How a bit of breeze and a big kite can save on seagoing energy costs

The Irish Defence Forces is looking to add wind propulsion to its naval arsenal

Telling someone to go fly a kite has taken on a whole new and more positive meaning. The Defence Forces' innovation unit is leading a research study to assess the benefit of using huge kites for propulsion, for electricity generation and to hold aloft airborne sensor platforms.

"It is blue-sky thinking that has three strands. Testing is under way at the moment and we have a kite that has been flown by Naval Service personnel," says the project leader, Col Peter O'Halloran of the Defence Forces.

“It started out when we came across commercial vessels using kites for propulsion,” he says. “The kites were the size of a football pitch.”

The overall project is called Aeolus and involves contributions from the Irish Maritime and Energy Resource Centre (IMERC); the Cork Institute of Technology's Nimbus and Halpin research centres; the Tyndall National Institute; and the University of Limerick. Funding comes from the Sustainable Energy Authority of Ireland (SEAI) and Enterprise Ireland.


Kite-driven generator

Coincidently the SEAI had come across something similar – kites used to generate electricity on ships at sea, says the authority’s chief executive, Dr Brian Motherway. The authority talked to a company in Hamburg, SkySails, which had developed a prototype kite-driven generator. It then got in touch with the Defence Forces.

“We work with the Defence Forces, who are into the innovation agenda and energy use reduction,” Motherway says. They are looking at a strategic control of energy use.” In fact the Defence Forces are targeting a 30 per cent overall reduction in energy demand by 2020.

The Defence Forces have an internal enterprise board that looks at energy conservation as well as new IT technologies that serve its various roles at sea and peacekeeping operations, says O’Halloran. Funds were provided to study the use of kites at sea through the authority’s Prototype Development Fund.

The propulsion aspect is straightforward, using a very large kite to pull a vessel through the water. While this only delivers a limited amount of propulsion, it still cuts back on a ship’s normal energy demands, bringing immediate savings, Motherway says.

Testing began using a kite of about 20sq m flown on a cable about 300m height and tethered to the LÉ Niamh. Monitoring rigs showed that a large kite should be able to deliver about six knots of speed, something that could deliver real energy savings, Motherway says.

Using a kite in this way to help cut energy costs would be feasible for anything from a fishing boat to a yacht to cargo vessel . This in turn is of great interest to IMERC, given its potential to save energy and increase innovation at sea.

“It is never going to pull a navy ship,” says Motherway, “but will part pull other vessels so they can reduce their energy bills.

“The Naval Services could not use it for propulsion, as this would have to be incorporated in the design phase of a ship, but we could use one for power generation,” he says.

Kite flying for energy was a second aspect tested on Naval Service vessels, looking at the generation system developed by SkySails.

The Hamburg company already has a working system that sees a tethered kite linked to a generator mounted on deck, says Motherway. The system delivers power by deploying the kite out about 300m and reeling it back in.

There is an energy demand when reeling the kite in, but an energy gain when carried up again by the wind. The system delivers between 70 and 90 per cent more electricity than it uses, he says.

The 20sq m kite attached to a generator was able to produce tens of kilowatts, he says , but a big kite of several hundred square metres might be able to deliver about a megawatt of electricity. “There is a lot of energy up there.”

The generator is still some years away from being fully ready, but SkySails has opened an office in Cork and will work with the Aeolus group to develop it.

Perhaps the most exciting development coming out of the project is the sensor platform, says O'Halloran. You arrive at a location, elevate the kite and then use the sensors carried by it effectively to see over the horizon,.

The Defence Force's Communicants and Information Services Corps has developed a specification of what might be on board a pod lifted up by the kite, and the Cork Institute of Technology is working on hardware integration and software support.

Better surveillance

This could dramatically improve surveillance capabilities, according to O’Halloran. The normal maximum visual range is 200 nautical miles, but this could be bumped up to a possible 3,000 nautical miles, he says.

Such a system could be deployed by a naval vessel that uses radar or optical technology to watch ships without having to move closer to them.

“That ties back into major energy savings if we don’t have to do all the sailing,” O’Halloran says. “We could see this being used for observation in Bosnia or Syria.”

It would also be possible to use the pod to control unmanned aerial vehicles, or drones, he adds. “If you could create a wifi hub ,you could fly UAVs out for surveillance. It is about being able to have a live data stream coming in.”

He praised the authority and Enterprise Ireland for its “lateral thinking and willingness to support innovative ideas”: “Everything is Irish. It is about supporting and delivering for the Irish recovery.”

The Aeolus project has commercial potential and the institute’s Halpin Centre is looking into business development.

It is “very early technology”, Motherway says. “We think this sector will become very important in a decade, so we are building our reputation.”

Dick Ahlstrom

Dick Ahlstrom

Dick Ahlstrom, a contributor to The Irish Times, is the newspaper's former Science Editor.