Video: GM's Hy-wire Hydrogen Fuel Cell Concept Car

The more I read about Hydrogen, the less impressed I am over it.

Petroleum takes less energy to extract from the ground then the energy that the result produces. The same goes for wind mills and highly efficient solar panels. They'll produce more energy over their lifetime then the energy that went into making them.

Hydrogen doesn't exist in a pure form on earth. It's so lite that it literally floats off the planet and into space. Because of this, you have to make hydrogen. Currently, the best process to make hydrogen is electrolysis. It takes as much energy to split water into hydrogen and oxygen as you get back when fusing them together; a net result of zero.

As with all electrical processes, you will always loose energy to heat, so really you're going to loose energy. Also, there is the shipping infrastructure of hydrogen to take in account as well; again, a loss.

Battery and capacitor technology is the best and most sustainable solution for the future of our transportation system.

I don't think hydrogen will be practical until we learn how to harvest hydrogen. Remember our solar system has lots of frozen and liquid hydrogen on other orbiting planets!

Hydrogen is an energy storage medium - just like batteries, and even just like fossil fuels.

The only difference is that we have abundant water and ability to generate electricity from renewable means (solar, wind, tidal, geothermal, etc). Same cannot be said of fossil fuels.

To use H2 you need abundant energy. To do it cleanly it needs to be non-carbon releasing generation.

First you need to split water

Second to store it you need to either compress it or cool it to very low temps.

Both use energy and if you can only get back the energy you put in your still on the losing side. No process is 100% efficent anyway.

OK so that's the bad. Now the good.

ICE are at best 30% efficent. Fuel cell stacks have promise to double this.

If you produce and compress H2 with non-fossel fuel electricity then no carbon is released.

Hydrogen is just a storage medium. Current batteries are not suited for the large amounts of energy we need for transportation. If any of those magical super capacitors ever pan out or someone decides to try a fly wheel, then maybe hydrogen will not be needed. But I'm guessing it will still be developed. We can have both. Yes making H2 is energy intensive, but is it any more intensive than if everyone plugged in their EV? What if they produced methane from some bacteria and made hydrogen from that?

Anytime you convert energy from one source to another you loose energy.

So if you use energy to convert electricity into Hydrogen and then back into electricity you will loose a significant amount of energy versus using electricity and storing it in batteries.

There are losses transporting electricity and in battery charging. So same basic source, electricity, and you still have losses.

I wasn't clear in my meaning in my last post, the biggest loss in hydrogen usage is the energy cost of compressing or cooling it for storage. This energy is just lost as you don't get it back. Compare that to pumping a liquid fuel into a vehicle fuel tank which uses pennys of electricity. It gets even worse if that claim that using cryogenic storage means you lose some of the fuel through boil off giving 100% loss of the energy that produced and cooled that part of the hydrogen. Not Very Good.

I hold out hope that some of these problems will be solved. If you can produce hydrogen in an efficent way and if fuel cells are made to be much more efficent than an ICE then the energy cost of compressing the hydrogen might not be a problem.

I can't see a battery car ever being able to be charged fast enough and have the range to drive cross country. The massive power input needed for a quick charge makes for a massive electrical infrastructure challenge. Inductive charging while driving, thought just popped into my head but probably wouldn't work.

Anytime you convert energy from one source to another you loose energy.

In practice, possibly. In theory, no. It's all relative, nor necessarily very meaningful.

So if you use energy to convert electricity into Hydrogen and then back into electricity you will loose a significant amount of energy

Really? How much?

versus using electricity and storing it in batteries.

Really? How much?

what ever the storage method capacitor, battery, or fuel cell, the energy to charge it will still need to be generated. After oil there will be far fewer motored vehicles. Our lives are about to change., Local and sustainable, with world wide networking, for idea exchange, and to avert any negative organisations rising to arms..,

MIT estimated the conversion of electricity to hydrogen stored around 40-45% of the energy potential. They predicted it would be possible to achieve 60% eventually. That means the best case scenario is you throw away 40% of the energy to store it.

Then there is the efficiency of the conversion of hydrogen to produce power (work). Fuel cells are around 30% efficient now with a lot of improvement possible, up to perhaps 60%.

