Boathook
Well-known member
Presently gas is generating over 49% of our electricity. If we use more electricity we will possibly use more gas ....
Tidal energy generator experiments in Littlehampton.
- Thread starter rotrax
- Start date
jamie N
Well-known member
I'd love to see that info on a regional basis. Here 'by Inverness', it's basically a windless day, so not a lot of renewable stuff. Orkney might be different with their current/tidal generators.
As an aside, I see that Scrabster is going to be the support port for a new windfarm in the Pentland Firth. Why wind and not tidal is a mystery to me.
As an aside, I see that Scrabster is going to be the support port for a new windfarm in the Pentland Firth. Why wind and not tidal is a mystery to me.
lustyd
Well-known member
That would depend on the gas. Our data centres now use Hydrogen which is made using excess wind and solar so in theory gas might not always be a bad thing in the future. I can't imagine there's enough production yet but it's early days
boomerangben
Well-known member
At the start of this, Rotrax mentioned a tidal power generation project and Sarabande mentions it being on one of the fastest flowing rivers. So does a fast flowing river feeding a tidal system benefit or reduce the effectiveness of a tidal power station?
I wonder as we march head long towards electric centric living, how the national grid is coping with distributing all this energy to the users. How is it going to be when everyone starts their hot water heating, car chargers, washing machines, home battery chargers, storage heaters etc the moment the cheaper tariff starts at midnight or whatever. Oh yes, I forgot. The cheaper tariff will disappear. Never mind. It needs to happen but what will be the real cost to the environment.
I wonder as we march head long towards electric centric living, how the national grid is coping with distributing all this energy to the users. How is it going to be when everyone starts their hot water heating, car chargers, washing machines, home battery chargers, storage heaters etc the moment the cheaper tariff starts at midnight or whatever. Oh yes, I forgot. The cheaper tariff will disappear. Never mind. It needs to happen but what will be the real cost to the environment.
MM5AHO
Well-known member
There's a proposal to install a tidal generator in the sound of Islay. Can be read on the Marine Scotland website.
rotrax
Well-known member
I suspect the most practical method long term will be small local projects using a mix of Hydro, Wind and Solar.
The Rolls Royce nuclear from modified submarine units might be a goer.
The Rolls Royce nuclear from modified submarine units might be a goer.
rotrax
Well-known member
I have had the opertunity to watch the tides in the estuary from the boat many times.
The river flow is such that until the flood tide reaches a good incoming flow it overcomes the early flood, holding it back.
Then a 'scum line' can be observed making its way up the river, moving steadily and following the course of the deeper channel. Seabirds scavenging on this 'scum line' mark it clearly. It is perhaps one sixth of the width and moves at about a knot. Outside this scum line the river flow is still going out until the flood volume increases, giving a short period of slack water
Shortly after the flood takes over and the tide is ripping in again.
Threequarters of an hour later the same situation occurs at Arundel, the river almost, but not quite overcoming the flood.
It is certainly different to a river with little flow.
On full ebb, it really rips, more than six knots at springs in the narrows.
dgadee
Well-known member
I don't think it was. On the CA forum it was reported that a problem with these situations (middle of strong tidal flow) is that there are lots of eddies and the flow is not parallel so they don't get the full expected benefit. A boat hit the generator, too, so not that safe when plonked in the middle of a channel. I kayaked past it a good few times at springs and the bow wave was magnificent.
Wikipedia (SeaGen - Wikipedia) tells us that it was experimental on a 5 year project, despite being described as commercial. It has now gone.
NormanS
Well-known member
Using tidal power is hardly a new idea. The town where I live had a "Sea Mill" hundreds of years ago. A tidal lagoon was dammed, and a conventional water wheel in the resultant mill race, was able to work on both the flood and ebb tide. That was long before electricity was discovered of course.
dgadee
Well-known member
Yes, direct power but the aim is to transfer that power elsewhere. The nodding ducks I remember from Tomorrow's World seem to have been forgotten, too, but through funding loss: "Salter's duck, also known as the nodding duck or by its official name the Edinburgh duck, is a device that converts wave power into electricity. The wave impact induces rotation of gyroscopes located inside a pear-shaped "duck", and an electrical generator converts this rotation into electricity with an overall efficiency of up to 90%. The Salter's duck was invented by Stephen Salter in response to the oil shortage in the 1970s and was one of the earliest generator designs proposed to the Wave Energy programme in the United Kingdom. The funding for the project was cut off in the early 1980s after oil prices rebounded and the UK government moved away from alternative energy sources. As of May 2018 no wave-power devices have ever gone into large-scale production." Wikipedia.
