NETL publishes review of safety challenges of production, transportation and storage of hydrogen
23 August 2023
The National Energy Technology Laboratory (NETL) has published The Hydrogen Safety Review for Gas Turbines, SOFC, and High Temperature Hydrogen Production to review and summarize the unique safety challenges involved with the production, transportation and storage of hydrogen.
The Review is part of NETL’s Hydrogen Safety Field Work Proposal to support the US Department of Energy’s Office of Fossil Energy and Carbon Management’s strategic vision for safe, widespread and large-scale production and utilization of hydrogen as a carbon-free energy storage medium.
Hydrogen power could be a key contributor to a net-zero carbon emissions energy sector, but many technological and cost challenges still remain especially in matters of handling hydrogen safely. It’s our hope that this report will serve as a valuable resource for stakeholders in charting future hydrogen projects and assist in building safe, sustainable bulk hydrogen production and power generation infrastructure.
—Ben Chorpening, supervisor of the NETL’s Advanced Systems Integration Team and technical portfolio lead
Hydrogen is a versatile molecule, useful as a clean energy carrier and chemical precursor. Hydrogen is the most abundant element in nature, and it currently plays an important role in chemical production and petroleum refining. Hydrogen can be extracted from different sources such as fossil fuels, biomass, waste plastics and water. When combined with carbon capture and storage, natural gas reforming and gasification are well positioned to produce large quantities of hydrogen from a variety of feedstocks, including waste coal with biomass, waste plastics or municipal solid waste.
New technologies such as solid oxide electrochemical cells (SOEC) and chemical looping are also being developed for hydrogen production.
However, hydrogen does have several safety concerns that must be contended with through careful engineering design and diligent operations.
For example, compared to natural gas, hydrogen has an increased flammability range and lower minimum ignition energy, which increases the likelihood of a fire starting from a hydrogen leak. The lower ignition energy makes smaller sparks a concern. Hydrogen flames are nearly invisible, making small fires difficult to notice and posing increased risk of harm to unaware personnel.
There are also matters of operating costs and facility designs to consider when using hydrogen safely. From a mechanical design standpoint, hydrogen also causes embrittlement in many steels and alloys. Consequently, safe material selection for hydrogen results in higher system costs than with natural gas.
In addition, the form of hydrogen stored may have a significant impact on safety issues with production and utilization technologies. Liquid hydrogen and ammonia offer potential benefits for storage and transportation of hydrogen but pose some additional safety hazards.
The report documents the unique safety issues for solid oxide fuel cells (SOFCs) and gas turbines fueled from hydrogen, and production of hydrogen from fuel reforming, gasification, chemical looping and SOEC. This report includes the approaches presently used to address hydrogen safety and identifies some potential technology advancements to improve the performance and reduce the cost for safety monitoring.
The hydrogen safety report examines these concerns and more in detail, offering a valuable resource for future hydrogen endeavors.
And here is a new analysis, persuasive in my view, from Stadler, a train maker, claiming that in central Europe and especially Germany short distances mean that battery electric and catenary charging at stations is almost always more economic than fuel cell trains:
https://www.hydrogeninsight.com/transport/hydrogen-will-almost-always-lose-out-to-battery-electric-in-german-rail-transport-train-manufacturer/2-1-1504868
' The primary reason for this is that railways in Central Europe are rarely less than 80km from a station with an overhead charging line, which can be used to charge the battery with 15,000 volts — 15 minutes of which is enough to power the train for a further 50-150km.
This effectively eliminates one of the main advantages of hydrogen trains, which can take on enough fuel in quarter of an hour to travel 500-600km, several times the length of most of the German branch-lines currently in need of decarbonisation.
“On most of the approximately 500 routes in Germany that are currently served with diesel, [batteries are] the more efficient and cheaper solution,” Obst observed. “These are usually between 40 and 80km long, which you can easily travel with a battery train.”'
Perhaps rather ironically, fuel cell trains seem a far better fit for North America, where some routes are very long, but where there has to date been far less interest.
Some here may imagine that I am a hydrogen enthusiast, but that is only to the extent that I think that we should keep all options open, and not try to make sweeping judgements based on often dubious assumptions and generalisations..
Where the data to hand changes, I change my mind!
Posted by: Davemart | 23 August 2023 at 04:35 AM
I'm having second thoughts on how credible Stadler is.
If I support something, I try to give the maximum credibility to arguments against.
However, they say:
' In addition, hydrogen fuel cells require significantly more maintenance than a batteries alone, requiring replacement within three years on average.'
3 years? What the heck are they doing? Of course, private use fuel cell cars do not have a comparable duty cycle, but they have been doing fine in buses, with a much more comparable usage.
In addition, they seem to think that batteries in contrast can be routinely fast charged without consequence to cycle life.
Of course, a lot of progress has been made recently in this respect, but I am starting to think that Stadler are 'arguing a case' rather than making an even handed comparison,.
Their critique still has some weight in my view, as short distances are going to mean that catenary charging at stations is a realistic option, but I am not totally convinced.
Posted by: Davemart | 24 August 2023 at 12:59 AM
@Davemart,
I have good news for you. No need for expensive and less-durable fuel cells. Diesel train locomotives today are already hybrid gas-electric, having a diesel engine powering a generator to supply electricity to electric motors. These trains could be supplied with catenary to take advantage of electrified tracks wherever available, and would only use diesel fuel where electricity won't be available. If we would use Green H2 in those trains instead of diesel fuel, then we could be having a 100% green train transport.
The high cost of Green H2 is only for now, and will come way down in the near future as predicted. Eventually, Green H2 will replace Natural Gas and will be available everywhere at competitive prices.
The reason for using Green H2 is that Renewable Energy (RE) is intermittent and have tremendous seasonal variation.
In seasons with high-electricity demand times like summers and winters, a train could use Green-H2 for days with high electricity demand such that fossil fuel power plants are used in large proportion, in order to avoid consumption of fossil fuel and overburdening the grid.
In Springs and Falls with high availability of RE and low grid power demand, trains could be using grid electricity that will be supplied mostly by RE during these seasons.
The increasing use of Green H2 will encourage much faster RE growth because surplus RE-electricity will make money by making Green H2 instead of being dumped away and making no money for RE investors.
Posted by: Roger Pham | 24 August 2023 at 01:05 AM
Hi Roger.
' No need for expensive and less-durable fuel cells.'
I am not convinced that they are. Expensive, sure, at current levels of production.
But less durable?
At least in bus fleets, low mainenance requiremens has been keeping the total cost of ownership down againt the diesel fleets.
However, estimates of TCO are all over the shop, at least going forward, but FCEVs certainly currently much more expensive than diesel to buy, so you have a point about hydrogen/methanol engines etc.
Here are a couple of TCO studies:
https://www.sciencedirect.com/science/article/pii/S2405844022037057
https://www.transport.gov.scot/media/52921/total-costs-of-ownership.pdf
Posted by: Davemart | 24 August 2023 at 03:05 AM