Sustainable transport shift: Battery EVs emerge as most efficient and scalable option

A new study provides an actionable roadmap for transitioning transportation systems toward sustainability. Published in Energies, the research titled “Analysis of Infrastructure Requirements for Sustainable Transportation Technologies,”  meticulously compares infrastructure needs for emerging transport technologies, battery electric vehicles (BEVs), hydrogen systems, and electrofuels, against the backdrop of renewable energy constraints and environmental realities.

The study focuses on the magnitude of energy consumption from transportation, nearly a quarter of global primary energy use, and the sector’s dominant reliance on fossil fuels. With BEVs, hydrogen fuel cells, and electrofuel-powered vehicles emerging as viable low-carbon alternatives, the author evaluates their energy efficiency from source to wheels.

The findings rank battery electric vehicles as the most efficient option, boasting an 80% energy efficiency rate, significantly higher than hydrogen fuel cell vehicles (29%) and electrofuel-based vehicles (21–23%). Hydrogen internal combustion engines trail with a mere 10% efficiency. These calculations account for energy losses in electrolysis, fuel conversion, compression or liquefaction, and drivetrain mechanics.

This ranking is critical, considering that road transportation consumes about 85% of all transport energy globally. The research highlights how BEVs, powered directly by solar or wind-generated electricity, can deliver the highest net return on renewable energy investments - a key metric as the world shifts away from fossil fuels.

What are the infrastructure demands of these technologies?

Transitioning the global transport sector to sustainable energy would require vast upgrades in electricity generation, storage capacity, and land use for energy harvesting infrastructure.

If BEVs were to replace fossil fuel vehicles globally, electricity generation would need to increase by 47% - a significant but manageable demand compared to the 370% increase required for hydrogen internal combustion vehicles. Hydrogen fuel cells and electrofuel vehicles would need 128% to 175% increases, reflecting their lower energy efficiency and added conversion steps.

Energy storage needs are also critical. To accommodate one day of transportation electricity demand through intermittent sources like solar and wind, BEVs would require around 38 TWh in storage capacity. This figure balloons to 300 TWh for hydrogen ICEs. In contrast, current global grid storage, mostly from pumped hydro, is a mere 1.86 TWh, underscoring a massive shortfall and a clear need for investment in large-scale storage systems.

On land use, solar-powered BEVs emerge again as the most practical choice. They would need only 1.7% of current global crop land to meet energy demands. Wind-powered systems, particularly for hydrogen and electrofuel options, could require up to 100% of the world’s cropland - a clearly untenable proposition.

How do broader environmental factors weigh in?

The analysis extends beyond raw numbers to consider secondary environmental impacts of each technology. BEVs, while energy-efficient, require substantial quantities of critical minerals like lithium and rare earth elements, raising concerns over mining impacts and material scarcity. Moreover, their heavier weight contributes to increased tire particle pollution.

Hydrogen systems pose challenges in fuel storage and transport, especially due to hydrogen's low volumetric energy density and complex infrastructure requirements. Electrofuels like methanol and ammonia offer practical retrofitting advantages for existing maritime and rail infrastructure, yet their production still hinges on energy-intensive processes and yields lower efficiencies.

In the air and maritime sectors, where energy density is paramount and weight constraints are rigid, hydrogen and electrofuels might still be necessary despite their inefficiencies. For example, the study notes that hydrogen fuel cell trains have already been deployed in Germany, while methanol-powered ships are operational in Europe.

Ammonia, which can be synthesized without carbon emissions, is emerging as a strong contender for marine engines, though it comes with toxicity and flammability risks that necessitate rigorous safety protocols.

Toward a tailored, multi-track transition

While no single solution fits all modes of transport, the study makes it clear that battery EVs are the most efficient and least infrastructure-intensive option for decarbonizing road transport. However, for aviation and shipping, hydrogen and electrofuels remain viable despite higher costs and infrastructure demands.

The study asserts that sustainable transport must be pursued through a mixed-technology approach, aligned with renewable energy capacity expansion. Key priorities include:

• Scaling solar and wind power generation,
• Expanding grid-scale electricity storage,
• Developing critical mineral supply chains responsibly,
• Investing in fuel cell and electrofuel technologies for niche sectors,
• Considering land use constraints in infrastructure planning.