Grauniad: Welsh tidal lagoon project could open way for ukp15bn revolution in UK energy

[Tim Streater]

That's pretty vague, it only just avoids being labelled wriggling. So lets have a bit more detail.

[The Natural Philosopher]

No, its cat belling nonsense.

If you only have one type of basket that actually CAN hold eggs at any sane price, that's where the eggs go.

Dave's stupid point would seem to be that its a choice between lots of little crappy renewable sources and just ONE power station to run the whole country.

Its not. We build many power stations. WE have many baskets.

That they are all of similar type, is the nature of useful baskets. Over years we have arrived at a pretty good idea of what constitutes a good basket.

[Chris Hogg]

I'm not quite sure where to begin in response. Let's try this:

The area of the UK is approximately 241,000 km^2. or 2.41*10^11 m^2. Solar insolation in the UK is approximately 100 W/m^2 (MacKay p.38), or over the whole country, 2.41*10^13 Watts, or 24100GW. The UK consumes roughly 35GW of electricity on average, which is 1.45% of the solar insulation. I don't know what the area of solar panels is in the UK, but it must be a minute fraction of the total area, and will always be so. Likewise with wind, the total cross-sectional area intersected by wind turbines must be a tiny fraction of the total cross-sectional area of the troposphere across the UK. With the possible exception of erosion on the east coast, waves and tides make little impression on the coastline; their energy is totally lost.

And all the solar and wind energy that's captured and converted to electricity ATM ultimately ends up as heat. OK, so it's redistributed slightly differently to when it was collected, mostly into cities etc., but it all comes back eventually.

While it might require the whole of Wales to be covered in windmills to power the UK or whatever, that's never going to happen. Nor will half the country be covered in solar panels, or whatever area is necessary, to power the UK. So I'm happy to repeat my assertion that renewables are never going to make other than a local impact on our overall environment.

[Chris Hogg]

Local communities are already resisting solar and wind farms, planning permission is being refused, and government subsidies are gradually being withdrawn. I don't think we'll see either being installed at the same rate as in the past. Offshore wind will continue, and tidal, either in the form of lagoons/barrages or tidal streams, hasn't yet made an impact, but will to some degree I'm sure, attracted by the high strike price. How long that will continue, remains to be seen.

[newshound]

That's with steam temperatures of ~ 650C, this will be a water reactor with steam temperature perhaps 315C.

Best fossil plant (without combined cycle) gets just over 40%, AGR a little less, water reactors around 30%.

IMHO size of condenser is not really a limit for a floating system!

[The Natural Philosopher]

There is in fact a massive struggle between the poqwers that be - as evinced by the EU, legal system, government etc, and te wishes =- reasonable wishes - of te citizens.

Just today I read this:

which if true,. is way beyond anything the soviet union did, and more akin to Nazi Germany.

Your argument is, I think, predicated in the assumption that the reasonable thing will happen. Mine is predicated on the assumption that those in power will do whatever they think they can get away with. And if that means foisting a windmill every half mile on the countryside, to justify raping us for 50p a unit electricity, that's what they will do.

There is a war on. Between the establishment and their fanbois like Plowperson. and the rest of us who actually think the country should be run a little bit for *our* benefit as well as for everyone elses. And windmills benefit no one except those who operate them.

So indeed we shouldn't have them. But that doesn't mean we wont.

[Chris Hogg]

A minor correction, for the record: 35GW is 0.145% of 24100GW, not

1.45% as I said above.

[The Natural Philosopher]

now calculate how much of the atmosphere is co2....

400 ppm? that's .4 parts per thousand, which is .04%.

And that apparently is going to destroy the world.

So the impact of 0,04% is so massive it justifies altering something else by .14%. which wont make any difference.

Oh and BTW 35GW is just the electricity. You left out all the gas an road fuel we burn, any you left out the fact that in winter, the insolation is about 10W/sq meter. And you left out the panel efficiency, which is about 15%.

[Chris Hogg]

Well, yes to most of that. But even if you triple the energy requirement, that still only gets you to less than 0.5% of the total insolation across the country. So there's 99.5% left to do what it's always done. There are of course variations in the insolation: day-night, summer-winter, north-south, all broadly taken into account by MacKay when he arrived at his average UK figure of ~100W/m^2, down from the ~1000W/m^2 under the blast of full sunshine at the earth's surface at the equator.

I still maintain that the energy extracted from the environment by solar panels and wind turbines isn't going to make any difference to the environment other than very locally.

[The Natural Philosopher]

By the same token CO2 emissions from power stations aren't going to make any difference to the environment except locally, so what is the point of renewable energy?

[Chris Hogg]

I doubt that it is by the same token, in fact, and anyway, it's a whole new argument, which I'm not getting into as I have serious doubts about it, as do you!

[whisky-dave]

For me it'd be someone in a much larger vehicle coming towards me at speed on the same side as I was on.

Or the EU decides to add a tariff on everyone that doesn't drive on the side of the road EU tells you to. :-)

[Vir Campestris]

You've missed hydro - not intermittent, highly dispatchable. But of course there's the Banqiao problem...

Andy

[Chris Hogg]

Like pumped storage, you need the right topography and rainfall, and we don't have enough of both together. Scotland is full of hydro schemes, but they're all small.

[The Natural Philosopher]

I haven't missed non-intermittent. I have deliberately restricted the discussion to *intermittent* renewables. Biogas etc are all fine, just hopelessly uneconomic. Hydro is great if you can accept the risk, the ecological impact and have suitable places to build it.

[The Natural Philosopher]

There's room to convert some to pumped and to add a GW or so more hydro if anyone can be arsed.

But it doesn't fit with the GreenVagina view that infests the Scottish consciousness.