Chris Christie, 18th May 2009
Passenger jets cruise at 10,700m (35,000ft) without a hiccup; in the US, catfish farmers lease ponds to biofuels entrepreneurs and venture capitalists sink $1billion or so into the lure of infinite green crude.
Read the media and one could be forgiven for believing that it won’t be long before we are filling the tanks of our vehicles with clean fuel mass produced via cultivating algae.
The idea of cultivating algae is not new. Energy’s editor was involved in precisely that several decades ago when working for the then UK White Fish Authority – but to provide a high-grade feedstock for feeding hatchery-reared baby oysters.
That was back in the late-1960s and early-1970s, and it worked, though the cultures were highly sensitive to variations in salinity and balance of nutrients. Cultures could crash overnight – literally.
Today, the main focus with algae is harvesting energy cleanly and sustainably, and among the leading proponents of this work is the National Renewables Energy Laboratory (NREL) in the US, following 10 years in limbo.
NREL’s work has resumed more than a decade after its original algae fuels programme was curtailed because the fuels were considered too costly to compete with petroleum.
Today, even though oil prices are back on the rise, algae-derived fuels are nowhere near close to being economically competitive with petroleum. So why the revival of interest?
The answer lies in a cocktail of forces: record high crude oil prices in 2008 with the prospect of big near-term rises as the impacts of recession are overcome; instability in the Middle East and other oil exporting regions, and climate-change worries.
Public interest has been captured after recent algae fuel demonstrations, including airliner test flights using blends with conventional jet fuel – most recently in Houston, by Continental Airlines.
However, it was Sir Richard Branson’s Virgin Atlantic that pioneered the use of biofuels, albeit based on babassu and coconut oils rather than algae, making a scheduled flight in February, 2008.
The Boeing 747-700 flew from London to Amsterdam carrying a 20% mix of biofuel in one of its four fuel tanks.
Some airlines and engine manufacturers hope to be using algae/other biofuel blends within a few years.
“I’m getting calls every day from people who want to get into algae fuels,” said Al Darzins, a group manager and principal researcher in NREL’s US National Bioenergy Centre.
“There are hundred of companies looking into it now here, in Europe and the Middle East.”
But he warns that “pond scum” will not be ready any time soon for commercial use. Indeed, “not remotely”.
Darzins says that biological questions about the organisms and engineering questions related to fuel production, distribution and quality standards must be answered for algae fuels to be competitive with oil currently priced in the $50-60 range.
“All we’ve really seen are tests involving one engine of a jet running on a blend using a small percentage of algal fuel – and there were no passengers, of course,” Darzins said.
“In my book, that’s a long way from commercialisation.”
However, NREL insists that the prospect is tantalising.
In a nutshell, algae are like microscopic factories using photosynthesis to transform carbon dioxide and sunlight into lipids, or oil. Some strains can double their weight in a few hours under the right conditions.
Algae can grow in fresh, salty or even contaminated water, and can generate 30 times more oil per acre than plants cropped for biodiesel and other biofuels. And algae don’t compete with food crops.
Scientists think algae might grow fatter and faster if they were force-fed extra CO, which could help alleviate the build-up of greenhouse gases. Smokestack emissions from power plants and other sources could be diverted directly into the ponds, feeding the algae while keeping greenhouse gases out of the atmosphere.
CO was used by the White Fish Authority in the late-1960s to promote growth in much the same way, so there is nothing new about the idea.
From 1978 until 1996, NREL pioneered research with its Aquatic Species Program under which scientists screened and characterised more than 3,000 potential strains; shed light on the growth conditions that stimulate lipid production; demonstrated open ponds for mass production of biomass, and made significant breakthroughs in genetic engineering.
Today, NREL has resumed that work, putting a greater emphasis on understanding the basic biology. When these micro-algae are starved of the nutrients they need, their lipid content can increase as much as 60%.
NREL’s algae experiments are currently limited to one-litre flasks under fluorescent light (again like the WFA). The plan is to upscale to 250 litres under natural light conditions, which can be 10 times more intensive than artificial lighting.
Again, there are uncanny parallels with the WFA work of 40 years ago in the UK.
“Some strains that look good now may not maximise photosynthesis when we scale up or expose them to natural light,” Darzins said.
Within a few years, the NREL scientist hopes to complete construction of outdoor ponds that will test algae strains, production systems and harvesting methods at scales up to 100 acres.