Hydrogen Vehicles - Truly Beneficial?


  • mod

    So, Toyota just announced that they are going to be switching their focus from plug-in EV to hydrogen fuel-cell vehicles. Right off the top of my head, I can think of a few counter-points here:

    • I can't imagine that hydrogen fuel cells are going to be very energy efficient when compared to plug-in EV. First you have to produce your hydrogen, during which process you will have a net energy loss. Then, the vehicle actual has to burn the hydrogen, resulting in another net energy loss. By comparison, plug-in EVs really have an energy loss when charging the battery. But EVs also have energy reclamation methods, such as charging the battery when braking.
    • Everyone is talking about how the only byproduct of burning hydrogen is water. That's true. But what about how you manufacture the hydrogen? The power to make usable hydrogen has to come from somewhere, such as the existing power grid. I'll leave it to the reader to decide if that makes hydrogen more or less "green" than gas based vehicles.
    • Isn't pumping water into the atmosphere going to impact the environment in a potentially harmful way? Sure, in some places, it might not make a difference. In other places, it could effect drastic climate change however. Take a highly populated city in a dry climate, such as Phoenix, for example. Replace all those commuter vehicles with cars running on hydrogen. Suddenly, Phoenix would become a very humid place, and those 120 degree summers wouldn't be very tolerable anymore.
    • Let's say that hydrogen fuel cells do claim a major segment of the automotive market. where's all that hydrogen going to come from? Well, the most common source of hydrogen is fossil fuels, and the main byproducts of hydrogen production are CO and CO2. I don't think that the environmentalists will be too happy once they figure out that their beloved hydrogen vehicles are just shifting where the greenhouse gasses are generated. Another option for hydrogen production is splitting water. They're saying that they want to start in California, a state suffering from the most severe drought in decades. Where are they going to get the water to manufacture hydrogen?

    I've said my piece. Now, discuss.

    Toyota Shifts Focus to Hydrogen Fuel Cell Vehicles



  • Hydrogen is the fuel of the future, and it always will be

    • Unknown

    The main problem is that our current best source of hydrogen is natural gas. Hydrogen fuel has a lower energy density (0.01005 MJ/L) than natural gas (0.0364 MJ/L), it takes energy to separate the hydrogen from the natural gas, we already have an infrastructure to distribute natural gas to homes, and we have fuel cells that work with natural gas.

    Why would I want to use hydrogen?


  • Discourse touched me in a no-no place

    @abarker said:

    But what about how you manufacture the hydrogen?

    You currently get hydrogen from chemically processing natural gas. Just FYI.

    @abarker said:

    Isn't pumping water into the atmosphere going to impact the environment in a potentially harmful way?

    No. There's already an enormous amount up there, even in relatively dry climates (much much more than CO2). We aren't going to make jack shit of a difference there any time soon. Now I have been in places where industrial processes were putting enough water vapour in the air to make a localised difference to weather (specifically it was downwind of a ~5GW power station on a rather wet day; the plume from the power station was like driving through a monsoon) but you're not going to get anything like that from even a whole freeway of traffic. There's orders of magnitude of difference here.

    It's also more likely to affect things in Seattle than Phoenix; local climate matters too.
    @abarker said:

    Where are they going to get the water to manufacture hydrogen?

    Well, if you're going to get hydrogen from water (expensive!) you might as well get it from non-potable water. FYI, California sits next to the Pacific…



  • @dkf said:

    FYI, California sits next to the Pacific…
    So ... the efficiency of electrolysis (the usual process for separating oxygen and hydrogen in water) drops precipitously when you start trying to use salt water.



  • @abarker said:

    Isn't pumping water into the atmosphere going to impact the environment in a potentially harmful way? Sure, in some places, it might not make a difference. In other places, it could effect drastic climate change however. Take a highly populated city in a dry climate, such as Phoenix, for example. Replace all those commuter vehicles with cars running on hydrogen. Suddenly, Phoenix would become a very humid place, and those 120 degree summers wouldn't be very tolerable anymore.

