I’ve been looking into renewable energy and other options relative to nuclear (not a big fan because of the waste), solar, wind, and thermal. Hydrogen fuel cell technology has popped up a bit and I’m wondering how this works. With my basic understanding, hydrogen is used as input and water (two hydrogens and an oxygen) are the output.
How does this reaction happen?
Is it not widespread because it’s energy intensive? If not, why haven’t more industries adopted this technology?
If so, why is so energy intensive and how much energy does it produce?
What’s holding us back from going balls deep into hydrogen fuel cell technology when the by products are clean (even usable) and the input is so abundant in the universe and on earth?
With the abundance of input material, It seems like this technology could be useful once we get to Mars as well.
Disclaimer: This isn’t for a class or anything. I’m a 31 year old bioinformatician just looking into a new interesting topic and wanted some context from someone with more knowledge.
In: Technology
I’m shocked no one’s mentioned the volatility of hydrogen itself, especially in a catastrophic situation (free oxygen and a spark).
Hydrogen fuel cells split hydrogen into hydrogen ions and electrons, the electrons are then used for power and the hydrogen ions, electrons and oxygen are then combined to make water. There are some issues with efficiency and how the hydrogen is created, but the fuel cell itself is non-polluting. – https://youtu.be/gh95X3Qb6zo
Additionally, hydrogen production is an inherent process of nuclear reactors. Radiolysis reactions of ionizing radiation and water results in H2 production. Should we implement a mechanism to harness that hydrogen, it would be yet another reason to rely upon nuclear power.
The “nuclear waste” isn’t a scientific issue as much as a political one. The “Waste” generated from nuclear reactors is actually composed of approximately 95% reusable fuel. Other countries, such as France and Japan, already reprocess the “spent” fuel to make it reusable. A long time ago in a galaxy far far away, Congress arbitrarily decided that the fuel from reactors would be discarded instead of reprocessed (due to “proliferation concerns”). This was an extremely short sighted decision that did not consider the possibility of a federal repository failing to be built. Yucca mountain was the US governments Plan A, B, C, and D. Since it is unlikely to ever receive nuclear waste, we should instead begin developing means to reduce the current inventory of waste. If your primary concern against nuclear energy is the waste issue, you would agree that reducing the waste by ~95% is a goal worth implementing.
I will note, I am assuming you are US based (as I am), but the logic behind my response holds universally. Especially since the vast majority of the Nuclear World implemented US strategies on waste handling. My kudo’s go out to those who went against the mold (France, Japan, Finland by my last count. Hopefully
More exist).
The reaction is facilitated by the “fuel cell,” a device where hydrogen goes in one side and oxygen the other, and has some special properties in its layers to produce electricity and allow hydrogen to combine with the oxygen to form water.
Getting pure hydrogen is energy-intensive, and without methods to also collect and use the waste heat from the cell they achieve efficiencies of 40-50%. While that’s a good figure, considering the amount of energy to produce the fuel, only getting use out of half of it is an even bigger kick in the rear. Collection of waste heat and finding ways to use it though can boost efficiency up to 85%!
Then there’s materials issues. The cell includes things like platinum powder (expensive), and also relies on some other materials that aren’t so exotic but will need machined to fit properly. Not a big issue, we already do lots of machining on standard engine blocks, but it requires setting up extra production equipment compared to an electric vehicle which could technically take advantage of production processes already in place.
Then finally there’s logistics. We have to build a whole network for transporting hydrogen and build fueling stations for it (according to Wikipedia, at a cost of $1-4 million each). Contrast that with electric. We already have infrastructure for electric pretty much everywhere, and it’s as simple as plugging in some Superchargers and maybe getting the distribution box upgraded to handle the extra load. No need to arrange more deliveries, no need to bury more big tanks in the ground.
Hydrogen does show promise and may become more prominent in the future, but electric has the advantage of already having 95% of what’s needed already in place, from distribution to plenty of people already making lithium cells and electric motors.
I’m not an expert on fuel cells, and the physics is out of my area, but I do know about the limitations.
1. Where do we get the hydrogen?
We end up getting it from water, but electrolysis is energy intensive, so no matter how efficient your fuel cell is, it is always hampered by the fact that water is hard to break apart.
2. Where do we fill our fuel cell cars?
We just don’t have infrastructure yet. It’s the same issue with electric cars, but to an even greater degree.
3. Storage
Hydrogen is a flammable gas, and the only way to store it efficiently is to pressurize it. That’s a bomb.
It’s not impossible to overcome any or all of these issues, but they are the reasons why we haven’t dove headfirst into hydrogen as an energy source.
TLDR: We can’t yet produce Hydrogen quickly or efficiently enough to use Hydrogen as a fuel source for cars.
>I’ve been looking into renewable energy and other options relative to nuclear (not a big fan because of the waste), solar, wind, and thermal. Hydrogen fuel cell technology has popped up a bit and I’m wondering how this works. With my basic understanding, hydrogen is used as input and water (two hydrogens and an oxygen) are the output.
