So nukes it is, then. They're, like, clean an' green. Well, they don't do much carbon emissions, which amounts to the same thing. Apparently several tonnes of radioactive muck that nobody knows how to properly dispose of is an acceptable legacy for the next 100 or so generations of peoplekind. Should the human race survive yea long.

This is of some relevance Round These Parts because Hinkley Point's just down the road. The prevailing wind comes this way. And there are trainloads of nuclear waste travelling through central Bristol each week.

Any new stations will almost certainly be built on the sites of existing or decomissioned ones. Only a couple of years ago there was a planning application in to built a wind farm on part of the Hinkley site! How times change ...

'Course if you're opposed to nuclear power, that's supposed to make you some flavour of Luddite, or some unrealistic hippy who wants to take us back to the middle ages. Hmmmm ... But actually there's nothing wrong with wanting to have electric lights, cookers, computers and televisions but believing that nuclear power is not the right way to do it. There's a strong case to be made that says that by the time any new reactors were up and running, 'green' energy technologies will have made so many advances that we may be able to close the gap without resorting to nuclear. We can figure out how much it'll cost to burn coal, to develop carbon-capture technologies, cover the Sahara desert in solar panels, plant wind-farms in Wales or give fat kids bicycle-powered televisions and games consoles. But we have no idea what the cost of nuclear energy will be. For that reason alone, it's not clever.

Meanwhile, there's all sorts of excited talk round here about building a Severn Barrage, an idea that's been regularly mooted since the 1840s but which now might well come to fruition.

There is an utterly fascinating philosophical conundrum at the heart of the Barrage proposals. On the one hand, this is a classic Big Engineering solution; a vast, hairy-arsed project costing billions involving up to 35,000 (according to one estimate) men (and not many women) in hard hats shifting millions and millions of tonnes of material. In return you get five or six percent of the country's current electricity needs supplied. Allegedly.

On the other hand, it's very macho bigness, its thrusting penile immensitude, its utterly unreconstructed male chauvinist global corporate-ness is, like, miles removed from the small, human-scale solutions that are the prevailing ideology of the environmental movement.

It's not a case of either/or. We may well get the Barrage as well as more nuclear power. The Barrage made the agenda big-time late last year when the Sustainable Development Commission (SDC) issued a report sort of endorsing the idea. See here.

It's thought that a major feasibility study into a Barrage or other methods of using the Severn to generate power will be announced soon. So in the meantime, and just because a bloke from the telly asked for a copy of it the other week because it apparently explains it all well, here is Byrne's own FAQs into the whys and why nots:

What, exactly, is this Barrage of which you chat?
A long line of enormous concrete blocks sunk into the water, holding turbines which will produce electricity from the movement of the water inwards and outwards. The Severn Estuary is particularly well suited to this because of its huge 'tidal range' – it goes up and down a lot. It’s still at the expensive government investigation stage, so nobody knows exactly what it’s going to look like.

But I’ve seen articles in newspapers and magazines and on the telly. There’s maps and diagrams and everything.
That’ll be the Severn Tidal Power Group (STPG) proposal, which is the most serious and detailed plan to date. The STPG is a consortium of blue chip engineering and construction firms (Balfour Beatty, Taylor Woodrow, Sir Robert McAlpine and Alstom), who produced a plan in the 1980s for a barrage running from Brean Down, just south of Weston-super-Mare, to Lavernock Point, South Wales. This envisages 216 turbines: sluices let the tide inwards, and are then closed to force the water out through the turbines after the tide has gone out quite a way. If the Barrage goes ahead, it’ll probably look a lot like the STPG plan. It might even have both a road and a railway line running along the top. Though it would also need locks to let ships through.

How much energy will it supply?
The STPG claims its Barrage will provide the same amount of electricity as three nuclear reactors and will last for 120 years. Up to 200 years if it’s looked after properly. Once you’ve gotten past the stupendous carbon-spend involved in building the thing in the first place – a workforce of 35,000 dropping immense lumps of concrete onto the sea bed - it’s clean, green, sustainable, and produces no waste. It would supply something like 5% of the electricity that the whole country currently consumes and would play a major part in reducing our dependence on finite and insecure oil and gas supplies.

