Are First-Generation Biofuels Sustainable?

(World Bio Market Insights) The sustainability of first-generation biofuels have attracted controversy, with questions around their true emissions savings and their impacts on other environmental metrics like water pollution and water consumption.

We look at recent scientific evidence on whether and how first-gen biofuels are contributing to climate mitigation and overall environmental benefits.

What are first-generation biofuels?

First generation biofuels are those made from corn, sugar cane, palm oil, and soybean oil. These have been the dominant feedstock for biofuels since the industry’s modern-day beginnings in the 1970s oil crisis when they were touted as the solution to the supply risks of petrochemicals.

Between 2015 and 2022, biofuel feedstock consumption increased 100%. Now, first-gen biofuels are a scaled, globally traded commodity and proponents say they are a vital market-ready alternative to fossil fuels.

Second generation biofuels made from non-food feedstocks, such as waste biomass or cellulosic biomass (from wood waste) are generally regarded as more sustainable. These have started to hit the market but have not achieved the same scale as first-gen biofuels.

Finally, we have third generation biofuels made from micro or macroalgae, as well as fourth generation feedstocks where genetically modified algae, cyanobacteria, and other microbes produce the fuel. Although technically feasible, these versions have not yet commercially scaled.

Biofuels can be a decarbonisation tool

In theory, biofuels in general are set to play an important role under global decarbonisation pathways modelled by the IPCC.

The international body recommends renewable liquid fuels, alongside low-emissions hydrogen, are vital in replacing petrochemical fuels in applications where electrification is not feasible: aviation, shipping, and heavy-duty land transport.

In practice, the extent to which switching from petroleum fuels to biofuels reduces carbon emissions and other environmental impacts varies by case, depending on the ways the feedstock is cultivated and industrially processed.

Genetic modification and new cost-effective production technologies have led to a ballooning in the global maize-based biofuel production industry. Another boost came from the US’ 2006 legal mandate for a certain percentage of fuel to include this biobased ingredient. Usually, around 10% of fuel in a US car gas tank consists of corn biofuel.

These were the conclusions of a paper in 2022 published by Colorado University researchers published their life-cycle assessmen of biofuels – a 360 degree view of the environmental impacts that come from each stage of biofuel harvesting, processing, and use.

They found that, as with all biobased products, the environmental impacts of the corn biofuel varies depending how they are produced. Corn crops grown with high nitrogen fertiliser will score poorly on wate pollution. Certain crop lands will have displaced biodiversity rich habitats, scoring poorly on biodiversity indiacots, while others have been grown on degraded land.

Their research made a significant contribution to the debate around the sustainability of biofuels because their analysis of US corn ethanol offers a very granular look at the supply chain. They conducted their life cycle analysis on a county-by-county basis, covering most counties in the US in 2017.

The researchers found that the average carbon intensity of US corn and soybean-based production and use amounted to 65.3 grams of carbon dioxide equivalent per megajoule of energy provided by the fuel. This is less than for petroleum-based gas, which emits 93 grams of carbon dioxide per megajoule that the fuel provides. So, biofuels can lower emissions, particularly when the corn feedstock has been grown in less carbon intensive ways.

A very recent review paper on the sustainability of sugarcane-derived bioenergy production in Brazil states that most sugarcane expansion there has occurred on what was formerly pasture land rather than rainforest.

The question then becomes how converting pasture land into sugarcane farms affects the environment: in particular, the soil’s carbon content, overall health, and its ecosystem services.

The most comprehensive soil carbon study of Brazilian sugarcane expansion looked at 135 sites where sugar crops displaced former natural vegetation or pastureland. In these cases, sugarcane cultivation leads to a net loss in soil carbon.

It takes 8 years for the new sugarcane crop on former natural vegetation to ‘earn back’ these carbon losses to the atmosphere – by displacing burnt fossil fuels – and 2 to 3 years for pastures.

The most promising pathway for biofuel sustainability is for producers to adopt more sustainable inputs like organic waste from farms and forestry as well as crops grown on degraded land unsuitable for human food or animal feed production. Adopting second-generation biofuels is one recommendation presented by the Royal Society paper on the environmental sustainability of biofuels.

One barrier in the way of changing the biofuels industry is that there is no standard way of auditing its supply chains so that policymakers can assess the true impacts of shifting part of fossil demand to renewable fuels.

These audits should account for the full spectrum of environmental impacts from feedstock to use and from greenhouse gas emissions to water pollution and biodiversity. Adding to the complexity of the task, standards for biofuel supply chain audits will have to give a methodology for assessing rural development and human health impacts. READ MORE