SaltIre
Well-known member
Tidal Flow doesn't continue 24x7 day and night. It reduces and stops four times a day then increases again in cyclical fashion - hence the need for storage or tidal generation in other areas with different times for HW & LW.
Maybe some folk who know about boating will be along soon to confirm.
cpedw
Well-known member
But around UK, the cycle phase changes at different locations. I don't know how the average works out but there is always somewhere that the level is changing. A network of generators connected together (a "grid") might generate continuously.Tidal Flow doesn't continue 24x7 day and night. It reduces and stops four times a day then increases again in cyclical fashion - hence the need for storage or tidal generation in other areas with different times for HW & LW.
Maybe some folk who know about boating will be along soon to confirm.
There were rumours that Salter's duck was scuppered by experts at Harwell who didn't want anything interfering with funding for nuclear energy research.
There was an experimental Trimaran with 4 propellors in the Falls of Lora winter 2017/18. Some of the blades fell off. There was also a report of increased corrosion of nearby mooring chains but that was hard to quantify or even verify.
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PeterWright
Well-known member
Saltire is, of course, quite right and this focuses on one of the common myths surrounding most renewable electricity production schemes. Any generator has an installed capacity i.e. the maximum power it is capable of producing measured in Watts, or more likely Megawatts. A thermal power station will generally operate at an availability of around 85 %, so produce energy of its installed capacity x 0.85 x 8760 (no. of hours in a year) MWh per year. For all sorts of reasons, like sun not shining at night, wind not always blowing, river flow varying with rainfall or amount diverted for irrigation, tidal flow increasing /reducing twice per day, most renewable plant will operate at availabilities more like 25% so, to produce the same amount of energy in a year 3from renewables, 3 or more times the installed capacity of a thermal plant is required.
This is not to say that renewables should not be developed where they give a valuable level of production for the resources employed, but they shuld be assessed on the basis of reasonably expected annual production, rather than installed capacity.
Peter.
This is not to say that renewables should not be developed where they give a valuable level of production for the resources employed, but they shuld be assessed on the basis of reasonably expected annual production, rather than installed capacity.
Peter.
NormanS
Well-known member
The potential power available from a tidal installation is entirely predictable, unlike that from wind, wave or solar.
dgadee
Well-known member
Or river.
SaltIre
Well-known member
I believe the plan for the Orkneys is to crack seawater with excess power and produce hydrogen to fuel their ferries - but my point was more about "lulls" in energy production at the turn of the tide. Another poster mentioned the Sound of Islay, but although the times of High Water are about 6 hours apart that means the turn of the tide is similar...
dgadee
Well-known member
"Why don’t Orcadians like to hear the islands referred to as "the Orkneys"?
In the same way you wouldn’t refer to "the Irelands", "the New Zealands" or "the Hawaiis", Orcadians don't refer to the islands as "the Orkneys". However it is a common mistake made by visitors and the national, and international, media.
It is just "Orkney"."
Having said that, they've had tidal experiments for some years (I have sailed past at least one) but they don't seem to move on commercially. Will it ever work?
SaltIre
Well-known member
The generator among the Orkney Islands is commercial - not experimental.
The 680-tonne turbine is now anchored in the Fall of Warness where a subsea cable connects the 2MW offshore unit to the local onshore electricity network.
dgadee
Well-known member
That was where I sailed past, but it must have been a different system about 5 years ago. Unlike seagen this one won't be hit by passing traffic, but looks the same kind of double prop device.
dgadee
Well-known member
Sorry, bit confused. Does it float? On watching interview it seemed to be undersea, but text says it is on surface.