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Author Topic: what is the Top Tidal power?  (Read 2852 times)

Offline Chem4u

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what is the Top Tidal power?
« on: 04/03/2015 20:09:15 »
Hello ^_^
I want to know what the top Tidal power Mean?
And what the Difference between Top Tidal power And Tidal Energy ?


 

Offline Colin2B

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Re: what is the Top Tidal power?
« Reply #1 on: 04/03/2015 22:27:40 »
Hello ^_^
I want to know what the top Tidal power Mean?
And what the Difference between Top Tidal power And Tidal Energy ?

Do you have a quote or reference we could look at?
Although there are different ways of harnessing tides, I've never heard 'Top Tidal' used.
Some methods use surface devices, but they are mainly wave powered rather than tidal.
Tidal, usually is either a turbine in a strong tidal current, or a dam/lagoon system.
 

Offline Chem4u

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Re: what is the Top Tidal power?
« Reply #2 on: 05/03/2015 13:36:48 »
Look At here
newbielink:http://www.sciencemuseum.org.uk/energy/site/EIZCaseStudy7Item4.asp [nonactive]
I have to make A report about  " Top Tidal Power"
And my friend about " Tidal Energy"
There are many Different Between Them
but i do not know it !!!!
 

Offline alancalverd

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Re: what is the Top Tidal power?
« Reply #3 on: 05/03/2015 17:59:35 »
Do you possibly mean "maximum tidal power?" The maximum power is delivered when the head difference is maximum (in a trapped tidal system, as shown in the Science Museum clip) or when the tidal flow is maximum, in an unconstrained system.

Tidal energy is the integral of tidal power over the entire tidal cycle.

Both maximum power and energy per cycle will vary according to the tidal range (between neap and spring tides, and additional local and celestial factors).
 

Offline evan_au

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Re: what is the Top Tidal power?
« Reply #4 on: 06/03/2015 21:40:56 »
Similar to alancalvard, could the question be asking about generating power at the "top of the tide"?
[Could you post the actual question, or do you have to translate it first?]

In most places, there are two high tides and two low tides per day (some places only get 1).
At the top of the tide, the ocean has the greatest height, and you can generate more power than at intermediate points on the tidal cycle. Similarly, you can generate more power at the bottom of the low tide, than at intermediate points on the tidal cycle.

However, the time of peak (and minimum) tide height changes a little each day, depending on the position of the Moon relative to the Sun.
Peak power consumption occurs in the morning and the evening, so you may choose to generate power at some time other than the top or bottom of the tide, as that is when it is most needed.
 
 

Offline evan_au

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Re: what is the Top Tidal power?
« Reply #5 on: 07/03/2015 02:31:27 »
Perhaps each student was given a power source, and then given a standard list of questions to answer about it?
O
One of the important concepts for petroleum is "peak oil": the observation that we are exhausting existing large oilfields faster than we are bringing the newer, smaller oilfields online. Some claim that we reached peak oil production as early as 2007 (but I haven't seen recent figures).

This concept is rarely applied to renewables like tidal power. But if you tried to answer this question, you may be asking "what does top/peak tidal power mean?".

Short answer: the available tidal power is unchanged on human timescales (like a million years).

Long answer: peak tidal power occurred a billion or more years in the past, when the moon was much closer, and tides were 10 or more times higher than today's tides.
In another billion years, the moon will be even farther from Earth, and the height of tides will be lower. The Earth will also be rotating more slowly, so high tides do not occur qu
ite as often.
But tidal power will be effectively unchanged over the next million years. We may just be harvesting a greater percentage of it.
 

Offline Chem4u

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Re: what is the Top Tidal power?
« Reply #6 on: 07/03/2015 18:50:58 »
We were divided into groups,,
One group was assigned to report on the Tidal Energy
And My Group About Top Tidal power
So I said, they're two different
 

Offline evan_au

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Re: what is the Top Tidal power?
« Reply #7 on: 07/03/2015 22:29:47 »
In normal newspaper usage, "a source of tidal energy" means the same as "a source of tidal energy", and the two terms are used interchangeably.

However, in Physics, Energy and Power are not the same; there is a very specific relationship between Power and Energy:
  • Power is measured in Watts (or MegaWatts, if you are talking about a power station).
  • Energy is measured in Joules (although the electricity supply people traditionally use MegaWatt-hours).
  • Energy=PowerxTime
  • If you deliver 1 Megawatt for 1 second, you generate 1 MegaJoule.
  • If you deliver 1 Megawatt for 1 hour, you generate 1 MegaWatt-hour.
     
Tidal energy is not produced at a constant rate, 24 hours per day. It may be able to generate for (say) 2 hours per day, and then wait another 4 hours for the tide to fully go out, or come in.
Even within the 2-hour operating window, the power output is not constant. Normally, at high tide, water will flow from the ocean into a lake - until the lake approaches the same water level as the ocean, and the generator output declines.

The peak tidal power occurs when the lake was emptied at low tide, and generation starts at the peak of high tide. It's even higher if the Sun and Moon are aligned (Full Moon or New Moon), and the Moon happens to be at the closest point in its orbit (perigee).

However, this almost never happens, because:
  • When the Earth and the Moon are not aligned, the tidal range is much lower, and power output is lower
  • Generation is taking place at the bottom of low tide, and top of high tide, so the lake never really reaches the extreme tidal range of the ocean
.

So the (Energy produced from a tidal generator) is far less than the (Peak Power of the tidal generator) x 24 hours x 365 days.
 

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Re: what is the Top Tidal power?
« Reply #7 on: 07/03/2015 22:29:47 »

 

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