If you read the Princeton University Study called Net Zero America, they have 5 plans on how to achieve Zero Global Warming Gases by 2050 and those plans all have a significant amount of Hydrogen in these plans. The plan with the most amount of hydrogen production is the Plan E+RE+ which they call their 100 % Renewable Plan. This plan produces 18,054,092,700,000,000 Btu/yr of hydrogen or 295,508,514,263 lbs of H2/yr. If you compare this to the amount of Natural Gas Consumed in 2022 that is 12,781,199,300,000,000 Btu/yr, so Hydrogen is 1.41 times more energy per year than our Natural Gas Consumption. Most of this hydrogen is going into the production of Synthetic Liquid Fuels to replace petroleum fuels like Jet Fuels, Diesel and some gasoline. Some Hydrogen will go to Medium & Heavy Duty Trucks and some to Electricity Production. In my view point the Synthetic Liquid Fuels which produce no CO2 emissions will be more expensive than petroleum fuels, but this is the price we will pay to reduce our CO2 emissions. The US Government has plans including subsidies to get the price of green hydrogen down.

The problem is that whilst hydrogen has a high chemical potential energy capacity by mass, hydrogen has very low density at normal atmospheric pressure and temperature. That means the volumetric energy density is very low. To overcome this, hydrogen must either be stored under extremely high pressure or, alternatively, liquefied, which requires extremely low temperatures. With high pressure storage, extremely robust pressure vessels are required, whilst for storing liquid hydrogen, the containers have to be extremely will insulated. Compressing hydrogen to the required level requires a lot of energy, and liquefaction requires even more.

In practice, for vehicles pressurised hydrogen is a lot more practical than storing liquid hydrogen.

In contrast, the electrodes and electrolytes in batteries are are solids or liquids which don’t require storage under pressure. They have lower energy density per unit mass than does hydrogen, but don’t need elaborate containment.

All that said, ultimately hydrogen would win out on energy density including containment for larger capacities. One kg of hydrogen allows a medium sized car to travel about 60 miles, or 100km. One model of hydrogen car has two tanks totally 85 kg with a capacity for 5 kg of hydrogen at a pressure of slightly under 700 atmospheres. That’s enough for a range of about 300 miles (480 km).

To compare, the 85 kWh battery pack in some Tesla S models comes in at 540 kg and has a range of about 260 miles (420 km).

Of course, the hydrogen-powered car also requires a fuel cell, but that is still a lot lighter than that 450 kg or so difference. In addition, larger hydrogen tanks would have a better capacity to weight ratio.

It’s an apple to oranges comparison. The two technologies have different characteristics and different use cases.

If you are flying an airplane, liquid hydrogen will allow you to exceed the range and speed of existing jet aircraft. Batteries will get you 100 miles or so at lower speed. Compressed hydrogen will get you 300 miles or so at lower speed.

If you are driving a car, batteries will let you refuel at home; if you have a wall socket at home. If not you will be stuck in a public charger somewhere for 30 minutes at a time, after you drive to, and find an open charger bay. You had better not be on your way to work. It can take hours. Hydrogen will let you fill up completely in 5 minutes. Just like going to a gas station. Which is where the hydrogen pumps are located anyway.

If you are an ocean going ship, the weight of a battery will sink you at the dock. You probably want liquid hydrogen instead.

If you are a long range Class 8 truck, the weight of the battery will directly reduce your load carrying capacity and your profits. Shorter routes are suitable for batteries. And the same is true for buses. But longer routes will be more profitable on hydrogen.

If you are a city, the really large battery bank you need is a huge, fire hazard, and potential toxic waste dump. You want to stick to batteries for short term energy storage only. And hydrogen can be used for longer term storage. A huge burned, hydrogen waste dump, is normally just called a lake. You can drink it, swim in it, and spawn fish in it.

If you need to get rid of a large amount of gaseous hydrogen in a hurry, you can just vent it into the air. It goes straight up fast. Watch out though, if it catches fire, it creates cumulus clouds. You know how scary they are.

Large buried liquid hydrogen tanks have promising economics. As do a number of new large scale energy storage technologies.

Storage is a big issue. So is the energy costs of compressing it into that storage, and the energy cost of transporting it from the production to storage locations. An even bigger issue is that the production itself consumes more energy than the resulting hydrogen will contain.

Combining the production, transportation, and compression, the resulting hydrogen only contains 40% of the original energy expended. If that same energy were transported over wires then 90% arrives at the destination.

In the end, hydrogen is nothing more than an energy transport medium (serving the same purpose as wires) with a low efficiency and a high price.

Hydrogen has only one benefit: it preserves the status quo of energy producers and distributors.

1.) Gaseous hydrogen has an extremely low mass density. Using the ideal gas approximation, one mole of any ideal gas occupies 22.4 L. But one mole of H_2 only weighs 2g. The density of H2 at STP is therefore only 2g/22.4 L = 0.09 g/L . This may seem like an advantage, since a mole of hydrogen is very light, 8 times lighter than a mole of methane for example. But:

Compare that with methane: 1 mol = 16g. 16/22.4 = 0.71 g/L, or 3 times the mass density. Since complete oxidation (i.e. combustion) of methane yields twice as my H_2O molecules as H_2 itself, plus a molecule of CO_2, the energy density of methane gas is greater than that of hydrogen.

