Study casts doubt on benefits of growing crops for biofuels

A study for the European Commission suggests growing biofuel crops can create more greenhouse gases than it saves.

Doubts have been cast on the EU’s biofuel policy in the wake of a European Commission study suggesting that growing biofuel crops may cause more greenhouse-gas emissions than it saves. 

Using biofuel in relatively small amounts can yield savings in greenhouse-gas emissions, but growing larger quantities might mean that “the environmental viability of biofuels is at risk”, according to the study, which was published by Commission’s trade department last week.

The EU’s law on renewables of 2008 sets a target of deriving 10% of transport energy from renewable sources by 2020. Since biofuel, in its various forms, is the most immediately available source of renewable energy in the transport sector, this suggests a significant increase in biofuel use. But green campaigners are concerned that the target will drive up demand for ‘unfriendly’ types of biofuel.

Indirect land-use change

The Commission’s trade department study explores the unintended consequences of growing biofuel crops on the use of farmland, a phenomenon known as “indirect land-use change”. The benefits in reducing greenhouse gas emissions are undermined when, for example, the use of agricultural land to grow biofuel crops displaces food production onto land that was previously forest or grassland.

The study makes a striking assumption that biofuel will make up only 5.6% of the EU’s road transport fuel in 2020 – significantly less than the 10% that national government leaders called for at the March 2007 European Council.

Even with a 5.6% target, the researchers still expect a net carbon saving. But the study found that greenhouse-gas savings diminish as biofuel production increases. An increase in biofuel use from 4.6% to 6.6% would “increase sharply the average emissions”, says the study.

Importantly, the study finds that there is no constant proportional relationship between increasing biofuel production and changing patterns in land use.

Instead, there is a tipping point: when biofuel production reaches a certain threshold, the demand for land increases more quickly. When demand for biofuel is fairly low, a farmer may turn to readily available spare land to grow biofuel crops. But as biofuel production expands, that stock of accessible land is used up, driving farmers to exploit forest or grassland.

Modest benefits

Timothy Searchinger, a professor at Princeton University, was one of the first researchers to argue that policymakers had to take indirect land-use change into account when considering whether to encourage the uptake of biofuel. His interpretation of the data in the Commission study is that beyond 4.6%, the benefits from biofuel are at best modest. “What you learn from this study is that, once you have used up the free land, the emissions either don’t get savings right away or you get increases,” he said.

But the Commission’s trade department finds that even where as much as 9.6% of transport energy comes from biofuel, there will still be some greenhouse-gas savings, though the savings are, on average, greatly reduced.

Searchinger said that the researchers were making a mistake in mixing up the average emissions with the marginal rate in moving from 4.6% to 9.6%. “After 4.6% they are going to reduce greenhouse-gas emissions, but only by a modest amount…remember, the whole theory of biofuels is not that they reduce emissions a little, but that they reduce emissions a lot.”

He also criticised the assumption that spare land is always free. “Nobody else treats this land as free and I don’t think it makes economic sense.”

“You always need reserve land. If we needed half the food that we need today we would need to have reserve land and if we needed twice as much food for biofuels and for other reasons, we would still need reserve land. These are your buffer lands.”

Others questioned the trade department’s starting-point, that only 5.6% of transport energy will come from biofuel. Nuša Urbanc?ic? at Transport and Environment (T&E), a campaign group, said that the Commission had chosen to base the study on 5.6% because “at that modest level biofuels still look environmentally reasonable”. T&E believes that a target of 7%-10% is more realistic.

‘Unscientific’ assumptions

The 5.6% figure is based on an assumption that one-fifth of all new cars sold will be electric by 2020. The 5.6% figure “underpins the concerns we have that the Commission would base [policy] on unscientific assumptions to show that biofuels are still good,” Urbanc?ic? said.

The Commission said that its study “makes progress towards a better understanding of the environmental and economic effects of biofuels and contributes to the Commission’s decision making process on this topic”.