    Burning hydrocarbon fuels (gasoline, diesel, natural gas, etc.) also produces water vapor. Hydrocarbons are made of hydrogen and carbon (who'd have guessed?). Both combine with oxygen to form H2O and CO2. Getting the same amount of energy by burning hydrogen would produce quite a bit more water vapor than burning more energy-dense hydrocarbon fuel, but it's still going to be insignificant compared to the volume of air in a city. One summer thunderstorm would put many orders of magnitude more water vapor in the air than all the hydrogen-burning cars imaginable.
    @abarker said:

    They're saying that they want to start in California, a state suffering from the most severe drought in decades. Where are they going to get the water to manufacture hydrogen?

    Ocean? It seems to me it would be well suited for electrolysis. The salt makes it naturally electrically conductive. H2O + electricity (solar?) -> H2 + O2.


  • Discourse touched me in a no-no place

    @rad131304 said:

    So ... the efficiency of electrolysis (the usual process for separating oxygen and hydrogen in water) drops precipitously when you start trying to use salt water.

    Yeah, but if you've got plenty of power and seawater and not much fresh water, it makes sense to lose some efficiency so you save the more limited resource for higher-value uses. You can even express it in economic terms: fresh water costs money, but if you're next to the sea, seawater is free. It then just becomes a matter of balancing the cost of the extra power (and maintenance) with the cost of the fresh water; classic Economics 101 problem.



  • @rad131304 said:

    the efficiency of electrolysis (the usual process for separating oxygen and hydrogen in water) drops precipitously when you start trying to use salt water.

    Serious question: How so? Electrolysis requires adding something to the water to make it conductive. Why not salt?


  • Discourse touched me in a no-no place

    @HardwareGeek said:

    Ocean? It seems to me it would be well suited for electrolysis.

    The most likely problem is the need for increased maintenance due to the amount of things living in seawater (algae, barnacles, etc.)



  • @HardwareGeek said:

    Serious question: How so? Electrolysis requires adding something to the water to make it conductive. Why not salt?

    Salt has no free ions.

    Also, it causes the creation of chlorine gas, which reduces the amount of free Hydrogen and Oxygen produced.



  • @dkf said:

    The most likely problem is the need for increased maintenance due to the amount of things living in seawater (algae, barnacles, etc.)

    Granted, seawater creates maintenance issues. In addition to critters that tend to foul the plumbing, it's also a bit corrosive (but probably no more so than whatever you'd add to fresh water to make it conductive). But that's a separate issue from @rad131304 said:

    the efficiency of electrolysis (the usual process for separating oxygen and hydrogen in water) drops precipitously when you start trying to use salt water.



  • @rad131304 said:

    Salt has no free ions.

    WTF? A crystal of salt in your kitchen cabinet doesn't, but salt dissolved in water sure does.
    H2O + NaCl -> H2O + Na+ + Cl-

    @rad131304 said:

    it causes the creation of chlorine gas

    Ok, I'll give you that one.



  • @HardwareGeek said:

    WTF? A crystal of salt in your kitchen cabinet doesn't, but salt dissolved in water sure does.H2O + NaCl -> H2O + Na+ + Cl-
    I'm not a chemist; it's just part of our "common knowledge" stuff @ work. Could be wrong, but I trust the chemist guy who told me it.


  • mod

    @dkf said:

    You currently get hydrogen from chemically processing natural gas. Just FYI.

    I pointed that out, as well as the potentially dangerous side effects of doing so. Try re-reading my original post.

    @dkf said:

    No. There's already an enormous amount up there, even in relatively dry climates (much much more than CO2). We aren't going to make jack shit of a difference there any time soon. Now I have been in places where industrial processes were putting enough water vapour in the air to make a localised difference to weather (specifically it was downwind of a ~5GW power station on a rather wet day; the plume from the power station was like driving through a monsoon) but you're not going to get anything like that from even a whole freeway of traffic. There's orders of magnitude of difference here.

    It's also more likely to affect things in Seattle than Phoenix; local climate matters too.

    I'm not so sure about that. I grew up in a fairly small area in south-east Washington that was pretty dry, aside from being on the banks of the Columbia river. Over the years, as the town grew, and more people started putting in automated sprinklers for their lawns, there was a noticeable shift in the humidity of the region. I bet that switching a significant percentage of vehicles to hydrogen fuel cells in a place like Phoenix would have a similar impact. Even if it doesn't change the climate beyond increasing the overall humidity, that change alone could make Phoenix summers unbearable for many who live, causing a measurable impact on the local economy.


