Wednesday, April 6, 2016

Reverse Photosynthesis & Artificial Photosynthesis: How Big are these Stories?

Today's headlines report a significant breakthrough in what is called "reverse photosynthesis". This is a process that might be used to break down biomass into plastics, chemicals, and biofuels. The process would be far more efficient and less polluting than today's industrial methods.

European scientists report the breakthroughs as a "game changer" and the technical details are in an article in the journal “Nature Communications.” The "game changer" is adding sunlight to the  enzymatic process.

From Discovery News:
It works like this: A given amount of biomass – straw or wood, for instance – is combined with an enzyme called lytic polysaccharide monooxygenase, found in certain fungi and bacteria. When chlorophyll is added and the entire mixture is exposed to sunlight, sugar molecules in the biomass naturally break down into smaller constituents. The resulting biochemicals can then be more easily converted into fuel and plastics. The key is using the very energy of sunlight itself to drive the chemical processes. By leveraging the power of the sun, reactions that would otherwise take 24 hours or longer can be achieved in just 10 minutes, researchers say. That means faster production, lower temperatures and enhanced energy efficiency in industrial production.
There is still much work that needs to be done, however, before it can be adapted by industry.

What about the other area of photosynthesis being researched, referred to as artificial photosynthesis?

The hope for "artificial photosynthesis" has been around for some time, although there are still many people who aren't aware of it. Artificial photosynthesis is a chemical process that replicates the natural process of photosynthesis, a process that converts sunlight, water, and carbon dioxide into carbohydrates and oxygen. If developed, artificial photosynthesis technology could yield low carbon gasoline, or, could perhaps capture CO2 at power plants and from engines which could be turned into energy, reducing CO2 levels. Researchers have been working on this for decades, and efficiency gains have been made recently, but still have a ways to go.

Which brings me to my 2014 interview of energy engineer, Bill Reinert, retired alternative energy vehicle researcher and company spokesman for Toyota. Here is what Reinert had to say about artificial photosynthesis during that interview:
There’s a big consortium centered at CalTech under the principle investigator, Nate Lewis, to do artificial photosynthesis. This is one of the few alternative fuel areas that’s not getting a lot of federal money, but it’s getting a lot of private money, and this private money is (largely) coming from the oil companies. There’s a ton of money being thrown at it, and it looks like they’re making some progress.

It has nothing to do with producing hydrogen for fuel cell cars. It has everything to do with producing low carbon hydrogen to be used at the refinery level to reduce the carbon emissions of gasoline or diesel during the production process. Because when the hydrocrackers start up, they use tons of hydrogen. The hydrogen right now is produced by the steam methane reformation reaction which is pretty effective, but still releases a lot of carbon.

If they can actually start producing hydrogen from photosynthesis, then, they can start getting low carbon gasoline, and that’s what the whole play is all about.

So, of all the things, it seems the furthest away. Make machines act like plants, really? The fuel companies aren’t saying anything about it. Neither are they trying to be green. They’re just trying to comply with regulations and they think that this just might work.
Getting back to the title of the post, just how big are these two stories? If they reach their potential in efficiency and usefulness industrially, they are huge, though, for potential, I see artificial photosynthesis as the far greater story. I have yet to be convinced that biomass logistical problems can be overcome for efficient or economical conversion of biomass into biofuels, but the applications for plastics and chemicals, or smaller applications using on-sight biomass may hold promise.

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