Breakthrough Discovery: Microbes that Generate Methane from Renewable Energy
In a surprising find, scientists have discovered a microbe that can efficiently convert direct electrical current into methane.
That may be good news for wind and solar power enthusiasts, who have long been faced with the dilemma of how to store energy when the wind isn’t blowing and the sun isn’t shining. This discovery opens the door for generating methane from those renewable power sources; the energy could then be stored as fuel for later use.
But is storing renewable energy in the form of a greenhouse gas like methane a solution, or just another problem?
The remarkable microbe, Methanobacterium palustre, is the first to be found which can biochemically synthesize methane using electrons directly from current in combination with hydrogen gas. Most significantly, it appears to transform the energy at 80% efficiency. That’s pretty darn good, according to researchers.
Before this discovery, the options were limited regarding how to store energy generated from wind or solar sources. Storing it in large capacitors and batteries offered the most practical solution, since converting the energy into a fuel like hydrogen made it difficult to compress and store. But that problem doesn’t exist for methane, which is the main component for natural gas. Natural gas is already carried around the world in pipelines, and it’s used in conventional engines.
Though despite the good news, utilizing this process may overlook some of the bigger reasons for switching to renewable energy. Specifically, if the primary benefit for using wind and solar energy is to reduce greenhouse gas emissions, then wouldn’t converting that energy into methane miss the point?
Yes and no. Methane is a very clean burning fuel, and compared to other hydrocarbons, burning methane produces less carbon dioxide for each unit of heat released. In other words, if the choice is between storing excess wind or solar energy as methane or having to use traditional, dirtier fuels like gas or coal to pick up the leftover energy burden, then converting clean energy into methane– while perhaps not the ideal solution– is still a significant step forward.
More research needs to be conducted to determine the exact molecular mechanism of the biochemical process, and practical means for employing the technology have yet to be worked out. But the exciting discovery does shed some creative light on the potential for renewable sources to supply all of our energy needs.
Source: Environmental Science & Technology
Image Credit: austrini on Flickr under a Creative Commons License
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June 4th, 2009 at 8:36 am
Hi Bryan – My first impression was ‘this is nuts’ but hopefully it is real.
Solving the storage problem would be absolutely super. 99% of the ideas you see about it on the net such as pumping water, compressing air etc are not really practical on a gW basis.
Be interesting to know a little more about it as they have said very little apparently. I suppose they have to keep most details quite close until patents have been filed and rights protected.
Hydrocarbons are not going away in the near or even not so near future. Methane can be used for many things and as you note is cleaner than most.
June 4th, 2009 at 6:50 pm
This seems like not very big news, and irresponsible hype as far as “renewable energy storage” is concerned.
Unfortunately, the process requires hydrogen gas, and where is that going to come from? H2 production requires its own energy input, whether from renewables or otherwise. The 80% efficiency number becomes meaningless when considered outside of that context. One would first need to consider the efficiency of producing hyrdogen, then multiply that by 4/5ths. It is doubtful that for renewables this two part process presents a storage advantage over batteries. It is doubtful it presents anything that can solve our energy problems on a macro-economic scale.
Now if these guys discovered a microbe that would do the same thing with WATER instead of H2, that would be news. Otherwise, this can only be one of a thousand necessary puzzle pieces, not a big break through on its own.
June 4th, 2009 at 7:56 pm
Seems to be this article needs a solid dose of scientific literacy.
Where does the carbon come from? The question of how “clean” the methane is means nothing without this question answered.
And of course, the emissions from production of the electricity and hydrogen is another big factor.
All in all, if the carbon is taken from, say, the C02 in the air, the methane would have a net emission of approximately 80% if that of the hydrogen used in the process (per unit of energy, and depending on the efficiency of the combustion.) If the carbon is taken from a source not already in the carbon cycle, say coal, the gain to the environment would be much less. Possibly negative.
June 4th, 2009 at 9:04 pm
tbydal,
I don’t see what you think is missing. Perhaps it’s not stated blatantly, but I think the obvious assumption is that the carbon is snagged naturally by the microbes from the air/environment. The original source abstract, from the journal of “Environmental Science & Technology”, didn’t feel the need to state it directly either, but I think that’s because it’s a non-issue.
Were you concerned that they’d be using something like coal to feed the microbes with?
June 4th, 2009 at 9:23 pm
You make a good point Bryan, perhaps this is something that should have been obvious to me.
However, let’s take a look at what i think (my opinion doesn’t count for alot, admittedly) should have been stated abit differently in the article.
You ask the question: “If the primary benefit for using wind and solar energy is to reduce greenhouse gas emissions, then wouldn’t converting that energy into methane miss the point?”
