoming unsafe; remote notification should be preferred.
The proposed technology should be suitable for continuous leak detection monitoring or/and periodic maintenance. Certain leak categories may be addressed by periodic measurement while other leak detection solutions may require interconnected mobile sensors or multiplexed arrangements.
Technologies related to hydrogen detection are based on the effects induced by the interaction of hydrogen with a selected sensing material. For example these effects can span catalytic, thermal conductivity, electrical and electrochemical, mechanical optical and acoustic properties. The scope of the topic is completely open to any kind of sensing technology.
Proposals are expected to contribute towards the activities of Mission Innovation 2.0 - Clean Hydrogen Mission. Cooperation with entities from Clean Hydrogen Mission member countries, which are neither EU Member States nor Horizon Europe Associated countries, is encouraged (see section 2.2.6.8 International Cooperation).
Activities are expected to start at TRL 3 and achieve TRL 5 by the end of the project.
The conditions related to this topic are provided in the chapter 2.2.3.2 of the Clean Hydrogen JU 2022 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2021–2022 which apply mutatis mutandis.
[1]https://www.geos.ed.ac.uk/~dstevens/publications/derwent_cc01.pdf
[2]https://ec.europa.eu/energy/sites/default/files/eu_methane_strategy.pdf
[3]https://eur-lex.europa.eu/resource.html?uri=cellar:06d0c90a-5d91-11ec-9c6c-01aa75ed71a1.0001.02/DOC_1&format=PDF
[4]https://www.globalmethanepledge.org/
[5]Understood as time between two measurements.
