When David Ha started an artificial intelligence company in Japan with his former Google colleague, they had a choice: create another huge, energy-intensive tool like ChatGPT, or go their own way.

Since its 2023 launch, the value of their company Sakana AI has soared past $1 billion, making it Japan's fastest startup to reach so-called unicorn status.

"In a space like AI, everyone's kind of doing the same thing. They're just like collecting the world's data, building a gigantic model, sucking up all this energy," Ha said.