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NickW
09-25-2013, 02:30 PM
I came across this on the seamagic blog ( http://seamagic.org/marine-turbines/ ). The Mygen website is here http://www.meygen.com/

Whilst a good idea, to supply ultimately 40% of the Scottish Highlands electricity requirements (398 MW) from renewables what happens at high and low tide when there is zero generation? The amount of conventional (coal/oil/gas/nuclear) that would have to be kept on either standby or part load (aka low efficiency) to ramp up every 6 1/2 hours will make the project, overall, uneconomic. The alternative of course is massive reinforcement of the grid to allow power flows to come further south to the Forth / Clyde corridor where existing installed capacity could be used to balance loading conditions.

I do wonder if it is feasible to install an intermittant generating system without any storage capacity to smooth out load changes?

Nick

Peerie Maa
09-25-2013, 02:37 PM
Fair isle has a wind turbine, with a standby diesel gen set for those few still days.
The benefit of nuclear power is that it can track load much more responsively than coal fired, and Scotland still has a lot of hydro electric generators that take seconds to spin up. Should not be insoluble.

AndyG
09-25-2013, 08:45 PM
what happens at high and low tide when there is zero generation?

Nick, tide tables for around Scotland show places that have strong tidal currents when other areas are at high or low water. Careful planning could get you round-the-clock tidal power.

Andy

Mad Scientist
09-25-2013, 09:34 PM
Nick, tide tables for around Scotland show places that have strong tidal currents when other areas are at high or low water. Careful planning could get you round-the-clock tidal power.

Andy

And I sincerely hope that a similar scheme will work in the Bay of Fundy.

Tom

Canoeyawl
09-25-2013, 09:43 PM
Maine Today
(http://www.pressherald.com/news/ORPC-turbine-off-Eastport-is-the-first-to-do-so-in-North-America.html)
http://media.pressherald.com/images/ElectricityFromTides0912WEB.jpg

Chip-skiff
09-25-2013, 11:13 PM
I came across this on the seamagic blog ( http://seamagic.org/marine-turbines/ ). The Mygen website is here http://www.meygen.com/

Whilst a good idea, to supply ultimately 40% of the Scottish Highlands electricity requirements (398 MW) from renewables what happens at high and low tide when there is zero generation? The amount of conventional (coal/oil/gas/nuclear) that would have to be kept on either standby or part load (aka low efficiency) to ramp up every 6 1/2 hours will make the project, overall, uneconomic.

The slack time is rather short, isn't it? That is, most of the time the tide is rising or falling. I might look at a pumped storage or catch-dam hydro scheme, that can be activated in proportion to the tidal state. Gravity's pretty dependable.

Steve McMahon
09-25-2013, 11:26 PM
Nice.
Look up Germany. They are making so much power with the windmills, solar and others they are paying citizens to use more. That is interesting.

Sorry - that is a myth. Germany is on an aggressive path to renewables, however, they are also aggressively pursuing energy management strategies to encourage using less power with the goal of reducing their dependence on nuclear power.

Steve McMahon
09-25-2013, 11:30 PM
And I sincerely hope that a similar scheme will work in the Bay of Fundy.

Tom

It will come, we have taken a few small steps in the right direction.

Chip-skiff
09-25-2013, 11:31 PM
Actually, Germany shut down a bunch of nukes and last year burned more coal than in previous years, making up the shortfall.

Steve McMahon
09-25-2013, 11:45 PM
Actually, Germany shut down a bunch of nukes and last year burned more coal than in previous years, making up the shortfall.

I am of the probably weird opinion that the long term effects of burning a bit more coal in the short term on their way to a sustainable energy system will be less damaging in the big picture than the nuclear option is.

Michael D. Storey
09-26-2013, 07:42 AM
The slack time is rather short, isn't it? That is, most of the time the tide is rising or falling. I might look at a pumped storage or catch-dam hydro scheme, that can be activated in proportion to the tidal state. Gravity's pretty dependable.

It is my understanding that installations close to short will often have a dam, thereby allowing the tidal change to creat a greater difference in water level. Near the beginning and end of the tidal flow there is not so much water moving, therefore less force. I am sure that the unusable time is longer than slack tide.