  • mod

    @HardwareGeek said:

    Ocean? It seems to me it would be well suited for electrolysis. The salt makes it naturally electrically conductive. H2O + electricity (solar?) -> H2 + O2.

    Maybe, but from the research I've done, they tend to avoid using sea water. I've been unable to determine the exact reasons, though it may be that it has too much salt.


  • mod

    @dkf said:

    Yeah, but if you've got plenty of power and seawater and not much fresh water, it makes sense to lose some efficiency so you save the more limited resource for higher-value uses. You can even express it in economic terms: fresh water costs money, but if you're next to the sea, seawater is free. It then just becomes a matter of balancing the cost of the extra power (and maintenance) with the cost of the fresh water; classic Economics 101 problem.

    California doesn't have plenty of power. They frequently run out of power, and they currently purchase most of their power from other states.



  • @rad131304 said:

    I trust the chemist guy who told me it.

    No offense, but I suspect a misunderstanding. Ask him specifically about salt dissolved in water, and I'm sure you'll get a different answer. Heck, even pure water has free ions — not many (one H+/OH- pair for every 5.55E8 molecules of H2O) — but some. Solubility of NaCl in water is given as 359g/l (I assume that's at 20C, but it doesn't vary a whole heck of a lot with temperature). That's one Na+/Cl- pair for every 9 molecules of water. (Seawater typically has about 1/10 that concentration.)


  • Discourse touched me in a no-no place

    @abarker said:

    California doesn't have plenty of power.

    Well yeah, but if you were serious about large-scale electrolysis you'd have to also be serious about getting a lot of power from somewhere, such as major solar power deployments in the Mojave. Electricity is nicely transportable between fixed installations. (Never assume that just one thing changes where you start building up a new class of infrastructure. Life's not like that.)



  • @abarker said:

    Over the years, as the town grew, and more people started putting in automated sprinklers for their lawns, there was a noticeable shift in the humidity of the region.

    Not necessarily a causal relationship.

    Pulling numbers out of my ass, I'd guess that one lawn sprinkler on a warm, windy day puts as much water vapor into the air as 100 cars.

    @abarker said:

    I grew up in a fairly small area in south-east Washington that was pretty dry, aside from being on the banks of the Columbia river.

    Changes in water temperature and flow (Any dams built during that era?), water temperature (Weather get warmer?) could all change the rate of evaporation from the river enough to affect local humidity.
    @abarker said:
    it may be that it has too much salt.

    Possible, I suppose. As @rad131304 pointed out, sort of, if the Cl- concentration gets too high, you may start getting Cl2 along with the H2 and O2.



  • @HardwareGeek said:

    No offense, but I suspect a misunderstanding.

    None taken - like I said, I'm not a chemist. Wouldn't be the first time I misunderstood something.



  • @HardwareGeek said:

    Possible, I suppose. As @rad131304 pointed out, sort of, if the Cl- concentration gets too high, you may start getting Cl2 along with the H2 and O2.

    Don't you also get NaOH - and isn't that pretty hard on metals?



  • @rad131304 said:

    Don't you also get NaOH

    Yep. That's what gets left behind when you remove the H and Cl.
    @rad131304 said:

    isn't that pretty hard on metals?

    Sure, but the concentration would, I would think, not be allowed to get very high. Some metals are more resistant to various chemicals than others; presumably, resistance to NaOH would be one of the things you would select for when choosing what to make your plumbing out of.



  • @HardwareGeek said:

    presumably, resistance to NaOH would be one of the things you would select for when choosing what to make your plumbing out of.

    I was actually just thinking the anode and cathode would need to be replaced pretty often, I didn't even think about the plumbing.



  • @rad131304 said:

    I was actually just thinking the anode and cathode would need to be replaced pretty often, I didn't even think about the plumbing.

    I suppose. I'm kinda thinking that mechanical abrasion from the flowing water and bubbles of H and O streaming from the electrodes would do as much long-term damage as the chemicals, but I dunno. I took like 3 semesters of college chem; I'm not a ChemE with experience building industrial-scale plants.

    I was using "plumbing" as a catch-all term for all the bits and pieces, not necessarily specifically the piping. But yeah.



