Overcoming Barriers to Sustainable Bioenergy: Key Challenges

Bioenergy holds genuine promise as a renewable energy source – it already accounts for around 60% of the world’s renewable energy supply, dwarfing contributions from wind and solar. Yet scaling it up sustainably is far from straightforward. From competition over land and water, to the high costs of advanced production technologies, to serious ecological trade-offs, bioenergy sits at the intersection of some of the most complex resource challenges of our time. Understanding these barriers is the first step toward addressing them.

Resource competition: land, water, and food security
Technological and economic barriers
Environmental trade-offs
Deforestation and land-use change
Soil degradation
Food security
Path forward for sustainable bioenergy
Innovations in feedstocks and production
Policy and governance solutions

Resource competition: land, water, and food security

Every hectare devoted to growing energy crops is a hectare unavailable for food production or carbon storage. This is the core tension at the heart of bioenergy’s resource challenge. According to the World Resources Institute, any dedicated use of land for bioenergy comes directly at the cost of not using that land for food, animal feed, or sustained carbon storage. The world already faces a projected 70% gap between crop calories available in 2006 and those needed by 2050. Expanding crop-based biofuel targets could push that gap even higher, to around 90%.

The water dimension compounds the problem. Bioenergy crops are thirsty. First-generation feedstocks like maize and sugarcane require substantial irrigation, while even third-generation algal biofuels carry a significant blue water footprint – estimated at 8 to 35 cubic metres per gigajoule. At regional scales, this can place serious pressure on freshwater supplies, even when the global impact appears manageable. Areas already experiencing water scarcity are particularly vulnerable.

There is also a socioeconomic dimension. When biofuel demand drives up prices for food crops like maize or vegetable oils, net food consumers – particularly lower-income households – bear the costs. Research published in Frontiers in Sustainable Energy Policy notes that between 2005 and 2018, global biofuel production more than tripled, with the rapid expansion of biomass cultivation directly displacing food crops in several regions, raising food prices and triggering broader supply chain disruptions. One partial solution is the use of abandoned or degraded cropland. A Nature Sustainability study identified 83 million hectares of abandoned cropland globally between 1992 and 2015, estimating that growing perennial grasses on this land could meet 11-68% of current bioenergy demand with only a 3% increase in global cropland area and an 8% increase in water use – and without encroaching on biodiversity hotspots or water-scarce regions.

Technological and economic barriers

First-generation biofuels – corn ethanol, palm biodiesel, sugarcane ethanol – are produced using mature, commercially established technologies. Their problem is that they compete directly with food systems. Second-generation (2G) biofuels, made from non-food lignocellulosic biomass like agricultural residues, wood chips, and grasses, promise to sidestep that issue. However, they face a different set of challenges: high production costs and technological complexity.

The central technical difficulty is recalcitrance – the structural resistance of lignocellulosic material to chemical breakdown. Converting cellulose and hemicellulose into fermentable sugars requires costly pretreatment processes and large quantities of specialized enzymes. According to a review in PMC, commercial production of cellulosic ethanol remains hampered by high research and production costs, with the three main processing steps – pretreatment, enzymatic hydrolysis, and fermentation – each generating their own bottlenecks.

The economics are stark. A comprehensive economic review in Energy Policy found that the cost of cellulosic ethanol is two to three times higher than gasoline on an energy-equivalent basis, while biodiesel from microalgae can cost as much as seven times the price of conventional diesel. Capital investment requirements also dwarf those for first-generation plants.

Real-world commercialization efforts have largely validated these findings. Analysis from the University of Illinois Chicago’s Government Finance Research Center documents how pioneer cellulosic biofuel plants in the United States faced poor economic returns and low technological readiness, compounded by policy uncertainty and low oil prices. By 2022, actual cellulosic biofuel production from agricultural feedstocks in the US represented just 0.21% of the mandated target. Even Brazil’s Raizen – among the most advanced second-generation operations globally – produced only 1.8% of its total ethanol output from cellulosic sources in 2024. Distribution infrastructure presents another layer of cost: biofuels require separate or adapted pipelines, blending facilities, and logistics networks, all of which add to the economic burden of scaling up.

A policy analysis by the International Council on Clean Transportation concludes that the most significant barriers to cellulosic biofuel deployment are ultimately economic, not technological: without major reductions in capital costs or sustained policy support, advanced biofuels risk remaining a perpetual “fuel of the future” rather than a present-day reality.

Environmental trade-offs

Deforestation and land-use change

Bioenergy is supposed to help fight climate change – yet under certain production models, it can accelerate it. When forests are cleared to make way for energy crop plantations, the carbon stored in those trees and their soils is released. According to the IPCC, tropical deforestation already accounts for roughly 20% of global greenhouse gas emissions, releasing approximately 1.5 billion tonnes of carbon annually. Bioenergy expansion driven by demand for wood pellets is now actively contributing to this trend. A 2024-2025 report from the Environmental Paper Network found that meeting projected biomass energy demand by 2030 would require a 13-fold increase in monoculture biomass plantations, with ongoing conversion of native tropical forests – particularly in Indonesia – to short-rotation plantations.

