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What is the take of CEans on this proposal for cheap renewable energy from aluminium and water?

The US company Trolysis claims:

Turn aluminum and water into hydrogen and electricity. Meet the new revolution in renewable energy.

I have some views on this but do not want to bias opinions here. What is the opinion of CEans on this claimed path breaking technology?

Sounds interesting but I doubt its efficiency. I don't think they have yet developed any breakthrough. Generally, there are many tech giants who are looking for such a solution. Given that the company and the technology have no backing of any of them as of now, I doubt their plans. 

Generally what we study is Aluminium is highly reactive to water. Scrap cans which we often say as Aluminium cans are not actually Aluminium but are alloys. They are already chemically treated that prevent them from reacting with oxygen/water. 

They are claiming that they will remove that barrier(plus other added elements) and then they will treat it with water to produce hydrogen and oxygen. I don't know how many soda cans I will need to power my cell phone in that way! 

 I think the best way to treat Aluminium wastes is to melt them and then recycle it back. 

Amit, you are right in that there is more to this than the claims make out to be. I am hoping that more CEans will come out with views. There’s a lot for us to learn from this.

Kaustubh Katdare
Kaustubh Katdare • Jun 4, 2018

I think they're a 'troll' website. Their founders don't even list the company in their LinkedIn profile. Could be a cheap publicity stunt.

Could be. Though some technical journals have reported about this. There are some basic issues with this technology. 

There is nothing wrong here theoretically. Power can be produced by the described process. I am waiting to see if CEans come up with engineering issues of concern.

The actual reaction is this:

2 Al + 3 H2O → 3 H2 + Al2O3

The reason I started this thread was to generate some active discussion on the numbers involved, eco issues, effectiveness and such as engineers always check such things out whenever something new is proposed.

With just some quick and dirty order of magnitude calculation the following appear to be applicable.

 The proposal can produce electricity. It is theoretically valid.

The reaction is 2 Al + 3 H2O → 3 H2 + Al2O3 . For 1 kg of Aluminum this will generate heat equivalent to about 8 KWHr and produce about 111 gms of Hydrogen gas.

Unfortunately Trolysis does not seem to harness the heat liberated. It uses the Hydrogen in a fuel cell to generate power. 111 gms of Hydrogen can give about 4.5 KWHr power at 100% efficiency, which is very doubtful.

We get in effect about 4 KWHr/Kg Aluminum.

The catch? Al2O3 can be recycled to Aluminum metal ONLY using electricity. It requires about 8.7 KWHr electricity at 100% efficiency to get back the 1 Kg Aluminum we started with.

This implies that about 9 KWHr of electricity is used to produce 4  KWHr of electricity using a very sophisticated (and costly) equipment.

Why ever on Earth should we do it?

(I have not done an exact heats of reaction calculation. An analytical solution may give a slightly different value. The order of magnitude should be correct)

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