Fuel Cells for Power Generation

[Bosun Higgs]

Isn't it ethanol that's produced from plants, for bio-fuel?

Certainly most ethanol I come across is produced from plants by the action of yeasts , and I believe it's ethanol that is produced where they have chopped down rainforest to grow bio fuel crops as in Brazil.

 

[Bobobolinsky]

My questions are, are the cells seviceable, can spare diaphragms be obtained, if they are poisoned? At what cost?
Have they got any plans for an LPG version?

 

[TomC]

It's great to log back in and see so much discussion on the subject.

I've been busy all afternoon but I shall endeavour to answer all your questions tomorrow morning.

As expected the most common issue is the price. They are an expensive option and the alternatives (solar, wind, portable generator) are a lot cheaper. However, as stated in a previous post, you gain extra benefits such silent running, "install and forget", no maintenance, etc.

Thank you for all your questions and comments.

Tom

 

[MASH]

Let's not forget, nor allow the single-issue fanatics to convince us otherwise, that both CO2 and oil/hydrocarbons/coal/gas and their products are all natural organic bio products - created from biomass after all - ie compost. As if being natural or bio has anything to do with being harmful/harmless/"good"/"bad"...Belladonna is natural and bio, as is a smallpox bacterium.

There's a lot of emotive twaddle talked about this natural bio eco CO2 business and little of it is good science.

On which subect, methanol burns easily? It does? You can put matches out in a bucket of the stuff, that's not my idea of burning easily. Its a damn sight less flamable than pertol, and who gets twitched about that?

Methanol corrodes metal? I can't say it doesn't because I'm not an expert chemist, but the concept of alcohol corroding metal is something I find hard to swallow. More info on that please!

Finally, what is the impurity that damages the fuel cell? Water by any chance? Because Methanol is highly hydroscopic and any exposure to air will cause it to absorb moisture, thus the fuel has to be kept hermetically sealed, it's not a matter of glugging it into an atmospherically vented and grubby tank as we do with our (natural biologically produced) diesel. Fuel storage is not going to be simple I suspect.

 

[bbg]

Fuel storage

Because Methanol is highly hydroscopic and any exposure to air will cause it to absorb moisture, thus the fuel has to be kept hermetically sealed, it's not a matter of glugging it into an atmospherically vented and grubby tank as we do with our (natural biologically produced) diesel. Fuel storage is not going to be simple I suspect.

In some respects fuel storage is simple - at least from the point of view of keeping it clean. The fuel comes in sealed plastic containers. When one cartridge runs out, you take the screw lid off the next, but even that is sealed. I think you could turn the thing upside down, with the lid off, and nothing would come out. To plug it into the fuel cell there is another cap which screws onto the cartridge, and that cap has a tube poking down, which goes into the cartridge and draws up the methanol.

The only problem with fuel storage is finding a place to keep the plastic containers.

 

[rotrax]

I've said this before but here goes.

Methanol burns with an invisible flame. It also burns damned hot, it catches fire pretty easily, it corrodes metals and has a particularly aggressive dislike for aluminium.

So. fuel cells are good when the sun is not shining and when a reliable power source is required. Perhaps then in bad weather? So, you want me to take this potentially dangerous liquid and funnel it into a fuel cell on a pitching boat?

There are a few kinks to iron out I think, let alone £5 / litre for fuel!

Fuel will have to be stored in the original containers to ensure it stays 100% pure - how about making that container plug into the fuel cell ( if it doesn't already that is! )

For £1750 I can line the most of the deck with solar cells, double or even treble the size of the battery bank and reduce the risk of ever needing such a power source.

For £5k I can get a pretty slick, on demand 220v diesel generator with water cooling

99.5% methanol costs about £5. Its a hell of a leap to £50 for 5l!

