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Hydrogen Fuel Cells – The Basic Facts

One of the more exciting vehicles that’s scheduled to come to Australia at some unspecified date in 2019 is the Hyundai Nexo – one of the vehicles recently awarded the Best in Class for all-round safety by Euro NCAP.  This vehicle combines regular batteries with hydrogen fuel cell technology. Three vehicles made by major marques have been designed to run on HFCs: the aforementioned Hyundai Nexo, the Toyota  Mirai and the Honda  Clarity.

Toyota Mirai concept car

Hydrogen fuel cell technology is another option for overcoming our addiction to fossil fuels (the other two are biofuels and electricity).  But what is hydrogen fuel cell technology and how does it work?  Is it really that sustainable and/or environmentally friendly?  Isn’t hydrogen explosive, so will a car running on hydrogen fuel cell technology really be safe?

OK, let’s start with the basics: how does it work?

Diagram of a hydrogen fuel cell

A hydrogen fuel cell (let’s call it an HFC for short) is designed to generate electricity, so a vehicle that’s powered by HFC technology is technically an EV.  A chemical reaction takes place in the cell and this gets a current going, thanks to the delicate balance between positive and negative ions (all chemistry is, ultimately, to do with electricity). How is this different from a battery?  Well, a battery uses what’s stored inside it but an HFC needs a continual supply of fuel.  Think of a battery as being like a lake, whereas the HFC is a stream or a river.  The other thing that an HFC needs is something for the hydrogen fuel to react with as it passes through the cell itself, which consists of an anode, cathode and an electrolyte solution – and I don’t mean a fancy sports drink.  One of the things that hydrogen reacts best with and is readily found in the atmosphere is good old oxygen.

Naturally, there’s always a waste product produced from the reaction that generates the charge. This waste product is dihydrogen monoxide.  For those of you who haven’t heard of this, dihydrogen monoxide is a colourless, odourless compound that’s liquid at room temperature.  In gas form, dihydrogen monoxide is a well-known and very common greenhouse gas, and it’s quite corrosive to a number of metals (it’s a major component of acid rain).  It’s vital to the operation of nuclear-powered submarines and is widely used in industry as a solvent and coolant.  Although it has been used as a form of torture, it’s highly addictive to humans and is responsible for hundreds of human deaths globally every year.  Prolonged contact with dihydrogen monoxide in solid form causes severe tissue damage.  You can find more information about this potentially dangerous substance here*: http://www.dhmo.org/facts.html

For the less alarmist of us, dihydrogen monoxide is, of course, H2O or good old water, like the stuff I’m sipping on right now on a hot summer day.  Yes – that’s the main waste product produced by HFCs, which is why these are a bit of a hot topic in the world of environmental motoring.

OK, so air goes in one bit of the HFC, hydrogen gas goes in the other, and water and electrical power come out of it.  The next question that one has to ask is where the hydrogen fuel comes from (this question always needs to be asked: what’s the source of the fossil fuel substitute?).  The cheapest source of hydrogen gas as used on HFCs is natural gas, which is, unfortunately, a fossil fuel.  So are some of the other sources of hydrogen gas.  However, you can get it out of methane, which is the simplest type of hydrocarbon.  Methane can be produced naturally by bacteria that live in the guts of certain animals, especially cows.  Not sure how you can catch the methane from burping and farting cows for use in making hydrogen gas for HFCs.  And, just in case you’re wondering, some humans (not all!) do produce methane when they fart.  It’s down to the particular breed of bacteria in the gut (archaea if you want to be picky – they’re known as methanogens).  They’re as common as muck – literally.  So yes, there’s potential for hydrogen gas to be produced from natural sources – including from sewage.  The other thing is that producing hydrogen gas from methane leaves carbon dioxide behind.  But this has way less effect as a greenhouse gas than methane, so that’s a plus.

If you’re currently feeling that HFCs might not be quite as environmentally friendly after all and we all ought to drive straight EVs, then I encourage you to do a thorough investigation of how the electricity used to charge EVs comes from. It’s not always that carbon-neutral either.  Heck, even a bicycle isn’t carbon-neutral because when you puff and pant more to push those pedals, you are breathing out more carbon dioxide than normal.  All in all, HFCs are pretty darn good.  The worst thing they chuck out as exhaust is water, and the hydrogen gas needed to power them can come from sustainable sources – very sustainable if you get it from animal manure and/or sewage, which also means that poop becomes a resource instead of a problem to get rid of.  They’re doing this in Japan – and they’ve also managed to get the carbon bits of the methane to become calcium carbonate, which sequesters carbon and has all sorts of fun uses from a dietary supplement through to agricultural lime.

Another plus about HFCs is that they are a lot more efficient than combustion engines.  A large chunk of the potential energy going in turns into the electrical energy that you want, which is then turned into kinetic (motion) energy by the motor so your car gets moving (or it turns into some other form, such as light energy for the headlights or sound energy for the stereo system).  Some comes out in the form of heat.  Combustion engines waste a lot of the potential energy in the form of heat (lots of it!) and noise (ditto).

The amount of electrical energy produced by a single HFC isn’t going to be very large, so inside any vehicle powered by hydrogen technology, there will be a stack of HFCs, which work together to produce the full amount of oomph you need. The fun part in designing a vehicle that runs on HFC technology involves ensuring that the stack has the oomph needed without being too heavy and working out where to put the tanks of hydrogen gas.  However, this isn’t too hard.

The other problem with manufacturing HFC vehicles is that the catalyst inside the cells is expensive – platinum is common.  This is probably one of the biggest barriers to the spread of the technology, along with the usual issue of nobody buying HFC vehicles because nobody’s got an easy place to get the gas from and nobody’s selling the gas because nobody’s buying HFC cars.  They had the same issue with plug-in EVs too, remember, and we all know how that’s changed.  However, last year, our very own CSIRO came up with some technology to get hydrogen fuel for HFC vehicles out of ammonia and they want to go crazy with this and use it all over the show.  This is exciting stuff and probably deserves a post of its very own, so I’ll tell you more about that another day.

