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Researcher Quantifies Water Requirements for Transitional Hydrogen Economy; A Significant Impact on A Critical Resource

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Annual water consumption as a coolant and as a feedstock for generating 60 billion kg of hydrogen as a function of the fraction that is produced by thermoelectrically powered electrolysis and for a range of electrolyzer efficiencies. Click to enlarge.

A researcher at the University of Texas has provided the first analysis of the water intensity of a transitional hydrogen economy. Michael Webber, Associate Director at the Center for International Energy and Environmental Policy at the University of Texas at Austin, quantified the direct and indirect water requirements to annually manufacture 60 billion kg of hydrogen partly by thermoelectrically powered electrolysis.

While the hydrogen economy is expected to be in full swing around 2050 (according to a 2004 report by the National Research Council [NRC]), a transitional hydrogen economy could occur in about 30 years, around 2037.

The analysis, which is published in the open-access journal Environmental Research Letters, determines that up to 143 billion gallons of water would be directly consumed as a feedstock, with a total consumption including evaporation of cooling water at power plants of 0.5–1.7 trillion gallons annually.

Total water withdrawals for thermoelectric cooling (most of which is not consumed) are expected to increase by 27–97% from 195,000 million gallons/day used today by the thermoelectric power sector to generate about 90% of the electricity in the US. The amount of the increase depends primarily on the aggregate efficiency of electrolyzers that will be in place and the portion of hydrogen that is produced by thermoelectrically powered electrolysis.

On a per unit basis, thermoelectric power generation for electrolysis will on average withdraw approximately 1,100 gallons of cooling water and will consume 27 gallons of water as a feedstock and coolant for every kilogram of hydrogen that is produced using an electrolyzer that has an efficiency of 75%.

...if the hydrogen economy includes thermoelectrically or hydroelectrically powered electrolysis as a prominent source of hydrogen, then we can expect significant increases in water withdrawals and consumption for fuel production over today’s use of gasoline. Given that water withdrawals have remained steady for decades, these increases in water use represent a significant potential impact on a critical resource.

If minimizing the impact of water resources is a priority and electrolysis becomes a widespread method of hydrogen production, it is likely that the power for electrolytic hydrogen production will have to come from non-thermoelectric, non-hydroelectric and non-irrigated renewable sources. Consequently, almost all the new electricity generating capacity for hydrogen production would need to be from hydrogen production pathways that do not use much water (such as wind or solar), or effective water-free cooling methods (e.g. air cooling) will need to be developed and widely deployed.

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Comments

Roger Pham

It is not practical nor efficient to generate electricity via a power plant and then use that electricity to produce H2. It would be far cheaper and twice as efficient to produce H2 directly via gasification (and water-gas shift reaction) of the fuels that will go into the power plant.

The amount of water that will be used for high-temp electrolysis will be minuscule in comparison to the amount of water used daily for home, industry ( eg. petroleum refining) and irrigation. The water produced from FC can be recycled for home use as well.

Yet another reason to quit messing with hydrogen for consumer vehicles and build battery powered EVs

jack

Yet another reason to quit messing with hydrogen for consumer vehicles and build battery powered EVs

How's the Kool Aid? Grape flavor today?

George

What, Jack's a hydrogen weenie? I thought he was an environmentalist. Really, Jack, if you care about the environment, H2 is not the way to go.

jack

What, Jack's a hydrogen weenie? I thought he was an environmentalist. Really, Jack, if you care about the environment, H2 is not the way to go.

Another great argument presented. Good job.

François

I didn't catch your argument, jack. May you recall it ?

Neil

"While the hydrogen economy is expected to be in full swing around 2050 (according to a 2004 report by the National Research Council [NRC]), a transitional hydrogen economy could occur in about 30 years, in 2037."

By 2037 expensive oil will have already pushed us into one alternative or another (probably electricity). The only thing left for hydrogen will be niche markets and range extension. If hydrogen backers can't get their product to market a whole lot faster, they'll have missed the boat.

itsme

"A researcher at the University of Texas" ...

"
On a per unit basis, thermoelectric power generation for electrolysis will on average withdraw approximately 1,100 gallons of cooling water and will consume 27 gallons of water as a feedstock and coolant for every kilogram of hydrogen that is produced using an electrolyzer that has an efficiency of 75%.
"
pretty bullshit

Alain

Producing 1100 gallons of (hot) cooling water needs an enormous amount of heat. I wonder how you achieve a 75% efficiency when you need to 'heat' that amount of cooling water to produce one kg of H2.
The actual crude arrives in the west mostly by boats. If we locate the H2-production sites in those harbors, there is plenty of water.
The problem is not lack of water, but wasting of energy.
Most of the H2 will probably be produced by electrochemical processes. There is no need to first make electricity, so you need no steam turbines, no cooling towers and no inefficient electrolysis needing expensive catalysers.
Additionally, if there still is 'waste'-heat, it shouldn't be wasted in a cooling tower. Many industrial processes need heat (for instance ethanol production), so building these installations close to a power station allows to reuse the 'waste'-heat.
--> Much higher 'overall efficiency' and no need for cooling water.

marc

hey itsme you have a problem with university of texas?
have you even graduated from high school? your post does not show even the slightest hint of intelligence. after all, anyone can take a statement and just say "thats (some word that shows your limited vocabulary)"
why don't you try what an intellectual would do and formulate an argument based on facts, that contradict the facts presented you see as false. that is, if you want to talk to real people here in the real world.

sjc

Jack,

Give it a rest. Either clean up your act or get off this site.

jack

Give it a rest. Either clean up your act or get off this site.

You funny.

wintermane

When they first come commercial fuel cell cars will only need about 2x the total energy as a pure ev and then only when in range extender mode. They will have greater range.

By 2025 much of that energy oremium will be gone and the range will be even better.

In 10 years h2 will likely be cheaper then gasoline. They already used it to MAKE your gasoline...

H2 used to cost 250 a kilo not all that long ago... it now costs less then chocolate.

Rafael Seidl

Fresh water consumption becomes a non-issue if you use the waste heat from a steam-based power plant to thermally distill salt water in a high vacuum. You'll lose some efficiency in the electricity production, but in such systems, you need to look at aggregate efficiency.

Mind you, all I'm saying is that water isn't going to be an insurmountable problem for the hydrogen economy. Political opposition to wind farms (NIMBYs), to wasting NG and/or to producing radioactive waste plus, the difficulty of distribution and storage and, the cost of automotive fuel cells are all more daunting challenges.

If the Li-ion battery manufacturers make good on their promises, there won't be a market for fuel cell vehicles and the hydrogen highway will be stillborn. Not that politicians will stop throwing money at it any time soon...

Engineer-Poet

Jack, you act as if trite dismissals are a substitute for detailed analysis.  They aren't.

George, sjc and François are right; you should clean up your act or take it elsewhere.

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