The problem is compounded by the concept of indirect land use change (iLUC). Even when bioenergy crops are grown on non-forest land, the displacement of food agriculture to other areas can trigger deforestation elsewhere in the supply chain. This is why the European Parliament has capped biofuels derived from edible crops like palm oil, corn, and soy at 7% of transport fuel, following evidence that many such biofuels emit more greenhouse gases than the fossil fuels they replace when iLUC emissions are included.

Soil degradation

Soil health is another concern. Intensive harvesting of crop residues or dedicated biomass crops reduces organic matter and nutrient content in soils, increasing the risk of erosion and long-term fertility loss. When agricultural residues like straw and corn stover are removed for bioenergy instead of being left to decompose, the soil loses the organic matter that sustains its structure and microbial life. A European Commission policy brief specifically flags the removal of agricultural residues as a pathway to reduced agricultural productivity over the long term, while also noting that fast-growing second-generation energy grasses like miscanthus and switchgrass can place significant pressure on local water supplies.

Food security

The food security implications of bioenergy are well-documented and extend beyond simple land competition. When government mandates drive food crops into fuel production – as occurs with maize ethanol in the United States and palm biodiesel in Southeast Asia – food prices rise globally. A review published in Renewable and Sustainable Energy Reviews found that among 427 observed land-use outcomes, trade-offs with food security and water availability were among the most consistent negative impacts of dedicated bioenergy crop production. The feedstock type and previous land use were more decisive factors in determining whether outcomes were harmful or beneficial than climate zone or soil type – underscoring the importance of context-specific bioenergy planning.

Path forward for sustainable bioenergy

The challenges are real, but they are not insurmountable. A combination of technological innovation, smarter feedstock choices, and robust policy frameworks is steadily narrowing the gap between bioenergy’s promise and its current limitations.

Innovations in feedstocks and production

The most promising near-term opportunities lie in bioenergy systems that do not require dedicated land. Using timber processing wastes, urban wood waste, landfill methane, crop residues that are surplus to soil fertility needs, and municipal solid organic waste avoids competing with food production altogether. The World Resources Institute recommends prioritizing these “additional” biomass sources – particularly for uses like aviation fuel where low-carbon alternatives are hardest to achieve. Growing perennial energy grasses on recently abandoned cropland is another high-potential strategy, combining productive land use with reduced ecological risk.

On the technology side, advances in synthetic biology, enzyme engineering, and consolidated bioprocessing are gradually reducing the cost and complexity of converting lignocellulosic biomass into fuel. Biochar – a co-product of biomass pyrolysis – can be applied to soils to improve fertility and sequester carbon, creating a system where bioenergy and soil health reinforce rather than undermine each other. Algal biofuels, while still costly at scale, offer the possibility of high-yield production on non-arable land using saline or wastewater.

Policy and governance solutions

Technology alone is insufficient. The IEA Bioenergy framework emphasises that sound bioenergy development requires transparent sustainability criteria applied consistently across feedstocks, production systems, and jurisdictions. This means strong mandatory lifecycle greenhouse gas assessments that account for land-use change emissions, clear prohibitions on sourcing biomass from high-biodiversity forests, and differentiated policy incentives that reward genuinely advanced biofuels rather than treating all bioenergy as equivalent.

Dedicated support for second-generation technologies – including long-term R&D funding, production tax credits, and consumption mandates that specifically target cellulosic and waste-based biofuels – can help bridge the cost gap until scale economies kick in. Regulatory stability matters too: as the experience of US cellulosic biofuel mandates has shown, policy uncertainty can deter private investment just as effectively as high production costs. International cooperation on sustainability standards, land tenure rights, and just transition frameworks for communities affected by bioenergy development will be equally critical as the sector scales up.

Ultimately, sustainable bioenergy is not a binary choice between expansion and abandonment. It is a question of which feedstocks, which technologies, and which governance structures are in place. When those elements align, bioenergy can genuinely contribute to a lower-carbon energy system without trading away food security, forest cover, or soil health.

What do you think? Given the significant resource and environmental challenges outlined here, should governments prioritise phasing out crop-based biofuels entirely in favour of waste and residue-based systems? And how should the costs of transitioning to more sustainable bioenergy pathways be shared between industry, governments, and consumers?

References

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Table of Contents

Resource competition: land, water, and food security 🔗

Technological and economic barriers 🔗

Environmental trade-offs 🔗

Deforestation and land-use change 🔗

Soil degradation 🔗

Food security 🔗

Path forward for sustainable bioenergy 🔗

Innovations in feedstocks and production 🔗

Policy and governance solutions 🔗