Climate Change and the Oceans

It appears that people are finally seeing that climate change is real, although the depth of their realization leaves much to be desired. Thus German politicians are going to close down their nuclear reactors and presumably burn more carbon. Not exactly constructive. A number of US politicians simply deny it, as if to say that if you deny it often enough, it will go away. Here in New Zealand we have politicians who say, yes it is real, but what they are doing about it tends to be to encourage electric vehicles and bicycles, with a bit of tree planting. Good intentions, but perhaps the commitment is a little less than necessary, but still better than the heads in sand approach. So, consider the size of the problem: the Intergovernmental Panel on Climate Change has stated that to limit global warming to 1.5 degrees compared with pre-industrial levels could require the removal of 20 billion tonnes of CO2 from the atmosphere each year until 2100. That is a much bigger than average ask. However, planting trees is a start, and the good news is they keep working at it, year after year. So, what to do? In my opinion, there is no one big fix. The concept of beating climate change with a thousand cuts is more appropriate. Part of the problem is to persuade people to do something. They turn around and say, why me? Who pays?

As an example, it has been argued that in the US the application of biochar to soils could improve grain harvests by 4.87 – 6.4 %. The carbon tends to last for maybe hundreds of years, at least to some extent, so the argument goes that it will eventually pay for itself, but initially it is a cost. This works particularly well in acidic heavily weathered soils, where the yields are generally somewhat low because they do not hold nutrients well. This is also not exactly a single bullet solution, since with good uptake, it would sequester and offset about 0.5% of US emissions.

There was an article in a recent edition of Nature that summarised marine geoengineering. Rather pickily, they stated that none of the proposals have been rigorously tested scientifically nor published in peer-reviewed journals. Part of this gripe is fair: they complain that results have been published, but in places like websites that no longer work. That is a separate issue really, and provided the work is properly done, peer-reviewed journals, following editorial contractions to save space, may not be the best. But let us leave that for the moment. The oceans are an attractive place for one reason: they are not doing much else other than being a place for fish to live in. Land tends to be owned, and much is either required for environmental reserves or food production. Certainly, there is a lot of land that is little better than waste, often left over from previous forest harvesting, and there is no reason why this could not be planted. Another useful contribution, but what are the options for the sea?

The first approach noted by Nature is to try to reduce the albedo, by reflecting incoming sunlight. Two ways proposed for doing this would be to put films on the water, or to spray water upwards and let it form clouds. The latter should be reasonably harmless, leaving aside the problem of whether some places might be adversely affected, a problem that applies to any such proposal. The former could have a serious adverse effect on marine life. Squirting water into the air to form clouds would seem to reasonably easily tested, but it also leaves the question, who is going to do it because ultimately this concept involves a cost for which there is no return.

Two more processes noted in the article are the spreading of alkaline rock into the sea to absorb CO2, and the spreading of iron-rich fertiliser to promote the growth of microalgae. The problem for the first is what sort of rock? A billion tonne of burnt lime per year would do, but first it would have to have its CO2 pyrolysed off, so that would emit as much as it saved. We could try basalt, such as peridotite, but if we powdered that it would make more sense to apply it to land where previously we had applied lime because it does much the same job, but also absorbs carbon dioxide. The iron fertiliser case is more interesting. There have been experiments to do this. An example: a ship sailed around, spread the crushed rock, and found that yes, there was a microalgal bloom. However, they also concluded that the amount of carbon that was fixed by sinking to the bottom of the sea was insufficient to justify the exercise. That, however, omits two other thoughts. First, what happened to the algae? If it was eaten by fish (or mammals) that would increase the food supply, and an increase in animal biomass also fixes carbon. The second thought is that if it were harvested, it could well be used to make biofuels, which would reduce the requirement for oil consumption, so that is equally useful. Can it be harvested? That is a question that needs more research. As a general rule, if there is just one thing that needs doing, there is usually a way, if you can find it. The making of fuel is easy. I have done it. There is, of course, the problem of making money from it, and with the current cost of oil that is impossible. Also, scale-up is still a problem to be solved.

The final two proposals were to cultivate macroalgae and to upwell deep water and cool the top. The latter does nothing for the carbon problem, so I shall not think too hard about that, but it is almost essential for the former. In the 1970s the US Navy carried out experiments on growing macroalgae on rafts in deep water, and they only grew when deep water was brought to the surface to act as a fertiliser. These algae can also be used as fuel, or the carbon absorbed somewhere else, and some algae are the fastest growing plants on Earth. It is quite fascinating to watch through a microscope and see continual cell division. This may be easier than some think. Apparently floating Sargassum is filling up some sections of the Atlantic and off the coast of Mexico.

So the question then is, should any of this be done? The macroalgae probably have the lowest probability of undesired side effects, since it is merely farming on water that is otherwise unused. However, to absorb enough carbon dioxide to make a serious difference an awful lot of algae would have to be grown. However, the major oceans have plenty of area.

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