Hi,As a long time motorcycle racer in diciplines where methanol was the fuel I must disagree with your statement about methanol corroding aluminium.It was always a requirement to drain the carburetor after use otherwise a white sediment would form-probably an oxide-but it was never a significant problem in the real,as opposed to theoretical world.A bigger problem was white streaks on paint.That is why Speedway bikes have plated frames.One of methanols major advantages is that a bucket of water will put out a methanol fire-thats why the Yanks use it in Nascar racing.I used three 205 litre drums every year.The Customs and Excise watch it carefully in the UK and it is nearly always priced with fuel duty,and we all know how much that is!The price in Dollars was realy good,but it is about £8.50 for 5 litres at a motorsports supplier.It is hygroscopic and absorbs water.This is not too much of a problem in an internal combustion engine as below a certain level it can be benificial for cooling.Record attempts at Brooklands were often made using a half pint of water in each gallon of methanol.During a visit to the Czech republic when it was minus 16 degrees C the guy I was interviewing was showing me his race bikes in a barn.My teeth were chattering.He poured about two litres of methanol into a drain tin and lit it.In a few moments it warmed up nicely.From my experience it burns significantly cooler than petrol and requires about 20% more by weight to combine with the available oxygen than petrol. You are right about not seeing the flame-in bright sunlight it is invisible.Otherwise it is the same as an alcahol stove.I always used methanol instead of meths in the burner of our fondue set-I had a supply in the workshop for the bikes.The metal parts are still fine after 30 years.The price quoted per litre is way out of touch.A motorcycling freind is Operations Director for a pharmasutical company.They use methanol in a major industrial procedure by the thousands of litres.It must be as pure as you can get it.After processing they get a duty rebate on the recovered methanol. They pay a fraction of the quoted price than the fuel cell makers own.Draw your own conclusions.

 

[Gwylan]

Fuel cell - what might it cost?

Feel that Tom has a hard sell for this or any other unit at these prices.

I saw a unit at the Boat Show and was really impressed with it - would like one, but £3000 and being 'had' for the fuel for ever more is another matter.

The capital price could be swallowed, or justified to the domestic ways and means committee, if the cost of the fuel was reasonable.

Right now the temptation is to stick with the alternator and run the engine for an hour or two more.
I know it does not serve the engine too well - but £3000 buys a lot of engine maintenance and a few litres of diesel over a few seasons.

The green brigade ought to think about the environmental cost involved in making solar panels too!

What would I pay?

Well if the 3 year cost or 250 running days @10 hours a day was upto 30% dearer than say 140 watts of solar panels?
Anyone got a calculator?

 

[bbg]

Fuel will have to be stored in the original containers to ensure it stays 100% pure - how about making that container plug into the fuel cell ( if it doesn't already that is! )

On the two brands I am familiar with, the container does plug into the fuel cell. You don't add fuel - you change fuel cartridges.

 

[fergie_mac66]

I see that these are designed for 12v systems. My electrics are 24v, do they do these or would I need 2 x 12v in series? Very expensive if even possible, and I suppose, twice the fuel consumption @ £3.65/litre (based on 2x10l containers for £73).

What is their expected service life? Are they serviceable (user-serviceable) or do you just have throw it away at the nend of its life?

Output/£ purchase/running cost doesn't seem to stack up against solar (ok it will still work when its dark!). I could have quite a large solar array for the same price and then free power for 20 years when the sun is shining.

I would be possible to get a voltage doubler made up .

Feb PBO has a simple ac voltage doubler circuit

but as 12 volt is dc would require a small switching unit between the 12dv and the voltage doubler. You would still only get same wattage from unit just half the amps and you would lose perhaps couple of watts in heat so if you needed 60 watts from fuel cell you would have to go for a 70 watt unit to cater for the loss. Would not cost much to do a lot cheaper than 2 fuel cells!

 

[TomC]

As promised I'm going to try and answer the questions posted:

Lifespan: As someone has previously stated, our FAQ says that we've had units back with 4,000 hours that have started to have problems.

Take the example that was posted: "65 watt model in use by a liveaboard 365 days a year and generating for ten hours a day". The unit would have 3,650 hours logged. However, if you were to upgrade to the 90W model, you would only be running for about 6.5 hours a day. At the end of the year you would then have 2,372 hours logged, thus increasing the lifespan.

It was also asked if they can be serviced to increase the life. If the stack has been damaged, then no. If the unit is outside of warranty you may open it up and spot something you can fix yourself.