  • @HardwareGeek said:

    Yep. That's what gets left behind when you remove the H and Cl.

    NaOH and HCl? That sounds dangerous.



  • To put that 5GW plant's water output in perspective, assuming 33% efficiency of conversion, it would be evaporating 3 tons of water a second. Now, consider the entire motoring population of Los Angeles. If each car normally uses 4 gallons of gas per day, and all of that is replaced with hydrogen (burning at the same efficiency as the gasoline was), then the power plant is still putting out (slightly more than) twice as much water vapor.

    I should also note that hydrogen production is likely overall somewhat more efficient than power production, as there is one fewer conversion step required in the process chain. While battery efficiency is quite good (80%, seems to be a good estimate), its power source is rather less so (20% is roughly the right number). Hydrogen production through thermolysis is about 60% efficient, and fuel cells are about that too, giving an overall efficiency of around 36% efficiency, vs the (without transmission losses) 16% efficiency of using batteries.

    Also, salt does improve electrolytic efficiency (see this), so seawater is a great target for large scale electrolysis, and salt has no effect on thermolysis at all. A good reference for the efficiency of electrolysis is this.



  • What if we take the water emitted from our hydrogen vehicles and use the power from the solar FREAKIN roadways to split it back into oxygen and hydrogen, which we use to power our hydrogen vehicles.

    I mean, the energy has to come from somewhere. Even if you're burning fossil fuels, a large chunk of that energy was probably at some point contained in the sun.



  • @ben_lubar said:

    NaOH and HCl? That sounds dangerous delicious.


    Filed under: Delicious chemicals, random stuff because Discourse thought my post was empty



  • @rad131304 said:

    it causes the creation of chlorine gas, which reduces the amount of free Hydrogen and Oxygen produced.

    Chlorine gas comes from removing electrons from Cl- ions, while hydrogen gas comes from adding electrons to H+ ions, so it's pretty clear that the chlorine and hydrogen would be evolving at different electrodes: the chlorine would contaminate the oxygen stream coming off the positive electrode in an electrolytic cell, not the hydrogen stream coming off the negative. Sodium reacts incredibly readily with water, so any Na+ converted to Na at the negative electrode would instantly react with water to make free hydrogen and OH- ions. Far from making the process less efficient, the dissolved Na+ actually catalyzes the production of hydrogen.

    Your main problem would be what to do with all the caustic soda the cell makes, but caustic soda is a valuable industrial chemical with a heap of uses so that shouldn't be enormously hard. Also, you could arrange for some portion of the liberated chlorine to get dissolved back into the feedwater, which should poison it enough to deal with the biological fouling issue.

    FWIW, the best available electrolysis and fuel cell techniques mean that you can get 55-60% energy efficiency from the round trip through an electrolyzer and fuel cell. This is not as good as batteries, which can typically achieve around 70%, but may be worth it due to the superior mass energy density of hydrogen (important for automotive use). The main problem with hydrogen for vehicles is the insane pressures you need to put the stuff under to get the volume energy density up to feasible levels. The upside of this problem is that any container strong enough to resist that kind of pressure is also going to be virtually indestructible in a crash, and would certainly pose a lower fire risk than a conventional tank of petrol.

    Making a feasible hydrogen fuel cell vehicle requires some pretty radical lightweighting to reduce the required drive power enough to match the feasibly available energy storage. Using carbon fibre as the main structural material is probably going to be required, which looks kind of expensive (about 3x as much per kg as steel) until you realize that it's quite feasible to use thermoplastics such as nylon for the carbon fibre matrix rather than the traditional thermosetting resins (this also improves recyclability). In any case, comparing a simple cost per kg for structural materials is not really appropriate. You need to look at whole-system costs.

    Tooling up for carbon fibre manufacture, especially for short runs, is way less expensive than doing the same thing for steel whose only real advantage is the tremendous amount of infrastructure already in place for handling it. Carbon fibre also lends itself to producing a far wider range of one-piece structural shapes than does steel, which lets you radically lower a car body's parts count and assembly cost. It can also be made with a gloss-finished colour gelcoat included so you save on painting. All in all it works out quite a lot less expensive than the simple cost per kg vs steel calculation would suggest, and if it ever becomes dominant in vehicle manufacturing should even result in lowered cost per vehicle overall.

