hipernoico writes to tell us Wired News is reporting that hundreds of semi trucks now on the roads are being partially powered by hydrogen. From the article: "These 18-wheelers make hydrogen as they go, eliminating the need for high-pressure, cryogenic storage tanks or hydrogen filling stations, which, by the way, don't yet exist. These truckers aren't just do-gooders. They like Canadian Hydrogen Energy's Hydrogen Fuel Injection, or HFI, system because it lets them save fuel, get more horsepower and, as a bonus, cause less pollution."
http://science.slashdot.org/article.pl?sid=05/11/15/2314241&from=rss
Let’s be straight about this. Using Hydrogen as a terrestrial fuel carrier is very stupid. The mathematics do not add up nor do the IQ points of those who continue to propose this for mainstream use. Any student who has passed Physics 101 knows this is true yet the dreamers seem to persist in disillusioning the masses about the benefits of using hydrogen.
The first rule of physics is that energy can be neither created nor destroyed. Energy may be converted from one form to another. A good fuel source for terrestrial use is one that occurs in abundance naturally, is easy to harvest, store and distribute and also converts cleanly with minimal impact on our environment. Coal, wood, oil all match some of this criteria. For example, wood is very abundant on our planet. It grows by converting the sun’s energy into biomass that may be easily harvested and transported then subsequently burned to release thermal energy. Thermal energy can be converted into kinetic energy very easily.
As with everything on this blog, do not take this for granted. Question it and do your own research.
So why is hydrogen as a fuel source for terrestrial application a bad idea? Let examine some facts and what hydrogen’s role is.
In most hydrogen powered vehicle scenarios, Hydrogen essentially acts as a battery or transporter of energy. It exists to store energy to allow it to be mobile. Similar to how recharge-able batteries work, it takes energy to produce hydrogen pure enough to be useful as a power source. At the target, the hydrogen’s stored energy is essentially converted to electrical energy, although it may also be converted to thermal energy which may be more efficient to convert to kinetic energy.
Hydrogen is highly unstable as a gas and does not readily occur in nature. Unlike hydrocarbons, which are relatively stable compounds, hydrogen will do everything it can dissipate or change state if released into the atmosphere of our little green planet. As such, pure hydrogen is extremely rare on this planet. Even if you found a reserve of hydrogen, you would still need to harvest and transport it to distribution centre’s which in itself may take more energy than the hydrogen you harvested had in it.
Let’s look at the pattern.
1. A natural process leaves energy stored in a manner that is easily harvested by human actors. Examples – the energy of the sun creates wind patterns on the surface of the planet which may be harvested by windmills or solar energy is converted via photoelectric arrays into electrical energy.
2. The energy is distributed in some form. Example - a power grid distributes electricity via wires or it may be used to charge a battery which may be transported physically to the site.
3. The energy is consumed. In reality – it is simply converted into some other form since energy can neither be created nor destroyed.
To make this work, the energy used to retrieve and initially convert the energy from its natural state (rE) plus the energy to refine, store, transport and distribute the energy to the point of consumption (tKw) must be less than the energy retrieved in step 3 when the energy is consumed (nKw). If rE + tKw > nKw, the process is a net waste of energy and this is before you consider the energy used to create the specialized mechanisms to consume an energy transport medium like hydrogen. Remember, fuel cells take more energy to design, manufacture, test and integrate into industry.
In general, we should not even consider anything less than a situation where
Hydrogen is not dense enough in a gaseous state to even contain enough energy to overcome the energy required to create, purify, store and transport it. Hydrogen as a terrestrial carrier of energy is a very dumb idea.
I agree. In a country where we have a tremendous amount of space to grow bio mass for biofuels, vehicles that can run on a blended fule such as the flexi fuel cars in Brazil and Sweden seem the better choice to go. Over 60% of new cars sold last year in Brazil were flexifuel cars. Why in Brazil? Due to too much sugar cane, they are able to produce an ethanol-blended fule and have invested in building the infrastructure (gas stations with biofuel) to support such vehicles. This trend is also only increasing in Sweden as well...
ReplyDeleteCarmen
As per my last comment, many poor decisions can be made when trying to choose more sustainable initiatives. That is why a scientifically rigorous definition of sustainability, one that has attained concensus in the scientific community, such as the Natural Step, should be followed when developing new technologies to accomodate the future outcomes and markets as a result of our current trends. To read more about TNS and the founder of my program in Sweden, check out this article http://www.naturalstep.ca/articles/CK_KH_Robert_April2004.pdf
ReplyDeleteI think you miss the bigger picture of hydrogen as a fuel. There are many reasons that hydrogen fuel cells are not a viable energy source today but it has nothing to do with your arguments.
ReplyDeleteIt's a complex topic so I can't really do it justice in a blog comment.. but you might consider the following...
Hydrogen (and oxygen, the other required reactant) could be easily produced from hydrolysis of water.
Renewable energy sources such as wind turbines, solar panels, etc are generally useless in the bigger picture as you can only rely on the lowest output as a benchmark for your electricity output (assume anything else and you will experience brown-outs). A coal fired power station can't be shut down each night as it's too expensive to shut down and restart so it runs all day and all night regardless of whether or not the electricity is needed.
You cannot "store" electricity. Forget batteries, they represent an extremely small storage mechanism and are wholly unsuited to industrial electricity production. On a windy day you throw away the excess.. not enough users of electricity at night, you throw away the excess.
Imagine a hydrogen economy that works with other energy sources, including fossil fuels; where cities have very large storage units of hydrogen gas, generated from excess electricity.