Now this is a valid question to ask in the article, in my opinion, but the answer seems to be a bit off. You go on to answer that methane is a relatively clean fuel, which means it’s very preferable to traditional fuels like gasoline. While this is true in itself, i think it misses the point; how clean the new fuel is, C02-wise, is completely irrelevant if the carbon comes from C02 in the air anyway. If this new process made gasoline instead of methane, that would be an equally preferable feat, perhaps more considering you’d not have to change existing infrastructure to use it for transport purposes. That is, if this new process generated gasoline at the same efficiency, even if gasoline combustion releases more C02, it doesn’t matter since every molecule of C02 would be taken from the air in the microbe process anyway. As such the only source for C02 with this process, regardless of it’s fuel product, is the emissions from the production of the needed H2 and electricity.
In summary: Hydrogen production and electricity generation, combined with the efficiency factor of the process is the source of emissions here; not the methane. The advantages of this process over hydrogen is the transportability of methane, which you mention. This *could* be an important discovery, considering the transport of hydrogen is perhaps its major obstacle to effective use.
I apologize if my first comment came off as a bit hostile. I very much appreciate what you are doing here, we definitely need more people talking about new alternatives for future energy production and carriage. Thanks
June 4th, 2009 at 10:00 pm
tbydal,
From what I have gleaned, you aren’t the first person to ask about the carbon source– so thanks for bringing it up to allow for the short explanation.
Regarding the greenhouse gas emission concern: you bring up a good point here. You’re right that if the carbon is coming from CO2 already in the atmosphere, that then burning the methane shouldn’t actually add any CO2 to the atmosphere than what was already there.
Of course, the carbon could also come from organic material, or non-atmospheric carbon, from other environmental sources, which the methanogens also utilize naturally. In that case, it could potentially be turned into unwelcome extra atmospheric CO2 when the methane is burned. I think this is a controllable or minor concern though, so I think your point is still probably justified here: Greenhouse gas emissions are not a big concern.
Of course, that just makes this discovery all the more intriguing!
In asking the question about greenhouse gas emissions while writing the article, I was thinking in terms of comparison just regarding the electrical output directly from wind and solar power– which if used immediately obviously doesn’t require any conversion into methane at all, and thus doesn’t need to involve any carbon. As you point out, though: the process can still be carbon neutral even after the electricity is transformed into methane, assuming that the microbes are being fed atmospheric CO2 exclusively.
Good point!
June 4th, 2009 at 10:08 pm
Yes! I think we have come to an agreement here
Small point: If the microbes got carbon by the decomposition of organic material, that would still be considered carbon neutral. The regular decomposition of the same organic material would also lead to the carbon moved to the atmosphere in the form of C02! Therefore it is equivalent to taking it out of the air. (Well mostly, there are discussions of this aswell but would be too much of a digression.) Only carbon added to the carbon-cycle would constitute a real emission, which in general means drilling it out of the ground.
June 5th, 2009 at 1:23 am
Unfortunately, the process requires hydrogen (4 hydrogen for every carbon) which is most efficiently created from methane. Do you see the problem here?
Back to the drawing board.
June 5th, 2009 at 11:48 am
Yes Rick exactly, now if only they could get the Hydrogen from water and generate the methane, THAT would be something
June 5th, 2009 at 5:06 pm
Bryan,
why are you not answering the ‘hydrogen source’ question
Vishva
June 7th, 2009 at 11:17 am
Storing energy is the main challange in Renewable energy generation. It appars too good to be true. However more work with commercial angle would clear all apprehentions. I wish great success to the scientists working on the project.
June 7th, 2009 at 6:32 pm
Electrolysis of water using DC current from excess solar or wind generation will also produce Oxygen and Hydrogen which can also be used directly for energy storage. Don’t know the efficiency levels, but Oxygen has many medical, commercial and industrial uses and atmospheric oxygen for combustion is inexpensive and the combustion product is water. Hydrogen is harder to store and transport
June 8th, 2009 at 1:59 pm
Where is the hydrogen coming from
August 27th, 2009 at 4:44 am
Isn’t the Hydrogen source coming from water?? This then puts back presumably two molecule of O2 by taking one molecule of CO2.
2H20 + CO2 -> CH4 + 2O2
But we need to remember this is a cyclic conversion because as you burn CH4 you also us O2.
CH4 + 2O2 -> CO2 + 2H2O
Anyway my chemistry may be wrong, please correct me. But if we are to fully understand what is going on we need to think of it in these terms.
September 10th, 2009 at 9:56 pm
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