The Biofuel Controversy

Buses powered by soybeans. Agricultural waste transformed into car fuel. These possibilities have inspired governments around the world to include biofuels as a substantial part of their renewable energy standards, which mandate some percent of a country's energy come from renewable and/or carbon-free sources. The European Union will count biofuels towards their goal of using renewables for 10% of their transportation energy use, and the United States is aiming for 12% of energy in transportation to come from biomass by 2025.¹

But are biofuels truly the revolutionary oil replacement that governments hope them to be? They are generally renewable on annual to decadal timescales, depending on the type of crop used, but are they carbon-free? Policymakers assume so, but this is actually not the case. And how would the huge increase in biofuel production conflict with land use for food and animal feed?

These are central questions that must be answered before biofuels can be confidently included in renewable energy portfolios on a large scale. Here we explore answers that wave bright caution flags in front of the ambitious governmental goals described above.

What is biofuel?

A large part of the biofuel appeal is the wide range of plants, crops, and waste that can be used as the starting point. A biofuel is generally any fuel derived from a recently living organism, which can include animal fat and vegetable oil used for biodiesel, maize and sugarcane for ethanol, and cellulosic biomass from crop waste or grasses for a variety of uses.

This allows farmers, originally only in the food business, to reach a whole new energy market. Agricultural lobbyists are working to push for more biofuel subsidies, as evidenced by recent battles on Capitol Hill in the US when the EPA considered reducing biofuel mandates. Given the enormous amount of cropland in the United States, a large industry will reap the benefits if biofuel is deemed carbon-free and a valid alternative to meet renewable energy standards.

Faulty counting

Climate change weighs largely on the mind of policymakers trying to find fast ways to reduce carbon emissions and transition the transportation sector away from oil. Biofuels have the inherent advantage that they work with internal combustion engines already in most cars. This would allow an economy to transition to biofuels without the significant infrastructural change required for a new grid of plug-in stations for electric vehicles powered through solar energy or fuel cells.

Maybe it is this convenience that has created such a strong bias towards considering biofuels a carbon-free source. Almost all policymakers currently do so. The problem is that it's not true, and a double counting error made in almost all policy calculations overestimates the impact that biofuels use will have on carbon emissions.² Here's why.

All plants and trees act as a huge carbon sink to take in CO₂ from the atmosphere through photosynthesis - without this sink, our planet would be much hotter than it already is. Burning biofuel for energy use does release CO₂, but policymakers argue that this is balanced by the regrowth of the new biomass used for future biofuel production. The exact amount of CO₂ emitted by burning biofuels is reabsorbed by the crops being grown for the sole purpose of biofuel production.

At first glance, this argument looks great, but the problem lies in a hidden assumption that the land used to grow biomass for biofuels would not have already been a carbon sink before it was used for biofuel production.² Actually, biomass for biofuels would be grown on arable land on which trees, grass, prairies, etc. are already growing, happily absorbing CO₂ and helping to reduce the pace of global warming. This carbon sink would have to be removed to grow the biomass for biofuels, which essentially creates a net gain of zero in terms of carbon sink size. When the biofuel is later burned as fuel, this would emit CO₂ to the atmosphere, contributing to greenhouse gas emissions and global warming in the same way as fossil fuels. The double counting comes from incorrectly counting the carbon sink from the natural woodlands already in existence on top of the carbon sink from the grown biomass (read Reference 2 below for more details on this argument - it's not intuitive at first but well worth thinking about!).

Food or fuel?

The only way that biofuels could help reduce emissions is by reserving additional land not currently acting as a carbon sink to be used for biofuel production. This is a possibility for specific types of biomass, for example, algae grown in ponds or liquids that do not absorb CO₂ alone,³ but large-scale biofuel production this way seems unlikely. Any region of the Earth that does not already have trees or grasses growing, like deserts, would be far from ideal for growing biomass. And much of the other arable land is used for farming, which already takes up over half of the Earth's land, so finding room for more biomass would be difficult!

This leads into the second problem with biofuels - they inevitably compete with land use for food production. Between 2006 and 2050, the world needs to grow 70% more calories worth of food to feed the growing population, known as the calorie gap (6500 trillion kilocalories!).² The Food and Agriculture Organization of the United Nations (FAO) also predicts that meat and milk production must be increased 80% by 2050.⁴ It's hard to overestimate the undertaking this will require in cultivating additional farmland, finding more water-efficient irrigation techniques, and increasing crop yield, since arable land is already a scarce and cherished commodity.

If arable land were used for biofuel production, this would only create pressures for other arable land to be used for farming, removing the carbon sinks through deforestation and leading to more CO₂ accumulation in the atmosphere. On top of this, research indicates that poor agricultural practices have degraded more than half of Africa's arable land, further constraining the potential land available for either food or biofuel production and increasing the competition between them.⁵

We live on a finite planet, and there's only so much land to go around. Globally, there are about 12 million square miles of arable land, and we lose about 38,000 square miles per year to poor land management.⁶ This is not the trend you want to see when considering introducing an energy source that requires more fertile ground that also competes with food production and a growing population. From a land management perspective alone, it seems to be better policy to focus on renewable technologies like solar or wind whose land requirements do not overlap with food production.

Is there still hope for biofuels?

So biofuels are not actually carbon-free, and they dangerously compete with arable land for food production during a time when the global population will increase to 9.6 billion by 2050. Is there no place for them?

There may be applications in small doses. Certain forms of biofuel would provide a carbon-neutral source that doesn't compete with food production. For example, using residue from crops would be a carbon-free energy source because they're taken from already-existing plants used for food and are otherwise burned by farmers anyway. To this end, recent research has developed a method to ferment crop residue on-site, in the crop fields, greatly reducing transportation and manufacturing costs to have the same process done in large factories.⁷

Municipal waste can also be used that would otherwise be combusted at landfill facilities, leading to carbon emissions. A company in Florida has just developed one of the first large-scale facilities to process such waste into ethanol, a significant achievement.

Overall, however, using waste and crop residue will never amount to enough biomass to be more than a niche in the energy market, and certainly not the sizeable 10-12% shares that governments hope can occur through large-scale devotion of crop fields to biofuel production. Policymakers must acknowledge how to truly count carbon emissions from biofuels and focus on the inherent unsustainability of taking resources away from food production. The first steps include changing the accounting books and removing biofuels from renewable energy standards.

References

1) OECD (Organization for Economic Cooperation and Development) and IEA (International Energy Agency). Biofuels for Transport. Paris: International Energy Agency Publications (2011).

2) Searchinger, T. and Heimlich, R. Avoiding bioenergy competition for food crops and land. Installment 9 of Creating a Sustainable Food Future. Washington, DC: World Resources Institute (2015).

3) Lundquist T.J. et al. A realistic technology and engineering assessment of algae biofuel production. Energy Biosciences Institute (2010.

4) Searchinger, T. Understanding the trade-offs between indirect land use change, hunger and poverty. Princeton, NJ: Princteon University Monograph (2013).

5) Glatzel, K. et al. No ordinary matter: conserving, restoring and enhancing Africa's soils. Montepelier Panel Report (2014).

6) FAO (Food and Agricultural Organization of the United Nations). FAOSTAT. Rome: FAO (2013).

7) Horita, M. et al. On-farm solid state simultaneous saccharification and fermentation of whole crop forage rice in wrapped round bale for ethanol production. Biotechnology for Biofuels, 8, 9 (2015).

Photo Credit

Soybean bus photo by Vincecate at Wikipedia

Arable land diagram from Wikipedia