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Hydrogen has a great energy density, that's why it is used in rockets. It may have similar range as battery electric cars but it can scale better. It can be re

by GuB-42 5y ago

Hydrogen has a great energy density, that's why it is used in rockets. It may have similar range as battery electric cars but it can scale better. It can be refueled in minutes, like gas cars. And the economy is based on using "waste" renewable energy. The problem is that solar panels and wind turbines don't produce energy when we need it the most (see: duck curve). The idea is to store that energy as hydrogen and use it in vehicles. For commuters with a garage and a charging spot, batteries are more convenient but I think big trucks can benefit more from hydrogen. Now the big question is, can we modify these hydrogen trucks to "roll steam" at these pesky Teslas.

thehappypm 5y ago
Hydrogen isn't used in rockets much. It's actually not energy dense enough compared to more exotic fuels.
- GuB-42 5y ago
  You are right, but considering that many people think it is too dangerous to put hydrogen tanks in cars, I wonder what they are going to say about "exotic rocket fuels" :) For reference, here is a quote from the Ignition! book about Chlorine trifluoride. It is an oxidizer, not a fuel but you get the idea. > It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.
bkor 5y ago
> And the economy is based on using "waste" renewable energy. The problem is that solar panels and wind turbines don't produce energy when we need it the most (see: duck curve). The idea is to store that energy as hydrogen and use it in vehicles. I've seem this statement loads of times before. But actually, Hydrogen production is not economical if you do not produce it continuously. Meaning, it does not make economical sense to only use excess energy capacity. Further, Hydrogen for cars is highly inefficient if you take all of the steps into account. For the foreseeable future the common expectation is that Hydrogen is produced from fossil fuels (e.g. read forecasts from analysts or companies such as Shell). This while at the same time they pretend it'll make this more green. Hydrogen is already produced in huge quantities btw, but it's somewhat hidden as it's used by industry. Meaning, most people wouldn't even notice it. Unlike e.g. seeing a new hydrogen gas station.
bryanlarsen 5y ago
> Hydrogen has a great energy density, that's why it is used in rockets. Per kg, but its energy density per litre is very poor. Every modern rocket uses RP1 (kerosene) or Methane (natural gas) for their first stages now. > It can be refueled in minutes, like gas cars. If your hydrogen station has 10,000 PSI hydrogen available. A typical station can fill 3 cars per hour quickly. More than that and you have to wait for it to get back up to 10,000 PSI. > And the economy is based on using "waste" renewable energy. The problem is that solar panels and wind turbines don't produce energy when we need it the most (see: duck curve). The idea is to store that energy as hydrogen and use it in vehicles. You can also store "waste" renewable energy in EV batteries.
- GuB-42 5y ago
  > You can also store "waste" renewable energy in EV batteries Yes you can, but the time when solar energy is the most abundant is in the the middle of the day, typically when people are away from home and not charging their cars. Hydrogen can be stored for years in huge tanks so it is really "on demand". Unlike batteries, tank benefit from the square cube law and therefore makes large scale storage cheaper. And BTW, personally, I am not convinced by hydrogen cars, but it doesn't look completely stupid either.
SigmundA 5y ago
Electrons are more energy dense than hydrogen unfortunately you need a heavy battery to store and use them properly. However hydrogen needs high pressure tanks and fuels cells to store and use it properly so there is basically no energy density advantage right now in a car, both fuel cells and batteries are increasing in energy density due to R&D not sure which will win out it the end. My current opinion is batteries are simpler in every way and have good enough energy density. All the current cars also need a lithium buffer battery because the fuel cell can not put out enough burst power nor do regenerative braking.

by GuB-42 5y ago

thehappypm 5y ago

Hydrogen isn't used in rockets much. It's actually not energy dense enough compared to more exotic fuels.

GuB-42 5y ago
You are right, but considering that many people think it is too dangerous to put hydrogen tanks in cars, I wonder what they are going to say about "exotic rocket fuels" :) For reference, here is a quote from the Ignition! book about Chlorine trifluoride. It is an oxidizer, not a fuel but you get the idea. > It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.

bkor 5y ago

> And the economy is based on using "waste" renewable energy. The problem is that solar panels and wind turbines don't produce energy when we need it the most (see: duck curve). The idea is to store that energy as hydrogen and use it in vehicles. I've seem this statement loads of times before. But actually, Hydrogen production is not economical if you do not produce it continuously. Meaning, it does not make economical sense to only use excess energy capacity. Further, Hydrogen for cars is highly inefficient if you take all of the steps into account. For the foreseeable future the common expectation is that Hydrogen is produced from fossil fuels (e.g. read forecasts from analysts or companies such as Shell). This while at the same time they pretend it'll make this more green. Hydrogen is already produced in huge quantities btw, but it's somewhat hidden as it's used by industry. Meaning, most people wouldn't even notice it. Unlike e.g. seeing a new hydrogen gas station.

bryanlarsen 5y ago

> Hydrogen has a great energy density, that's why it is used in rockets. Per kg, but its energy density per litre is very poor. Every modern rocket uses RP1 (kerosene) or Methane (natural gas) for their first stages now. > It can be refueled in minutes, like gas cars. If your hydrogen station has 10,000 PSI hydrogen available. A typical station can fill 3 cars per hour quickly. More than that and you have to wait for it to get back up to 10,000 PSI. > And the economy is based on using "waste" renewable energy. The problem is that solar panels and wind turbines don't produce energy when we need it the most (see: duck curve). The idea is to store that energy as hydrogen and use it in vehicles. You can also store "waste" renewable energy in EV batteries.

GuB-42 5y ago
> You can also store "waste" renewable energy in EV batteries Yes you can, but the time when solar energy is the most abundant is in the the middle of the day, typically when people are away from home and not charging their cars. Hydrogen can be stored for years in huge tanks so it is really "on demand". Unlike batteries, tank benefit from the square cube law and therefore makes large scale storage cheaper. And BTW, personally, I am not convinced by hydrogen cars, but it doesn't look completely stupid either.

SigmundA 5y ago

Electrons are more energy dense than hydrogen unfortunately you need a heavy battery to store and use them properly. However hydrogen needs high pressure tanks and fuels cells to store and use it properly so there is basically no energy density advantage right now in a car, both fuel cells and batteries are increasing in energy density due to R&D not sure which will win out it the end. My current opinion is batteries are simpler in every way and have good enough energy density. All the current cars also need a lithium buffer battery because the fuel cell can not put out enough burst power nor do regenerative braking.