    Carbon fibre can be engineered with much better crash energy absorption and safety characteristics than steel. It also tends to absorb crash energy locally rather than causing widespread plastic deformation in the whole body, meaning that much more crash repair should end up consisting of simple replacement of damaged body modules rather than the kind of expensive stretching and bending you need to do on a crashed steel vehicle.

    A fuel cell vehicle would almost certainly include a Li-ion battery pack sized just big enough to make regenerative braking work; wouldn't make any sense to design an electric-motor-powered vehicle without that feature. Such a pack would only need to be something like a twentieth of the size and weight of the main battery in a Tesla S.

    Even given the reduced efficiency of the total fuel cell round trip, the efficiency gain you'd get from lightweighting the vehicle and powering it with a 95% efficient electric motor rather than a 20% efficient internal combustion engine should mean that a fuel cell vehicle easily outperforms an ICE model with comparable range and carrying capacity on greenhouse gas production, even if ultimately powered by coal. That's already true for the Tesla S, which ends up somewhat more energy-hungry than a properly lightweighted FCV due the the weight of its battery pack.

    Also worth considering when thinking about the feasibility of FCVs on cost grounds is that these are early days, and market uptake plus mass production really does do tremendously good work in lowering costs. I can see no in-principle reason why these things could not be made to work, and they would certainly be a lot faster to refuel than any battery vehicle not based on swap in / swap out battery packs.



  • @abarker said:

    Over the years, as the town grew, and more people started putting in automated sprinklers for their lawns, there was a noticeable shift in the humidity of the region. I bet that switching a significant percentage of vehicles to hydrogen fuel cells in a place like Phoenix would have a similar impact.

    Again, this is an argument where quantities matter. If you burn 10kg of hydrogen in your fuel cell vehicle, which would probably take most people about a week, you've made roughly 80kg of water. How long does it take to dump 80 litres of water onto a lawn with a sprinkler? Minutes, not a week.



  • @flabdablet said:

    Chlorine gas comes from removing electrons from Cl- ions, while hydrogen gas comes from adding electrons to H+ ions, so it's pretty clear that the chlorine and hydrogen would be evolving at different electrodes: the chlorine would contaminate the oxygen stream coming off the positive electrode in an electrolytic cell, not the hydrogen stream coming off the negative. Sodium reacts incredibly readily with water, so any Na+ converted to Na at the negative electrode would instantly react with water to make free hydrogen and OH- ions. Far from making the process less efficient, the dissolved Na+ actually catalyzes the production of hydrogen.

    Oh, I was thinking per quantity of energy put in, not where in the circuit the gasses were created. My understanding was pure water would produce more Hydrogen and Oxygen if Salt wasn't involved because the salt absorbs some of the energy to create Chlorine and Sodium Hydroxide so you'd need a larger volume of salinated water and more energy to produce the same quantity of hydrogen and oxygen that "pure" water would produce (ignoring timescales of the reaction here).

    Again, I'm not a chemist so it's quite possible I'm absolutely and completely wrong.



  • Breaking the molecular bond that holds H2O together requires a lot more energy than breaking the ionic bond that holds NaCl together. Also, the main cause of inefficiency in an electrolyzer is straight heat production due to the electrical resistance of the electrolyte, which filling it with mobile ions like Na+ and Cl- makes much lower. I think you'll find that sea water is easily a net electrolytic win.


  • mod

    @dkf said:

    Well yeah, but if you were serious about large-scale electrolysis you'd have to also be serious about getting a lot of power from somewhere, such as major solar power deployments in the Mojave. Electricity is nicely transportable between fixed installations. (Never assume that just one thing changes where you start building up a new class of infrastructure. Life's not like that.)

    Considering power is generally a utility, and in many states, the infrastructure is owned and maintained by the state, this could still pose a problem. From what I can find (look here, for example), it appears that the electric utilities in California are a mixture of state run and Investor-Owned. Let's rule out the state run ones, seeing as how California is billions of dollars in debt already. Ok, that's doable, except for one thing. Each of the investor-owned utilities is limited to operating in an area that is defined by California Public Utilities Commission (basically, the state).

