The broad term biofuels covers all solid, liquid or gaseous fuels made from renewable biological materials. Some biofuels can provide renewable and more environmentally friendly alternatives to fossil fuels. They may reduce greenhouse gas (GHG) emissions and dependence on unstable foreign suppliers. The former is particularly of interest for the transport sector, still heavily reliant on fossil fuels and as a result, responsible for some 14% of global emissions according to Statista data.

However, the environmental benefit and net zero status of biofuels varies widely and is highly dependent on land use. Recent studies in Nature and other journals have found that current land-use regulations are inadequate and consequently CO₂ emissions from biofuels production may actually exceed those caused by fossil diesel combustion. Some biofuels can also have higher emissions levels than fossil fuels on an energy-equivalent basis, depending on the feedstock and production process.

Moreover, demand for biofuels is anticipated to grow considerably with significant repercussions for land use as it necessitates the allocation of large areas of agricultural or natural land for growing crops. Fierce debate rages over what areas should be used for these crops and which sectors should receive the fruits of that labour.

Production and consumption
According to the International Energy Agency (IEA), the US, Europe, Brazil and Indonesia are responsible for most of the consumption growth of biofuels. The Agency predicts a 44% growth in demand for these fuels over the period 2022–2027, equivalent to 21bn litres. Its findings predict a 56% demand increase, or 79mn tonnes, for vegetable oil, waste and residue oils and fats over the same period, driven largely by the fact these types of biofuels meet GHG and feedstock policy objectives in the US and Europe.

The IEA’s Net Zero Scenario sees bioenergy transitioning to 100% sustainable sources of supply and use. This involves a huge reduction in the use of biofuels from food crops to avoid conflicts between food production and affordability. By 2050, bioenergy demand is expected to be met by solid bioenergy (about 60%), liquid biofuels (almost 30%) and biogas (over 10%).

Achieving this requires ‘concerted government actions to control the sustainability of bioenergy supply, facilitate the transition to advanced bioenergy, and maximise the efficiency of bioenergy production processes and use’, says the Agency. There must be no overall increase in cropland use for bioenergy production and no bioenergy crops cultivated on forested land.

As Leon Merfort, Doctoral Researcher at the Potsdam Institute for Climate Impact Research, speaking to New Energy World put it: ‘Sustainable sources for biofuel production are… sources that do not increase the pressure on land. That would be feedstocks grown on marginal lands, ie lands with rather low economic value, but still potential to grow, for example, modern lignocellulosic feedstocks, and residues/waste, ideally at the end of the value chain, to maximise the utilisation. The problem is that the potential is rather low.’

Demand for the most commonly-used wastes and residues is already close to supply limits. This is being fuelled by the renewable fuel standard, state-level low-carbon fuel standards, and tax credits for renewable diesel and biojet fuel under the Inflation Reduction Act (IRA) in the US; the consumption of renewable diesel and biojet fuel alongside the phasing out of palm oil and introduction of limits on other feedstocks in the European Union (EU); and increasingly stringent biofuel blending mandates in Brazil and Indonesia.

Indeed, demand for ethanol made using sugars and starches will likely help meet the growing need for biofuels this decade. The US can meet most of its requirements thanks to its domestic production of ethanol from corn grain, with supplements from soybean oil, rapeseed oil, and considerable used cooking oil and animal fats supply. Ethanol biofuel in the US is typically a 10% blend (E10) with gasoline.

Likewise, Indonesia uses domestic palm oil to make biodiesel and has a significant domestic supply. Brazil depends largely on its soybean oil and sugarcane for making ethanol biofuel. The latter tends to be used as a 100% ethanol fuel (E100) or in gasoline blends with 85% ethanol (E85).

Europe faces serious issues around meeting domestic supply and is looking elsewhere for bio-feedstocks. The EU has various measures in place to try to ensure the sustainability of its biofuels, including compliance stipulations about meeting sustainability criteria and achieving minimum lifecycle emissions savings compared to fossil fuels equivalents under the 2008 Renewable Energy Directive (RED). In January this year, the European Commission launched its Union Database for Biofuels (UDB) requiring the registration of all biofuels consumed in the EU.

Global policies needed
Without careful thought, the cultivation and production of biofuels can lead to more environmental issues and emissions than fossil fuels. This has attracted criticism. For example, a 2023 US federal lawsuit charged the Environmental Protection Agency (EPA) with ignoring the harm caused by biofuels production. The Center for Biological Diversity alleges that the EPA is failing to protect endangered species while setting new rules to expand national biofuels use over the next few years. Further, it claims that the EPA has avoided two court orders to investigate those impacts, motivated by the politically powerful corn lobby that depends on ethanol production. The UK newspaper The Guardian reported that the EPA refused to comment on the issue as it related to an ongoing lawsuit.

Some biofuels experts, such as Thuy Mai-Moulin, Group Sustainability Manager at Blue Phoenix Group, have more faith in the US and its regulations. Responding to a question about land-use and biofuels, she told New Energy World that in some regions there are enough abandoned fields to grow bioenergy crops – for example, some eastern EU countries. She adds: ‘In Southeast Asia or South America, I would be extremely cautious in biofuel purchase, but as long as we have biofuels certified by RVO – one of the most credible certification schemes, I can trust the sourcing.’ RVO stands for the US’ Renewable Volume Obligation, which is set by the EPA.

