https://www.geopura.com/in-action/cairn ... he-charge/
Seems like a good step forward.....

Interesting that they're not also offering to supply the hydrogen as a fuel....
Guess the lack of demand for hydrogen vehicles made it uneconomic....?
Moderator: Peak Moderation
How can hydrogen be produced at home in a manner that is positive in terms of EROEI? Never mind being positive in terms of cost versus profit.BritDownUnder wrote: ↑01 Jan 2024, 21:25 I can only see hydrogen being a suitable fuel source if batteries become less economic or the raw materials become unavailable, or if there is a requirement for propulsion in a remote inaccessible place where batteries are not available, or if 'refuelling' times of less than several minutes are required and long ranges are required. Otherwise the EROEI of hydrogen goes against it.
Just one other thought. Production of hydrogen can in theory be done at home or outside of government control and taxation. Electricity charging can also be considered as well but maybe the powers that be don't like the thought of people filling up their own cars with untaxed hydrogen?
It can't, but in some circumstances electricity supply from an isolated solar PV system might be stranded and not usable for anything else except for electrolysis of hydrogen at a EROEI<1.northernmonkey wrote: ↑02 Jan 2024, 20:52How can hydrogen be produced at home in a manner that is positive in terms of EROEI? Never mind being positive in terms of cost versus profit.BritDownUnder wrote: ↑01 Jan 2024, 21:25 I can only see hydrogen being a suitable fuel source if batteries become less economic or the raw materials become unavailable, or if there is a requirement for propulsion in a remote inaccessible place where batteries are not available, or if 'refuelling' times of less than several minutes are required and long ranges are required. Otherwise the EROEI of hydrogen goes against it.
Just one other thought. Production of hydrogen can in theory be done at home or outside of government control and taxation. Electricity charging can also be considered as well but maybe the powers that be don't like the thought of people filling up their own cars with untaxed hydrogen?
Whist the terrible EROEI involved in industrial food production is a real issue, it is a secondary one. Food production is further downstream.BritDownUnder wrote: ↑02 Jan 2024, 21:32It can't, but in some circumstances electricity supply from an isolated solar PV system might be stranded and not usable for anything else except for electrolysis of hydrogen at a EROEI<1.northernmonkey wrote: ↑02 Jan 2024, 20:52How can hydrogen be produced at home in a manner that is positive in terms of EROEI? Never mind being positive in terms of cost versus profit.BritDownUnder wrote: ↑01 Jan 2024, 21:25 I can only see hydrogen being a suitable fuel source if batteries become less economic or the raw materials become unavailable, or if there is a requirement for propulsion in a remote inaccessible place where batteries are not available, or if 'refuelling' times of less than several minutes are required and long ranges are required. Otherwise the EROEI of hydrogen goes against it.
Just one other thought. Production of hydrogen can in theory be done at home or outside of government control and taxation. Electricity charging can also be considered as well but maybe the powers that be don't like the thought of people filling up their own cars with untaxed hydrogen?
Don't forget that most mechanised food production already has something like a 0.1 EROEI.
I think solar PV has a lifetime EROEI of more than 10 but on each charge or batch of hydrogen produced will have a EROEI < 1 due to the second law of thermodynamics. This doesn't matter because the energy input (the Sun) is free energy and infinite over a 100 million year timescale.northernmonkey wrote: ↑02 Jan 2024, 23:02Whist the terrible EROEI involved in industrial food production is a real issue, it is a secondary one. Food production is further downstream.BritDownUnder wrote: ↑02 Jan 2024, 21:32It can't, but in some circumstances electricity supply from an isolated solar PV system might be stranded and not usable for anything else except for electrolysis of hydrogen at a EROEI<1.northernmonkey wrote: ↑02 Jan 2024, 20:52
How can hydrogen be produced at home in a manner that is positive in terms of EROEI? Never mind being positive in terms of cost versus profit.
Don't forget that most mechanised food production already has something like a 0.1 EROEI.
If the actual generation of usable energy costs more energy to generate than is contained in the generated usable energy itself, then its total a non starter except in very specific instances of one off usage where the benefits outweigh the costs.
