Power for Change - 2 (of 13) The Duck wave energy device

[sailingsolar]

3 pence per unit? OK I can figure out the value of 3 pence at any given time. What is a unit? 1kw?

[levanteIRL67592]

A quick question; From around 3:10, when the compliance of the support was increased in the surge direction, was there a power takeoff mechanism on the support to utilise its motion, or was the increase in efficiency purely due to a better response from the duck in pitch?

[MrJamieTaylor]

@levanteIRL67592 The meter is showing efficiency based purely on the power converted from the 'nod' motion. ( 'pitch' : rotational motion of the spine. 'Nod': rotation of duck about the spine). Here the Surging-Heaving rig was not providing any (significant) damping on the heave and surge axes. We are showing how variation of the stiffness of the spine (controlled by joints), affects power capture. We went on to include power capture at the spine joints - as later realised in Pelamis.

[levanteIRL67592]

@MrJamieTaylor

Thanks for the quick reply. Do you think that the duck will ever go to sea as a viable wave energy device? It seems like the industry is moving towards more less efficient, but more mechanically simple devices.

[MrJamieTaylor]

@levanteIRL67592 In this context its inventor, Stephen Salter, sees one of itsmajor advantages being that it makes the best use of the available sea-space - so you can get more power out of given area of sea. There is great deal of novel, but very well thought out, technology in the Duck - some of which is currently being developed. My hope is that, in time, this comes together to make the Duck viable. We always felt that simplicity is not an option - otherwise it would have been done already!

[levanteIRL67592]

@MrJamieTaylor

Do you think that the cost of implementing the Duck could be lowered if it was combined with an already-existing reference frame, like the tower of an offshore wind turbine, perhaps using a support structure similar to that of the Surging-Heaving rig? Or would scaling that sort of support up to operational size be impractical?

[MrJamieTaylor]

@levanteIRL67592 A feature of a string of Ducks is that it is 'self-referencing' (i.e. no power take-off reactions are required from the sea-bed), so the mooring loads are relatively very small and no external structures are required. We tried various forms of solo ducks. In contratst to the Duck-string, these need some kind of external constraint and you can see an example in the YouTube video 'Desalination Duck tests'.

[gambit2300]

I seen this today and had the same thought as guildwarsSNOW, if they set the ducks outside of Palm beach where the beach is disappearing wouldn't it prevent the sand from getting washed away?

[MrJamieTaylor]

The idea of using wave energy devices to reduce beach erosion is an old one. My understanding is that most beach ersosion is due to long swell waves and storm waves. It is not likely to be economically worthwhile to make wave energy devices efficient at removing the energy from those waves (they would have to be oversized) .

[Musicmatttheonly1]

@MrJamieTaylor beach erosion is inevitable and pointless, i feel to try and stop.

[guildwarsSNOW]

Why can't anyone see the potential for the duck as a means of reducing coastal erosion rather than simply as a device for generating electricity?

[Musicmatttheonly1]

@guildwarsSNOW id say becuase beach and coastal erosion is natural and can become useful.........further more they can also create new land mass for people to live on :)

[Musicmatttheonly1]

@guildwarsSNOW the example for you is spurn point in the UK