Nevertheless, researchers agree that land-use regulations are imperative for exploring bioenergy for climate change mitigation. One study, published in Nature last year, concluded that ‘comprehensive coverage (>90%) of carbon-rich land areas worldwide is key to containing land-use emissions’. Without it, bioenergy cannot provide the emissions reductions necessary to support the global energy sector’s transition to net zero.

The study’s lead author, Leon Merfort, told New Energy World that the findings demonstrate that: ‘One single jurisdiction does not have the levers to make biofuel production from purpose-grown plants sustainable. The only effective mechanism is a combined, globally-comprehensive ecosystem protection regulation, which is obviously missing.’ He added: ‘Even if single regions, for example the EU, have rather stringent forest regulations, this does not imply that [purpose-grown] biofuels being produced in that region can be labelled sustainable.’

However, Luc Pelkmans, Technical Coordinator at IEA Bioenergy, admitted to New Energy World that he was more optimistic. He said: ‘The aim is indeed to work towards internationally agreed frameworks and there has already been a lot of work and international cooperation on this. There is already an ISO norm… which specifies principles, criteria and indicators for the bioenergy supply chain to facilitate assessment of environmental, social and economic aspects of sustainability. But we do see that regions can put somewhat different priorities [depending on their markets, type of agriculture/forestry, climate conditions], so it is difficult to have one uniform international framework.’

When asked if there were any jurisdictions that already have sufficiently-stringent rules around biofuels’ sustainability and land use, Pelkmans pointed to Europe’s first Renewable Energy Directive (RED) in 2008 which ‘included a first strong set of requirements around biofuels sustainability, particularly in terms of greenhouse gas emissions reduction and land-use impacts. These requirements have been further strengthened in the second version of the RED in 2018 and the third version in 2023’.

He added that the US, and in particular California, as well as Brazil, through its RenovaBio programme, also have quite stringent rules related to the climate impact of biofuels (including land use).

Building on Pelkmans’ answers were comments from Göran Berndes, Professor of Biomass and Land Use in the Division of Physical Resource Theory in the Department of Space, Earth and Environment at Chalmers University of Technology (Sweden). He explained: ‘Bioenergy systems are often components of value chains or production processes that produce multiple bio-based products. It can therefore be difficult to disentangle “bioenergy impacts” (positive or negative) from impacts associated with other products provided by the forestry and agricultural sectors.’

‘One single jurisdiction does not have the levers to make biofuel production from purpose-grown plants sustainable. The only effective mechanism is a combined, globally-comprehensive ecosystem protection regulation, which is obviously missing.’ – Leon Merfort, Doctoral Researcher at the Potsdam Institute for Climate Impact Research

A solution to decarbonising transportation?
Transportation is a significant contributor to GHG emissions, which biofuels could assist in decarbonising. Most road vehicles built since 2000 can use gasoline-ethanol blends of up to 15% ethanol by volume (E15) without modification. This is useful in the short term whilst the existing fleet is being replaced, particularly for long-distance, heavy vehicles.

Pelkmans suggested: ‘For the medium- to longer-term, there is more focus on “difficult to abate” transport sectors that will continue to rely on liquid fuels to operate. In particular, aviation and marine transport come into focus and some regions (like the US and the EU) have specific programmes to support this.’

However, once again, the limited availability of land for biofuels curtails the decarbonising potential of biofuels. For instance, to completely replace fossil fuels in aviation, the world would need to use four to five times as much land for growing biofuels as it uses today. If all the world’s biofuels today were used for aviation, they would only meet one-third of global demand.

Aviation demand is predicted to increase steeply. However, the conversion of natural land to biofuels crops would create far more emissions and reduce the planet’s ability to absorb CO₂, lead to major competition for using crops for food and is energy-intensive and costly for airlines compared to using traditional jet fuel.

Sanjay Relan, General Manager in Optimisation & Decarbonisation at Pacific Basin Shipping, also discussed the use of biofuels for shipping. He said there are at least 60,000 ocean-going vessels with engines that cannot burn methanol, hydrogen or ammonia, and less than 5% of these can be retrofitted. With both aviation and shipping competing for the limited supply of biofuels, Relan suggested that biofuels crop production should be scaled up.

Relan stated that much agricultural land is currently used for rearing cattle or growing cattle feed, and that a global reduction in meat and dairy consumption would make more of this land available for biofuels. In addition, it would reduce the considerable emissions and water wastage caused by the meat industry, as rearing cattle contributes to between 11–19% of annual emissions while shipping emissions are around 2.5%. The problem lies in changing people’s diets.

Alternatively, he indicated that there may be enough waste crops available worldwide for sustainable biofuels. Sugar cane, olive oils, rice and other crops present 10.5bn tonnes of available bio-waste which is often being incinerated. This quantity is sufficient to produce 3bn tonnes of fuel oil, 10 times the annual demand of shipping. On the downside, the scaling up and delivery of biodiesel produced from bio-waste would be a major challenge.

When asked which sectors should be prioritised for receiving biofuels, Relan said: ‘Shipping is the workhorse of international transport with more than 80% [of cargo] being carried by sea. It needs to be getting ahead of aviation to buy any sustainable biofuels. Sustainable biofuel is the only drop-in fuel that current engines can burn on ships... It is very much a viable solution, but I do not see that it will be available in sufficient quantity.’

• Further reading: ‘A new era for biofuels traceability in Europe’. An introduction to the EU’s new bioenergy database.
• Find out how biofuels are a big success story in Brazil, where government mandates and a preference for flex-fuel vehicles sustain biofuels’ prominence.