Potential for tidal power generation? Sailors thoughts.

[Keef]

Hi guys and gals,

I was talking about this with a friend and colleague earlier. I guess figuring out all the numbers-logistics would take a long time (must be a PHD in there for someone), but given the UK's huge tides we could surely generate most of our energy needs with just tide?

Obviously the downside would be the huge amount of energy expended on such a massive project, inconvenience to sailors and shipping and other costs I haven't even thought about.

On the whole it would make sense though. Massive investment in self sufficiency, skills, infrastructure. It certainly beats dirty coal and expensive nuclear power.

Numbers? Thoughts? Given that Bristol channel has one of the highest tidal ranges in the world the potential for turning that into clean energy must be tremendous.

Cheers, Keef

 

[Keef]

Sorry I missed an apostrophe in the thread title. If a mod could step in it would be much appreciated.

 

[Boathook]

They have only just recently removed a tidal 'windmill' from NI as far as I'm aware. Not to sure why but I believe that it was to do with growth on the moving parts and possible excessive wear. Hopefully others will be able to expand and or correct my comments.

 

[Plum]

Hi guys and gals,

I was talking about this with a friend and colleague earlier. I guess figuring out all the numbers-logistics would take a long time (must be a PHD in there for someone), but given the UK's huge tides we could surely generate most of our energy needs with just tide?

Obviously the downside would be the huge amount of energy expended on such a massive project, inconvenience to sailors and shipping and other costs I haven't even thought about.

On the whole it would make sense though. Massive investment in self sufficiency, skills, infrastructure. It certainly beats dirty coal and expensive nuclear power.

Numbers? Thoughts? Given that Bristol channel has one of the highest tidal ranges in the world the potential for turning that into clean energy must be tremendous.

Cheers, Keef

There are a number in existance....eg.
http://www.bbc.co.uk/news/uk-scotland-highlands-islands-41107521
Although ongoing maintenance and antifouling is a problem

Www.solocoastalsailing.co.uk

 

[NormanS]

There are at least two different ways of harnessing tidal power. One consists of turbines suspended in the tidal flow. That type is/was tried in Stangford Loch, and the Pentland Firth, and probably other places. That system causes the minimum of disruption to navigation, but can only harness a tiny fraction of the available energy.

The other method is by constructing a barrage (dam) with turbines built into it. Think of a dam across the mouth of a loch, or indeed the Bristol Channel. This method has the potential to generate a huge amount of power, but has many environmental opponents, and would obviously impact on navigation.

 

[pagoda]

As quoted- there are several rotor based designs around, either floating- but tethered or on pylons piled driven or gravity mounted on the seabed. My younger son is involved in the rotor design and construction of this device . http://www.scotrenewables.com/technology-development/sr2000
It was built mainly by Harland and Wolf at Belfast. It is in situ off Eday in Orkney, producing a fair amount of electricity. A larger device is in planning.
Much of the backing is overseas venture capital and big industrial concerns... UK content is a bit lacking as one might expect?

 

[lpdsn]

They have only just recently removed a tidal 'windmill' from NI as far as I'm aware. Not to sure why but I believe that it was to do with growth on the moving parts and possible excessive wear. Hopefully others will be able to expand and or correct my comments.

I hadn't seen the chart correction for that. Not sorry to see the back of it as it was a bit of a navigation hazard - bit risky for those unused to the tide who may have left the decision of which side to pass too late. Dodging the rocks in Strangford L entrance is generally far easier as the tide mainly flows around them.

Locals have told me that its availability as a power generator was also very poor. There are also not many places where the tides reach 7 knots so it never really had potential as a generic design. There are other forms of tidal turbines around that offer more promise for use in far more places and are less of a navigation hazard and I hope some of those start to take off soon.

 

[guernseyman]

They have only just recently removed a tidal 'windmill' from NI as far as I'm aware. Not to sure why but I believe that it was to do with growth on the moving parts and possible excessive wear. Hopefully others will be able to expand and or correct my comments.

Indeed, similar considerations have proven the impossibility of propellor-driven ships and boats.

However, the Strangford Loch tidal turbines have provided valuable R&D data, and will be replaced by a later technology.

 

[{151760}]

I hadn't seen the chart correction for that. Not sorry to see the back of it as it was a bit of a navigation hazard - bit risky for those unused to the tide who may have left the decision of which side to pass too late. Dodging the rocks in Strangford L entrance is generally far easier as the tide mainly flows around them.

Locals have told me that its availability as a power generator was also very poor. There are also not many places where the tides reach 7 knots so it never really had potential as a generic design. There are other forms of tidal turbines around that offer more promise for use in far more places and are less of a navigation hazard and I hope some of those start to take off soon.

Actually, I rather hope not...

