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
>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.
Latest Answers