75MWe out of 300MWt is indeed a bit low; Hinkley C will produce 9,000 MWt, 3,200 MWe, an efficiency of 35.5%. Ignoring the source of heat, once you've created the steam, the turbine and generating bit is much the same for nuclear plants as it is for coal-fired plants, the latter having around 30-35% efficiency, so much the same as nuclear, as you would expect.
Se my other po9st. That's with full condensers and reasonably high superheated steam temps.
Both of those increase plant costs and weight, which is significant in a 'floater'
5.8 GW of heating is literally a drop in the Bristol Channel, but couldn't it be used e.g. to "hothouse" a giant algae lagoon, which you harvest for biofuel?
only if it works
They get paid for the leccfy they generate
if the prediction that it will silt up is correct they will get paid nothing by the *bill*payer (not the tax payer)
tim
Or any of the below:
En el artículo , The Natural Philosopher escribió:
Wrong again. Quelle surprise.
How about you read what is actually written before knocking out a knee- jerk reply? Then you wouldn't look such a d*****ad.
You're turning into a know-it-all-but-actually-knows-f*ck-all like Wodney.
That general idea has been considered. In the late David MacKay's book, he refers to work by Cartwright on estimating the average tidal powers across major sea boundaries around the UK*. For example, across the Strait of Dover, 16.7GW; across the Irish Sea from Wexford to St. David's Head, 45GW; a long one running from Malin Head in N. Ireland all the way around Scotland and the Shetland Isles to Floro in Norway,
60GW, and an even longer one across the Western Approaches, from Valentia in S.W. Ireland across to Ushant in Brittany, 190GW.But somehow I don't think anyone is actually going to build barriers across any one of them to tap that power!
Then of course there's this:
In message , Tim Streater writes
Not me. I liked the tidal flow job but, if the sums don't work, stick with nuclear.
>
Oh come ON. Giant cannabis greenhouses!
En el artículo , Tim Lamb escribió:
agreed, Chris did a nice analysis.
+1.Those figures seem quite small when one considers the size of the projects and the unpredictable effects of changing the way the currents and tides run.
The problem seems to be that no matter what you try to generate power from any naturally occurring force like wind or tides or even the sun, you actually are taking power from the earth and if you do enough of it, you alter the environment in some way, often a way which was unexpected.
Brian
I don't think so Brian. There may be local effects, such as reduced wind speed downwind from a wind farm, or smaller waves 'downwave' of a wave farm, but the effects are small in the grand scheme of things. Wind energy is dissipate when it shakes trees; wave energy is dissipated when the waves hit the coast; solar energy is wasted when the sun heats the ground. All man is doing is diverting that energy from being wasted into something useful. After all, all that energy ultimately comes from the sun, which is going to keep shining for a good few years yet and what we do with the small amount of its energy that reaches us isn't going to change that.
Even the energy of the tides is wasted, and the tidal forces exerted by the moon and dissipated by distorting the solid bits of the earth probably vastly exceed those dissipated just by moving the sea to and fro. The moon is slowly moving away from the earth, at a rate roughly equivalent to how fast your finger-nails grow, and it was been doing so long before anyone thought about harnessing the tides to do something useful.
That is ONE problem Brian. Environmental impact. Essentially 'renewable energy' comes in low power density, so that automatically and irrevocably means, with no possibility of technological development changing it, that the devices used to capture it will be *LARGE*.
Let me repeat that for the avoidance of doubt. Low power density means that all renewable power generation will be *LARGE*. And hence of high environmental impact.
And potentially expensive.
Let me stress again that this is simply unavoidable. Anything big enough to get the very low grade energy out of the environment will have to be big enough to make a significant impact on the environment. There simply is no answer to that.
The second problem is intermittency. Not unpredictability, but the sheer fact that the power is not coming from an energy store, but has to be generated and used when the energy source is available. Again no amount of clever technology cam make the wind always blow steadily or the sun always shine, at least on the earth's surface.
And if attempts are made to store the intermittent energy, you run into two further problems.
Firstly it's very costly to store large amounts of electrical energy. and secondly is very dangerous. Depending on the energy density it may also be quite big, and therefore exact a further environmental penalty.
