A few years ago, biofuels were being heavily promoted as environmentally-friendly alternatives to fossil fuels. At first glance, they appeared capable of answering our mounting energy woes: they’re made from plants that grow up around us year after year and burn relatively cleanly while also eliminating the need to drill for nasty, polluting oil. Indeed, investors and governments were taken in and by now biofuel targets are enshrined in legislative policies from Brussels to Washington.
At a European level, the EU Renewable Energy Directive requires that 10 per cent of energy used in transport be ‘renewable’ by 2020 and in 2008/09 the UK surpassed the government’s goal of increasing biofuel’s share of road transport fuel to 2.5 per cent (or 1.3 billion litres). Perhaps more worryingly, our car-crazy cousins across the Pond have enthusiastically embraced the idea of biofuels: their government has thrown billions upon billions of dollars into them and the US Energy Independence Security Act of 2007 calls for 36 billion gallons of renewable fuels from biomass per year by 2022 (more than 136 billion litres).
I say this is perhaps worrying because we’ve come to realise that biofuels aren’t necessarily as wonderful as they first seemed. Kenneth Richter, Friends of the Earth’s biofuels campaigner, explains the drawbacks: “The impacts go under three main headings. One is biodiversity – when you’re expanding palm oil plantations or soya or other crops, then usually a lot of that happens at the expense of natural forests and rainforests. The second is social impacts – in countries like Indonesia land rights for people who have lived in the forest for thousands of years are not being recognised, and also the demand for agricultural land is pushing up food prices in the world. The third thing is that in many cases the biofuels don’t save any emissions and in fact the opposite is true.”
The question of emissions calculations is indeed a contentious one. While advocates claim biofuels create substantial environmental and carbon savings, many others disagree. The Renewable Fuels Agency’s (RFA) first annual report to Parliament following The Renewable Transport Fuels Obligation Order 2007 (which requires transport fuel suppliers to ensure that five per cent of their fuel is ‘renewable’ by the end of this year) found that in 2008/09, biofuels used in the UK delivered a 46 per cent carbon saving compared to fossils fuels, but, significantly, the methodology did not account for indirect effects.
Ann Ballinger, a consultant for Eunomia, claims that calculating emissions for biofuels is “much more complicated than is normally suggested”, and indeed there are many factors that affect a fuel’s impact on emissions. For first-generation biofuels made from food crops like corn, soya or palm, you must consider direct emissions created by growing the plants and converting them into fuel, and also things like transport, fertiliser use and changes in land use. The effect of fertiliser is significant partly because its production is carbon intensive, but mainly because, as Richter notes: “If you put a lot of nitrogen fertiliser on the fields, then you get emissions of nitrous oxide, which is 300 times more potent than CO2.”
The most often ignored factor by far, though, is the impact of land-use change. According to Richter: “If you’re cutting down forests to make huge plantations of palm oil, you’re releasing huge amounts of CO2 both from the vegetation as well as the soil and it’s particularly bad when it happens on peat land because peat releases a lot of both methane and CO2.” What’s more (and this is the bit that’s most often ignored), even when biofuel growth doesn’t directly cause destruction of forests, it often indirectly does, as in Brazil – the world’s largest exporter of ethanol – where sugarcane for biofuel is taking over more and more agricultural land in the un-forested south, thus displacing cattle to the north and into what was once rainforest.
First-generation biofuels still constitute the bulk of those used to reach governments’ renewable fuel goals, but most people now agree that they will not solve the problems of energy and emissions (a biofuel plant that would have run initially on palm oil was recently refused permission in Bristol and even the US government has limited the amount of fuel that will be coming out of the ‘Corn Belt’ by capping corn ethanol production at 15 billion gallons per year). But what of so-called ‘second generation’ or ‘advanced’ biofuels, made from things like cellulosic waste or algae?
Richter, for one, advises caution, and points out that these fuels could also have drawbacks: “Cellulosic ethanol basically means you’re turning the whole plant including the woody bits into a biofuel, which is more efficient, but there are also dangers. If you’re using all the straw and everything from the field, then you’re depleting the soil because you’d normally plough some back in and put nutrients back in. Also, there have been studies that found cellulosic ethanol doesn’t necessarily have better greenhouse gas saving characteristics.” Indeed, a 2008 Stanford University study found that cellulosic ethanol performed marginally better than corn ethanol in terms of emissions, but worse than any other form of power generation, including fossil fuels.
As for algae, which advocates claim can produce many times more oil than traditional biofuel plants and thrive on being fed extra CO2 or sewage, Richter cautions that, if they are grown in the open ocean, there could be problems with uncontrolled algal blooms and if they are grown in tanks or ponds (potentially of wastewater), it would still require a lot of land: “One figure from ExxonMobil is that algae are three times more land-efficient than palm oil, which isn’t actually that great. It still means you would need the amount of land twice the size of Greater London of individually managed ponds to meet the 10 per cent target for the UK.” What’s more, a recent report by the University of Virginia has shown that algae production consumes more energy, has higher greenhouse gas emissions and uses more water than other biofuel sources like corn or switchgrass.
It seems that the more research that is done, the less attractive biofuels become. But one area where this might not be the case is with biofuels from organic waste, where those indirect effects – which make most biofuels so unsustainable – could actually be positive. Ann Ballinger was involved in producing a report for DECC and the RFA on the indirect effects of using wastes, residues and by-products for biofuels, and she notes: “Those indirect impacts are not always negative. In the case of waste, for example, the indirects we were looking at were associated with where the waste would be treated if it wasn’t treated in a biofuel-type process. So, you actually get a positive indirect impact there because if you were, for example, landfilling the waste, then the environmental implications of landfilling that waste would be negative.” Indeed, the report found that the total impact of switching municipal solid waste away from landfill to anaerobic digestion (AD), for example, represents a benefit of 3,618 kilogrammes of CO2 equivalent (kg CO2e) per tonne of biogas produced. Using biogas as transport fuel, therefore, represents a carbon saving of 193 per cent over fossil diesel.
At the moment, though, biogas resulting from the AD process is not always used as a biofuel, and in fact, government policy – in the form of Renewables Obligation Certificates and Feed-in Tarrifs for electricity – encourages companies to use biogas to generate electricity instead. Ballinger has also investigated different uses for biogas from AD and found that using it to generate electricity results in fewer carbon savings than using it as a liquid vehicle fuel, largely because heat and electricity are both lost when biogas is combusted in a gas engine for electricity generation. Her research found
that using the biogas created from the AD treatment of one tonne of source-separated organic waste to generate electricity saves only 100kg CO2e, whereas using it as a biofuel saves 150kg CO2e.
According to Ballinger, because so many factors affect the sustainability of biofuels, “it makes it very difficult to be sure you’re going to get emissions reductions when you use these types of fuels”. Interest in biofuels just isn’t going away, though. In addition to all the government targets for road fuel, the aviation industry is now also investing and British Airways has vowed to create 16 million gallons of jet fuel through gasification of waste biomass every year by 2014. New biofuel technologies are emerging by the day and people are eagerly embracing them. Again, at first glance, some appear like they might help to answer to our mounting energy woes. But this time, we must be sure not to be taken in too soon – the last thing we need is another intended boon that turns out to be a blight.