Wave and Tidal power in Caithness

[orkneycadian]

There is a big difference in onshore wind and anything offshore, and tidal is far more predictable than wind. For the record I am 100% behind tidal power in the Firth and also the Beatrice development.

Whays your meters saying about onshore wind output vs tidal output from Orkney these days ywindy?

[ywindythesecond]

Whays your meters saying about onshore wind output vs tidal output from Orkney these days ywindy?

I try never to make the same mistake twice Okn. Tell me please, how much tidal output is there in Orkney these days?

[thebigman]

Yes that is the popular myth. We know when the tides are years in advance but we don't know how strong they'll be and so I'm afraid to say that there is nothing valuable to the National Grid with tidal that is over and above that of wind with respect to predictability.

I have tide tables with predict tidal ranges up to the year 2026 so that's not bad for predictability.

[Rheghead]

I have tide tables with predict tidal ranges up to the year 2026 so that's not bad for predictability.

I'm glad you agree about predictibility of tidal. What this means for the National Grid in terms of operations for backing up the tide is that because the tide ebbs and flows almost 4 times per day they must keep the back-up on hot standby in readiness the whole time. The NGY can't retire any fossil fuel generation and capacity credit will be just as low as for wind.

[Kenn]

Am I being denser than usual here as I thought it was possible to generate both on the ebb and the flow of a tide so that would mean set times when generation comes on line.
Another point, what is the tidal time difference between the north and south of these islands? If the time differs by a sufficient amount then surely a system that encompasses the whole coast would enable almost continuous generation.
Another point that makes me ponder is why can't the power be used for local consumption instead of feeding it into a national grid that suffers substanstial wastage?
I would also ask why are there no small turbines proposed on shore as there are a number of rivers and mill races within the county which again could generate sufficient power to serve small rural communties?

[Rheghead]

Am I being denser than usual here as I thought it was possible to generate both on the ebb and the flow of a tide so that would mean set times when generation comes on line.Another point, what is the tidal time difference between the north and south of these islands? If the time differs by a sufficient amount then surely a system that encompasses the whole coast would enable almost continuous generation

You are correct on your point on ebb and flow but only for certain types of tidal generation.

In a theoretical world where we could design our coastline with an evenly distribution of generation sites of all types then yes it could be envisioned that uniform power could be generated. Our coast isn't like that though. Like with wind, wide distribution is good, trouble is, the most feasible areas for development are situated in a few sites, one is up here, the Severn and Morecambe bay and a few minor sites. That will cause an uneven power curve.
.

Another point that makes me ponder is why can't the power be used for local consumption instead of feeding it into a national grid that suffers substanstial wastage?

Preventing waste of energy is always a good thing ,however, as I understand it, modern HVDC powerlines lose about 2% of the energy on a 900km line if that puts things into perspective. So developing an industrial landscape may be good for jobs, it would only serve to create an eyesore for tourists for minimal savings on energy and at 900km Pentland tidal energy is well within distance to Scotland's central belt and north of England where we are accustomed to having heavy industry. However some extra energy is lost through transforming voltages to consumers which happens to all generation even if close by.

I would also ask why are there no small turbines proposed on shore as there are a number of rivers and mill races within the county which again could generate sufficient power to serve small rural communties?

This would seem feasible at a first glance. However, Caithness is largely a lowland area and small hydro requires a large head of water in a small stretch which I think would be very limiting.

[ywindythesecond]

You are correct on your point on ebb and flow but only for certain types of tidal generation.

In a theoretical world where we could design our coastline with an evenly distribution of generation sites of all types then yes it could be envisioned that uniform power could be generated. Our coast isn't like that though. Like with wind, wide distribution is good, trouble is, the most feasible areas for development are situated in a few sites, one is up here, the Severn and Morecambe bay and a few minor sites. That will cause an uneven power curve.
.


Preventing waste of energy is always a good thing ,however, as I understand it, modern HVDC powerlines lose about 2% of the energy on a 900km line if that puts things into perspective. So developing an industrial landscape may be good for jobs, it would only serve to create an eyesore for tourists for minimal savings on energy and at 900km Pentland tidal energy is well within distance to Scotland's central belt and north of England where we are accustomed to having heavy industry. However some extra energy is lost through transforming voltages to consumers which happens to all generation even if close by.




This would seem feasible at a first glance. However, Caithness is largely a lowland area and small hydro requires a large head of water in a small stretch which I think would be very limiting.

I agree with Reggy.

[Kenn]

Thanks for the information.
With regard to onshore small turbines,I was n't thinking of dam type installations, more the turbine screw (think that 's the name,) that has been very successfully employed in old mill races in some parts of the country .

http://www.reuk.co.uk/Electricity-from-Waterwheels.htm