This story was originally published December 11, 2017

(CNN Business) Cruise ships have a bad rap with environmentalists. One cruise operator is hoping to change that.

Peace Boat, a Japanese non-governmental organization which runs educational cruises, is working on an ambitious project to build the most sustainable vessel in the booming industry.

Now in the last stages of planning, the "Ecoship" will be built by Finland's Arctech. It will cost about $500 million, financed in part by impact investors -- funds, rich families and individuals who want to use their cash to improve the world as well as make a profit.

"Ecoship was a dream for me," said Peace Boat founder Yoshioka Tatsuya. "Using a conventional ship was frustrating for us, even though we tried our best to reduce the emissions."

A conventional cruise ship can burn hundreds of tons of heavy fuel oil a day and emit as much particulate matter as a million cars, according to German environmental group NABU.

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