Monday, 26 June 2017

The power of pond scum: are microalgae biofuels a realistic proposition?

I've previously discussed some very humble organisms but they don't get much humbler than microalgae, photosynthetic organisms that generate about half our planet's atmospheric oxygen. Imagine then what potential there might be for their exploitation in a world of genetic manipulation and small-scale engineering? The total number of algal species is unknown, but estimates suggest some hundreds of thousands. To this end, private companies and government projects around the world have spent the past few decades - and a not inconsiderable amount of funding - to generate a replacement for fossil fuels based on these tiny plants.

For anyone with even a microgram's worth of common sense, developing eco-friendly substitutes for oil, coal and gas is a consummation to be devoutly wished for, but behind the hype surrounding microalgae-derived fuel there is a wealth of opposing opinions and potential some shady goings-on. Whilst other projects such as creating ethanol from food crops are continuing, the great hope - and hype -that surrounded algae-based solutions appears to be grinding to a halt.

Various companies were forecasting that 2012 would be the year that the technology achieved commercial viability, but this now appears to be rather over-eager. Therefore it's worth exploring what happens when hope, high-value commerce and cutting-edge technology meet. There are some big names involved in the research too: ExxonMobil, Shell and BP each pumped tens to hundreds of millions of dollars into microalgae fuel projects, only to either make substantial funding cuts or shut them down altogether since 2011.
Microalgae-derived biofuel
Manufacturing giants such as General Electric and Boeing have been involved in research for new marine and aircraft fuels, whilst the US Navy undertook tests in 2012 whereby algae-derived fuel was included in a 50:50 blend with conventional fossil fuel for ships and naval aircraft. Even shipping companies have become interested, with one boffin-worthy idea being for large cruise ships to grow and process their own fuel on-board. Carriers including United Airlines, Qantas, KLM and Air New Zealand have invested in these kerosene-replacement technologies, with the first two of these airlines having trialled fuel blends including 40% algae derivative. So what has gone wrong?

The issue appears to be one of scale: after initial success with laboratory-sized testing, the expansion to commercial production has encountered a range of obstacles that will most likely delay widespread implementation for at least another quarter century.

The main problems are these:
  1. The algae growing tanks need to be on millions of acres of flat land and there are arguments there just isn't enough such land in convenient locations.
  2. The growing process requires lots of water, which means large transportation costs to get the water to the production sites. Although waste water is usable, some estimates suggest there is not enough of this - even in the USA - for optimal production.
  3. Nitrogen and phosphorus are required as fertiliser, further reducing commercial viability. Some estimates suggest half the USA's annual phosphorus amount would need to be requisitioned for use in this one sector!
  4. Contamination by protozoans and fungi can rapidly destroy a growing pond's entire culture.
In 2012 the US National Academy of Sciences appeared to have confirmed these unfortunate issues. Reporting on the Department of Energy goal to replace 5% of the nation's vehicle fossil fuel consumption with algae-derived biofuel, the Academy stated that this scale of production would make unfeasibly large impacts on water and nutrient usage, as well heavy commitments from other energy sources.

In a bid to maintain solvency, some independent research companies appear to have minimised such issues for as long as possible, finally diversifying when it appeared their funding was about to be curtailed or cut-off. As with nuclear fusion research, commercial production of microalgae fuels hold much promise, but those holding the purse strings aren't as patient as the researchers.

There may be a hint of a silver lining to all this, even if wide scale operations are postponed many decades. The microalgae genus Chlorella - subject of a Scottish biofuel study - is proving to be a practical source of dietary supplements, from vitamins and minerals to Omega-3. It only lacks vitamin B12, but is an astonishing 50-60% protein by weight. As well as human consumption, both livestock and aquaculture feed supplements can be derived from microalgae, although as usual there is a wealth of pseudoscientific nonsense in the marketing, such as the notion that it has an almost magical detox capability. Incidentally, Spirulina, the tablets and powder sold in health food outlets to make into green gloop smoothies, is not microalgae but a B12-rich cyanobacteria, colloquially - and confusingly - known as blue-green algae. Glad that's cleared that one up!

If anything, the research into microalgae-derived biofuels is a good example of how new technology and commercial enterprise uneasily co-exist; each needs the other, but gaining a workable compromise is perhaps just a tricky as the research itself. As for Government-funded projects towards a better future for all, I'll leave you to decide where the interests of our current leaders lie...