[Kosh]

Re: Double standards : Thu Feb 02, 2012 1:42 pm  

Ferocious Aardvark wrote:

So is the issue then an inability to meaningfully store up hydro-generated electric power, when generated?

No. The issue is that just sticking a turbine in a river delivers very little electricity and is impossible to control as the flow in the river is constantly varying. This is why the vast majority of hydro power is delivered by falling water from some sort of reservoir - typically an artificial lake formed by damming a major river.

There are 'run of river' hydro plants that don't use a reservoir (or at most a very small one) but these still require a large river with constant flow and a significant drop in order to ensure sufficient water through the turbine under controllable conditions.

Ferocious Aardvark wrote:

You see, I can easily see a system whereby a whole bunch of electricity could be generated by installing turbines to tap into the strong flow of water down the Aire at Saltaire (or wherever). This electricity if fed into the grid would reduce the need to generate it by burning fossil fuels to an equivalent amount.

See above. The contribution would be tiny and quite possible outweighed by the environmental and energy costs of building, installing, and maintaining the generators.

Ferocious Aardvark wrote:

On a more epic scale, one resource the British Isles has is we are in the middle of a set of very tidal seas, and almost 24/7 there is an unstoppable flow of trillions of gallons of water either coming in or going out. Surely, if we could harness the power of nothing more than the flow of water, which will flow whether we harness it or not, it would generate a very significant amount?

Tidal power is a whole different ball game and well worth pursuing. Sadly successive administrations have been swayed by the extremely active wind power lobby and most of the development funding has gone into wind turbines. However, there is now some promising activity in this field and hopefully we can realise it's potential. The UK has nearly 50% of the sites identified as suitable for large-scale tidal arrays in the world (8 out of 20 at last count I think) and some estimates claim that tidal could produce as much as 20% of our energy requirements.

Re: Double standards : Thu Feb 02, 2012 1:46 pm  

I remember reading articles about hot rocks power in New Scientist, way back in the 1980s: any advances on that or is it unlikely, does anyone know?

Re: Double standards : Thu Feb 02, 2012 2:07 pm  

Kosh wrote:

...
Tidal power is a whole different ball game and well worth pursuing. Sadly successive administrations have been swayed by the extremely active wind power lobby and most of the development funding has gone into wind turbines. However, there is now some promising activity in this field and hopefully we can realise it's potential. The UK has nearly 50% of the sites identified as suitable for large-scale tidal arrays in the world (8 out of 20 at last count I think) and some estimates claim that tidal could produce as much as 20% of our energy requirements.

Sounds good. It always seemed palpably crazy to me to spend a load of money on the odd wind turbine sticking out of the sea, reliant on nothing but the breeze, when you had the potential for an unbroken line of turbines, taking advantage of a flow of liquid rather than gas which was not only uber reliable, but surely with the potential to produce many factors more units of power per metre of sea bed.

Re: Double standards : Thu Feb 02, 2012 2:41 pm  

I'll have a google gander but i read somewhere that the machines used to harness tidal power are unreliable and eventually broke and they are currently looking into better more reliable technology before committing to a long term solution on tidal.

[Kosh]

Re: Double standards : Thu Feb 02, 2012 2:50 pm  

Horatio Yed wrote:

I'll have a google gander but i read somewhere that the machines used to harness tidal power are unreliable and eventually broke and they are currently looking into better more reliable technology before committing to a long term solution on tidal.

All machines eventually break.

Tidal power is technically challenging, which is why so few suitable sites have been identified worldwide. There have been some promising recent developments though. It doesn't help that for years, in the UK at least, research into tidal power has been low on the priority list for Government funding.

Re: Double standards : Thu Feb 02, 2012 2:51 pm  

Maybe not so unreliable: http://www.marineturbines.com/3/news/article/57/decc_s_greg_barker_backs_marine_current_turbines__plans_for_its_first_tidal_farms/

Maybe not so unreliable: http://www.marineturbines.com/3/news/article/57/decc_s_greg_barker_backs_marine_current_turbines__plans_for_its_first_tidal_farms/

Re: Double standards : Thu Feb 02, 2012 5:13 pm  

Kosh wrote:

No. The issue is that just sticking a turbine in a river delivers very little electricity and is impossible to control as the flow in the river is constantly varying. This is why the vast majority of hydro power is delivered by falling water from some sort of reservoir - typically an artificial lake formed by damming a major river...

We've got dozens of those reservoir thingies oop North.

[Kosh]

Re: Double standards : Thu Feb 02, 2012 6:25 pm  

El Barbudo wrote:

We've got dozens of those reservoir thingies oop North.

How many of them are on top of mountains or high up in steep river valleys? How many are actually fed by significant rivers rather than being catchments for rain and/or minor rivers and streams? Or spring fed?

If widespread hydro power were feasible in the UK we'd be using it. Just look at the amount of effort and engineering that's gone into the ones in Wales and Scotland - that wouldn't have happened if there were an easier alternative.

Re: Double standards : Thu Feb 02, 2012 10:57 pm  

Kosh wrote:

All machines eventually break.

Unfortunately they tend to break A LOT quicker when exposed to salt and moisture. At Toyota we had numerous forklifts on long-term lease in seafood factories, canneries, salt distributors etc. Unlike other customers whose trucks we almost never saw returned to the depot for repairs within the five year extended warranty these often lasted no more than a year before manifesting major faults. And when they came back they looked not years but decades old. Wheel nuts, load chains, king pins, tie rods etc. were seized solid and usually required the help of burning gear to remove. The lads hated working on them because even simple tasks ended up taking hours to accomplish. Salt is hideous stuff and it wreaks havoc with not just metals but electronic circuitry, too. It was very common to find a truck inoperable because of a dead short within a corroded wiring loom.

Of course, there are materials resilient to salt corrosion. But they tend to be expensive and/or unsuitable for engineering tasks. This is the reason wave energy didn't take off years ago.

[Kosh]

Re: Double standards : Fri Feb 03, 2012 7:30 am  

Mugwump wrote:

Unfortunately they tend to break A LOT quicker when exposed to salt and moisture.

I know.

Mugwump wrote:

Of course, there are materials resilient to salt corrosion. But they tend to be expensive and/or unsuitable for engineering tasks. This is the reason wave energy didn't take off years ago.

It's one of the reasons. However, engineers have been coping with salt water issues for centuries and none of these problems are insurmountable.