    Let's say that, somehow, one of those utilities got everything together to build a massive array of solar farms in the Mojave Desert. There's one problem: they would need to get approval from the feds, specifically the National Park Service, because the most of the open land in the Mojave desert is part of the Mojave Desert National Preserve. I pretty much guarantee that they aren't going to get approval for that.

    @HardwareGeek said:

    Not necessarily a causal relationship.

    Pulling numbers out of my ass, I'd guess that one lawn sprinkler on a warm, windy day puts as much water vapor into the air as 100 cars.

    Changes in water temperature and flow (Any dams built during that era?), water temperature (Weather get warmer?) could all change the rate of evaporation from the river enough to affect local humidity.


    Most people in the area run their sprinklers in the early morning, when it is about 60-70 degrees F, even in the summer. The common reasoning is that this helps to maximize the amount of water soaking in the the soil instead of evaporating away. Also, many people did this to avoid having their lawns wet at night, believing that it would discourage fungal growth. I never actually saw anyone run their sprinklers in the afternoon, when temperatures could reach 115. I did occasionally see people run their systems after sundown, when temps had dropped back into the 90's.

    The last dam built on the Columbia river was completed in 1984, in British Columbia, before the time period I'm talking about. Before that, the last dam constructed in the area was finished in 1973 (also in BC), unless you count the refurbishing of the Grand Coulee in 1974 (I don't, they just added another turbine). The overall weather, aside from the humidity, remained about the same. Well, the winters have gotten colder, and some winters have seen more snow than usual, but the summers are about the same. The average annual water temperature was pretty consistent. Obviously, there were fluctuations from year to year, but most everything has stayed pretty much the same, aside from the humidity.

    Let me clarify: this wasn't a sudden one year thing. This change occurred over the course of several years. If it had been a change in water temp, it probably would have been an occasional issue, depending on the conditions each year. It really wasn't a change in water flow. The only noticeable changes in flow have been the low years when the snow packs feeding the river were minimal, and that would probably have resulted in reduced humidity, not increased. And like I said, the only changes in local weather were during the winter, not really during the summer, when the increased humidity is noticeable.


  • mod

    @lushr said:

    To put that 5GW plant's water output in perspective, assuming 33% efficiency of conversion, it would be evaporating 3 tons of water a second. Now, consider the entire motoring population of Los Angeles. If each car normally uses 4 gallons of gas per day, and all of that is replaced with hydrogen (burning at the same efficiency as the gasoline was), then the power plant is still putting out (slightly more than) twice as much water vapor.

    I should also note that hydrogen production is likely overall somewhat more efficient than power production, as there is one fewer conversion step required in the process chain. While battery efficiency is quite good (80%, seems to be a good estimate), its power source is rather less so (20% is roughly the right number). Hydrogen production through thermolysis is about 60% efficient, and fuel cells are about that too, giving an overall efficiency of around 36% efficiency, vs the (without transmission losses) 16% efficiency of using batteries.

    Also, salt does improve electrolytic efficiency (see this), so seawater is a great target for large scale electrolysis, and salt has no effect on thermolysis at all. A good reference for the efficiency of electrolysis is this.

    Good to know. This answers some of the questions I had about the effects of switching to hydrogen as a fuel source.



  • @abarker said:

    Let's say that, somehow, one of those utilities got everything together to build a massive array of solar farms in the Mojave Desert.

    I don't know if this counts as a massive array:

    At 354MW, I doubt it, but I guess it's a start.


  • mod

    @flabdablet said:

    A fuel cell vehicle would almost certainly include a Li-ion battery pack sized just big enough to make regenerative braking work; wouldn't make any sense to design an electric-motor-powered vehicle without that feature. Such a pack would only need to be something like a twentieth of the size and weight of the main battery in a Tesla S.

    I don't see why a fuel cell vehicle would "certainly" include a Li-ion battery pack. That's taking back to a hybrid, albeit a different flavor of hybrid. Sure, the fuel cell is technically a refuelable battery, so you would have an electric motor, but that doesn't necessarily mean that people will want both kinds of batteries.

    @flabdablet said:

    ... even if ultimately powered by coal. That's already true for the Tesla S ...