Then there are issues dealing with creating and distributing the hydrogen. Hydrogen needs to be extremely highly compressed to store enough power to provide decent range; that compression can use a surprising amount of energy. Because of its small molecular size there are all kinds of problems dealing with hydrogen; tolerance that are ok for air are way too loose to contain hydrogen. So as you can see the energy conversion can be very lossy and problematic.

Storing electricity in batteries on the other hand is relatively efficient, and the electricity is ready to be used (unlike hydrogen which has to undergo a inefficient conversion). With batteries you aren't switching between two entirely different mediums like you are when dealing with the electricity to hydrogen to electricity conversions. You are using electricity throughout the whole process, which makes it so much simpler and easier to optimize as an effecient system.

There is no way that an electric-hydrogen-electric system can avoid a lot of lost energy.

Electric systems on the otherhand are simple by comparison. We can produce systems and phase in incremental improvements as better batteries and other improved components are improved.

With batteries/capacitors, the problems that need to be solved are trivial compared to developing an entirely new hydrogen based energy system.

Hydrogen may be the best answer in the longer term, but not using the methods available to us in the near term.

There's significantly much more to consider than just the losses in conversion or refueling. Both of these points have been touched on in the previous comments but here they are again:

1. Whatever energy source we end up using to replace petroleum needs to have the ability to be replenished rapidly. "Magic capacitors" would be great but we don't have them. Electric cars make great city cars but they're useless cross-country.

2. This new energy system really needs to be a renewable resource. Saying petroleum is more efficient is really irrelevant for this reason.

Ya batteries are soooo easy, that's why the tech is relatively unchanged since they were invented That's why my cell phone dies in a day. Or I can use my laptop for 2 hours.

There are other and more energy dense ways to store hydrogen than in it's diatomic state. But hey we are all arm chair scientists here right? Let's just continue with thinking what ever we want.

MIT estimated the conversion of electricity to hydrogen stored around 40-45% of the energy potential. They predicted it would be possible to achieve 60% eventually. That means the best case scenario is you throw away 40% of the energy to store it.

According to this article, it's already at 80% at low flow rates, and will be at 75% at higher flow rates in the near term.

http://www.greencarcongress.com/2006/09/quantumsphere_f.html

From what I've read about batteries is, they store about 80% of the potential. Ultra-capasitors store even more. If current batteries are already +20% more efficient then the max possible use of hydrogen; it doesn't take a genius to realize it's wasted.

The numbers that I have seen well to wheel efficiency, originating from the European Fuel Cell Forum (which does NOT advocate hydrogen fuel cells) is that H2 fuel cells from electricity generation to wheel are 25% efficient with electrolysis, while the same from elect. generation with battery storage to wheel is around 90% efficient. And remember these are folk that would ordinarily want to sell you on fuel cell technology but for environmental reasons are advocating an "electron economy".

Capacitors are incredibly efficient at storing power, potentially well up to the 95% range. The only losses are induction losses from "forming" the capacitor and heat, from normal electrical resistance. Batteries can easily store well over 80-85% of their input energy, which is very good.

Compare that with a best case plug to wheel efficiency of 40-45% for hydrogen.

Overall, a lot of this automotive application development is recent. Batteries in particular have had little development specific to automotive use. All automotive batteries used currently are repurposed power tool batteries or laptop batteries.

When industry re-tools for large automotive specific batteries designed for volume production, it will be a much improved situation performance and cost-wise.

But if GM can keep attention on their work with hydrogen FC and flex-fuel ethanol/gasoline cars, they will not be pressured to do anything with plug-in hybrids. That way they don't have to do the messy work of designing electric motors & battery systems and show how far behind Toyota and others they are. They can claim technical superiority while selling us the same dreck they do now.

Except GM did have the first EV, so Ya I suppose they know nothing about electric motors or battaries.

Even if battaries are designed specifically for cars, they still are not up to speed with current needs. If they were, our laptops and cell phones would last for days.

GM did have the first EV

Under what criteria?

http://inventors.about.com/library/weekly/aacarselectrica.htm