Royal Caribbean Cruises is going green in a major way.

The company has announced plans to power its newest class of ships with liquefied natural gas and introduce the use of fuel cell technology.

Royal Caribbean has signed a memorandum of understanding with shipbuilder Meyer Turku under the project name “Icon.”

The vessels will be delivered in the second quarters of 2022 and 2024, with plans to begin testing fuel cell technology on existing Oasis-class ships in 2017.

“With Icon class, we move further in the journey to take the smoke out of our smokestacks,” said Richard Fain, chairman and chief executive officer of Royal Caribbean Cruises, Ltd. “We are dedicated to innovation, continuous improvement, and environmental responsibility, and Icon gives us the opportunity to deliver against all three of these pillars.”

For now, Icon design elements are in the early stages, the company said, although they will likely accommodate 5,000 passengers.

“Our guests expect us to push every envelope we can,” said Michael Bayley, president and chief executive officer of Royal Caribbean International. “And on this new class of ship, we began by challenging ourselves to find a new approach to power and propulsion that is safe, reliable, and more energy-efficient than ever before.”