How do you select the right hydrogen storage technology for your application?

Compressed hydrogen is currently the most suitable storage option for hydrogen-powered vehicles. It is a well-established technology with a high storage capacity and quick refuelling times. Ongoing technological advancements are expected to increase the hydrogen pressure in compressed hydrogen tanks up to 1000 bar. This would boost the storage capacity of compressed hydrogen significantly, making it a more feasible option for light-duty vehicles such as passenger cars. Moreover, it would also decrease the size and weight of compressed hydrogen tanks, making them more practical for a wider range of applications. If you need a lightweight and compact storage system, then metal hydrides or liquid hydrogen may be a better choice.

Material technology for hydrogen tank application is advancing so fast. Carbon fiber tanks are almost indestructible and also light weight.

For the larger projects with significant hydrogen storage needs due to intermittency or a project with only solar then salt cavern storage is hard to beat when it comes to delivered cost of released hydrogen. Again very few sites are advantaged with an underground salt cavern however I think the feasible first mover large projects that don’t benefit from a subsidy will need to have very inexpensive renewables coupled with salt cavern storage for the produced hydrogen thereby eliminating the needs for 400 MWH to 1 GWH of battery storage. You lose 10 percent of your energy on a RT from the battery - plus battery degradation I think you’ll see a lot of salt cavern storage projects that will be very attractive along the US Gulf Coast

The only practical option is compressed gaseous hydrogen (GH2) Liquid hydrogen (LH2) is cost/energy prohibitive, even at scale. LH2 technology is behind GH2. As is the regulatory framework and essential safety standards needed for safe scalable deployment of LH2 Cryo-compressed Hydrogen (CcH2) is liquified hydrogen under pressure, expected to eventually surpass LH2 at scale. As with LH2 technology and standards are yet to mature. Liquid organic hydrogen carriers (LOHC), whilst existing Ammonia infrastructure could be adapted easily, cracking technology is inefficient and yet to mature Hydrides show promise also but are heavy. All of the latter are derived from GH2 still requiring auxiliary compression for mobility applications.

The selection process requires a balanced evaluation of advantages and challenges. The optimal solution emerges from a system (BOP) and objectives. ? Physical-based Compression: Boosts volumetric density, minimizing footprint, but raises safety concerns and requires pressure reduction for fuel cells. ? Physical-based Liquid Hydrogen: Increases volumetric density while reducing pressure for enhanced safety but requires energy-intensive cryogenic cooling. ? Material-Based Technologies: Improves volumetric density and safety with less compression but demands careful thermal management. ? Hydrogen Carriers: Suitable for long-distance transport but Safety concerns due to the toxicity of carrier materials, especially near residential areas.

Liquid hydrogen can be used to produce synthetic fuels. Synthetic fuels are fuels that are produced from renewable energy or biomass. Liquid hydrogen can be used to produce synthetic fuels in different ways. Fischer-Tropsch synthesis converts hydrogen and carbon monoxide into liquid fuels like gasoline, diesel, and jet fuel. Methanol synthesis turns hydrogen and carbon dioxide into methanol that can be used as a fuel or feedstock for chemicals. Ammonia synthesis transforms hydrogen and nitrogen into ammonia that can be used as a fertilizer or fuel. Synthetic fuels derived from liquid hydrogen can be used in existing transportation and infrastructure systems without the need for significant modifications.

As an industrial gas professional, we look at liquifying hydrogen when we need to transport hydrogen over long distances or we need to transport hydrogen to high consumption applications. Logistics of any industrial gas is expensive and sending it over land or sea is best done by sending it in liquid form. Why? Because the cost of the logistics needs to be absorbed by the molecules. Having more molecules in a concentrated form (liquid) allows the cost to be spread out over more molecules. Liquid hydrogen is considered a national product as it can be moved very efficiently over long distances when done in liquid form.

Metal hydrides have been identified as a promising technology for hydrogen storage due to their promising properties, such as moderate storage capacity, low cost, and high safety. While complex metal hydrides have shown promising results, there is still a need to develop materials with an even higher hydrogen content for specific applications. Another challenge is to improve hydrogen absorption and desorption kinetics. The rate at which hydrogen is released from the hydride is crucial for applications such as fuel cell vehicles. Additionally, for widespread adoption, metal hydride systems need to be integrated seamlessly with other components, such as hydrogen production and utilization technologies.

Metal hydrydes as hydrogen storage is still early in its development but it has a very high upside. Being able to store and transport hydrogen at ambient pressure and temperature may be one of the ground breaking invention that hydrogen needs to replace oil and gas as energy source.

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Carbon-based materials are being researched and developed for hydrogen storage due to their potential for low cost, high safety, and scalability. Researchers are working on developing new carbon-based materials with higher hydrogen storage capacity. Currently, carbon-based materials have limited applications due to their low hydrogen storage capacity. However, they have the potential to be used in a wider range of applications in the future, such as portable hydrogen fuel cells and hydrogen-powered vehicles. Carbon-based materials can be derived from renewable sources, such as biomass, which makes them a more sustainable option for hydrogen storage compared to fossil fuel-based materials.

Technologies for storage and transportation can be very different based on application. Hydrogen for mobility stored in liquid phase and gasified on site to put into vehicles is best for filling stations. Applications like glass manufacturing that consume large amounts are also stored in liquid form and gasified on site. Smaller applications usually have steel storage on site and it is brought to them in gas form via tube trailer

Hydrogen-powered vehicles currently have limited options for storing hydrogen. The most common method used today is high-pressure compressing hydrogen gas, which has its own set of disadvantages. There are other methods like storing hydrogen in the form of cryogenic liquid, but that requires extremely low temperatures, while others like metal hydrides require high operating temperatures. However, scientists are exploring the possibility of using carbon nanomaterials for hydrogen storage. These materials show great promise as they have over twice the energy density of compressed hydrogen gas. However, more research is required to improve their energy storage capacity.

Liquid anhydrous ammonia: This is made from hydrogen and nitrogen and is considerably cheaper to store than gaseous or liquid hydrogen. It has physical properties similar to methane and can use the same storage facilities, though brass fittings must be swapped for stainless steel. Other advantages are that it is lighter than air, even small leaks are very obvious, and it cannot explode at atmospheric pressure. A disadvantage is the energy required to make it after already losing energy to making hydrogen. But it may be worthwhile to consider for long term storage where capacity is important and it can be made over a long period with off-peak energy.

Two different forms of hydrogen carriers that are gaining momentum are ammonia and methanol. These two hydrogen carriers are good options if hydrogen needs to be stored in large volumes or if the hydrogen needs to get transported very long distances.

Selecting the right hydrogen storage for applications also depends on factors like required storage capacity, weight, volume, and ease of handling. Consider options like compressed gas cylinders, liquid hydrogen, or advanced materials like metal hydrides or carbon-based materials based on specific application needs and constraints. Evaluate factors such as energy density, safety, and cost to make an informed decision.