SEOUL

Toyota Chief Scientist Gill Pratt has called for a more nuanced and diverse approach to reducing automotive carbon emissions. Rather than solely focusing on battery electric vehicles (BEVs), Pratt envisions a future where multiple technologies—including e-fuels and hydrogen—play crucial roles in the global fight against carbon emissions.

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Addressing concerns about lithium availability, Pratt introduced the "1:6:90 rule" to illustrate the efficiency of different electrification strategies. This principle suggests that the battery materials required for one BEV could alternatively power six plug-in hybrid vehicles (PHEVs) or 90 full hybrids. "Although individually those six PHEVs don't reduce CO2 emissions as much as one BEV, because we can make six of them using the same amount of battery materials, they can reduce CO2 five times as much," Pratt explained.

This perspective gains relevance as experts at Benchmark Mineral Intelligence predict a significant lithium supply shortage by 2026-27, potentially reaching crisis levels by the decade's end. Pratt cautioned that switching to alternative battery chemistries wouldn't significantly alleviate this issue, as the fundamental lithium requirements remain similar across different technologies.

Despite scepticism about e-fuels' viability, Pratt sees significant potential in this technology. While critics point to high production costs—potentially exceeding €20 per litre—and competition from aviation and maritime sectors, Pratt argues that demand could surpass current predictions.

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"The reality is that the changeover [to electric vehicles] will not be quick," Pratt stated, noting that many of the world's 1.25 billion vehicles will remain in operation for decades, often transitioning from developed to emerging economies. He emphasised that many regions lack reliable electrical infrastructure, making liquid fuels a necessity for the foreseeable future.

Toyota continues to explore hydrogen as an alternative fuel, both for fuel cells and internal combustion engines. While hydrogen-powered engines produce minimal CO2 emissions—a few grams per kilometre from burning lubricant oil—their classification as zero-emission vehicles remains under consideration by regulatory bodies in Europe and the United States.

Regarding hydrogen's viability for heavy vehicles, Pratt emphasised the need for balanced infrastructure development. "We believe that hydrogen vehicles can work for transportation if you have an environment where you provide the right amount of hydrogen to the right number of vehicles," he explained.

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Pratt expressed scepticism about battery-powered heavy trucks, citing multiple concerns:

1. Reduced payload capacity due to battery weight

2. Extended charging times

3. Prohibitive infrastructure costs

He illustrated this with a striking example: "A truck with a 1-megawatt-hour battery would require a 10-megawatt charger to achieve a 6-minute charging time, demanding enormous capital investment and operating costs."

On the topic of battery lifespan, Pratt noted that usage patterns significantly impact durability. Slow, home-based charging—the most common scenario—promotes longer battery life, while frequent fast charging can accelerate degradation.

Throughout the interview, Pratt consistently returned to his central thesis: the need for a diverse, pragmatic approach to reducing global carbon emissions. Rather than advocating for a single solution, he emphasised the importance of adapting strategies to different regional contexts and infrastructure realities.