Hydrogen Power from Sewage?

MOST was intrigued by an article with the headline “Flush, then fill up: Japan taps sewage to fuel hydrogen-powered cars” from this Sunday’s Los Angeles Times.  As MOST Subscribers realize, MOST knows his … sewage!  And energy and the environment — as well as sewage — are near and dear to our heart.  Here is the article:


Hydrogen is a great fuel.  NASA has used it for decades.  And when combusted, its sole waste product is water!  How great is that for the environment?  No more pesky greenhouse gases.  Not so fast!  The greatest and most important of all greenhouse gases on Planet Earth is water.  Our planet would be uninhabitable without the greenhouse effect, so this is not necessarily a bad thing.  We know that you’ve been conditioned (by ill-informed or agenda-driven media outlets like the L.A. Times) to believe that carbon dioxide is the root of all environmental evil, but that is simply not so.

The source of this hydrogen is biogas, which is produced at all wastewater treatment plants that use anaerobic digestion for sludge processing.  And that includes almost all wastewater treatment plants.  While the article is informative and presents both good and bad aspects of hydrogen as a fuel, it fails to address two important issues that  MOST is happy to discuss.

First, most wastewater treatment plants are already using their biogas as a fuel!  Many are burning it onsite to run the blowers that supply air for their activated sludge process, or to fire an electric generator for plant power needs — which are extensive in waste treatment.  Wastewater plants have been champions of energy conservation for decades!  Even the waste heat generated by these blowers and generators is usually captured and used to heat up the anaerobic digestion process.  And larger regional facilities often produce sufficient excess biogas that they use it to generate electricity for surrounding communities.  So, MOST was offended by the implication that this was an un-tapped resource that was just being wasted by the boneheads in the wastewater industry.  Nothing could be further from the truth.

(Note:  Long-time MOST readers will recognize that MOST is easily offended.)

Next, any third-year Chemistry student can tell you that it would require more energy to extract hydrogen from biogas than the amount of energy derived from burning the hydrogen.  (Do the Gibb’s free energy calculation yourself!)  So this process could be viewed as wasting energy!  Where would this extra energy come from?  Probably from the combustion of fossil fuels because, all breathless bloviating to the contrary, that is still the source of virtually all of our energy.

As the late, great Paul Harvey used to say, “And now you know the rest of the story.”  It’s too bad that the L.A. Times couldn’t deliver that.

2 Responses to Hydrogen Power from Sewage?

  1. avatar onelazyop says:

    I agree with Most concerning the hydrogen extraction. It has a lot of value for the PR crowd and those enamored with the futuristic tech stuff, (like Tesla owners). Better to encourage diesel conversions, (are you VW guys paying attention?) to CNG, which is a renewable fuel. We just need more digesters, as it is a presidential election year, to handle the excess production of raw material in order to produce more biogas. That way I can fill up the Honda Civic (CNG) at a lower price.

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