Diesel, batteries and biofuels: Setting our ferries on course for a green future (Stuff)

If Greta has taught us one thing, it’s that trains are good and planes are bad. But without access to a zero-carbon yacht, what do you do if you need to cross Cook Strait?

At the moment, all public ferries operating here run on fossil fuels. Smaller boats use diesel that’s akin to what’s sold at petrol stations. But large vessels, including the Cook Strait ferries, burn a fuel made of leftovers from the refining process, says engineer Brent Yardley​.

“Residuals are thicker, blacker and more polluting as they contain a lot of contaminants like toxic heavy metals. [They] commonly contain about 2 per cent sulphur by volume, which is two thousand times more than normal diesel.”