Hydrogen fuel cells have existed for decades and were in fact used as power generators on the Apollo missions. Hydrogen and Oxygen are pass through the fuel cell where the combine to form water. This process releases an electron which creates an electrical current.
>Is it not widespread because it’s energy intensive? If not, why haven’t more industries adopted this technology?
It’s not widespread because free Hydrogen is difficult to manufacture. Current processes either decompose fossil fuels (which doesn’t eliminate our dependence on them) or use electrolysis to break apart water molecules. We don’t have the infrastructure or technology yet to make hydrogen on any kind of practical scale.
>What’s holding us back from going balls deep into hydrogen fuel cell technology when the by products are clean (even usable) and the input is so abundant in the universe and on earth?
We need to find an environmentally friendly and efficient means of produce vast quantities of Hydrogen.
Other problems like safe storage and transport are fairly straight forward to resolve by comparison.
>With the abundance of input material, It seems like this technology could be useful once we get to Mars as well.
Yes, fuel cell technology is very relevant in terms of space travel. Hydrogen is the most common element in the universe and Oxygen is also abundant. It just happens that we don’t have access to large quantities of raw Hydrogen on Earth, almost all of it exists as water.
Because it’s not really a fuel source as much of an energy storage system. The hydrogen needs to be created from water using electrolysis, and it will use as much electricity to do that as it would take to make an electric car go the same distance, if not less because of inherent inefficiencies any time one form of power is converted to another and then back to another one again. So on top of that, it’s dangerous to have a big tank of highly compressed gas in a car.
It’s simpler to just store the electricity directly with batteries.
>Is it not widespread because it’s energy intensive?
Couple reasons. At present fuel cells require platinum and palladium for electrodes. There simply isn’t enough supply of these rare and highly expensive precious metals to meet the demand that would be created by widespread use of hydrogen fuel cells. The already high cost of the metals would skyrocket quickly rendering the cells unprofitable.
There’s a fair amount of research to find new electrode materials that don’t require plantinum group metals (PGM’s.) So far such materials haven’t been reliable. Because of hydrogen’s small atomic size it can diffuse through seemingly solid materials and build up in subsurface voids causing damage to them.
Secondly, hydrogen is difficult to store for several reasons. Compressing it into high pressure cylinders takes a lot of energy, as does refrigerating it into a liquid. (although you could potentially recover some of that energy to run a small pneumatically driven generator) Even so, because of the low density of H2, you don’t get nearly the same energy for the weight and volume as diesel fuel for example. On a weight and space basis it turns out to be only slightly better than lithium-ion batteries which are a well proven technology, if you include the weight of the fuel cell.
Thirdly, the easist way to create hydrogen gas in the first place is from fossil fuels such as coal or natural gas. In the latter, NG is mixed with water vapor and heated (usually by burning some of it in air to heat the rest.) This is passed through a ceramic catalyst producing CO2, carbon monoxide, hydrogen, methanol, formaldehyde, and some other products. Then the hydrogen needs to be seperated from other gases which is a somewhat complex operation and takes additional energy.
This process is commonly done in refineries, as the resulting hydrogen is used in other steps in the refining process, namely hydro-cracking of heavy petroleum products into lighter fuels.
(You can also use biomass/biochar, but this is less cost effective than natural gas.)
While electrolyzing water can be done, this requires gobs of electricity, which you could otherwise use to just charge other kinds of batteries directly from the grid. Without the extra steps of hydrogen gas storage, distribution, and fuel cells. Or just continue use diesel, propane, and natural gas internal combustion engines and forget about adding more steps.
>If not, why haven’t more industries adopted this technology?
It’s too complex and expensive. Other types of batteries or other energy storage means are simpler and cheaper.
>What’s holding us back from going balls deep into hydrogen fuel cell technology
It’s not a magic cure for anything. It has a long list of problematic downsides, storage of the gas being a huge one. The major benefit is water is the waste product from the cell itself, however a lot of CO2 will probably need to be produced somewhere else to get the hydrogen you need in the first place.
>when the by products are clean (even usable)
The byproducts would likely be burned fossil fuels used to create the hydrogen, resulting in carbon dioxide waste that’s difficult to get rid of. Dumping it into the atmosphere at large is what we as a society sent to stop doing. But fossil fuels companies have historically not cared, which is why they’re the ones doing most of the research into hydrogen fuel cells.
>and the input is so abundant in the universe and on earth?
It is *not* abundant on earth in forms that can be used in fuel cells. Some natural gas wells produce 1-2 parts per thousand hydrogen in the stream, however this is unusual and wouldn’t satisfy demand. In the case of water you need to invest very large amounts of electricity or heat to seperate it.
>With the abundance of input material, It seems like this technology could be useful once we get to Mars as well.
There’s no immediately useful source of hydrogen in mars. There are no fossil fuels on mars. Although we’d probably at some point need to electrolyze water from buried ice around the poles, to use as rocket fuels. It’s even more difficult to generate there than it is on earth. On earth we have something called infrastructure and existing power plants. Nuclear power is probably the way to go on mars. A few tens of kilograms of plutonium can supply electricity and heat to a mars colony for more than a decade, as long as they were frugal about usage.
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