    Actually, that statement is only true sometimes it depends on how the power in your local is generated. It could be solar, nuclear, coal, hydroelectric, etc. I know that in some places I've lived, it wold not have been coal based power. It would have been purely hydroelectric and nuclear. Where I live now, I could get a setup that would ensure it was at least 75% solar.

    @boomzilla said:

    I don't know if this counts as a massive array:

    At 354MW, I doubt it, but I guess it's a start.

    If CA were going to seriously ramp up power production to take on hydrogen production, they would probably want to first make up their current shortfalls. I imagine that they would need to build a couple dozen plants that size (total ass pull). I'm just not sure that there's enough free land (read: not in a national park) to make that possible.



  • @abarker said:

    If CA were going to seriously ramp up power production to take on hydrogen production, they would probably want to first make up their current shortfalls. I imagine that they would need to build a couple dozen plants that size (total ass pull). I'm just not sure that there's enough free land (read: not in a national park) to make that possible.

    Yeah, it's absurd that it's difficult to find real estate in the Mojave for this sort of project.

    Of course, if your goal is hydrogen production, you probably can't do the conversion on site. But, since these aren't great for base load power, it makes sense to use it to create some sort of power storage.


  • mod

    @boomzilla said:

    Of course, if your goal is hydrogen production, you probably can't do the conversion on site. But, since these aren't great for base load power, it makes sense to use it to create some sort of power storage.

    Actually, from what I've read about the projects to build hydrogen refueling stations, they want to build stations that have on site hydrogen production. Or is that not what you were talking about?



  • @abarker said:

    Actually, from what I've read about the projects to build hydrogen refueling stations, they want to build stations that have on site hydrogen production. Or is that not what you were talking about?

    I just think it's more practical to ship the electricity out of the California desert than to ship the water in. I could be wrong.


  • mod

    @boomzilla said:

    I just think it's more practical to ship the electricity out of the California desert than to ship the water in. I could be wrong.

    The point has been made, though forgotten by now, that water is not the preferred source for hydrogen. Fossile fuels are! Here's a refresher:

    @abarker said:

    Let's say that hydrogen fuel cells do claim a major segment of the automotive market. where's all that hydrogen going to come from? Well, the most common source of hydrogen is fossil fuels, and the main byproducts of hydrogen production are CO and CO2. I don't think that the environmentalists will be too happy once they figure out that their beloved hydrogen vehicles are just shifting where the greenhouse gasses are generated.

    @rad131304 said:

    The main problem is that our current best source of hydrogen is natural gas.

    @dkf said:

    You currently get hydrogen from chemically processing natural gas. Just FYI.

    So, while the discussion about making hydrogen from water has been entertaining, we've been ignoring the primary production method for hydrogen, and the main byproducts: CO and CO2. Who cares about shipping in water? Ship in the fossil fuels! We already do that now for our gas stations.



  • @abarker said:

    The point has been made, though forgotten by now, that water is not the preferred source for hydrogen. Fossile fuels are! Here's a refresher:

    But if you have natural gas, why are you fucking around with solar?



  • @abarker said:

    The common reasoning is that this helps to maximize the amount of water soaking in the the soil instead of evaporating away.

    Not really relevant to the question of humidity generation, which doesn't care whether the water vapor got there by direct evaporation or by lawn grass leaf transpiration. By far the greatest portion of what you dump on a lawn is going to end up airborne one way or another.


  • mod

    @boomzilla said:

    But if you have natural gas, why are you fucking around with solar?

    Well, I wasn't the first to bring up solar, but I can think of a few possible arguments:

    • If we want to use natural gas to get hydrogen, we probably don't want to use it as our fuel source to generate the energy to drive the hydrogen production. Using it for both would use up our fuel sources faster, and we don't want that.
    • Using natural gas as an outright fuel source will upset the environmentalists. They are already aware of the byproducts of burning fossil fuels. Apparently, they aren't aware of the byproducts of producing hydrogen, because hydrogen is being touted as "green".
    • In some places, it can be more economical to generate electricity from solar power than from natural gas.


  • @abarker said:

    I don't see why a fuel cell vehicle would "certainly" include a Li-ion battery pack. That's taking back to a hybrid, albeit a different flavor of hybrid.