As for your example of a domestic solar pv, it would logically make more energetic sense to convert that to electricity and consume the electricity directly as opposed to then converting the electricity to hydrogen prior to consumption with all of the energy losses incurred in the secondary conversion
I didn't say the sun was not (effectively) infinite or that solar panels are not EROEI positive in terms of generating electricity (though that is debatable depending on the metric you use, but we'll leave that for now). I am saying, however, that, the negative EROEI of hydrogen production in terms of the energy in (electricity) to energy out (hydrogen) makes no sense given that you have used a form of energy to obtain it that was, in EROEI terms, a positive energy source (just). Thus, It matters little if the energy source you use to generate your final energy is infinite if the energy you get out the end is less than the energy you used to get it.BritDownUnder wrote: ↑03 Jan 2024, 21:15 I think solar PV has a lifetime EROEI of more than 10 but on each charge or batch of hydrogen produced will have a EROEI < 1 due to the second law of thermodynamics. This doesn't matter because the energy input (the Sun) is free energy and infinite over a 100 million year timescale.
On the last point you made matching energy generated to energy required is one of the main issues of renewable electricity generation. Some see hydrogen as a useful store of electricity even if it has a lousy EROEI. In most cases a lithium ion batter beats hydrogen anytime but if the battery materials are not available or capital costs too expensive, or the refuelling time has to be very quick I can see hydrogen as a 'niche' storage/fuelling system. Hydrogen can also be used (very inefficiently in existing diesel engine systems so this might save on capital costs) We will see if this pans out. From what I can see hydrogen fuelling stations are not being built around the world like battery chargers are.
Energy Returned / Energy Invested.northernmonkey wrote: ↑31 Dec 2023, 16:04 The negative EROEI in hydrogen might also have something to do with it.
Nope.johnny wrote: ↑04 Jan 2024, 01:16Energy Returned / Energy Invested.northernmonkey wrote: ↑31 Dec 2023, 16:04 The negative EROEI in hydrogen might also have something to do with it.
In order for EROEI<0, then energy returned must be <0.
How does the process of creating hydrogen from say, water, with some small engine using energy Y to create the hydrogen which has energy X, which is LESS than Y maybe (EROEI>0 and EROEI<1), but how does this basic process not only NOT make any hydrogen, but actually makes energy......somewhere...somehow...disappear?
Does the water you are running electricity into get...colder? As oppsoed to just creating hydrogen and oxygen like it normally does?
Feel free to correct my equations up above? There are only two parts to this thing, we both know what the words are, and if energy out => the energy in, EROEI>=1northernmonkey wrote: ↑04 Jan 2024, 01:27 In order for EROEI to not be <0, the energy out must equal or exceed the energy in.
Ignoring the 2nd Law of Thermodynamics hiccup in that statement, there are two parts to the equation. If energy out doesn't matter, then remove it from the equation and presto....you aren't talking about EROEI anymore but just....energy in.northernonkey wrote: It doesn't matter what energy you get out. It must exceed the energy in.
You shouldn't. Energy isn't money, and I do physics, not money handling.northernmonkey wrote: I'll put in in financial term as I suspect you might be better able to grasp this concept.
Yes. Money isn't energy. And you REALLY don't understand EROEI.northernmonkey wrote: It doesn't matter if you make a million dollars on a deal if the deal costs you 1.5 million dollars.
Get it?
Okay, one more try:johnny wrote: ↑04 Jan 2024, 01:46Feel free to correct my equations up above? There are only two parts to this thing, we both know what the words are, and if energy out => the energy in, EROEI>=1northernmonkey wrote: ↑04 Jan 2024, 01:27 In order for EROEI to not be <0, the energy out must equal or exceed the energy in.
In order to be negative, one of the two terms must be negative. Putting energy in is defined as part of the process, to even calculate EROEI you have this idea of...I put energy IN. Therefore energy in by definition is >0. Otherwise there is no metric to discuss.
Therefore the only way you get a negative EROEI is if the top term, energy returned, is LESS than 0. So in my example, in trying to make hydrogen, you make energy...disappear...somehow. Hence the water getting colder crack.Ignoring the 2nd Law of Thermodynamics hiccup in that statement, there are two parts to the equation. If energy out doesn't matter, then remove it from the equation and presto....you aren't talking about EROEI anymore but just....energy in.northernonkey wrote: It doesn't matter what energy you get out. It must exceed the energy in.You shouldn't. Energy isn't money, and I do physics, not money handling.northernmonkey wrote: I'll put in in financial term as I suspect you might be better able to grasp this concept.Yes. Money isn't energy. And you REALLY don't understand EROEI.northernmonkey wrote: It doesn't matter if you make a million dollars on a deal if the deal costs you 1.5 million dollars.
Get it?