Or perhaps.. consider having your own in-house fuel cell the size of a fridge powering your personal requirements. Put a solar panel on your roof and you might be self-sustaining from time to time. Imagine millions of residents contributing back to the grid when they have more power than they need.
You may also not know that there is plenty of exciting work in the field of hydrates, providing solutions for storing hydrogen gas at low pressure.
ReplyDeleteHydrogen as a fuel source is coming whether you believe it or not :)
In understand what you have said but it is still like trading US dollars for Mexican pesos 1:1. You lose about 90% of the energy in the process. Batteries, despite all their flaws, still are at least 4 times more efficient. The problem lies mainly in the conversion from electricity to hydrogen. If you try to do this via reverse electrolysis, the problem is that it is a *very* slow and lossy process. If you try to run the current higher, you add heat to the equation which results in steam contamination and takes even more energy to correct.
ReplyDeleteIf you have electric energy, there are better ways to store it. Batteries are currently the best for short term. The only way it would ever make sense if it was the only choice for a place where there were free unlimited kilowatts of electrical powere that could not be used or distributed by any other means. Even then, one would still have to factor in the cost of transporting the newly created hydrogen to another place. If you are going to invest in hydrogen generating infrastructure, you would probably consider an infrastructure to distribute the gobs of electricity instead. Without running the numbers, I would guess that laying wires to move the electricity is cheaper and more efficient than building hydrogen generation utilities and transporting the hydrogen.
You are correct - it is a very complex topic. Is there any place on the net where there is an active discussion board?
Duane
The following text is posted here with permission of Don Lancaster (the Guru's lair), one of my favorite sources of a seemingly endless mish-mash of scientific musings. Don's weblog can be viewed at http://www.tinaja.com/whtnu05.asp
ReplyDeleteNovember 19, 2005
There's some lively discussion going on in the newsgroups over a new "trucker's hydrogen injection system" based on electrolysis via an alternator. To me, the numbers simply do not add up. Not by a country mile. Time will tell how much of this is a scam, how much is the placebo effect, and how much is real.
First, there definitely is credible peer reveiwed research that shows that a modest (typically 5%)hydrogen injection can improve combustion to significantly raise fuel economy. It
is also possible that lower hydrogen injection levels can reduce carbon and other deposits. The latter has yet to be convincingly shown.
Two key questions are whether any new mechanical load needed to produce the hydrogen is greater or less than the benefits derived; and whether the fully burdened cost amortization will ever let the system pay for itself.
Few people realize how ludicrously inefficient a conventional alternator driven electrolysizer would be. The odds are utterly
overwhelming that there is no way in hell that the benefits could remotely approach the input loading penalty.
First, the fanbelt itself may be limited to the three the five horsepower range. Its efficiency is probably around 97 percent, caused by flexing and air turbulence. Car alternators are a lot less efficient than most people suspect, typically being in the 70 percent range. While the largest losses are in the rectifier diodes, the wider air gap, less-than-optimal regulator, cheaper magnetic materials, and field losses all make car alternator efficiency a secondary consideration. A typical 100 amp 12 volt car alternator is also only a 1-1/2 horsepower device. For decent efficiency, you cannot simply connect an electrolysizer to the output of an alternator. Because the alternator is a somewhat constant voltage device, and an efficient electrolysizer demands a carefully controlled current. The fancy switchmode electronics required to do this would probably end up in the 80 percent efficiency range. Analog control circuits or direct connection, of course, would be much worse.
While an electrolysizer can theoretically be fairly efficient (neglecting the staggering energy hit, of course), most will operate well into their exothermic range for decent gas volumes.
This introduces at least another 70 percent efficiency drop. Further,
most add-on manufacturers might tend to cheat and use stainless steel or nickel rather than the platinized platinum required for decent efficiency. this can add up to another 60 percent efficiency hit due to the hydrogen overvoltages involved. Details in any electrochem book.
Finally, the engine itself is probably only 35 percent efficient at converting fuel to shaft horsepower. Let's see. If we start with 1000 watts at the crankshaft, we get 970 watts at the alternator
input and 679 watts at the alternator output. And 543 watts at
the switchmode regulator. And 380 watts for the exothermic drop. The stainless overvoltage puts us down to 228 watts. And the engine efficiency finally delivers a mere 87 watts of mechanical power!
The dilemma is this: The amount of hydrogen producible with one fan belt and an unmodified alternator seems uselessly low and is in the
"homeopathic dose" range. While significant hydrogen production
seems to me to demand multiple fanbelts, custom heavier and much
more efficient alternators, and other complex modifications.
While other means of hydrogen injection (such as exhaust gas
reformation or a refillable on-board tank) might eventually be shown to be useful, I strongly feel that the insane efficiency losses in onboard alternator electrolysis absolutely guarantee that this flat out ain't gonna happen. And that's BEFORE amortization. In short, both the engineering economics and the thermodynamics suck. More in our Electrolysis and Energy Fundamentals tutorials.
From Duane - thanks Don. Also - when you add in the energy it takes to manufacture and distribute the devices for each truck (including trucking them to the end users), I am sure this is loser-proposition.
hello I am an inventor and I want to build a car that runs on magnitism and not fuel so that the world can use our one and only supply of fule for other purposes and not our stupuid cars.
ReplyDeleteBrainy Boy:
ReplyDeleteYour idea has merit and could work. If a tractor drive was used within large cities instead of overhead wires for electronic buses, all vehicle traveling in the city could utilize the grid of tractor drives to draw power from.
A smart guy would prototype some variation of the maglev train technology and marry it to a road, then demo the result. It ideally shouldn't be too hard. There are lots of processor controlled caterpillar drives on the market.