A new study published June 25 in Nature Climate Change evaluates the potential for recently described methods that capture carbon dioxide from the atmosphere through an “electrogeochemical” process that also generates hydrogen gas for use as fuel and creates by-products that can help counteract ocean acidification.
First author Greg Rau, a researcher in the Institute of Marine Sciences at UC Santa Cruz and visiting scientist at Lawrence Livermore National Laboratory, said this technology significantly expands the options for negative emissions energy production.
The process uses electricity from a renewable energy source for electrolysis of saline water to generate hydrogen and oxygen, coupled with reactions involving globally abundant minerals to produce a solution that strongly absorbs and retains carbon dioxide from the atmosphere. Rau and other researchers have developed several related methods, all of which involve electrochemistry, saline water, and carbonate or silicate minerals.
“It not only reduces atmospheric carbon dioxide, it also adds alkalinity to the ocean, so it’s a two-pronged benefit,” Rau said. “The process simply converts carbon dioxide into a dissolved mineral bicarbonate, which is already abundant in the ocean and helps counter acidification.”
The negative emissions approach that has received the most attention so far is known as “biomass energy plus carbon capture and storage” (BECCS). This involves growing trees or other bioenergy crops (which absorb carbon dioxide as they grow), burning the biomass as fuel for power plants, capturing the emissions, and burying the concentrated carbon dioxide underground.
“BECCS is expensive and energetically costly. We think this electrochemical process of hydrogen generation provides a more efficient and higher capacity way of generating energy with negative emissions,” Rau said.
He and his coauthors estimated that electrogeochemical methods could, on average, increase energy generation and carbon removal by more than 50 times relative to BECCS, at equivalent or lower cost. He acknowledged that BECCS is farther along in terms of implementation, with some biomass energy plants already in operation. Also, BECCS produces electricity rather than less widely used hydrogen.
“The issues are how to supply enough biomass and the cost and risk associated with putting concentrated carbon dioxide in the ground and hoping it stays there,” Rau said.
The electrogeochemical methods have been demonstrated in the laboratory, but more research is needed to scale them up. The technology would probably be limited to sites on the coast or offshore with access to saltwater, abundant renewable energy, and minerals. Coauthor Heather Willauer at the U.S. Naval Research Laboratory leads the most advanced project of this type, an electrolytic-cation exchange module designed to produce hydrogen and remove carbon dioxide through electrolysis of seawater. Instead of then combining the carbon dioxide and hydrogen to make hydrocarbon fuels (the Navy’s primary interest), the process could be modified to transform and store the carbon dioxide as ocean bicarbonate, thus achieving negative emissions.
“It’s early days in negative emissions technology, and we need to keep an open mind about what options might emerge,” Rau said. “We also need policies that will foster the emergence of these technologies.”
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The paper: https://www.nature.com/articles/s41558-018-0203-0
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Am I wrong again to be confused by the understanding that of all the atmospheric CO2, the anthropogenic contribution is some 5%, signifying that the whole exercise is far more an exercise in transferring money than an effective transfer of CO2, and geo-engineering has so far proven to be a great source of demonstrating unintended consequence….
[QUOTE FROM RAU] ““It not only reduces atmospheric carbon dioxide, it also adds alkalinity to the ocean, so it’s a two-pronged benefit,” Rau said. “The process simply converts carbon dioxide into a dissolved mineral bicarbonate, which is already abundant in the ocean and helps counter acidification.”
How does removing CO2 from the air add “alkalinity” to the ocean, if the reaction of CO2 and water produces H2CO3, or carbonic acid? While seawater does contain salts (notably of calcium) that act as buffer solutions, precipitating them out as carbonates or bicarbonates deprives seawater of cations (positive metal ions such as Na+, Ca++) that contribute to the alkalinity of seawater.
Is the idea to use electrolysis to remove hydronium ions (from acids) from seawater as hydrogen gas? This would reduce acidity and increase alkalinity, but where does the electrical energy come from to perform electrolysis? Burning some fossil fuel at a power plant that produces CO2? In that case, this process actually increases CO2 emissions, because it takes more energy to electrolyze water than is liberated by the combustion process that produced the CO2 in the air (since all energy conversion processes lose some energy as heat due to the Second Law of Thermodynamics).
