Emma Kennedy

(CNN Money) -- 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.

The "Ecoship" will be fueled by a much cleaner combination of solar panels, wind power and liquid natural gas, and should produce 40% less carbon dioxide than a traditional cruise ship.

"We will have 10 sails, so it will use the wind like traditional sailing ships," Tatsuya explained.

Peace Boat is talking to impact investors in Europe, America, China and Japan and could offer them bonds or equity. It will also use loans, and possibly crowdfunding, to raise the total.

"We need to choose carefully who we work with, as they need to share our long-term vision, not just want to finance an asset," said Tatsuya.

"Shipping finance companies are quite conservative and our design and plan is quite creative, quite unique. That uniqueness adds value but it can be a challenge to convince conservative financiers."

The "Ecoship" is designed to mimic the shape of a whale. While smaller than many cruise ships currently being built, it will accommodate 2,000 passengers, and host conferences and events while docked.

Charting a new course

Peace Boat hopes it will set sail on its maiden voyage in 2020, and that it will quickly become a showcase for the future of the industry.

"There's potential with a very green cruise ship to get a lot of attention at each port of call and that can make an impact," Tatsuya said.

And he doesn't plan to stop at one ship. Demand for cruises, and green tourism is booming.

"At least five ships by 2030 is necessary because of market demand," said the Peace Boat founder. "That's the first step, but in time, 10 ships."

Passengers on Peace Boat cruises pay between $15,000 and $18,000, which includes travel, meals and on board activities.

There's a mixture of entertainment, wellness programs, lectures and workshops on topics such as peace, politics, environmental change and human rights.