    Well not really, since you'd still only have one source of motive power. The only reason you'd put a battery pack in it is for temporary storage of energy recovered by the regenerative braking which comes essentially for free once you have an electric motor, so the battery pack would only need to be relatively small; might even be feasible to use a supercapacitor. It would easily pay for itself in reduced energy consumption, and would mean you could get away with a smaller hydrogen tank or get more range from a big one.



  • @abarker said:

    Actually, that statement is only true sometimes it depends on how the power in your local is generated.

    Actually it's not. Coal is the most greenhouse-intensive energy source there is, and the Tesla already beats any comparably capable internal combustion powered car on greenhouse emissions per km even if totally powered by coal. If it's powered by anything cleaner, obviously that's an even bigger greenhouse win.


  • mod

    @flabdablet said:

    Actually it's not. Coal is the most greenhouse-intensive energy source there is, and the Tesla already beats any comparably capable internal combustion powered car on greenhouse emissions per km even if totally powered by coal. If it's powered by anything cleaner, obviously that's an even bigger greenhouse win.

    Apparently, I misunderstood what you said. I took the meaning that you were saying that the Tesla S is ultimately powered by coal, which is the point I was contending. Now that I understand your full meaning, I concede the point.



  • @abarker said:

    possible arguments

    Yeah, the reality is that you should probably just use the natural gas to begin with. At least until you're using the hydrogen for fusion instead of combustion.

    @abarker said:

    Using natural gas as an outright fuel source will upset the environmentalists. They are already aware of the byproducts of burning fossil fuels.

    Even if they mischaracterize a lot of them. :frowning:



  • @abarker said:

    Using natural gas as an outright fuel source will upset the environmentalists. They are already aware of the byproducts of burning fossil fuels. Apparently, they aren't aware of the byproducts of producing hydrogen, because hydrogen is being touted as "green".

    Wouldn't upset this environmentalist, unless it was coal seam or shale gas and required fracking to extract and the fracking was done in such a way as to fuck up an aquifer, or unless the wells were leaky and released significant methane to the atmosphere. Natural gas makes electricity with less greenhouse emission per generated watt-hour than coal, so even if it only ever generated hydrogen in the most inefficient and greenhouse-stupid way possible - being burnt to generate electricity to power electrolyzers somewhere else - it would still be an improvement on doing the same thing with coal.

    Natural gas that's currently getting extracted from the typical gas bubbles that exist over an oil well is an even better proposition to this environmentalist, because you could reform it to hydrogen on site. The first step in the reforming process makes hydrogen and carbon monoxide. Having separated those, you can burn the carbon monoxide to make carbon dioxide plus more than enough heat to power the first step. The whole process could be integrated into a thermal power plant, turning that excess heat into electricity to be pushed into the grid.

    The really cool part about wellhead reforming is that the resulting carbon dioxide could then be re-injected into the very same well you're getting your methane feedstock from. One molecule of methane makes one molecule of carbon dioxide, so reinjection would maintain the same gas pressure as already exists underground. You're dealing with a gas reservoir that has proven itself capable of storing methane at that pressure for millions of years, so it would certainly sequester carbon dioxide just as effectively. Also, carbon dioxide is about three times as dense as methane, so if it were injected back into the bottom of the space it would pool there and help push the remaining methane out, extending the viable life of the well. Onsite natural gas reforming is just win, all the way round.

    The only downside, as far as I know, is that it's not renewable.


  • BINNED

    Ah, I see the problem now. I thought I saw it emerging in your previous posts, but now it's clear what's been bugging me.

    What you're using here is stuff like logic and efficiency.


    Filed under: I would like a pony too, shamelessly stealing jokes


  • mod

    @flabdablet said:

    Wouldn't upset this environmentalist ...

    Well, I was referring to the (apparently) more extreme environmentalists I've spoken to. Environmentalists like you, I can respect. You've actually educated yourself enough to know what's going on. Most people who label themselves environmentalists haven't done so, and just go around screaming about how everything needs to be green. That seems to have become more common since An Inconvenient Truth came out, so I blame Gore.



  • @abarker said:

    Most people who label themselves environmentalists haven't done so, and just go around screaming about how everything needs to be green.

    It's an example of the good being the enemy of the perfect. In some cases due to extremism, others due to ignorance.


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