I feel in the need for some 1,3,7-trimethylxanthine theine combined with dihydrogen monoxide in solution with β-D-galactopyranosyl-(1→4)-D-glucose and calcium phosphate, also known as a cup of coffee, so it’s time for me to stop and to wish you safe and happy driving – hopefully without too much methane inside the cabin of your car on long journeys!

*Some people in the world have far, far too much time on their hands.

9 comments

  1. Peter Carden says:

    A fun article and very informative.
    I also understand that the Csiro have patented their invention and now see Aust being the centre of the universe for hydrogen production – just hope they don’t sell it without royalties as they did with wifi.
    Cheers

    January 21st, 2019 at 1:20 pm

  2. Bill Nixon says:

    The only truly environmentally friendly form of transportation is sail power. Everything else creates something we don’t want. Sail powered tricycles might be the transport form of the future.

    January 21st, 2019 at 1:22 pm

  3. Pirthpall Sekhon says:

    Fantastic.
    You’ve made it simple and enlightening.
    Thanks

    January 21st, 2019 at 1:47 pm

  4. norbert kraft says:

    Natural gas is of course essentially methane once in commercial form. The problem of CO2 being a by product of hydrogen production from natural gas is being tackled in a very innovative way by the Australian company mineral developments [MIN] . This involves a complex bit of chemistry whereby the carbon part of the molecule is used to produce carbon fibre ; this stuff being stronger than steel and much much lighter is turned into railway wagons in place of traditional iron. This in turn means a life long [wagon life] saving in energy used to transport railway cargo [ currently iron ore ] and renders this form of hydrogen production much more environmentally sustainable.

    January 21st, 2019 at 2:13 pm

  5. ted Vause says:

    a fellow I know runs his vehicle on hydrogen gas derived from electricity &water which is generated as he drives

    January 21st, 2019 at 2:28 pm

  6. ted Vause says:

    hydrogen gas can be used to power vehicle by using electricity & water which is generated as you drive

    January 21st, 2019 at 2:31 pm

  7. Gary Brown says:

    Thankyou for clearing up how HFC cars work.

    January 21st, 2019 at 5:31 pm

  8. Jason says:

    While Battery Electric Vehicles (BEV) do source their electricity from the grid, that can be mainly coal or other fossil fuels, the same can be said for the manufacture of hydrogen. As the grid gets cleaner then the BEV and Hydrogen Fuel Cell Vehicle (HFCV) will get greener. Hydrogen manufactured by fossil fuels vs Lithium Ion batteries (of which a HFCV also has a battery).
    The BEV is a VERY simple design, there is the battery and there is the motor and there is the electronics to control it, and this means the dealer networks are worried because it means LESS servicing. A HFCV is a pretty complicated system, certainly not as bad as the Internal Combustion Engine (ICE) but still likely to require more servicing than the BEV, so dealers are probably more interested in that.
    The other aspect is efficiency. With the BEV you just put the electricity (hey, it could come from your home solar panels) into the battery and then take it out of the battery to drive the motors. Notice that part about your home solar panels, that’s right you can charge the battery at home, just like your mobile phone. Contrast that to the HFCV, you have to use electricity to make hydrogen (in a BEV you just put that electricity into your battery), then you have to use electricity to compress the hydrogen so that it can be stored (in a BEV you just put that electricity straight into the battery), then you need to transport the hydrogen to the service station (that’s right, you guessed it, the power to move the hydrogen could have been used directly in your BEV to move you, not the hydrogen), and then you need to use electricity to pump the hydrogen into your HFCV (again, that electricity could have just been put into your battery), and finally there is the chemical reaction that turns the hydrogen into electricity (isn’t that what we started with that we just put straight into our BEV?). Oh, that’s right, we got water as a by-product (the BEV has NO by-products, truely zero emissions).
    So who else has a vested interest in HFCV? You guessed it, the Service Stations and Fossil Fuel industry. With a BEV you just charge it at home (or where ever you park the car at night, more work needs to be done in that regard) but with the HFCV you have to drive to the Service Station, so if you like Service Stations then you’re good to go, but if you prefer to spend that time doing something else then BEV might appeal to you.
    How do I know? It’s because I drive a BEV. Haven’t been to a Service Station in more than 2yrs. Every single day my car has a full take of electricity. The costs have been hugely reduced (less maintenance, about 1/3 the cost of a petrol/diesel car in fuel. By the way, Hydrogen currently costs about twice the price of petrol/diesel, so really who wants to pay twice the price to refill? The car companies try to hide this by including it as part of the lease). BEV still have a long way to go in Australia, but HFCV haven’t even started, so if you think it is a problem to drive a BEV, then imagine the impossibility to drive a HFCV. There is a huge push for HFCV, I don’t understand why. Do some simple research and it just does not make sense to us consumers, it makes heaps of sense to the Fossil Fuel industry and to a lesser degree to the Dealerships.

    January 22nd, 2019 at 6:42 am

  9. Dave says:

    It is interesting how dangerous dihydrogen monoxide is as waste product being as it is usually only a carrier of pollutants. Certainly, a lot of deaths are caused directly by breathing in its liquid form and conversely, a lot of lives are saved by imbibing this liquid.
    If we use a chemical approach here we all will be able make more sense of this authors twist.
    dihydrogen monoxide ie di 2 and hydrogen chemically is H (getting where I am going here) and a monoxide is O.
    Yes, correct H2O (water to the average layperson).

    January 22nd, 2019 at 2:38 pm