23 Feb 16
My first thought was that it might be a useful technology to deal with carbon captured at power stations, but then I realised that the power input to achieve this must necessarily exceed the power produced by the power station.
Also this statement:
"Our process also has an important advantage over battery or gaseous-hydrogen powered vehicle technologies as many of the hydrocarbon products from our reaction are exactly what we use in cars, trucks and planes, so there would be no need to change the current fuel distribution system,"
My opinion is that hydrogen powered vehicles are just plain stupid, so we can ignore that, but to call maintaining the current fuel distribution process over battery powered vehicles an 'advantage' is only valid if you happen to be in the fossil fuel distribution business. The reality is that electricity has many advantages over the current fuel distribution system and maintaining that system is decidedly not an advantage.
There is no mention of efficiencies in the article. Clearly however there will be inefficiencies and you will need to put in as much power and more than you can take out from the fuel. This begs the question as to what your power source will be. Fossil fuels perhaps?
23 Feb 16
Originally posted by twhiteheadThey're talking about getting all the energy inputs from sunlight. Essentially it is a way of chemically storing solar energy. I think this is useful, aside from anything else, because of the large number of infernal [sic] combustion engines already around. In the U.K. there are probably around 30 million cars all of which are petrol or diesel driven. Conversion to electric cars isn't something that can be done without an environmental impact, so I think this is a useful idea. Whether they can generate enough fuel to replace fossil derived hydrocarbons is another matter. The danger is more of a political one where the oil industry can claim that there is no reason to change, because of the new technology, but the new technology can only provide about 0.1% of the fuel needed.
My first thought was that it might be a useful technology to deal with carbon captured at power stations, but then I realised that the power input to achieve this must necessarily exceed the power produced by the power station.
Also this statement:
[quote]"Our process also has an important advantage over battery or gaseous-hydrogen powered vehicle tec ...[text shortened]... rom the fuel. This begs the question as to what your power source will be. Fossil fuels perhaps?
23 Feb 16
Originally posted by DeepThoughtAnd where will the CO2 come from? Presumably the only place this makes sense is next to a power plant that is producing a lot of CO2. But if you are getting energy from sunlight, why not simply use it to produce electricity?
They're talking about getting all the energy inputs from sunlight.
I think this is useful, aside from anything else, because of the large number of infernal [sic] combustion engines already around.
So to save all those infernal combustion engines, we build new fuel plants? I would like to see the figures to see if it actually adds up.
Conversion to electric cars isn't something that can be done without an environmental impact, so I think this is a useful idea.
I agree that currently existing cars should be allowed to stay on the road until they die out. I do think that all possible efforts should be put into producing electric cars.
The danger is more of a political one where the oil industry can claim that there is no reason to change, because of the new technology, but the new technology can only provide about 0.1% of the fuel needed
Agreed.
23 Feb 16
I think using hydrogen to power most kinds of things would be a deeply flawed and even potentially counterproductive strategy and for many reasons.
The only application where it might make some sort of strategic sense is to power aircraft, but even there it would be questionable mainly for safety reasons as we have safer alternatives.
23 Feb 16
Originally posted by humyAs far as H2 goes, safety has been dealt with using solid state H2 adsorbers and new versions of that appear all the time.
I think using hydrogen to power most kinds of things would be a deeply flawed and even potentially counterproductive strategy and for many reasons.
The only application where it might make some sort of strategic sense is to power aircraft, but even there it would be questionable mainly for safety reasons as we have safer alternatives.
The question of efficiency of this CO2 process was hinted at in the article, where he said better catalysts were needed to use the sunlight in the most efficient way possible so they know the process as it stands is low on the efficiency scale, my guess is around 10% but that is just a guess.
23 Feb 16
Originally posted by sonhouseReference please? I am pretty sure that hydrogen powered cars still used plain compressed or liquid hydrogen. Even with hydrogen absorbers, dangers still exist and little or no benefits.
As far as H2 goes, safety has been dealt with using solid state H2 adsorbers and new versions of that appear all the time.
The question of efficiency of this CO2 process was hinted at in the article, where he said better catalysts were needed to use the sunlight in the most efficient way possible so they know the process as it stands is low on the efficiency scale, my guess is around 10% but that is just a guess.
They would have to beat solar cells to even begin to make sense.
23 Feb 16
Originally posted by humyWhich is why it has been pushed so heavily by the fossil fuel and automotive industry.
..... and even potentially counterproductive strategy .....
I still recall many years ago a Scientific American article that said 'get ready for the hydrogen economy' or something to that effect, but if you actually read the article it listed all the reasons why it simply didn't make any sense. It was as if they had been pressured into promoting it for political reasons.
23 Feb 16
Originally posted by twhiteheadHere is one recent piece on a solid adsorber, 13% by weight. I think 8% is the government lower limit for usable fuel.
Reference please? I am pretty sure that hydrogen powered cars still used plain compressed or liquid hydrogen. Even with hydrogen absorbers, dangers still exist and little or no benefits.
[b]The question of efficiency of this CO2 process was hinted at in the article, where he said better catalysts were needed to use the sunlight in the most efficient wa ...[text shortened]... but that is just a guess.
They would have to beat solar cells to even begin to make sense.[/b]
http://www.sciencedirect.com/science/article/pii/S0378775303000545
This is just the abstract but it shows what the stuff is and the percentages.
23 Feb 16
Originally posted by sonhouseSo not actually "dealt with" but still in research and still worse energy density than methane.
Here is one recent piece on a solid adsorber, 13% by weight. I think 8% is the government lower limit for usable fuel.
http://www.sciencedirect.com/science/article/pii/S0378775303000545
This is just the abstract but it shows what the stuff is and the percentages.
The only places where batteries may take a while before they are a viable solution to transport are aircraft and large ships. Aircraft need the best energy density possible. I don't see ships running on hydrogen any time soon, and in fact I expect they will go battery powered before they go hydrogen powered.
Hydrogen as a fuel just doesn't make sense except for rockets.
23 Feb 16
1 edit
Originally posted by twhiteheadEven in rockets it's not ideal. O2/H2 gives about 450 ISP which is the max you are going to get with chemical rockets so we need something more like the Vasimr or the Hall effect thrusters which can go into the thousands of ISP points which means faster spacecraft.
So not actually "dealt with" but still in research and still worse energy density than methane.
The only places where batteries may take a while before they are a viable solution to transport are aircraft and large ships. Aircraft need the best energy density possible. I don't see ships running on hydrogen any time soon, and in fact I expect they will ...[text shortened]... fore they go hydrogen powered.
Hydrogen as a fuel just doesn't make sense except for rockets.
It is said the Vasimr rocket can get a mass to Mars in about a month V chemical rockets which take at least 6 months or more. It runs 24/7 but with a much lower g force, like 1/20th g or some such.
The problem with Vasimr is it wants hundreds of kilowatts of electricity so you have to mount a BUNCH of solar panels which adds to the mass which lowers the max velocity. A small lightweight nuclear reactor or something like it could also be used but all that is in the future.
23 Feb 16
Originally posted by sonhouseYes, but there is still a place for hydrogen in launches. There is no place for it in cars.
Even in rockets it's not ideal. O2/H2 gives about 450 ISP which is the max you are going to get with chemical rockets so we need something more like the Vasimr or the Hall effect thrusters which can go into the thousands of ISP points which means faster spacecraft.