Excellent. So what are we waiting for?
One thing you absolutely must fix in your head is that this would be one of the biggest civil engineering projects in all history and would dramatically change a vast lump of England and Wales. The Severn Estuary is an unusual ecosystem, covered in mudflats which are home to a lot of wildlife which would be driven out. Environmentalists are very concerned, while the SDC says a Barrage would require “a long-term commitment to creating compensatory habitats on an unprecedented scale", i.e. we’d have to spend vast quantities of money on trying to relocate the wildlife, which is a complicated, expensive process. Or an utterly pointless one if you don’t think the wildlife matters much.

Fine. So we let the birdies die. Or make them nice new homes. Whatever. Why can’t we just get on with it?
One of the more amusing aspects of the Barrage debate is that the negative arguments mostly focus on the wildlife. Nobody seems bothered that if this is screwed up we might lose Weston-super-Mare, Burnham-on-Sea or some or all of the Somerset Levels. We need a proper study to investigate the likely impact of flooding and/or silting on coastal towns both inside and outside of the Barrage. It’s possible that the beach at Weston might be lost, for instance.

Personally, I can live with all of Weston being washed away. Are there any other potential environmental benefits?
Sure. The water upstream of the Barrage will become less turbulent and therefore clearer. You’re bound to get other types of fish and bird life moving in.

And would a Barrage protect us from the sort of floods we had this summer?
No. Those resulted from abnormally heavy rainfall. But a Barrage would protect the land around the Estuary from high spring tides and storm surges, and with global warming likely to lead to higher sea levels and extreme weather events, that’s got to be a plus.

Are there any less intensive methods of harnessing the tidal power of the Severn Estuary?
Loads. The STPG proposal was drawn up back when Mrs Thatcher was still prime minister and when I still had a luxuriant mane of thick, black hair. Technologically it's on a par with CB radio, Space Invaders machines the size of wardrobes and Hofmeister Lager. There are many other possible ways of harnessing the Severn's tidal range and these haven't really made it onto the agenda. Last year, frinstance, the Green Party and Friends of the Earth endorsed artificial concrete 'lagoons' which use the flow of water in and out of them to generate power. The SDC is highly sceptical about these and the engineers ridicule them as costly; a single barrage would cost a lot less than a load of lagoons generating the same amount of electricity. Here's a PDF of a Friends of the Earth document on lagoons.

Why not put it somewhere else with a lot of sea, like Scotland?
Aside from the tide range making the Severn especially suitable, it’s also close to several major population centres. It’s easier to get the resulting electricity into the national grid than it would be from some remote part of Scotland.

And how much will it cost?
The current builder’s estimate is £15 billion and it’ll take seven years. It’ll probably be more. Mind you, the last structure to be built across the water here, the Second Severn Crossing, came in on time and under budget.

And who pays?
You will, silly! One way or another. The SDC says it should be a publicly owned asset, but don’t expect New Labour to listen to such old-fashioned sentimental nonsense about public ownership and accountability. If it goes ahead under this government, private money will build it for private profit. This may or may not be a bad thing, but what you really need to watch is all the other sweeteners the developers manage to screw out of the government. This will never ever ever just be about a big electricity-generating thing. It’s also about all the development opportunities associated with it - houses, roads, shopping centres and loads of watery leisure facilities. Some people claim that this great generator of green electricity might lead, ironically, to the end of any green belt around Bristol, and they could well be right.

Hah! It’s all about money, innit? Big business.
Big business is on a win-win whatever happens: we’re building something, whether it’s a barrage, nuclear power stations, lagoons, whatever… As has been pointed out by many a wise brain, the Green party's preferred option of lagoons would be much, much, much more lucrative for whoever got the contract. One very big and successful local business, namely the Bristol Port Company, who run the Avonmouth Docks, aren’t keen on it at all. They want to build new docks facilities to take the world’s biggest ships and are worried that their business will be ruined by ships having the hassle of having to come in through locks in the Barrage.