 

[Kelpie]

There have been plenty of PhDs on this subject already.
One such person told me that, at least for now, none of the designs are cost effective. As mentioned, fouling is a huge problem. You can send down divers or you can lift the whole thing out of the water, either way it works out far more expensive than a wind turbine.
The big selling point of tidal is the reliability of the energy source, compared to wind and solar. But wind and solar are now so cheap that it makes sense to install a huge generating capacity, even if some of the turbines have to be switched off on windy days.
I think we will see a wholesale change in energy production/distribution/consumption: smarter appliances switching on at times of abundant generation, and a huge increase in storage capacity via grid connected electric vehicles.

 

[KellysEye]

My view has always been it was wrong to build wind and solar farms when tidal power guarantees power for most of 24 hours, 365 days a year.

 

[Mistroma]

I remember reading a book by the late Prof. David MacKay. It covered renewable energy on a scientific basis and was very persuasive. I seem to remember a couple of minor flaws but it's been a long time since I read it.

Pretty certain this is the book I downloaded as a PDF https://www.withouthotair.com/download.html and just had a quick look.

Section on Tides calculates total available if entire UK tidal energy captured (France to Ireland and then to Norway). This gives a maximum figure of 250GW. Of course that's a theoretical max. and you have losses, conversion efficiency etc. bringing output down to around 100kWh/day per person. That's based on a theoretical max. and Prof. MacKay calculates the output from the areas where we could realistically build something to harness the power. I think the figure comes out at around 11kWh/day per person when current total energy use is around 200kWh/day per person.

I like his approach of starting with theoretical max. figures and working down what's likely to be achieved at extreme levels of implementation. I cringe whenever I hear someone on TV stating that there's lots of renewable energy and so we don't need anything else at all. Pretty certain that they have no inkling of likely value of "lots".

 

[Kelpie]

Well Scotland has now had several days on which 100% of our energy needs were met by renewables. So it sounds as though there is lots of renewable energy up here, if conditions are right.

 

[johnalison]

I see that the OP hails from Korea, about which I know very little. I presume that his musings originated from thinking about the Sihwa power station, but conditions may be very different in the UK. Local interests and concerns about wildlife would make it very difficult to start a major project unless it was a matter of immediate national concern. If it were easy it would already have been done in the Bristol Channel region. For myself, I rather hope that projects of this kind are not necessary. Similar enclosures in Holland have resulted in very dull landscapes.

 

[capnsensible]

Chekkit

https://en.m.wikipedia.org/wiki/Gibraltar_Wave_Farm

 

[blackbeard]

Just a thought - anyone who has been to Bembridge will have seen, and probably walked along, the sea wall enclosing the pound for a tide mill.
Would it be cost effective to harness the tide power available here? after all, it worked for the mill (and a similar mill at Eling is still occasionally working). Should be good for a few kW ... and the expensive bit, ie building the sea wall, has already been done.

 

[Tranona]

Just a thought - anyone who has been to Bembridge will have seen, and probably walked along, the sea wall enclosing the pound for a tide mill.
Would it be cost effective to harness the tide power available here? after all, it worked for the mill (and a similar mill at Eling is still occasionally working). Should be good for a few kW ... and the expensive bit, ie building the sea wall, has already been done.

The barrage on the Rance near St Malo is effectively a big tide mill that has been operating successfully for decades, but as a supplementary source of power as it does not operate continuously.

Small tide mills were quite common in the past as they are cheap to build and operate on a small scale such as at Eling. However they are only run twice a day so are only useful for short term operation such as flour milling.

 

[chrishscorp]

Just a thought - anyone who has been to Bembridge will have seen, and probably walked along, the sea wall enclosing the pound for a tide mill.
Would it be cost effective to harness the tide power available here? after all, it worked for the mill (and a similar mill at Eling is still occasionally working). Should be good for a few kW ... and the expensive bit, ie building the sea wall, has already been done.

Yes seems completely obvious doesnt it......... I was part of a group that tried to get a hydro electric generator, installed pre 1930s still in place still able to work permission to run on an adhoc basis for school visits and the like, what were we thinking ?

A big meeting onsite with the EA was about as fun as stripping anti foul, and we still dont have permission, threats of huge fines, they even admitted the fish only swim up the river at night and we would have only operated it during the day for visiting school parties ( they were worried about fish getting damaged by swimming upstream through the turbine ) We did mention grandfather rights as it was an ancient bit of kit, we thought we had them, NO you will need an abstraction liscense and we grant those and the answer is no.

How to describe the EA and Natural England, difficult i dont wish to be red carded by the Mods !!

 

[Keith 66]

I recently saw the old tide mill lake at Bembridge & if that is not an ideal site for small scale tidal power nothing is. These sites were once relatively common, there is a similar sized derelict one at Walton on the naze, power can be generated as the fill up and as they empty. To any sane person it should be a no brainer. But as said try & get it past The EA & Natural england.

 

[Hydrozoan]

The barrage on the Rance near St Malo is effectively a big tide mill that has been operating successfully for decades, but as a supplementary source of power as it does not operate continuously.

Small tide mills were quite common in the past as they are cheap to build and operate on a small scale such as at Eling. However they are only run twice a day so are only useful for short term operation such as flour milling.

I seem to recall, but may be mistaken, that there was once a small tide mill of the latter kind on the Rance itself.