LONDON - South Korea's SK Innovation has led the latest $46 million funding round for climate tech start-up Amogy, which aims to accelerate the shift to zero-emissions fuels for heavy industries such as shipping, its chief executive told Reuters.

With transport accounting for around 17% of the world's greenhouse gas emissions, the company said it aims to help drive the transition to greener fuels by converting carbon-free ammonia to power.

Widely used in industrial applications, ammonia's suitability as a transport fuel has been limited because of the technical challenge of converting the chemical into energy in a confined space.

"The problem the company is solving is basically the problem of the battery," said Seonghoon Woo, CEO at Amogy. While they were useful for small electric vehicles, forms of transport such as ships, trucks and planes need a fuel with more energy density.

"The energy storage system we've built basically converts ammonia to electrons very efficiently in a small footprint, so you can use it in different vehicles."

Apart from SK Innovation and Saudi Aramco , the world's largest oil company, others backing the round include retailer Amazon, through its Climate Pledge Fund, AP Ventures and Newlab, Amogy said.

This takes Amogy’s total funding close to $70 million since its founding in 2020, Woo said.

He said the money would be used to scale up Amogy's technology for trials in sectors including shipping, where it plans to test a demonstration vessel over the next year with the aim of developing ammonia-based power for ocean-going ships.

With about 90% of world trade transported by sea, shipping accounts for nearly 3% of the world's CO2 emissions, yet environmental campaigners say efforts by the sector to cut emissions are too slow.

The International Maritime Organization's (IMO) goal is to reduce overall GHG emissions from ships by 50% from 2008 levels by 2050, below targets set by countries such as the United States that have pushed for the agency to adopt a zero emissions target by 2050.

The IMO said it will issue a revised GHG strategy in 2023.

(Reporting by Simon Jessop; editing by Barbara Lewis)