It’s hard to think that the annoying slime that turns your pond water green in spring and early summer could be the future of biofuels – but that’s a possibility that a surprising range of research institutions, private firms, oil companies, NASA and even the Pentagon are looking at very carefully.
Admittedly, it’s not exactly a new thought; the first suggestion that algae could be used as an alternative form of fuel emerged back in the dark days of World War II – in 1942, to be exact – and the idea has resurfaced periodically at fairly regular intervals ever since. Today, however, many think algal fuels have come back in the spotlight at just the right time, as the economics of oil prices, the uncertainty of supply, and the widespread desire to reduce fossil fuel dependency make conditions ideal for its uptake.
It’s been debated in the House of Commons, and suggested as a sustainable alternative to fracking, so, just what is so special about algae, and is it really going to be the fuel of the future?
Advantages of Algae
One of the great potential advantages that algae has as the starting point for biofuel is that it gets around the principal problem typically levelled at other plant candidates – its production doesn’t lead to competition for agricultural land. Obviously there’s not much of an environmental gain if the end result of making ‘green’ fuel is impoverished local food production, especially since the places most suited to growing biomass crops tend to be the emerging nations of the world. Since algal cultivation simply needs a site – not good, fertile soil – it can easily be carried out on land which is unsuitable for agriculture.
Although, obviously, it does need to be grown in water, algae itself has no real impact on water resources, and can be grown in brackish water – or even in many kinds of wastewater – and in the event of spillage or release, it is a highly biodegradable material, and so does little to harm to the environment.
Expensive but Productive
In fairness, it has to be said that algae does not have it all its own way. The growing facilities are relatively big-budget items to build in the first place, and costly to run, which means that compared with other land based biomass plant operations, it is considerably more expensive on a like for like basis, although algae is said to be much more productive per acre.
In that regard, while some of the massive estimates of algal productivity which have been quoted over the years are hard to take seriously, there is solid evidence from reputable sources that some kinds of algae can achieve three times the plant oil yield of the best land-grown biofuel crops. According to NASA, for instance, the pyramidal micro-alga Botryococcus braunii can produce a staggering 1,760 gallons of oil per acre.
Exciting New Breakthrough
At the end of 2013, a new breakthrough was announced that could soon see that oil being turned into a fuel cheaply and quickly enough for it to compete with conventional petrol or diesel.
Researchers at the US Department of Energy’s Pacific Northwest National Laboratory have found a way to process algae into a type of crude oil substitute in under an hour. This algal-crude can then be subsequently refined using the same technology used for petroleum crude to yield useable fuels, and according to estimates of the costs at full commercial scale, could sell for as little as $2 a gallon. Obviously US and UK forecourt prices are very considerably different, but ‘green’ algal petrol at little more than £1 a gallon really would be quite something!
Like algal fuels themselves, the technique itself isn’t entirely new; it’s a version of a process that rejoices in the name “hydrothermal liquefaction” – something first proposed back in the 1970s – but this time given a few tweaks and twists to make it more cost effective.
In essence, it’s a long, thin pressure cooker that cooks a mixture of one part algae to four parts water at a temperature of around 350ºC, and a pressure of 3,000 pounds per square inch. In many ways, the process is replicating the natural events that formed crude oil in the first place – only speeding up the millions of years it took to around 60 minutes.
At the end of that hour, a bio-oil, chemically similar to light sweet crude oil will have been formed; the yield is slightly over half the original weight of algae put in.
Does this mean algae finally is going to let us break our dependency on petroleum-based oil and become the new and – quite literally – ‘green’ fuel of the future?
It’s probably too early to say for certain. After having invested $600 million US dollars in algal research, the international oil major ExxonMobil concluded in mid 2013 that algal fuels were (then) probably more than 25 years away from being commercially viable.
This latest discovery, however, now seems to have brought that day a good deal closer, and while there’s obviously still a way to go before algal fuel becomes mainstream, it looks increasingly likely that sometime around the middle of the century, it really will be at filling stations everywhere.
Makes you look at slimy green ponds a bit differently, now doesn’t it?