Biofuels are touted as environmentally friendly substitutes for fossil fuels. Nick Slawicz drills into the details.
In the search for a replacement for petrol and diesel, biofuels once seemed the perfect solution: they can be grown naturally, actually absorb CO₂from the atmosphere as the plant material grows (releasing it upon combustion to be carbon neutral overall), and – thanks to the wide variety of crops and waste products that can be turned into biofuel – are suitable for implementation pretty much anywhere on the planet. Yet some argue that life isn’t that simple. Is it ever?
Biofuel production can generally be put into four distinct categories: first-generation, which refers to fuels made directly from sources such as starch, sugar, animal fats and vegetable oil; second-generation, which includes fuels made from waste products or non-food sources (including wheat stalks and specifically grown energy crops); third-generation, made from algae; and the catch-all fourth-generation, which is used to refer to all other means of biofuel production, including hypothetical new methods and those still in the experimental stage. In many ways, the four categories are massively different, each offering its own advantages and disadvantages with regards to environment cost.
All biofuel sources, it seems, are not created equal.
Three years ago, first-generation biofuels were voted bottom on a list of 18 technologies supposed to lower CO₂levels over the next 25 years. While 70 percent of respondents (governments, NGOs and private sector industry workers from over 100 countries) agreed that solar energy would help to lower overall carbon levels in the atmosphere without unacceptable side effects, and around 40 percent were willing to put their faith in nuclear and second-generation biofuels, only 21 percent believed that first-generation biofuels could compete (EurActiv, 2007).
Although efforts have been made to improve the foothold biofuels are making in the alternative energy industry, in recent years their effectiveness has been called into question owing to emissions of nitrogen compounds with a global warming potential (GWP) of approximately 300 times that of carbon dioxide, not to mention their effect on the ozone layer. Reports from the US National Oceanic and Atmospheric Administration note that nitrous oxide (N₂O) is currently “the most important ozone-depleting gas that is emitted” and is not yet regulated by the Montreal Protocol which phased out the use of CFCs in the 1980s and 1990s. It’s also going to be extremely difficult to control N₂O emissions, as they result from fertiliser use (and emerge in the production of most plant products, with the exceptions of legumes and a group of species known as actinorhizal plant that can capture and fix nitrogen from the air).
A recent report in the journal Nutrient Cycling in Agroecosystems found that “the contribution of N₂O emissions from fertilizer production and application make the greenhouse gas balance for certain biofuels small positive or even negative for some crops compared to fossil fuels”, because “N₂O is a 300 times more effective greenhouse gas than CO₂” and emissions of nitrogen compounds during the production of biofuel “might be a factor 2-3 higher than estimated up until now from many field trials”. A similar report in 2007 from Nobel Prize-winning chemist Paul Crutzen found similar reasons for concern, which were generally upheld by a third survey by the International Council for Science (ICSU) in 2008 It seems that the biofuel industry needs to convincingly address these issues before biofuel can be embraced as a viable energy source for the future.
That’s not to suggest that biofuels are a complete waste of time as the industry stands at the moment – they definitely are not. Certain plants (especially sugar cane and legumes such as soya) produce considerably fewer nitrogen compounds during the production process, making them valid options for future development – despite once again raising the “food versus fuel” debate. The potential for third- and fourth-generation biofuels is yet to be determined. Some of these crops can be grown on marginal land, as long as irrigation is possible and doesn’t deprive local populations. Experiments are currently taking place with salt-tolerant crops, in order that sea water may be used instead of fresh water.
So what can you do if you’re thinking about investing in a green company? The answer is simple: ask; probe; research. Insist on details. Look at reports from the companies themselves – and from independent scientists and journals. Run an internet search on the production method used. Enquire as to the total environmental impact of the plants being grown, specifically including their nitrogen compound emissions. Probably one of the most pragmatic people when it comes to biofuels is venture capitalist Vinod Khosla (www.khoslaventures.com). Keep an eye on his writings on the subject. As ever, don’t just rely on glossy brochures or websites before making investment decisions.