wave energy

[SteveT]

I wonder if there are any Physics/Scientists out there who remember something about wave energy and the bobbing ducks which were classed as highly efficient at extracting energy from the waves off shore.

Although not considered to be economical to manufacture then, around the early seventies as energy was so cheap.

Would the same be the case today with all the massive rises in oil gas etc?

Why are we buying American extremely safe nuclear systems for billions if we can harvest the west coast of Scotland?

[Huguenot]

The problems with wave energy are scale, maintenance and consistency.

In fact the UK has both the largest current wave farm being built (in Scotland at 3MW or about 1,000 houses), and the largest planned (in Cornwall at around 30MW).

The Salter's (bobbing) Ducks were fantastically efficient but bloody complex and weren't considered scalable.

Saltwater is fantastically corrosive and this is having a major impact on the development path.

The other thing with wave energy (as with all renewables) is that it doesn't reach its peak when we want it to, and we can't have the UK with the lights off in December because of a calm day on the west coast.

The answer would be a 'global' energy/electricity grid but I guess that's probably a 'pipe' dream.

[KalamityKel]

Dont you people sleep?!! ::o

[SeanMacGabhann]

Singapore time darling Kel, Singapore time..

Interesting that so many Greens are turning to nuclear as the only realistic option for energy sources. Personally I think it's a wonderfully convenient and lazy option which our children (and our children's children etc etc etc) will pay teh price for - but I can see why it's attractive.

A couple of days with the lights off might concentrate the minds wonderfully. I just do not believe that the combined minds and resources we as a species can not develop power from a combination of wind, sun and sea. I'm aware of all the current "challenges" but it's still a better bet than nuclear power. I'm not against the science behind it - I just don't believe we are able to deal with the byproducts or the logistics of keeping plants safe

[Brendan]

I wrote an article on the Cornwall wave energy scheme about a year ago but the details have drained out of my sieve like mind. I will dig it out and see if there is anything interesting in it.

On the point of nuclear power there are some new technologies like South Africa?s new pebble bed modular reactor which are seen as a lot safer and more environmentally friendly. Problem is they still produce waste which is the real issue with all nuclear power.

[SteveT]

I new this thread would bring out the high tech' scientific boffins.

It's very reassuring and amazing, the wide ranging talent on this forum.

[david_carnell]

It's amazing what they teach at the University of Wikipedia these days Steve.

Ignore me, I'm merely jealous of Brendan's polymath tendancies. I console myself with his lack of cricketing ability. Then I remember my lack of cricketing ability and cry a little inside.

[Brendan]

I was speaking to some South African engineers recently about their pebble bed reactor. On the one hand they are making all these new advances with nuclear power while on the other they are trying to deal with the fact that most of the country?s power comes from failing coal plants and they can?t generate enough to run the economy properly.

I?m sure there is a metaphor about yesterday?s cricket match somewhere in there but I?m too depressed to pull it out.

[Jeremy]

I think the problem with all the renewable sources is just that they're too expensive. Unfortunately the average consumer would rather their power was as cheap as possible, regardless of environmental factors. The energy companies don't have an incentive for really investing in cleaner energy.

Also it seems that whenever a windfarm is planned, there is a massive resistance from the local population. Should the government have the power to override these local concerns? Doesn't sound like vote-winner...

[Huguenot]

Good points Jezza.

The price of energy from renewables hasn't changed much recently (although it has massively across the last 10 years), and won't unless we achieve major economies of scale. However, the price of fossil fuel energy has rocketed, and it's apparent that those countries that control these resources (e.g. Russia) are more interested now in gaining political as well as financial advantage.

Interestingly, nuclear power is probably the most expensive of the lot, but the price is hidden through government subsidies (in other words we pay on the tax invoice rather than the London Energy one).

In particular, fossil energy costs do not include the cost of clearing up afterwards, which is something once more paid through the public purse and hidden from the public eye.

If you legislated that power stations could not indiscriminately release the amount of uncontrolled environmental pollution that they do now, you'd see fossil fuel energy costs skyrocket.

So it's possible that in fact renewables are overall cheaper energy sources, but it's the lack of scale, consistency and political will that's holding them back.

Totally agree with SMG.

[elipie]

How about tidal energy? Presumably that would be more predictable than wind or solar energy but you never seem to hear it mentioned when people talk about renewables. Is there some massive disadvantage I'm missing, apart from maybe increased costs to set up and maintain?

[Jeremy]

regarding predictability - none of these sources are continuous, so surely with any of them, the energy needs to be stored so it could be drawn upon on demand?

[Huguenot]

Yep, by all accounts we have zero options on storage for the kind of energies we're talking about. That's where the 'global grid' thing makes more sense.

Instead of storing it, you sell it to whoever wants it at their time in the world, and then you buy theirs back when they don't want it because they're asleep.