2.) What about liquefying hydrogen? But hydrogen condenses at a very, very low temperature (compared to methane, for example). Therefore, in order to take advantage of the greater density of liquid hydrogen vs. its gaseous form, the former must be stored at deeply cryogenic temperatures in well-insulated pressure-resistant containers. This is extremely inconvenient when the gas has to be transported. I’m thinking of rockets here (Forget automobiles. Are you kidding?). They must be filled with cryogenic liquids at the last minute. They can’t just sit inside the rocket on the launch pad for hours without venting the tanks.

3.) Safety issues. H_2 gas has extremely low viscosity. Storing it requires very tight-fitting valves and fixtures, or it will leak. The liquid has a greater viscosity than the gas, of course, but storing the liquid requires fixtures that can withstand extremely low temperatures that might for example, freeze and/or crack polymer parts.

The problem of leakage is more than that of storage efficiency. Hydrogen combustion happens over a large range of rich/lean mixtures. This simplifies design of internal combustion engines, but it poses a fire/explosion hazard in the environment of hydrogen storage containers and transfer operations.

4.) Metal hydrides have been investigated for their storage potential for decades. Because of their high energy density compared with the gas, and no requirement for cryogenic apparatus, this seems promising. However, the metals needed are not cheap and plentiful in that the method places an added demand on supplies of rare earth metals and so forth. The hydrides also have safety issues, since metal hydrides are commonly pyrophoric.

How viable is hydrogen as a storage medium (as opposed to, say, batteries), to the energy storage problems that wind and solar present?

The production of Hydrogen and then the usage of it produces about 30% of the original power from what I read. If you have a lot of free energy not being used (e.g. wind or solar), 30% is better than nothing. However you would be much better pumping water uphill for a dam or similar or storing the energy in a battery.

However, the main use is to replace fossil fuels of transportation. Electric is best, but some things like a truck or bus may require more power. The problem is, currently the Hydrogen is not being done by using electric (electrolysis), but by using methane to produce Hydrogen and CO2. Methane as you should know is a fossil fuel. And this is why fossil fuel companies push Hydrogen. It is still using fossil fuels. And this is the problem.

Also, Hydrogen currently doesn’t have an infrastructure of Hydrogen filling stations, and has problems with storage and distribution. So as much as Hydrogen seems like a solution, sadly it is not.

The pro’s are that if you have an abundant source of cheap electricity you can make hydrogen from water by wasting the oxygen into the atmosphere. There are a variety of modern processes ranging from 70 to 90% efficient, and I don’t know the details or whether any of the more efficient processes are too expensive.

At 1.5 cents electricity cost, hydrogen from water becomes cheaper than current hydrogen from natural gas. The U.S. has one public price for wind power at 1.1 cents, and another country has one solar price for 1.35 cents. Both are less than three years old, and these prices are not normally made public, so there may be many more similar projects that we don’t know about. If not, there will be.

Hydrogen can be easily reformed into ammonia. 9% of the U.S. supply of natural gas is used to make ammonia fertilizer. In the future this will be replaced with hydrogen from renewable sources, but it is pretty far down the ladder in terms of easy pickings for the new cheap renewable energy sources. Don’t expect to see it for a few years.

Ammonia can be burned like gasoline. Offshore wind and solar developers are planning to build ammonia factories so that freight shipping can use the ammonia instead of diesel or bunker oil or whatever they use today, because it will be cheaper. The offshore folks already see a point where they have excess capacity, and can use it to make fuel at whatever price it takes to sell it, but they also think the market will be strong enough to take over driving the expansion of offshore wind and solar. A lot of countries lack good land for wind and solar farms, but have ocean ports and pipelines.

Both hydrogen and ammonia can be piped through existing pipelines which are now used for natural gas and petroleum or petroleum products. Both have higher energy density.

Hydrogen is a little tricky to handle and store. The molecules are so small that it leaks through steel. This doesn’t matter if it is used fast enough.

Storing hydrogen in the existing natural gas storage facilities seems to be attracting investors today. A number of projects are under way. Existing natural gas power plants can be converted to hydrogen, or new similar plants can be made for the purpose of running on hydrogen. This solves some technical aspects of grid power management which come from the fact that wind and solar don’t have massive metal turbines spinning, which automatically react to changes in consumption. It is not clear if electronics will obviate that issue, but for now, the idea of having hydrogen generation to complement wind and solar seems like the optimum path to a sustainable electricity future.

The existing U.S. natural gas storage network can hold enough hydrogen to power the entire U.S. electric grid for about eight or nine months. We would never need that much storage, but it exists. The natural gas caverns which form this network contained hydrogen for millions of years before we sucked it out and burned it, so it seems likely that the leakage would not be a serious problem.

Hydrogen can be reformed into all of the chemicals and plastics feedstocks we presently get from fossil fuels. If the electricity is cheap enough, hydrogen will push most of those fossil fuel chemicals out of the market.