Industrial-scale electrolysis processes require lots of DC power at low voltage but extremely high currents of thousands of amperes, and huge rectifiers to convert AC from the power company into DC, which lead to energy losses in the conversion. The rectifiers are so powerful that nearby workers have to grip steel tools very tightly so they don’t fly into the rectifier due to the strong magnetic field.
The researchers may be able to get enough electric power from a “renewable source” to run this process at a small scale in the lab. But if they want to run this process at an industrial scale to remove thousands of tons of CO2, the only non-fossil-fuel electric power source that could produce enough electricity would be nuclear fission, which has low fuel costs and zero emissions but high capital cost.
What’s the point of all this nonsense? The predominant ion produced by carbon dioxide dissolution in water is already the bicarbonate ion, arguably one of the most important buffers in the world. This solution of bicarbonate ions is in equilibrium with hydrogen ions, carbonate ions, and gaseous CO2 as well as large amounts of solid calcium carbonate, calcium and magnesium ions and a few other species in sea water. That’s why the ocean pH is what it is and that’s also why that pH won’t drop significantly regardless of the amount of CO2 in the atmosphere. The bicarbonate/carbonate buffer system is intrinsic to life on this planet and helps maintain stable pH for most aerobic physiological processes of metabolism amongst other things.
As several other point out, electrolysis of sea water generates caustic soda and chlorine gas which recombine to produce sodium hypochlorite and this principle is used for salt water pool chlorination. I think this guy needs to go back to chemistry class.
“The process uses electricity from a renewable energy source…”
Yeah, right. Sounds green in theory but renewables can’t come close to meeting the electrical needs of the grid, and they think there will be capacity for this too? Sounds like they’ve indulged in too many recreational drugs.
“The process uses electricity from a renewable energy source…”
Yeah, right. Renewables can’t even come close to meeting the needs of the grid and they think they’ll have enough for this? I wonder what color the sky is in their world.
Removal of CO2 from the atmosphere? How about burning more dirty coal.
“We suggest that the surge of fossil fuel use, mainly coal, since 2000 is a basic cause of the large increase of carbon uptake by the combined terrestrial and ocean carbon sinks. One mechanism by which fossil fuel emissions increase carbon uptake is by fertilizing the biosphere via provision of nutrients essential for tissue building, especially nitrogen, which plays a critical role in controlling net primary productivity and is limited in many ecosystems.”
http://iopscience.iop.org/article/10.1088/1748-9326/8/1/011006/meta
Based on the paleoclimate record and the work done with models, one can conclude that the climate change we have been experiencing today is caused by the sun and the oceans over which mankind has no control. There is plenty of scientific rational to support the idea that the climate sensitivity of CO2 is zero. But even if we could stop the climate from changing, extreme weather events and sea level rise are part of the current climate and would continue unabated. The optimum climate has never been defined and even if it were defined we have no idea as how to achieve it.
CO2 is vital to all hydrocarbon life on this planet. Over the eons, CO2 has been sequestered in the form organic matter we often refer to as fossil fuel, and carbonate rock. The sequestering has caused CO2 levels in the Earth’s atmosphere to drop well below that which is optimal for life on this planet. The burning of fossil fuels is helping the situation to improve but to sustain life on this planet at optimum levels it may require us to actively convert carbonate rock back to CO2. So the last thing that we want to do is to actively convert CO2 in the atmosphere to carbonate rock and in so doing remove Carbon from the biosphere. What we really need is a scheme that will use solar energy to convert carbonate rock into atmospheric CO2 that will enhance global plant growth.
For those that believe in a radiant greenhouse effect caused by trace gases in the Earth’s atmosphere with LWIR absorption bands, the most important socalled greenhouse gas is not CO2 but rather H2O by far. One could remove all the CO2 in the atmosphere and it would have no significant effect on the over all greenhouse effect. To reduce that overall radiant greenhouse effect one has to reduce the amount of H2O in the Earth’s atmosphere but so far there is no effort underway to do that as if any practical way existed.
Another concern is that the AGW conjecture depends upon that existence of a radiant greenhouse effect that has not been observed anywhere in the solar system including the Earth. The radiant greenhouse effect is science fiction hence the AGW conjecture is science fiction as well. I am very leary of any scheme that is based on science fiction.
“..The negative emissions approach that has received the most attention so far is known as “biomass energy plus carbon capture and storage” (BECCS). This involves growing trees or other bioenergy crops (which absorb carbon dioxide as they grow), burning the biomass as fuel for power plants, capturing the emissions, and burying the concentrated carbon dioxide underground…”
That is serious?
