Oil and coal *are* renewable, it just takes a while. What's 10m years to a bureaucrat?

Kiss good bye to the economy,

Say Hello deep recession and poverty.

Is that 20% of current consumption? i.e. 81TWh? I hope it's not 20% of 2020's leccy consumption!

Suppose for a second instead of the Severn tidal barage we did one out in the north sea. A circular dam enclosing a circle of north sea, which would generate electricity by water flowing in during high tide and out during low tide. It would be out at sea because it's less likely to be killed by environmental objectors. It would be circular so it uses less concrete for maximum sea area, and in the north sea because it's reasonably shallow at <100m.

How big would it be?

1 Kg falling 1 metre is about 10 Joules.

3 cubic metres is 3000 litres, dropping 3 meters is 90000 joules.

Or 0.025 KWh for each ebb or flow of the tide per m2 of sea.

80% efficiency say, 0.02 kWh...

Which is 20,000 KWh per Km2

So 81 TWh / 365 days / 2 tides per day / 2 ebb_flows per tide

= 55 GWh per ebb_flow of the tide.

Which I make out to be 2750 km2 of sea, or 60km diameter circle, so about 190km of dam.

Payback time 70 Euro per mwh, = 70 million per TWh = 5 Euro billion a year in income.

http://ec.europa.eu/energy/electricity/publications/doc/review/2006_01_qr06.pdf

No sure how much it costs, say the three gorges dam is about $10 billion per km of dam, i.e. $1.9 trillion, but they had to relocate people, and we wouldn't, so say less than half that, about 500 billion euros for our dam. Ouch, way too high, thats 100 year interest free loan even before the contractors have done their overruns.

Ahh, forget that idea. For tidal to work, it looks like it has to be in existing tidal channels.

Twats.

Typical blinkered thinking by politicians.

Lets see how 'economically sustainable' coping with annual flooding and storm damage is as it continues to get worse thanks to global warming. Parts of the UK are under water again, having just recovered from last July's innundation.

Actually, I think that Sarko's griping is because it's a specific commitment to renewables rather than the more usual CO2 yardstick and nothing to do with any objection to Doing Something About Global Warming (and, by association, Getting Seen On TV More).

FR is currently in pretty good shape on CO2 but not due to a heavy investment in renewable energy. Nuclear power you know. Lots of it. This means they have a very mature Nuclear industry and it would be a piece of the proverbial for them to chuck up more reactors to meet any CO2 target on offer.

This target wipes out their advantage and puts them on the same footing as everyone else (Not Having A Clue Where To Start But Wanting To Be Seen To Be Doing Something).

What if tomorrow someone invented a way of powering an entire village for a week on one lump of coal? I can guarantee you one thing - the EU would still insist we generated 20% of our energy with ugly/expensive renewables because that was the target. I'm exaggerating, but the fact is that using renewables is a means towards clean energy, not an end in itself. Treating it as inherently virtuous is self-evidently stupid.

Government targets are always arbitrary in any case and now they're being applied to something also completely arbitrary. It makes about as much sense as trying to stamp out MRSA by saying that x litres of water must be used in cleaning the hospital every day. Or that we can teach our children to read, write and do sums if they turn over a prescribed number of pages in their textbook per lesson.

@anonymous coward

"Kiss good bye to the economy, Say Hello deep recession and poverty."

What is that supposed to mean?

In Denmark since the last couple of years 20% of electricity has been made by wind turbines. And DKs economy has certainly not been in recession the last 5-10 years.

Of all EU countries Britain has the best wind resources available. However Britain has been very late to start using renewable power source. it is only in the last 3 years that there has been any significant uptake in using wind turbines.

I will claim that renewable energy is good for the economy, it is the "do not change anything" attitude that gives stagnation and leads to recession.

Hi

15% is the backbone of the grid currently provided by Nuclear electricity.

There is no way in hell that the UK is going to be able to provide that much power from wind farms - its just not viable as a mass power source.

We have not even started to tackle wave powere, despite all the bullshite promises over the last 30 years. I remember it happening in a 'couple of years' time on Tommorows World, 25 years ago.

Crudely put, if you covered scotland in wind turbines, you might be able to powere manchester on a windy day.

Its that inefficient.

Mind you, who would notice?

Its not as if anyone lives there.......