Wave Energy Concept Ready for Ship Propulsion

fishing boat
An artist's impression, not the actual hull structure, presenting placement on the outside of the hull and leaving the deck space clear for normal operations.

Published Aug 2, 2017 3:19 AM by The Maritime Executive

Wave energy technology is ready to be combined with solar and wind power to create zero emission ships, says José Luis Gutiérrez-García, CEO, ZShips International CCC. 

ZShips is a Canadian company readying a proprietary wave power system that uses oscillating water columns integrated into a ship's hull. ZShips' concept involves converting wave energy into stored energy in the form of compressed air. The compressed air can be stored as potential energy or used on demand to generate electricity.  

The company is initially looking to retrofit its technologies on fishing vessels. Global fisheries burned almost 50 billion liters of fuel in 2000, representing about 1.2 percent of the global oil consumption, says Gutiérrez-García. In doing so, fishing boats emitted more than 130 million tons of CO2 into the atmosphere to land around 80 million tons of fish and invertebrates. “This means that for each ton of live-weight landed fish product, 1.7 tons of CO2 are emitted.”

For retrofit, the wave energy system will be tailor-made to match the hull’s existing shape. Depending on the vessel's dimensions, the wave energy system will cover a large part of the total energy demand. 

“We chose a large fishing vessel as a pilot project because fuel costs represent 60 percent of the OPEX for these vessels. Fishing vessels are numerous compared to other larger vessel types, and the cost to obtain one for demonstration purposes is reasonable.

“We evaluated the limited deck space for alternatives such as sails, Flettner rotors and placement for solar and wind on board a working fishing vessel. Larger cargo vessels may have more deck space available, however they also have to load and unload cargo. This has to be considered too when installing renewable technologies.”

He says other technologies for reducing emissions are available in the market today, but they can only reduce emissions by a few percent each. Few reduce CO2 and, while scrubbers can remove NOx and SOx along with particular matter, they increase fuel use and operating costs and lower overall efficiency.

“New propeller systems, hull modifications or under hull air bubbles systems can also improve fuel economy by a few percent, but these are expensive due to down time and retrofit costs,” says Gutiérrez-García. “We considered our retrofit cost compared to LNG and other potential modifications. All still have fuel costs whereas we have zero fuel costs and zero emissions, including CO2 which may (will) be taxed in the future. While LNG retrofits can reduce emissions considerably. They are also very expensive and not practical for many vessels.”

ZShips is looking for investment partners for 3D virtual prototyping and subsequent research and development with the aim of reaching the cargo and passenger ship markets as well as well as fishing vessels.

ZShips technology can be used for new ships or to retrofit older ships; any large displacement hull vessel is a potential ZShip. Superyachts, ferries, research vessels, cruise ships, handysize, handymax, Panamax, neo-Panamax are all excellent candidates for becoming zero emissions vessels. There is no known limit on how much energy ZShips technology can produce, Gutiérrez-García says. “The longer the ship the more area we have to work with and the more power we can produce.”

ZShips is going straight to zero avoiding expensive incrementalism, says Gutiérrez-García, with the added benefit of unlimited range, reduced underwater noise and vibrations and reduced harm to marine life and the environment.