Liquid Fuels from Algae

In the previous post, I discussed biofuels in general. Now I shall get more specific, with one particular source that I have worked on. That is attempting to make liquid fuels from macro and microalgae. I was recently sent the following link:

https://www.fool.com/investing/2017/06/25/exxonmobil-to-climate-change-activists-chew-on-thi.aspx

In this, it was reported that ExxonMobil partnering Synthetic Genomics Inc. have a $600 million collaboration to develop biofuels from microalgae. I think this was sent to make me green with envy, because I was steering the research efforts of a company in New Zealand trying to do the same, except that they had only about $4 million. I rather fancy we had found the way to go with this, albeit with a lot more work to do, but the company foundered when it had to refinance. It could have done this in June 2008, but it put it off until 2009. I think it was in August that Lehmans did a nosedive, and the financial genii of Wall Street managed to find the optimal way to dislocate the world economies without themselves going to jail or, for that matter, becoming poor; it was the lesser souls that paid the price.

The background: microalgae are unique among plants in that they devote most of their photochemical energy into either making protein and lipids, which in more common language are oily fats. If for some reason, such as a shortage of nitrogen, they will swell up and just make lipids, and about 75 – 80% of their mass are comprised of these, and when nitrogen starved, they can reach about 70% lipids before they die of starvation. When nitrogen is plentiful, they try to reproduce as fast as they can, and that is rapid. Algae are the fastest growing plants on the planet. One problem with microalgae: they are very small, and hence difficult to harvest.

So what is ExxonMobil doing? According to this article they have trawled the world looking for samples of microalgae that give high yields of oil. They have tried gene-editing techniques to grow a strain that will double oil production without affecting growth rate, and they grow these in special tubes. To be relevant, they need a lot of tubes. According to the article, if they try open tanks, they need an area about the size of Colorado to supply America’s oil demand, and a corresponding lot of water. So, what is wrong here? In my opinion, just about everything.

First, you want to increase the oil yield? Take the microalgae from the rapidly growing stage and grow them in nitrogen-starved conditions. No need for special genetics. Second, if you are going to grow your microalgae in open tanks (to let in the necessary carbon dioxide and reduce containment costs) you also let in airborne algae. Eventually, they will take over because evolution has made them more competitive than your engineered strain. Third, no need to consider producing all of America’s liquid fuels all at once; electricity will take up some, and in any case, there is no single fix. We need what we can get. Fourth, if you want area, where is the greatest area with sufficient water? Anyone vote for the ocean? It is also possible that microalgae may not be the only option, because if you use the sea, you could try macroalgae, some of which such as Macrocystis pyrifera grow almost as fast, although they do not make significant levels of lipids.

We do not know how ExxonMobil intended to process their algae. What many people advocate is to extract out the lipids and convert them to biodiesel by reacting them with something like sodium methoxide. To stop horrible emulsions while extracting, the microalgae need to be dried, and that uses energy. My approach was to use simple high pressure processing in water, hence no need to dry the algae, from which both a high-octane petrol fraction and a high-cetane diesel fraction could be obtained. Conversion efficiencies are good, but there are many other byproducts, and some of the residue is very tarry.

After asking where the best supply of microalgae could be found, we came up with sewage treatment ponds. No capital requirement for building the ponds, and the microalgae are already there. In the nutrient rich water, they grow like mad, and take up the nutrients that would otherwise be considered pollutants like sponges. The lipid level by simple extraction is depressingly low, but the levels that are bound elsewhere in the algae are higher. There is then the question of costs. The big cost is in harvesting the microalgae, which is why macroalgae would be a better bet in the oceans.

The value of the high pressure processing (an accelerated treatment that mimics how nature made our crude oil in the first place) is now apparent: while the bulk of the material is not necessarily a fuel, the value of the “byproducts” of your fuel process vastly exceeds the value of the fuel. It is far easier to make money while still working on the smaller scale. (The chemical industry is very scale dependent. The cost of making something is such that if you construct a similar processing plant that doubles production, the unit cost of the larger plant is about 60% that of the smaller plant.)

