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Environmental Impacts of Biofuels

The Emissions Issue

Apart from the security of supplies argument, the main reason for the push towards biofuels is their purported environmental benefits. The DfT (2007: 2), for instance, states that 'evidence from lifecycle analysis suggests that sustainable biofuels can offer significant reductions in greenhouse gas emissions compared with fossil fuels and so represent an opportunity to address climate change.' The EPA (2002) calculated that with a 40 per cent biodiesel mix, NOx would increase by around 4 per cent, particulate matter and CO would both decrease by around 22 per cent and hydrocarbons would decrease by about 36 per cent. If the biodiesel mix was increased to 80 per cent, the corresponding figures would be +9 per cent, -40 per cent and -60 per cent. Thus, emissions of most pollutants decrease with the use of biodiesel but emissions of nitrous oxides increase. The big gains are from a near-complete elimination of sulphur emissions, with reductions in hydrocarbons and other local emissions. Results of tests by the International Energy Agency support these findings; they conclude that 'Biofuels (ethanol and FAME biodiesel) generally produce lower tailpipe emissions of carbon monoxide, hydrocarbons, sulphur dioxide and particulate matter than gasoline or conventional diesel fuel.' They state, however, that ethanol-blended gasoline produces more volatile organic compounds (VOCs). They also point out that the hydrocarbons that are produced are different from those in conventional fuels and that the health effects of these hydrocarbons are not yet fully known.

Most research suggests that there will be slight increases in the emissions of nitrous oxides (NOx) as a result of the use of biofuels. However, tests also indicate that once sulphur has been eliminated from fuel (which seems entirely possible in the near term), this will enable the use of powerful NOx-breaking catalysts that cannot be used when sulphur is present. So, in the future, it is possible that the NOx gases can be reduced too, thereby improving the environmental credentials of biofuels.

The change in the level of emissions of carbon dioxide (CO2) resulting from a switch towards biofuels is much more debatable. The EPA (2002: iii) stated that they were 'not able to identify an unambiguous difference in exhaust CO2 emissions' between conventional fuel and biodiesel. Other research suggests that there is a 10 per cent increase in the tailpipe emissions of CO2 when using biodiesel, but that the sequestration effect of growing the plants to start with is calculated to offset this increase (DfT, 2007). Indeed the EPA state that 'it should be noted that the CO2 benefits commonly attributed to biodiesel are the result of the renew-ability of the biodiesel itself, not the comparative exhaust CO2.' This is very interesting given the arguments now looming over the land-use change effects of the push towards biofuels (see section on 'The land-take issue' below). The net effect on life cycle emissions of CO2 (but see below) is purported to be a reduction of between 10 per cent and 100 per cent, depending on what exactly is included in the calculation (eg the source of the biofuel, the amount and type of fertilizer used in the crop production and the energy used in the production process), the blend of fuel used and the type of conventional diesel to which the biodiesel is added (EPA, 2002). Emissions savings from biofuels can vary widely. The use of wheat-based ethanol produced CO2 savings from as little as 7 per cent to as much as 77 per cent in the United Kingdom (Defra, 2007).

Turning to energy efficiency, the EU estimates that fuel consumption increases by about 10 per cent with the use of biofuels. The IEA argues that because of the higher cetane number of biodiesel, it has a higher burning efficiency and this, combined with the fact that the lubricity of biodiesel is higher, means that the energy efficiency is just a little below that of traditional diesel.

The Land-Take Issue

Until recently, it was assumed that the benefits of biofuels were mostly positive. However, this notion is now being challenged. In 2007, the DfT (p 3) cautioned that 'major land-use change, particularly deforestation and draining of peat bogs, can completely negate the carbon saving from biofuels as well as causing damage to biodiversity and other ecosystem resources.' However, although local impacts were being recognized, it was not until late 2007, when the OECD (2007) published a report questioning the whole biofuels policy, that the global implications of their widespread use were fully realized. Searchinger (2008: 1) summarized the growing concern:

Previous studies have found that substituting biofuels for gasoline will reduce green house gases because biofuels sequester carbon through the growth of feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland. New analyses are now showing that the loss of greenhouse gases from direct and indirect land-use changes exceeds the other benefits of many biofuels over decades.

The issue is one of demand. For small quantities of biofuels, crops can be grown on marginal land and excess crops or leftover frying fat can be used without causing too much environmental damage. However, as global demand for biofuels increases, this approach is no longer tenable. Inevitably, the prices of the biofuel crops increase, which in turn causes distortions in global agricultural production as a whole, and land previously considered uneconomic is cultivated (including rainforest and wetlands, which contain extensive stores of carbon). In turn, increasing food prices impact particularly hard on the poorest in the world. Grunwald (2008) attributes food riots in Mexico and the destabilization of Pakistan to soaring corn prices, which themselves are a result of increased ethanol production for fuel in the United States. He concludes by stating that 'biofuels aren't part of the solution at all. They're part of the problem,' a view that Sperling (2008: 5) concurs with in relation to the corn ethanol produced in the United States. He states: 'In sum, corn ethanol is expensive and provides no net environmental benefits. The main societal benefit is a small reduction in oil imports, gained at a substantial cost.' According to Anon (2008) the palm oil industry has already used 6.5 million hectares of plantations in Sumatra and Borneo and removed an estimated 10 million hectares of rainforest in order to produce biofuels.

It is in the wake of these arguments raging over the environmental impact of biofuels that the UK government ordered the Gallagher Inquiry to consider the appropriateness of the RTFO target. The resulting report (Renewable Fuels Agency, 2008) suggested that the 2.5 per cent (by volume) target for 2008/09 be retained but that the 5 per cent target for 2010 should be extended to 2013/14 to allow for more understanding of the life cycle effects (DfT, 2008).

Previous analysis by the EU to assess the impact on prices of the 10 per cent by energy target by 2020 concluded that prices for agricultural raw materials would increase by 3 per cent – 6 per cent for cereals and by 5–18 per cent for oilseeds (DfT, 2007). The IEA (2004) has estimated that displacing 5 per cent of EU petrol and diesel consumption would take 20 per cent of EU cropland. The problem is that biofuels cannot be produced solely from crops grown in the EU and oils would still need to be imported from the United States and Asia (Environmental Audit Committee, 2008). Biofuels targets are now being revised until new research comes up with better solutions.


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