Making Fuel Out of Seawater Is Only One Part of An Energy Solution

So I recently saw this post about a recent breakthrough the Navy made in producing fuel from water make a small round on Facebook from questionable “alternative news” site Addicting Info and it kind of set off my BS detector. First, because this story is a few months old. It actually turned out the article was from April, so part of my skepticism was unfounded. But the opening claim that this wasn’t being reported much in mainstream outlets is wrong, as several sites beat them to the punch (even FOX NEWS! Which would probably make Addicting Info’s head explode.). The other thing that struck me as odd was how the Addicting Info piece seemed to think this technology is practically ready to use right now.  That surprised me, because for nearly the last two years, my graduate research at UVA has been focused on developing materials that could help produce fuel from CO2.

This Vice article does a pretty good job of debunking the overzealous claims made by the Addicting Info piece and others like it. As Vice points out, you need electricity to make hydrogen from water. Water is pretty chemically stable in most of our everyday lives. The only way the average person ends up splitting water is if they have metal rusting, which would be a really slow way to generate hydrogen, or by putting a larger battery in water for one of those home electrolysis experiments.

The Naval Research Lab seems kind of unique among the groups looking at making fuel from CO2 in that they’re extracting hydrogen and CO2 from water as separate processes from the step where they are combined into hydrocarbons. Most of the other research in this area looks at having metal electrodes help this reaction in water (nearly any metal from the middle of the periodic table can split CO2 with enough of a negative charge) . Because of water’s previously mentioned stability, they often add a chemical that can more easily give up hydrogen. A lot of groups use potassium bicarbonate, a close relative of baking soda that has potassium instead of sodium, to help improve the conductivity of the water and because the bicarbonate ion really easily gives up hydrogen. In these set-ups, the goal is for the electricity to help the metal break off an oxygen from a CO2 to make CO, and when you get enough CO, start adding hydrogen to the molecules and linking them together.

A chemical diagram shows a CO2 molecule losing a carbon atom on a copper surface to make CO. When another CO is nearby, the two carbon atoms link together.

Carbon atoms are initially removed from CO2 molecules on a copper surface, forming CO. When CO get close to each other, they can bond together. From Gattrell, Gupta, and Co.

But basically, no matter what reaction you do, if you want to make a hydrocarbon from CO2, you need to use electricity, either to isolate hydrogen or cause the CO2 to become chemically active. As the Vice article points out, this is still perfectly useful for the Navy, because ships with nuclear reactors continually generate large amounts of electricity, but fuel for aircraft must be replenished. If you’re on land, unless you’re part of the 30% of the US that gets electricity from renewable sources or nuclear plants, you’re kind of defeating the point. Chemical reactions and industrial processes always waste some energy, so burning a fossil fuel, which emits CO2, to make electricity that would then be used to turn CO2 back into fuel would always end up with you emitting more CO2 than you started with.

However, this process (or one like it) could actually be useful in a solar or wind-based electricity grid. Wind and solar power can be sporadic; obviously, any solar grid must somehow deal with the fact that night exists, and both wind and solar power can be interrupted by the weather. (Nuclear power doesn’t have this issue, so this set-up would be irrelevant.) However, it’s also possible for solar and wind to temporarily generate more electricity than customers are using at the time. The extra electricity can be used to power this CO2-to-fuel reaction, and the fuel can be burned to provide extra power when the solar or wind plants can’t generate enough electricity on their own. This is also where the Vice article misses something important. Jet fuel can’t have methane, but methane is basically the main component of natural gas, which is burned to provide about another 30% of electricity generated in the US today. And because methane is a small molecule (one carbon atom, four hydrogen atoms) it can be easier to make than the long hydrocarbons needed for jet fuel.

Also, one thing I’m surprised I never see come up when talking about this is using this for long-term human space exploration as a way to prevent to maintain a breathable atmosphere for astronauts and to build materials. If you can build-up the carbon chains for jet fuel, you could also make the precursors to lots of plastics. The International Space Station is entirely powered by solar panels, and solar panels are typically envisioned as being part of space colonies. Generally, electricity generation shouldn’t be a major problem in any of the manned missions we’re looking at for the near future and this could be a major way to help future astronauts or space colonists generate the raw materials they need and maintain their environment.

If you want to read more about the Naval Research Lab’s processes, here are some of the journal articles they have published lately:

Cosmos Tackled Climate Change in a Wonderfully Satisfying Way

So I worked out while watching this week’s episode of Cosmos. I’m several weeks “behind”, if it’s possible to be behind for a documentary series (though I’ve DVRed them all for future marathon sessions). But this was a wonderful episode to come back to. It was a really good primer on contemporary understanding of climate change, especially addressing rebuttals from skeptics that have become more common over the last 20 years or so. In particular, I liked these points

