Hydrogen propulsion

strakeryrius

strakeryrius

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A few days ago I watched a re-run of Top Gear, the one where they gave out all the awards for 2008. Their car of the year was this one. Honda Clarity

Basically they feel that the technology will change the face of motoring - its the first electric car that is viable as it will allow drivers to continue motoring in the way that we already do, rather than have to change our habits to suit our vehicles in the way of conventional electric cars. It'll do 0 - 60 in sub 10s, and over 250 miles on a tank of hydro-gas.

I've been pondering on this for a few days and got to thinking how long it might be before we see an application of the technology that is viable in boats. The green-blue guys would be ecstatic as the only emission is H2O, A lot depends on how efficient the engines are when fuelled by H.

Also, after a bit of pondering I came up with this. The generally accepted idea of space exploration is that to go inter-stellar we would need our space ships to be able to skim the atmosphere of gas giants and scoop up H from the atmosphere to use for fuel (after suitable filtration). Now what if that could be brought to boats - skimming up H2O for free, stripping out the H to use for fuel, and producing only H20 and the by-products of the filtration as emissions waste. I can see how, if it can be made to work, it could open up whole new vistas in boating.

What does the panel think - can we revolutionise boating with this technology?
 
Breaking the bonds in H2O to create hydrogen requires a great deal of energy, so you'd still need an engine to create the electric to run the onboard electrolysis plant
 
No you wouldn't. The car is an electric car, but the huge difference with previous electric cars that you had to plug in to charge up is that the elctricity is generated on-board - by the Hydrogen fuel cell. The Hydrogen cell creates the power that drives the electric motor. The electric motor is what drives the boat in the same way that it does in the Honda, but if it could be set up so that some of the energy could be used to break apart the H2O it would be viable. It would have to be something akin to an alternator, driven by the engine/belts as it spins. A lot would depend on the efficiency of all the constituent parts to achieve this.

Even without that, just having a boat driven by electric power (created by the fuel cells) would have so many other benefits, not just the emissions - think how quiet they would be. The car is only a "compact" so is only big enough to carry one engine, but that outputs 134 bhp, so on a boat with more room you could have bigger cells, allowing bigger engines and multiple outputs.
 
As I said a lot would depend on the energy efficiency of the constituent parts. They are selling the H-gas at the fuelling stations in California cheaper than petrol, so it must be possible to free up H from its normal compound state fairly cheaply. Maybe its a case of finding the right compound to liberate it from?
 
There are not many ways to create hydrogen, and electrolyis of water is the usual one. You wouldn't be able to fuel a boat by scooping up water, as the amount of energy required to create an equal amount of hydrogen to power the boat is just not feasible, other wise you'd have a perpetual motion machine. You'd have to fill up with hydrogen from some sort of supply, just like diesel or petrol, and the amount of energy required to create the hydrogen from powerstations, doesn't make a great deal of sense, unless the powerstation is nuclear, or hydro etc.
 
You cannot create enough hydrogen from the engine, to make it a perpetual device

You will always have to 'fill up'

Basic chemistry and physics.
 
Maybe not. It would be different in boats to cars. Think how long your average boat sits doing nothing most of the time, and then work out how much H it could produce by solar or wind power in all that time, and I reckon that for sub-40' boats this could become a serious alternative power source.

As I mentioned even in this small car it can carry enough H to power a motor that produces 134 bhp for 250+ miles. Scale up those figures for a 40' boat, with much larger tanks and room for larger engines and we may not even notice the difference in practice.
 
The Hydrogen would be working as a (very) inefficeient battery. You can top up your battery with a windvane and a solar panel, but if you're using it to drive the boat, it won't get you very far.

I can't see that it has a future, myself, because batteries are more efficient, and getting better all the time. Have you seen this one: http://www.teslamotors.com/
 
Massive problem that has not been yet solved is how to store the hydrogen, as it is the smallest molecule. That is why the current fuel cells use petrol or methane to provide the H2. BMW have some 7 series H2 cars for demo, but need refuelling daily, and consumption is much worse than petrol as the power generated is only about 60% of petrol engine. Need to go a long way to beat diesel.
 
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you'd need a very small low powered engine to make the equations work. Why not use a sail instead?

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Brendan, that's a brilliant plan, I'm going to invent a sailing boat that you give a little shove to on a still day, and the apparent wind then keeps it sailing.

I'm gonna be rich I tells ya

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The Hydrogen would be working as a (very) inefficeient battery

Not in this car - it produces 134 bhp, allowing speeds of 100 mph and a range of 250+ miles. This is a whole new generation of both powerful electric motors and efficient fuel cells.

You're not using the wind vane/solar cells to top up the batteries - there are no batteries to top up - you use it for electrolysis to create the hydrogen to fuel the cells.
 
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That is why the current fuel cells use petrol or methane to provide the H2.

That's the point - this is a whole step forward - a whole new generation of fuel cell technology. As I've said - range of 250 miles and cruising speeds the same as petrol/diesel cars.

That's why this is such a big leap forward - we can change over to using electric cars but carry on motoring in the same way and with all the same habits as we have always have - fillup with H at a filling station every couple of hundred miles, turn the key and go, no plugging in to recharge batteries as it has none. It generates the power on the fly from the H-cells as the motor demands it.

The application for boats may mean that with the improved technology - which will only get better with time - is that we may eventually be able to run our boats much more cheaply than we do now - if the H-generation hardware can be made to work.

I agree this is still a long way off, but what we are seeing with the car may be the "genesis" of how we power our boats in years ahead - especially after the oil has run out.
 
There are two main reasons why the clarity is not yet commercially available to buy (you can only lease on a short term basis and in california alone).

Availibility of the hydrogen (do you want a controlled substance sitting beneath the street in a ungurded petrol station - AlQuada would love that)

Its volatility. Remeber the Hydrogen Bomb? Still work to be done to make it eay to move/transport to fuel and to make sure its 100% safe.
 
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You're not using the wind vane/solar cells to top up the batteries - there are no batteries to top up - you use it for electrolysis to create the hydrogen to fuel the cells.

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You've misunderstood me - I meant the idea of storing power for later use is like a battery. i.e. your solar panels and wind vane are generating electricity. You want to use this electricity to create a source of power you can use for propulsion later.

An assumption you've made, but not stated, is that using the electricity to split water into Hydrogen and Oxygen, and then using the Hydrogen in an internal combustion engine is more efficient than simply storing the electricity in a battery. This assumption is wrong.
 
I think that one point that you missed is that a car engine, although capable of delivering 134hp, very, very rarely ever delivers it because most of the time you only need a fraction of the power. Think.... do you drive around with your foot flat on the accelerator ALLthe time?

Boats , however, do require the power to be delivered close to maximum output for long periods.

Hence the 134hp , 250+ miles is a bit of a red herring.
 
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What does the panel think - can we revolutionise boating with this technology?

[/ QUOTE ] Nothing will happen until they can find a way of charging four times as much money for a marine version and fortune to service it. Oh, and don't forget expensive parts - you need very expensive parts.
 
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