This is an expensive, unnecessary, and wasteful way to remove CO2. Ocean Iron Fertilization can rejuvenate the oceans, feeding hundreds of millions, and allow for control on the CO2 levels. CO2 is a resource, not a problem. RussGeorge.net
How about paying grants to just think about it instead of another full-scale boondoggle? I guess they already do that.
Just madness. and in such a tiny world that they live in.
Think big.
Sahara Desert. Big. 2.2 billion acres of big. Quite sunny. in the daytime.
Mountains to the north. not many people around. not anything much for that matter
lots of atmosphere – 6 or 7 miles thick? That’ll do.
What’s not to like?
does it get windy there on a fairly regular basis, if yes, all the better
I think we’re set, let’s go…..
1. Plant your renewable energy (RE) system in the desert. solar and wind if its available
2. Use said RE to take chunks off the mountains (Atlas will shrug) and grind up said bits
(it won’t need computer grade ‘grid’ electric. any old ruffty tuffty will do to mash up a few rocks)
3. Use also some RE to oxidise some of the 7 mile high atmosphere. Ideally we want to make any old oxide of nitrogen (NOx)
4. Next bit may need a bit of ‘organising’ but we need water to dissolve the NOx into to make a crude but effective acid. Add acid to a mashed up rock. Doesn’t need a lot. (it releases a load of stuff including magnesium, essential for chlorophyll production – 1 Mg atom per molecule
5. Start near the top near The Med but eventually spread acid-treated rock all over The Desert. At least 50 tonnes per acre.
6. Let Nature take its course.
Alert readers will realise we’ve created what were supposed to be the very things that initially started Life on Earth – lightning strikes fixing nitrogen – which is THE Liebig Limiter for all plant and bacterial life on this Earth.
Sorry no, its not CO2 no matter what you imagine happens inside commercial greenhouses. Sahara desert is NOT spontaneously going to go green.
Assuming the ‘garden’ we’ve just made is as productive as Oregon larch forest – it should pull down 11 gigatonnes of CO2 annually. It might be ‘a bit more’ considering the solar input.
Maybe repeat in Australia – there’s another 10GT easily.
Maybe run a few buffalo over it and get back to a healthy diet for ourselves.
‘They’ won’t be happy will they
sigh
This is before or after they turn base metal into gold ?
will require not only reducing emissions of carbon dioxide, but also active removal of carbon dioxide from the atmosphere
Full stop at that point due to absurdity. Are taxpayers paying for this fake-science?
Above a pH of 7.0 a solution is alkaline and becomes more or less alkaline.
Below a pH of 7.0 a solution is acidic and becomes more or less acidic.
The ocean’s pH is about 8.1. That’s alkaline. Variations are more or less alkaline, not more or less acidic. The obvious reason for incorrectly using the term “ocean acidification” is a propaganda gambit to scare the gullible and uninformed who associate acid with bad, like alien blood and spit.
Highly alkaline compounds such as caustic soda can be just as dangerous as acidic compounds, e.g. concentrated bleach, sodium hypochlorite, pH 9 to 13. On the other hand: rain has a pH of 4.5, lemon juice has a pH of 2.0, tomatoes a pH of 4.5, and vinegar a pH of 2.2. If they get on your hands the flesh doesn’t melt and they don’t burn a hole in the kitchen counter.
A pH of 6 is a weak acid and its chemical reactivity is very low.
A pH of 7 is neutral and its chemical reactivity is zero.
A pH of 8 is a weak base and its chemical reactivity is very low.
A solution goes from pH 0.0, dangerous acidity, to pH 7.0, completely nothing/harmless, to pH 14.0, dangerous alkalinity.
A change from 8.2 to 8.1 is a -26% change in the direction of lower alkalinity, not more acidity.
But a change from 9.0 to 8.0 is a -900% change in the direction of lower alkalinity.
Applying percentages to a logarithmic scale/function is very dicey.
Makes the -26% look pretty trivial – which it is.
So, 8.1 is moving in the direction of slightly more nothing from 8.2 which is not much to begin with.
Improperly using the term ocean “acidification” to scare the public over bogus CAGW is a disgrace to science. Spit out the Kool-Aid and grow a backbone.