Why did fuel cell technology seemingly disappear as a possible alternative to gas/petrol in vehicles?
In: Technology
Hydrogen fuel cells are a type of chemical battery. They produce electricity by separating hydrogen and oxygen with a membrane. When allowing them to come together that membrane collects electrical energy from the reaction.
You can allow the product of the reaction (water) to escape via exhaust, and refill the fuel cell with hydrogen and oxygen when it runs out (refillable), or you can collect the water and use electricity to re-separate it into the gases to be reused (rechargable battery).
The first problem with hydrogen/oxygen batteries is their energy density. A fuel cell with the same electrical specs as a lithium ion battery, for example, weighs many times more. That means a vehicle powered by fuel cells will weigh more and therefore require more electricity to go the same distance as one powered by lighter, more efficient batteries. If the electricity comes from fossil fuels, the fuel cell has a larger carbon footprint per distance traveled. IIRC fuel cell vehicles powered by the grid had similar or larger carbon footprints per mile/km than hybrid vehicles.
The second problem is the storage of hydrogen gas. Hydrogen is the smallest and lightest atom. It’s so small that it can easily escape any container by passing directly through the material of the walls. That makes it impossible to store a fuel cell in a “charged” state.
The third problem is safety. Hydrogen and oxygen each react violently with each other and practically everything else. Keeping them next to each other, separated by a thin membrane, in a collision prone vehicle, is not a great idea.
Hydrogen infrastructure is far more difficult to create than charging points both in terms of expense and uncertainty.
Hydrogen has a *lot* of problems, most of which stem from the fact that as the smallest and lightest element, it is very difficult to effectively contain and transport. It simply leaks out of *everything*. Not to mention the fact that it’s under pressure and explosive. That means you can’t have the kind of production and distribution network that oil and gas have: no continent-long pipelines or large tractor-trailer tanks delivering hydrogen to fueling stations.
Instead, each individual station would have to have its own production facilities to produce hydrogen more or less as needed. That’s a huge added expense for fuel stations, who usually want nothing to do with *making* stuff and only want to buy fuel in bulk and then sell it to consumers. Also, hydrogen production is costly in terms of energy. Sure, water is everywhere but breaking it apart to get the hydrogen is hard. It’s exactly *because* of that strong bond that you get so much energy *out* of combining hydrogen and oxygen, and you must by the laws of thermodynamics put more energy *in* than what you get *out* to reverse that reaction.
That’s all well and good for plants and other natural processes because they generally go about it slowly. There’s lots of sunlight available for plants to do just a little bit at a time, over a very long time. But that slow, inefficient process can’t keep up with our needs. Instead, we have to pump a *lot* of energy into a *lot* of water all at once to get a *lot* of hydrogen quickly. That creates its own energy production and distribution problem.
In any case, the main benefit of the hydrogen fuel cells was that they powered an electric generator, and *that* provided power to electric motors. This can be very efficient because you can keep the engine running at its most efficient speed and charge a battery when you need less power to move and drain the battery when you need more power to move. Except…that’s what gas-electric hybrids do. So, the efficiency of gas-electric hybrid cars is rapidly approaching that of a hydrogen fuel cell, which somewhat negates the need for them. At the same time, battery technology is improving drastically so fully-electric cars are totally viable and more affordable, also negating the need for hydrogen fuel cells. And both of those alternatives use the production and distribution networks already in place in just about every country.
It was never viable and it was just being used by old technology companies to divert your attention from the much more practical battery electric vehicles.
It didn’t. [South Korea is making it a big priority](http://www.koreaherald.com/view.php?ud=20190117000468). Toyota and Honda make Fuel Cell cars. However, it isn’t worth selling cars in markets without Hydrogen fuel stations.
There is kind of a chicken and egg problem in selling H2 cars and making H2 fuel stations in a market. It’s not worth having a dealer infrastructure to sell cars if there are no fuel stations, and it isn’t worth building fuel stations if there are no cars in the market.
The main thing holding fuel cell cars back is economics.
One of the big issues with the hydrogen economy is how we actually get usable hydrogen. It’s extremely abundant on Earth, but it’s mostly locked up in other compounds. You can either extract it from fossil fuels, or by electrolysis of water. Which are both costly and energy intensive. So it doesn’t really solve any of the problems it seeking to address. Conventional internal combustion and battery-electric technologies are still far more practical.
There’s also the added issue of storing and transporting bulk hydrogen. It’s explosive for one. It also has a tendency to leak out of its container, since the atoms are so small everything is porous to it. So you need really thick, heavy steel bottles to safely store it in. Whether at a filling station or in a car. Making the vehicle heavier. Petrol and electricity don’t have this problem. They also have existing infrastructure in place.
In order for hydrogen fuel cells to be feasible, there would have to be some major disruptive technology that drastically reduces costs.
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