According to the manufacturer, the stack can be damaged due to "chemical impurities such as sulfur, chlorine, sodium, and the like"

 

[TomC]

There has been some concern as to the safety of having methanol on board and having to refill the fuel cell. bbg has correctly answered this for me, thank you. The containers are sealed and you can turn them upside down with no spillage, even when partially used. To change the fuel, you simply unscrew the old one and screw on the new.

The containers are made from high strength plastic and have been put through numerous safety tests. The cost of the methanol is partly down to this container.

I do appreciate that methanol is available elsewhere a lot cheaper. I do hope to see the price fall to encourage more take up.

 

[TomC]

I was also asked for details on the fuel cell used for the fastnet:

We were sailing a Sigma 41 and installed the fuel cell, a 1600 (65W) in the navigators bunk. (it has since been relocated in the cockpit locker)

We were powering:
PC: ~2A for 24h
Monitor: ~3A for 12h
B&G: ~0.5A for 24h
Nav lights: ~2A for 6h
Plus others such as AIS, VHF, cabin lights, water pump etc.

Due to the high draw of the PC and monitor (and people forgetting to turn the monitor off) the 65W on board wasn't quite enough and we did have to run the engine once or twice. However, it was quite a tough race so more time was spent below with lights on.

We've since replaced the PC with a netbook so power consumption has dropped considerably.

 

[TomC]

Three related questions to the manufacturer if I may please (in order to judge when the moment to adopt fuel cells might arrive):

1. what is the overall energetic efficiency of the process? Ie how many Joules / kg of fuel used do we get as electrical energy compared to the number of Joules which one would get were the fuel to be burned?

2. How does that compare to a modern diesel engined generator, lets say a 5kW one? (ie does one have to carry more or less volume of fuel for the same amount of elctrical energy?)

3. What do you think is the likely improvement we can expect over time? (Please say if the improvement, if any, relies on other fuels such as hydrogen becoming availbale).

I don't have the exact figures to hand, so rather than post incorrect ones I shall find these out and post back at a later date.

 

[Ninpo]

This is an intereting thread

So far we've had reasonable discussions from both sides

 

[pvb]

We were sailing a Sigma 41 and installed the fuel cell, a 1600 (65W) in the navigators bunk. (it has since been relocated in the cockpit locker)

Was that the Sigma 41 owned by "yachting enthusiasts Tom and Karen Sperrey" who were apparently on your Boat Show stand according to this press release?

 

[pvb]

Lifespan: As someone has previously stated, our FAQ says that we've had units back with 4,000 hours that have started to have problems.

So what does that mean, Tom? If I buy one, can I expect it to last much more than 4000 hours?

Take the example that was posted: "65 watt model in use by a liveaboard 365 days a year and generating for ten hours a day". The unit would have 3,650 hours logged. However, if you were to upgrade to the 90W model, you would only be running for about 6.5 hours a day. At the end of the year you would then have 2,372 hours logged, thus increasing the lifespan.

I understand your theory, but the 90W model is £4615. Would it last more than 4000 hours? If not, £1+ an hour, plus fuel, seems a lot to generate only 7.5A charge.

 

[TomC]

pvb, yes, that was the boat. The same fuel cell was also used during the ARC last year.

 

[TomC]

The fuel cells do last more than 4,000 hours. However, we can't guarantee this so we advise customer to base calculations on this.

For a live aboard running continuously this will mean the fuel cell will reach this value fairly quickly. For someone who uses their boat only for a few weeks during the summer then it'll last much longer.

At the moment, as you say, the cost is high, and if this is the main consideration then solar or wind would probably be the better option. Fuel cells become an option when the other parameters such as small, silent and always available become more important.

 

[pvb]

The fuel cells do last more than 4,000 hours. However, we can't guarantee this so we advise customer to base calculations on this.

OK, so 4000 hours and then it's into the skip is it? Or repairable?

At the moment, as you say, the cost is high, and if this is the main consideration then solar or wind would probably be the better option.

What's your prediction on future pricing? Is it likely they'll be, say, half the price in 2 years' time? Are other makers looking at leisure fuel cells - all the ones I've seen so far have been Efoy units.

 

[bbg]

MaxPower also make units, but I have heard the internals of Efoy and MaxPower are made by the same company. Certainly the fuel cartridges are standardised between the two makes.