wave power

[philba]

It's far from utopian but one more interesting way to generate electricty
https://www.usatoday.com/tech/science/2007-04-18-wave-power_N.htm

I'd bet the two major complaints will be:
- ecological damage
- construction costs

 

[CheapSlider]

There does appear to be scope with the idea and several trials have been made over the last 30 yrs or so.

The main issues have been:
efficiency - if below a certain threshold then it's not worth the effort
reliability - has to be low maintenance
durability - can it withstand a battering from a storm ?
cost - will there be a return on investment ?

It does appear more attractive then wind, where backup capacity is needed in case of no wind.

Tidal power seems attractive due its predictability, but there are massive construction costs and environmental impact. Also the tides can't provide power continuously.
There has been a tidal barrage power plant at Rance estuary in France since 1966.

 

[Hero999]

Tidal power seems the best way of harnessing energy from the sea. Wave power seems like a waste of time.

 

[Pommie]

Out of pure curiosity, where does tidal power come from? As the energy has to come from somewhere, what will loose energy. Will the moon slow down? Earth slow down? Moon speed up? Earth speed up.

My vote goes with, moon speeds up.

Mike.

 

[Hero999]

Why would the moon speed up?

 

[Nigel Goodwin]

Why would the moon speed up?

Because it will get closer, so automatically speeds up as it's then in a lower orbit - lower the orbit, faster the speed!.

However, using tidal power won't have any effect on this, just the gravitational attraction between the earth and moon.

 

[Hero999]

Because it will get closer, so automatically speeds up as it's then in a lower orbit - lower the orbit, faster the speed!.

True if you increased the energy in the system that would happen, but if you removed energy from the system the moon would slow down and the orbit would get larger.

However, using tidal power won't have any effect on this, just the gravitational attraction between the earth and moon.

I agree.

 

[Oznog]

The energy comes from the kinetic energy of the moon's velocity relative to the earth. The moon will slow down and assume a closer orbit.

This has been happening since the moon was formed. The effect is quite small since the moon is such a huge mass. Furthermore, harnessing tidal power has no additional effect. The water will be lifted and fall back regardless of whether the energy is captured by man or not.

 

[Pommie]

The moon will speed up. This is due to the tide acting as a brake between the earth and the moon. The earth rotates at 1 rev per day, the moon at 1 rev per month. The brake effect will cause the moon to speed up and the earth to slow down. Eventually the moon will be fast enough to leave earth orbit. Thankfully, I won't be around when that happens. The rather surprising fact is that tidal energy does not come from the moon at all but instead comes from the earths spin.

Mike.
edit, actually the moon won't leave earth orbit, it will stop accelerating when the earth and moon rotate in unison once every 47 days!! **broken link removed**

 

[Oznog]

The moon will speed up. This is due to the tide acting as a brake between the earth and the moon. The earth rotates at 1 rev per day, the moon at 1 rev per month. The brake effect will cause the moon to speed up and the earth to slow down. Eventually the moon will be fast enough to leave earth orbit. Thankfully, I won't be around when that happens. The rather surprising fact is that tidal energy does not come from the moon at all but instead comes from the earths spin.

Mike.
edit, actually the moon won't leave earth orbit, it will stop accelerating when the earth and moon rotate in unison once every 47 days!! **broken link removed**

Ooops you're right! The moon will speed up, the earth slows down.

 

[philba]

Tidal power seems the best way of harnessing energy from the sea. Wave power seems like a waste of time.

the problem with tidal power is that it will cause significant [perceived] ecological impact. even a small change in the average water level will have impact on any species in the inter tidal zones. Constructing a man-made lagoon to harness the power will be expensive. I think in many countries, tidal power would be politically untenable.

Why do you think wave power is a waste of time? Unlike tidal power, it is fairly continuous and can be deployed in smaller, incremental units. Please expound on your point.

 

[Tim_B]

An advanced wave energy system being tested now

**broken link removed**

 

[Sceadwian]

Mmmm, sea water and electricity, wonderful combination!

 

[philba]

well, some smart people seem to think it's possible.

by the way, I saw a story about tidal generators in the lower Hudson River, it was short on details but seemed to say they are using underwater turbines "just like windmills underwater". I assume it wasn't a literal statement.

 

[Nigel Goodwin]

well, some smart people seem to think it's possible.

by the way, I saw a story about tidal generators in the lower Hudson River, it was short on details but seemed to say they are using underwater turbines "just like windmills underwater". I assume it wasn't a literal statement.

It's certainly possible, there are a number of tide and wave power generators all over the world.