The Green Report
Deep Green Revolutionizes Tidal Energy
In 2008, Greentech Media’s ocean energy report calculated that in the next six years, electricity production from the ocean could swell from just 10 megawatts currently to 1 gigawatt a year, a $500 million market.
As old as the beginning of time, water has long served as one of the most reliable sources of renewable and clean energy. So it is not surprising now that the ocean, and its powerful, sweeping tides, is being eyed as an abundant and endless source of energy for the future.
The first known utilization of ocean energy technology dates back to the 8th century when tide mills were used, still in existence along the French, Spanish and British coasts. Tide mills were nothing more than waterwheels used to mill grain, which extracted energy from the incoming tides.
Currently, tidal energy has been exploited chiefly through two devices. One is by building tidal barrages across estuaries that work similarly to a hydroelectric power station. The second includes offshore underwater devices that mine out energy from tidal streams and resemble a wind power station. Although the world’s first tidal power plant was opened in France in 1966, it wasn’t until 2003 that a tidal turbine was actually connected to the electricity grid. The installation powered up 35 Norwegian homes, supplying 700 MW per year.
Now Deep Green, a system that resembles underwater kites, aims to tap this primeval resource of water and free the world from the shackles of fossil fuels. The designer of Deep Green is Swedish firm Minesto, which was formed in 2007 as a spin-off from the automotive group Saab. Curiously enough, Deep Green, Minesto’s new kite-like tidal turbine, was originally designed as part of a Saab project in 2003. Thanks to the undying ebb and flow of the oceans, the company is banking on the fact that tidal and wave energy has the potential to become one of the most reliable systems to generate power. In this new application, the turbine can be anchored to the ocean bed by 100 meters of cable and will be capable of extracting energy at a very high speed from tidal currents, enough to generate 500 KW of power.
With just 12 meters of wingspan, Deep Green’s biggest advantage is its relatively small size compared to other tidal energy turbines. Minesto says that their technology can contribute significantly, by as much as 80%, to the tidal energy market. This is because, “one of the major advantages of this kind of technology is that it operates in low velocity depths of 60 metres. We’re alone in those areas so there’s no competition,” explains Anders Jansson, chief executive of Minesto, to Businessgreen.
Since wave and tidal power extraction technologies are an expensive affair, many installations around the world are set up with financial backing from governments, according to the European Marine Energy Centre (EMEC), which sets global standards for wave and tidal power resources. The U.K. is currently the largest backer of energy from the oceans, accounting for the bulk of the research. The country recently allotted $35 million for a new Marine Renewables Proving Fund that supports prototype development.
Deep Green shares its test site in Northern Ireland with SeaGen, the
world’s first commercial scale tidal turbine with 1.2 MW of power. It
started operations in 2008 and since then has supplied 800 MWh
to the national electricity grid.
Apart from costs, one of the biggest hurdles that wave and tidal power faces is infrastructure. Conditions along the coastline or ocean surface can cause the installations to be battered to a great extent by crashing waves, and the salt content of ocean water can corrode the machinery. This is where Deep Green comes in. With sea embedded kites that flow with the waves, the risk that its small turbines will crack up with the force of the waves is minimal. Also, tidal energy generation might be more expensive than solar or wind power, but unlike these sources, tidal power is extremely predictable, which according to Ted Rosendahl, the chief technical officer of Minesto, more than compensates for the exorbitant foundational costs.
Costs, though, are not seen as a deterrent to growth for the tidal energy industry. “This industry is about to grow up,” predicts Martin McAdam, CEO of Edinburgh-based Aquamarine Power, a company involved in tidal projects on the powerful Scottish seas. Indeed, Travis Bradford, co-author of the Greentech report, estimated in 2008 that energy from the ocean could ultimately account for up to 25% of the world’s electricity usage.
It is now up to Deep Green to prove its mettle. Minesto recently raised $2.5 million in funding from investors, and the first prototype is set to be operational off the coast of Northern Ireland in 2011. Jansson said the location was chosen based on the frequency and strength of high tides, as well as the large areas of unobstructed seabed, which have made Strangford Lough, County Down an ideal test site. Importantly, the Deep Green kite turbines must prove that they can not only withstand the punishment of the roaring waves, but eventually become cost-efficient and surmount the various other technical challenges.
If Deep Green’s trial runs are successful, Minesto will set up a full-scale demonstration plant, which will have around ten kite-like turbines. For this, Deep Green has to raise around $49.2 million. But the company is optimistic. Minesto’s Rosendahl expects a fully operational, commercial Deep Green tidal generator to be available in the next four years. He explains to CNN, “We are in the development stage at the moment so there are many things to look into.” But if Deep Green passes these litmus tests, the tides of the world might turn in its favor.
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