Then intermittency adds another problem. If the store and the source are not co-located, a further problem arises with intermittency, and that is the connectivity. High peak to mean power flows generate cables more costly than the mean flow would dictate. And these larger cables too, have more environmental impact.
Finally, if the dispatch side of the generation needs are not handled by (rechargeable) stored energy, they have to be handled by some other access to stored energy - typically fossil or nuclear. This means complete duplication of capital equipment, since all renewable sources are capable of simultaneously dropping to zero output over very large geographic regions, and if not co-operated with conventional power, they must incorporate very long, expensive and vulnerable inter-connectors.
Yet more cost, yet more environmental impact.
What needs to be stressed is that all these drawbacks are not something that can be 'developed out' of renewable energy. *THEY ARE INHERENT TO THE VERY NATURE OF IT*.
Renewable energy will always be large, and will never be more than a partial solution. Simply because the power density is low, and the source is inconstant.
You may ask 'why then are we bothering with it?'
Why indeed?
You would be surprised.
So shaking trees is 'not useful'
And you have just made the point that solar energy that DOESN'T hit the ground is obviously going to leave the ground colder than it was by a substantial amount.
When David Mackay talked of 'a wind farm the size of Wales' he wasnt joking.
That is a significant an serious environmental impact.
After all, all that energy
I am simply jaw droppingly flabbergasted at your complete and utter ignorance of what used to be called 'physical geography' and that is the actual impact that things like sun, wind, waves and tides have upon the environment.
AS I have pointed out before, the UK uses several Hiroshima sized bombs worth of just *electricity* every day.
Ultimately the environmental impact of that, done conventionally, is a little CO2, and a reasonable amount of heat. IIRC something like 10% of the sunlight falling on the UK. (that is of course what actually generates the 'rising temperatures' of 'global warming' as cities get built round thermometers and keep them toasty due to energy spill)
With energy needs in a crowded country like the UK being about 20% of the actual energy falling on it as an island from the Sun., its going to be a massive environmental impact however its done, and more so with so called 'renewables' than any other way.
Because they have to be HUGE to scrape it up. At least 20% of the land area for PV for example.
The lowest environmental impact of any is of course nuclear. The sole thing it produces is heat, and the oceans are big sinks (though it might help melt a tad of polar ice). The waste such as it is is compact and easily dealt with,.
Nuclear is far and away the 'greenest' technology there is, to generate large amounts of usable power.
Well, yes. Possibly. But then burning fossil fuels to produce power doesn't seem to be doing the environment much good either. Except in the opinion of the various nutcases on here, of course.
So what then is your solution, Our Dave?
Eggs. Basket. Put. Don't. Rearrange to suit. And preferably owned by the UK. Or rather England, as is likely by then.
of it's a lagoon in Wales, they might not like a "colonial power" owning it.
No; wrong kind of management.
In the 1970's Rolls having given Stanley Hooker the elbow found itself bank rupt after all it's high bypass engines failed the frozen chicken test for carbon bladed turbines.
When the government bought out the blighters and reinstalled god's gift to the jet-set, he redesigned them in titanium and found them much better minc ers.
Several frozen freezerfests later the Rolls Royce jet engine is worth milli ons.
The reason the river barrages are not viable is that they have to be closed to shipping. There is no accord in the world that will save the environnme nt from rich people and money. It wasn't even mentioned past a few editions of the News Chronical when the people who made the Conwy Tunnel decided to create a marina from the tidal flats that used to house most of the waterb irds in North Wales.
However if they dig a tunnel to direct a tidal range into a reservoir separ ate from the rivers then they can use any amount of wilderness that the gov ernment are willing to steal from the locals for their not using it properl y.
You know, I think its high time we had some DIVERSITY in the shape of wheels.
Putting all your eggs into the 'round wheel' basket looks like a really bad idea don't you think?
Almost as stupid as only investing in power generation technology that actually works eh?
But not actually as stupid as having roads where everyone has to drive on the left. I mean that flies in the face of individual freedom social justice and the principle of diversity. What right has anyone to force me, against my religion and culture, to drive on the Left?
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