  • Tyson pointed out that the greenhouse effect is “beneficial” in that Earth would be like 30 degrees cooler without it. But he also points out how little CO2 it takes to get that much of a shift, and how little CO2 we need to add to make temperature change too much.
  • It’s not that climate is changing that’s bad, it’s that climate change that is too fast can destroy ecosystems. Tyson pointed out the speed of anthropogenic CO2 emissions isn’t close to anything previously seen in Earth’s history aside from the previous mass extinction believed to be caused by climate change.
  • We can in fact figure out the difference between CO2 we’re emitting and CO2 from many natural sources, and that evidence points out most of the new CO2 is from our fossil fuels. How? The CO2 from fossil fuels is made up of carbon atoms that are different weights from what we would otherwise expect in the atmosphere.
  • The Sun hasn’t really appreciably changed to cause the temperature increases we see.
  • The ocean is warming up. Actually, I’m not sure the show mentioned the “greenhouse pause” people talk about, but what is important to note is that so-called “stop” in air temperatures doesn’t really tell the whole story. The Spaceship of the Imagination gave us an infrared view of the Earth to look at the planet’s heat emissions. We’re finding out that while the atmosphere may not have heated up over this last decade, the ocean definitely has. I’m also surprised the show didn’t mention the potential danger of ocean acidification.

I also loved the presentation of climate as better understood by large scale driving forces and not “just” the average of weather. I don’t know any climatologists, but I’m sure such a simplifying definition of their field has always bugged them. One major factor is energy conservation, and since I took a simple engineering class that tried to stress how much of understanding technical systems is based on just applying various conservation laws, I try to emphasize that more. Those space satellites let us measure how much heat Earth radiates away, and given that the sun’s input is relatively constant, if the atmosphere traps more heat in, then we must be heating up. (This is also the source of my very basic understanding as to why severe weather gets worse under climate change. We’re trapping in more energy, and so storm systems basically get stronger because it goes somewhere.) And I also loved that they tied in how our knowledge of other planets has helped inform our understanding of Earth. (And even gave a shout out to Carl Sagan’s research!) I do have one major peeve, though, and I want to point out that they did commit the cardinal sin of data presentation and not include any scale for the color representing temperature increases on their maps.

I had never heard of Frank Shuman before and now I want to look him up. It amazes me how similar his pointing out a small region of solar power generators could power civilization is to Rick Smalley’s idea, minus the nanotubes. If there’s anything I’ve learned the last two years in grad school while doing literature research for my own project, it’s how freakishly non-linear and coincidental energy research can be. To a more philosophically minded friend, I joked that learning about energy technologies has destroyed the last shreds of my old belief in logical positivism, the idea that human history is generally a linear progression towards more good. But I’ll be darned and say I’m still an optimist and had slight chills hearing JFK’s “We choose to go to the moon” speech with scenes of that (super utopian) city of sustainable energy and green spaces. 

When Your Home Starts to Dissolve You

Last weekmonth, a new study was published looking at ocean acidification, a (I think under-publicized) side effect of increasing CO2 concentrations.  A decent summary can be found at The Atlantic (in their health section, of all places).  The researchers (from a wide array of institutions in the US and Europe) focused on Arctic sea snails.  While that may sound incredibly boring, there are two main reasons they’re important to study.  First, their shells are calcium carbonate, which you’re probably more familiar with as limestone (or perhaps as the active ingredient in most over-the-counter heartburn medications).  Calcium carbonate makes up the shells of a lot of sea creatures.

Via The Atlantic

Happy snail

Via The Atlantic

Sad snail

And while we mention antacids, let’s bring up their counterpart, acids.  So carbon dioxide naturally dissolves in water to form a somewhat weak acid (you also see this idea come up with discussions of soda sometime – the CO2 from carbonation also dissolves in the soda and makes it acidic).  Although that’s a slight simplification because it actually turns out sea water is slightly basic (think the opposite of acidic) and has a pH somewhere around 8.15 , presumably because of the several thousand minerals that are dissolved from the coasts.  So if the ocean’s slightly basic, we’re fine, right?  Well, the term “acidification” is still accurate because the pH is lower (i.e. more acidic) than it used to be.  The process of sea creatures building up the calcium carbonate structures is sensitive to environmental conditions.  The carbonate dissolves more in solution with more carbon dioxide and/or lower pH (more acidic).  While that may initially sound like a good thing for any critters needing it (there’s more calcium carbonate in the water, right?), chemical equilibrium is a two way street; if it’s easier for something to dissolve, it’s harder to precipitate it back into a solid that might go into a shell.  Studies have shown that coral grows slower in acidic water because of this.

So what made this study important?  It looked at how acidification affects marine snails (also known more whimsically as “sea butterflies”) in the Antarctic, which are a very important part of the food chain (some marine biologists call them “potato chips of the oceans”).  The snails already showed significant signs of their shells dissolving.  While this isn’t a death sentence, it does make it easier for them to be eaten or catch diseases, and en masse, that could throw off population.

Of course, it’s important to note the researchers say the blame isn’t all on ocean acidification.  Part of the reason the seawater was so acidic was because of upswelling, an phenomena in which deeper water is pushed up to the ocean surface.  Deeper water tends to be more acidic (I can’t find why), so these upswells make the surface water abnormally acidic.  But upswelling is expected to increase with climate change.