Tech

When it comes to Bus, will Hydrogen or Electricity win?


Find new ways To power the world’s vehicles has long been a key ingredient in tackling the climate crisis. When it comes to small passenger vehicles, there is little question that the future lies in battery-powered cars, rather than those powered by hydrogen fuel cells — another possible alternative. . However, as the size of a vehicle increases, hydrogen could become an increasingly attractive option. As for buses, some argue that hydrogen power offers several key advantages over battery-powered electrics. Ultimately, whichever of them becomes the main technology in buses could also have an impact on other forms of transportation.

Electric and hydrogen fuel cell vehicles have similar propulsion systems. Both store energy to power electric motors. In the second case, however, the energy stored in the form of hydrogen is converted into electricity by the fuel cell, rather than being stored in a rechargeable battery.

Sell ​​electric car reach 3 million by 2020, up 40% from 2019, with about 10 million electric cars currently on the world’s roads. Hydrogen car registration numbers are still 3 places below this level, and there are only 26,000 won globally, concentrated in three countries: Korea, the US (mostly California) and Japan. While there are still a few hydrogen fuel cell cars available on the market, made by Toyota and Hyundai, they tend to be more expensive than battery cars and can be difficult to fuel at the moment: Buying hydrogen is very expensive. expensive and there are far fewer refueling stations than charging points in most places.

But when it comes to larger vehicles, the picture isn’t quite as clear. As vehicles get bigger, it’s becoming more difficult to electrify them, with a growing need for batteries. For energy-intensive applications such as long-haul trucks, some experts say hydrogen might be the best option.

Buses fall somewhere between cars and trucks on this spectrum. “The big issue is the mass of the bus,” said James Dixon, a research fellow in energy and transport system modeling at the University of Oxford. “Batteries have a relatively small energy density: The energy density is about 1/40 the energy density of a liquid hydrocarbon fuel, like gasoline or diesel.” Hydrogen also has a relatively low energy density (the amount of energy that can be stored per unit volume, volume or area) – about four to five times lower than petroleum fuels, he adds. , but much higher than the electric battery.

China has about 5,300 hydrogen fuel cells buses on the road, the bulk of the global fleet, but other countries are investing in the technology. Neil Collins, chief executive officer of Northern Ireland-based bus manufacturer Wrightbus, said his company is a technology agnostic and is manufacturing both electric and battery-powered buses hydrogen fuel cell. It provides trip data from bus operator customers into a tool to model different driving cycles for its vehicles, to help them find the best technical solution for their vehicle. that particular route.

The advantages of hydrogen include shorter refueling times and a generally larger tank range. Hydrogen technology and infrastructure is more expensive, Collins said, while industry skills using electric buses are also more likely than hydrogen. Dixon also notes that a concern about hydrogen has always been its safety. “It has a fairly wide flammability limit and is notoriously difficult to keep in a pressurized container without leaking,” he said. “In terms of infrastructure, it’s a lot easier to get electricity, because you don’t need trucks that run on liquid fuel.”

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