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when you want,” says Richard Knox, the inventor of the when you want,” says Richard Knox, the inventor of the concept. “Then there is the research combining the two concept. “Then there is the research combining the two technologies. Our aim was to get as much energy out technologies. Our aim was to get as much energy out from as small a footprint as possible.” from as small a footprint as possible.”

EC-OG’s tidal turbines are each just 2m high, in EC-OG’s tidal turbines are each just 2m high, in

AnalysisAnalysis a con? guration which optimizes the ? ow and a con? guration which optimizes the ? ow and power generation, and can be removed power generation, and can be removed individually from the frame. As each has individually from the frame. As each has its own DC generator, there is built in its own DC generator, there is built in redundancy, and they can start producing redundancy, and they can start producing electricity with a current ? ow as low as electricity with a current ? ow as low as 0.4m/sec. 0.4m/sec.

Key to the design has been to cre- ate a system that can sit in a compact, ate a system that can sit in a compact, over trawlable structure, which meets road over trawlable structure, which meets road transport regulations, for ease of logistics, and a turbine con-transport regulations, for ease of logistics, and a turbine con- ? guration which gets the most from the ocean current, Knox ? guration which gets the most from the ocean current, Knox says. The hub will also have an intelligent energy management says. The hub will also have an intelligent energy management system to get the maximum life out of the battery.system to get the maximum life out of the battery.

The ? rm started testing a model at Newcastle The ? rm started testing a model at Newcastle

University two years ago, using a one third scale University two years ago, using a one third scale unit. The testing at Fort William is due to run for unit. The testing at Fort William is due to run for about 18 months and will also demonstrate the about 18 months and will also demonstrate the power hub’s ability to be remotely control and moni-power hub’s ability to be remotely control and moni-

An EC-OG subsea tored subsea applications via a desk top, without the tored subsea applications via a desk top, without the hub. Photo from EC-OG. conventional umbilical. conventional umbilical.

While initially the concept was aimed at brown? eld sites, While initially the concept was aimed at brown? eld sites, something you would consider,” Ellison says. “But for typical where wells were being shut-in due to electrical failures, the crudes, condensate, gas, HPHT or any well with a meaningful ? rm is also looking at green? eld projects and even subsea water cut there is an opportunity to harvest the produced heat.” surveillance. It could also be used as a power source for remote

The technology itself – the Seebeck island communities.

effect – has been around a long time. “We are looking to offer a step change in electric current cost,

Thermoelectric generators or TEGs, are and to use subsea power hub to extend life of subsea wells,” maintenance free and because of this they Knox says. “We are looking at a truly disruptive technology were used to power many space missions which will reduce the cost of supplying electric power.” including Voyager, Ellison says. Since being

PowerBuoy developed for space TEG’s have been com- mercially developed and are now available While Ocean Power Technologies has not quite done away with as a relatively cheap component. “It is the need for a cable to transport the power from the source to

Stu Ellison now at a point where there are industrial the user, its PowerBuoy solution does offer a way to reduce the

Photo from Exnics.

applications and they can be bought off need for manned surface facilities or long step-out umbilicals to the shelf,” Ellison says. The ? rm is now preparing to conduct provide power for the likes of AUVs or power for electric Xmas demonstrations at their unit in Ellon. trees.

PowerBouy is a wave energy power generation device, one

Power alternatives of which is currently being used offshore New Jersey to collect

EC-OG, formed in 2013, has been developing a subsea power metocean data, the ? rm says could be used through the life of hub concept, an invention to use ocean currents to generate ? eld, from environmental impact assessment to front end engi- electrical power, and a full scale version of the concept is due neering studies, operations and decommissioning, with sensors to start trials next year. mounted from the device through the water column as well as

The subsea power hub concept consists of three vertical axis above the surface. turbines, each connected to direct drive DC power generators, The ? rm’s ? rst unit, APB-350, was built to produce 300w, and in turn batteries to store power, all housed in a no more but it has been producing 1000w offshore New Jersey. It was than 7m-footprint over trawlable frame. producing 25kW/hr late October. A larger unit, the PB10, is in

One unit can produce about 500w, according to EC-OG, with the design phase. additional units to be daisy-chained if additional power is “We have been looking at small units ? rst, to prove the sys- required. tem, make sure it is reliable as a monitoring and data solution,

The ? rm, which has been supported by a number of Scottish and once it is proven reliable operationally, we can scale it

Enterprise “Smart Grants” to support trials of a scale subsea up,” says Paul Watson, director of business development UK & power hub. It is due to start full scale trials at the bottom of Europe at the ? rm.

Loch Linnhe, at the Underwater Centre, Fort William, next year. Earlier this year, the ? rm formed an advisory panel with “Ocean current is predictable, and then there has been a operators, manufacturers, services companies and sensor massive leap in battery technology to store and deliver power companies, to involve the industry in the design phase of a unit

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