> Cost of energy is estimated at £100-150 (US$160 - $235) per MWh, which is higher than other renewable energy sources such as solar and wind at this stage.
It's not only much more expensive and require a lot of space, but just like those other renewables, that technology is intermittent so still require fossil-fuel thermal plants… which we must stop using.
At this point, we just can't accept the idea that our standard of living is going to decline for lack of valid alternatives to fossil fuels.

So many pilot wave-power schemes over the decades. When will one prove tough enough to be scaled up for commercial use?

This looks great and would be very useful to isolated communities on the coast.

Imagine a deep draft cargo ship slightly off course going thru this.

I would be interested in hearing more about the materials used, the connections made between the different types of material and the seals.
The ocean is a deeply hostile environment that seems to destroy everything man puts into it over time. What are the maintenance requirements and overall operating costs?

@Freyr Gunnar
"At this point, we just can't accept the idea that our standard of living is going to decline for lack of valid alternatives to fossil fuels."
The problem is that not only is our standard of living going to decline, so too is our population and by quite a large number. Seeing as nearly all farming equipment is fossil fuel dependent, it is pretty obvious how the reduction in population is going to be achieved.
I am very glad that I am in the autumn of my years, though I fear deeply for my son's welfare and that of his family.
Of course, even if this device is any good, and let's be charitable and assume that it will be, we still have the little matter that as thing stand, it will do nothing to fuel a tractor or combine-harvester. I remember reading somewhere that if we have to go back to horse-drawn methods, then about one to one and half billion will be the maximum supportable population load. Shale oil? Yeah, right! Beware of low flying pigs.

Using sustainable, renewable, clean energy to power offshore rig to drill for oil. How absolutely demented is that?

I was thinking the same thing Vanamonde. The fossil fuel industry is bent on ever-increasing our dependence on its products, and will find any way possible to make the public's perception of them as green and providing economies with lots of jobs. This is just another green thing they can latch on to. In Canada they are fervently trying to whitewash their image from a filthy tar sands operation to a "proud Canadian national energy conglomerate that provides opportunities", and they are spending big bucks to change this perception. The dubious Harper government is more than willing to be its stooge and to disregard the fact that most of its constituents want to get off this addiction.
When the seas are choppy, it's also windy, so essentially, which is more economical to use? The bottom line in producing a viable energy that is sustainable, is to have a combination of sources that work together to prevent gaps that need to be filled by fossil/nuclear energy.

Mass produce & place off CA HI FL Fl Keys VA CT ME, Med Sea: France & Spain, Italy, Greece Awesome

But what if the Navy declares it to be a "Hazard to Navigation"?
What if a ship gets snared in it, during heavy rain or Fog?
What about salt water corrosion, acting on the mechanical parts?