So the approach I favour involves taking mainly algal biomass, including some microalgae from the ocean (and containing that might be a problem) and aiming initially to make most of your money from the chemical outputs. One of the ones I like a lot is a suite of compounds with low antibacterial activity, which should be good for feeding chickens and such, which in turn would remove the breeding ground for antibiotic resistant superbugs. There are plenty of opportunities, but unfortunately, a lot of effort and money required it make it work.

For more information on biofuels, my ebook, Biofuels An Overview is available at Smashwords through July for $0.99. Coupon code NY22C

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Geoengineering: to do or not do?

For those interested in science, and in global warming, a recent issue of Nature (vol 516, pp 20 – 21) showed some of the problems relating to geoengineering, which involves taking action to change the climate. Strictly speaking, we are already doing it. By burning fossil fuels we are warming the planet through the additional carbon dioxide in the atmosphere. The question is, can we reverse this warming in a controlled fashion? The argument behind geoengineering is simple: we can either try it or not try it. If we do, we have the potential to create massive new problems; if we do not, sea levels will eventually rise somewhere between 20 – 50 meters, drowning all our coastal cities, destroying a surprising amount of some of the most productive farmland, and altering rainfall distributions quite dramatically. Then, of course, there are more violent storms. So, what are the options?
One is to try to increase the amount of light reflected to space, which can be achieved by forming more clouds. One way to do this is to spray salt water into the air. This has the advantage of being easy to do, and easy to stop doing. It is harder to know the consequences, but we should be able to predict to some extent because volcanic eruptions will do something similar to what is being proposed. Climate scientists, however, complain that this may reduce rainfall in some regions and possibly worsen ozone depletion. Of course they also warn that rainfall will be reduced anyway. Meanwhile, a computer simulation produced results that indicated changes in rainfall consequent to geoengineering “could affect 25 – 65% of the world’s population”. Charming! No comment that the changes could be beneficial. No comment either about the fact that any given model has consistently failed to predict details of weather.
However, from my point of view, the most bizarre outcome came from the proposal to seed the oceans to grow microalgae, which grow very rapidly and take up carbon dioxide in doing so. When the algae die, they should sink to the ocean floor and trap carbon. Trouble was, in some of the few experiments, it seems they did not, possibly because the algae did not die, or possibly because the experimenters did not count it properly. One other outcome might be that they get eaten by fish, thus improving the world’s food supply, and another might be that they give off dimethyl sulphide (and use up quite a bit of solar energy in doing so) which goes to the atmosphere, gets oxidized by absorbing more light, and then forms clouds, which reflects light. Ideal?
As a potential means of fighting climate change, I admit to liking this idea, nevertheless there is a problem, but not what you might think. Or maybe you would. Yep, it is financial embarrassment. Entrepreneurs decided to seed the oceans this way to generate large volumes of carbon credits, which could be sold to those who wanted to burn more coal, a sure way of reducing greenhouse gases! Yeah, right! Anyway, that was headed off by an international treaty, in which this activity was stopped by labeling it “ocean pollution”, and no further experiments have taken place. Talk about useless politicians!
The problem is as I see it that the politicians cannot seem to recognize that a technical problem needs a technical solution. The economists cannot solve this, as shown by that response to an emissions trading scheme noted above. The problem is, changing the prices of forms of energy cannot in themselves generate energy. Conservation may be encouraged, and that is good, but ultimately our lifestyle requires a very high fraction of what we currently use. Worse, there is no point in denying the fact that the planet is warming, and the only solution is to cool it. Cutting emissions is definitely desirable, but it is not enough to retain our previous climate because the gases currently there produce net warming, and this extra warming would continue for at least a hundred years if no further gases were emitted during that time. If we do not want to do something, who pays the price for what happens?