Hydrogen-Powered cars with Zero-Carbon-Emission?

Roland Piquepaille writes "Researchers from the Georgia Institute of Technology have a bright idea — at least at first sight. They want to create a sustainable transportation system by using hydrogen-powered cars. They would like to create an infrastructure where people could use a liquid fuel for driving while the carbon emission in their vehicles is trapped for later processing at a fueling station. 'The carbon would then be shuttled back to a processing plant where it could be transformed into liquid fuel.' Where will all this liquid carbon be stored? The researchers don't know. They suggest that it could be stored in geological formations or under the oceans."

Hydrogen? Carbon?

[_merlin]

First you say the cars are hydrogen-powered, then you say the carbon emissions will be trapped and disposed of when refuelling. Hydrogen doesn't contain carbon. Where do carbon emissions come from? This has to be the most contradictory Slashdot summary in a long time.

I thought

[Altus]

There were already some pretty good ways of storing hydrogen for cars and the issue was just creating the hydrogen in the first place.

Seems like using hydrocarbons and storing liquid carbon in the car for later processing would be a real pain for very little gain. Though maybe this would be a good way to get hydrogen to the "gas station."

Re:Hydrogen? Carbon?

[RingDev]

Step 1: Generate pure hydrogen in highly efficient processing plant
Step 2: Merge with carbon to create less stable and lower density hydrocarbon based fuel
Step 3: Using a vehicle based unit, crack the hydrocarbons back into hydrogen and carbon
Step 4: oxidize hydrogen to power fuel cell.
Step 5: return carbon to processing plant.

This would work amazingly if there were a shortage of carbon and an excess of easily accessible hydrogen. Unfortunately, our problem is the other way around. I can walk to any local gas station in the middle of summer and pick up a 20lbs bag of carbon for a few bucks. Getting my hands on 20lbs of hydrogen is a bit more challenging and expensive.

Not to mention there is no way they are going to get a vehicle based cracking unit to be more efficient than the factory unit. Not to mention that energy density is already an issue in pure hydrogen storage, turning it into hydro carbons isn't going to help on that issue if they are only using the hydrogen for energy generation.

The whole concept seems to fall on it's face as yet another attempt at a perpetual motion device.

-Rick

Can we make this any more inefficient?

[Radon360]

1. Fill up with regular gasoline
2. Instead of burning it outright, let's strip the hydrogen off the hydrocarbons and just burn that.
3. Somehow sequester the leftover carbon from the breakdown (this is the ???? step)
4. Return the carbon (somehow stored in liquid form) for recycling >>> Profit!

First, let's ignore how much energy we're throwing away in step 2 by not utilizing the full energy potential stored in the hydrocarbon molecules. Second, somehow we'll expend more energy to liberate the hydrogen and capture the carbon, both without oxidizing them. Third, we're going to tote around another 75 - 100 pounds of weight with the stored (and somehow liquefied) carbon that will be returned. Less energy potential that ever reaches the engine/fuel cell, and even more expended to refine something fairly energy dense into something that's a fair amount less energy dense.

The problem with this idea is there's too much fixation on sequestering every last bit of carbon, rather than focusing on a bigger, more important concept called energy efficiency. Work on improving that and the carbon emission reductions usually follow.

Re:Liquid carbon?

[KublaiKhan]

Not really an issue, actually. You'll just need to find a way to keep it at the right -pressure- that weighs less than the usual steel tank.

(Remember, phase changes can be accomplished with pressure changes, not only temperature changes. Your local fast food joint has a big ol' tank of liquid CO2 in back for the soft drinks)

Not the first company to try this

[edwardpickman]

There's a British company trying the same thing the article is confusing but the system essentially spilts off the hydrogen inside the vehicle then stores the carbon from hydrocarbon fuel. They reprocess the stored CO2 back into a hydrocarbon fuel so it's a closed loop system. It's more a way to store hydrogen as a hydrocarbon then recycle the storage medium, the carbon. It's in no way a fuel source it's a storage medium. ALL hydrogen based systems are storage mediums not fuel sources. Hydrogen is too friendly about combining with other elements so the hydrogen always needs to be spilt off to use as fuel. I take it you can store a lot of hydrogen safely this way if the system can ever be perfected but the real point is there's little difference from an electric vehicle other than faster refueling. Because of transfer losses I have to believe it's less efficent than straight electric. Even hydrogen cars are generally all electric so the hydrogen largely replaces batteries. Because of all the technical problems it seems focusing on improving batteries would be a better solution. There's no proof this system is in anyway practical let alone the technology still doesn't exist.