Cons: I see no downsides, except that this is not certain. A lot of other things might develop in the next few years to make it unnecessary. Hydrogen fuel cell cars received a lot of attention about thirty years ago, and some people don’t realize that the battery technology improvements which are at the root of the electric car have completely killed any reasonable market for passenger cars running on hydrogen.

I think fuel cell technology remains important for some niche markets, like trucks, buses, offroad vehicles. But this also remains to be seen. Batteries could become better.

I see chemical batteries, of which there are dozens or hundreds of types, as filling in the small needs of the grid for short term storage, power quality and reliability, while something bigger will answer the larger, longer term, slower needs of the grid. Hydrogen seems to have ten steps of a lead ahead of all the other technologies because of its usefulness as a chemical feedstock pre-component.

You may remember that most peanut butter contains “hydrogenated” peanut oil. Many food products have hydrogenated vegetable oil. It is not nutritionally valuable - sort of like eating Silly Putty. But it provides texture to things that would otherwise not taste like we want them to taste, and therefore we are used to stuff that uses hydrogen.

Most of the Sun’s energy is due to a nuclear fusion process that makes hydrogen into heavier elements. Without it we would not be here. But the use as an energy storage process is looking like a sure thing, but it isn’t here yet.

As we built a lot of utility scale wind and solar, there is a distinct pecking order for uses for the dirt cheap electricity that those facilities produce. Hydrogen is about two thirds of the way down the ladder. So the projects we see today are being developed by people who see the ladder the way I do, and want to be the ones to climb it.

It isn't.

I suspect if your expertise is hydrogen storage you would argue that it isn't. Storage is one challenge with hydrogen, but probably not the largest one.

For my twopence worth (and that's really all its worth) the real drawbacks are that you either make it by ‘cracking’ methane (a fossil fuel) making CO2 as a byproduct, so this isn't a low carbon, sustainable energy source. Or you can use electricity to split water. This is much more sustainable, no CO2, actually a by product is oxygen - happy days, it just takes a lot of electricity relative to the energy you get in the hydrogen that you get out of the process. Then more to compress it or cool it for storage. So it's okay if you've got surplus solar or wind power and need something to do with it.

The other issue is infrastructure, there is an industrial supply infrastructure but retail hydrogen filling stations are limited in number and will always be more complex and expensive, than electric car chargers which can be as simple as a 220v outlet and even when they aren't a 3 phase AC connection or something larger isn't a big deal, compared with burying tanks in the ground etc…

Batteries win the efficiency argument. You get back almost all the energy you put in. Plus fuel cells are not as numerous or cheap as many people think they are, and burning hydrogen in a piston engine is not more efficient than a petrol or diesel engine although its true you can use it as a fuel for water or space heating. There is a plan in the UK to add some hydrogen to the natural gas grid.

Weirdly it's seems hydrogen has its religious following, as do batteries. I'm a bit of a battery fan but very willing to accept hydrogen is going to have its place, I just don't think it will be powering passenger vehicles, batteries are cheaper, more efficient, require little additional infrastructure and are already here, over 5 million EVs are now driving around the world.

They will use nanomaterials to increase the storage density of hydrogen and reduce the energy used to liquify or compress it. H2MOF (metal-organic framework) can achieve a storage density of 40 grams per liter. The energy density (not counting energy losses) is 1.4 kWh per liter. Compare this to gasoline at 9.7 kWh per liter. More than half the energy used in making green hydrogen is wasted by the time it can be used, and green hydrogen is not commercially available for fuel. H2MOF will improve storage of hydrogen for those niche uses where it is better than the alternatives, but it will not replace battery energy storage.

Along with Nikola and Toyota, Hyundai Motor, Volvo, Daimler, Cummins and General Motors, are all developing long-haul trucks powered by hydrogen.

For some applications,FCEVs might make sense,such as long haul trucking,ships,and especially aircraft. The reason being that refueling sites would be few in number,and situated along routes trucks travel regularly. Same with ships,which could take on H2 at shipping ports. Aircraft could fuel up on hydrogen generated by electrolysis from solar panels situated on the grassy areas between runways. For private cars,forget it. You would need about 115,000 fueling stations spread across the country to give the same coverage as gasoline stations do today,and they would each cost about a million .

Hydrogen is stored as a pressurized gas in steel tanks for most applications. For vehicle fuel applications it is stored in high pressure carbon fiber tanks. As rocket fuel, it is stored as a super cold liquid hydrogen.

Ammonia is a way of storing hydrogen as a liquid at low pressure. And ammonia is a global commodity produced in huge volumes. The hydrogen is separated from nitrogen using iron catalysts at the point of use.

It is also possible to store hydrogen by hydrogenating liquid hydrocarbons and splitting out the hydrogen later. The hydrocarbon liquids used this way are called Liquid Organic Hydrogen Carriers.

Hydrogen under pressure can be stored in underground caverns. And the city of Los Angeles is very seriously looking at using this method to store enough renewable energy to keep the cities electric power grid running with very little fossil fuel.