Re:why?

[Nodamnnicknamesavial]

Because transporting and storing hydrogen is a lot more difficult than storing and transporting a liquid hydrocarbon.

Re:I never want to hear "zero emissions" again

[Charcharodon]

I've been looking at the Volt too. The thing with it it seems that technically it's a hybrid, but the motor they're talking about putting in it would be far too small to be able to drive around on. It would be more like a gas powered battery charger, you'd have to let it sit for a while in the parking lot running to get you enough battery power to make it home, if in the city, or to be able to get up to speed on the highway and then it could keep up once the load dropped and you were cruising.

Personally I like the idea alot. As a daily commuter a car like that would be perfect for me (6 miles - I would bike to work, but where I'm at between the weather and the crapy roads it would be a death sentence there's no way for anything but a few months out of the year.). Give it some black thin-film solar cell racing stripes and paint the rest of it blue and I'll take one.

I'm interested in anything that can do it completely without petrolium based fuel. As a back-up source like the Volt I can deal with. I want to be able to collect it myself and give the oil companies and countries the big double middle finger.

Re:Hydrogen? Carbon?

[cplusplus]

Water molecules also have a tendency to clump and fall to the ground. Carbon dioxide molecules don't. A massive increase in precipitation would probably affect things in detrimental ways.

Re:Hydrogen? Carbon?

[h2_plus_O]

You fuel at a station, but instead of just filling up with hydrocarbon (like we do now), you also give back the carbon that your car's been storing.

...so if you're going to reform hydrocarbon fuel to yield hydrogen, why do that on board the vehicle instead of simply having the vehicle take hydrogen as its fuel? If carbon capture and sequestration is anything but a pipe dream to begin with, it will be a damn sight easier to engineer without the added constraints of having to fit onboard a motor vehicle.

Re:Hydrogen? Carbon?

[apoc.famine]

Outside my house it is currently 21 degrees F. When I discuss with my students the potential of using hydrogen as a clean fuel, as it releases only water vapor as a byproduct, they generally realize that there is another issue with it other than greenhouse gas emissions. In a good portion of the world, there is this thing called winter. A massive increase in water vapor on roadways when the temp is below freezing is not necessarily a byproduct that many people think of when debating a hydrogen infrastructure.

Not to say that it can't be overcome, but it's not something that most people think of.

Re:What, nobody's thought of the obvious?

[mlts]

Another thing that the hydrogen/fuel cell "economy" is missing is the fact that there are virtually zero hydrogen fueling stops. The cost to put in hundreds of thousands of H2 pumps and the infrastructure to haul the liquid H2 to the corner gas station will be enormous.

Electric cars? Got a 120VAC or a 240VAC outlet? Its not that simple because 120VAC won't charge a car's batteries quickly (though its viable for overnight use.) However, adding circuits and having people standardize on a charging mechanism for cars when parked in parking lots is a lot simpler than the tanks, transportation, and specialized fuel dispensing systems needed for hydrogen. The technology for bringing electricity to every car in a parking lot does exist -- Many Alaskan shops and businesses have plugs for customers to plug in their engine heaters because at -20 (F) and below, the oil starts solidifying in the car.

I look forward to electric cars. In a lot of cities, 100% of power comes from wind and solar, so its not shifting the carbon to another source. Slow charging can be done at home, fast charging (especially with supercap batteries that can charge very quickly) can be done at the normal filling stations, so the existing gas stations won't be losing market anytime soon.

I don't look forward to a hydrogen economy, and the bugs and hassles a vastly new fuel infrastructure will bring with it. Not to mention the fact that someone has to pay the cost of sinking the H2 tanks underground in tens of thousands of gasoline stations... and that will end up being the customer.