Interestingly we still tend to think of energy generation as a 'centralised' resource, where small numbers of very big power stations (whether fossil, nuclear or renewable) provide power to all. The ideal situation would be highly decentralised local or individual power supplies - they're much less vulnerable and more politically stable.

[Asset]

Apparently the UK is the only country in the world which has massive spikes in its energy consumption at various times throughout the day, i.e. the advert break in Corrie.

[SeanMacGabhann]

that sounds suspiciously apocryphal to me Asset...

[Asset]

it was on a telly program just the other day!

[Huguenot]

It's plausible.

The USA is spread across numerous time-zones with programs running at different 'universal' times. Most Euro countries don't seem to have the obsession with appointment-to-view TV programs that we do, and meal times would be much more varied.

I can believe it!

I wasn't thinking of spikes in that sense though, just that in all countries demand varies with time of day and local renewables aren't very accommodating.

If we could get large scale catalyst-based hydrogen production, then we could all have our own little no pollution household generators?

[Moos]

I saw it too. The closing thumps of 'Stenders is apparently a moment of great energy drain.

[Asset]

ooo, pop the kettle on, we'll have a nice cuppa

[david_carnell]

Who the heck is still drinking tea past four o'clock?!

Why isn't the end of Eastenders accompanied by the sound of clinking glasses, the opening of cans and bottles, and the popping of corks?

Tea!? At 8 o'clock?! In the evening?! I thought this nation could pride itself on its alcohol consumption....

[Moos]

Hot toddies, maybe?

It just shows there are an awful lot of grannies out there.

[Keef]

I think it was on the first episode of "Britain from above" where they went to the power station and the guy was readying himself to deal with the after Eastenders kettle rush. Annoyingly we even have to rely on the French to lend us a hand during that surge!

Saying that, we probably have to help them when all their power station workers go on strike, so what comes around...

[Marmora Man]

Tidal power is predictable and huge (rise & fall in the Bristol Channel is never less than 20 ft and can exceed 35 ft). To my mind, it should be possible to harness quite simply and effectively by placing hydro turbines under the sea to capture the ebb and flow. With the correct design it should be possible to harness both the rising tide and the falling tide using the same (reversible) turbine. Thus generating power for almost 20 hours a day (allowing for an hour's slack at each high and low water period).

As for storing the power - there was an elegant solution in N. Wales where a hydro power plant used to use "off peak" power to transport water to a higher level and then, by releasing it generate power at the required times. Inevitably there was an energy cost to this - but it worked to shift power to desired time(s). (didn't get as much energy back as used in lifting the water to a higher level)

The undoubted difficulties of placing engineering plant on / close to the sea bed and connecting to the shore have been overcome by the N. See oil engineers, so don't see this as a big problem.

Tidal power in this way would be:

non polluting - gets the green tick

An extension of existing technology - so not too challenging

Doesn't create eye sores - thus better than windfarms

Is predictable - thus better than windfarms

Is pretty much eternal - at least until the sun goes out.

Would also add that, as one that spent much of the 80's living with a nuclear reactor at my feet, I have never feared them or their by products. A reactor with sufficient power to provide electricity to Southwark for 20 years wouldn't be much larger than a submarine reactor - ie about 10m x 10m x 10m. The ultimate waste products do indeed have a long half life - but much of the waste creates only very low level radioactivity - the bulk of it being shielding, pipework and other similar materials. The more highly reactive nuclear core would amount to only a few pounds weight.

[louisiana]

Huguenot Wrote:

-------------------------------------------------------

> It's plausible.

>

> The USA is spread across numerous time-zones with

> programs running at different 'universal' times.

> Most Euro countries don't seem to have the

> obsession with appointment-to-view TV programs

> that we do, and meal times would be much more

> varied.

>

Nor do they have all our kettles.

[louisiana]

Huguenot Wrote:

-------------------------------------------------------

> Yep, by all accounts we have zero options on

> storage for the kind of energies we're talking

> about. That's where the 'global grid' thing makes

> more sense.

>

> Instead of storing it, you sell it to whoever

> wants it at their time in the world, and then you

> buy theirs back when they don't want it because

> they're asleep.

>

> Interestingly we still tend to think of energy

> generation as a 'centralised' resource, where

> small numbers of very big power stations (whether

> fossil, nuclear or renewable) provide power to

> all. The ideal situation would be highly

> decentralised local or individual power supplies -

> they're much less vulnerable and more politically

> stable.

Distributed generation - micro hydro, wind, photov - is in my view the way forward, but domestic storage hasn't got much beyond deep cycle 'leisure' batteries (what you put in caravans). There needs to be some more development work. I understand there's a fair amount being done on using hydrogen as a carrier...

There does seem to be a national - government - obsession - with centralisation. Which ties in nicely with its wish to park as many people as possible into one-bed Barratt flats on brownfield sites in cities. If you have no autonomy in your property - if you have no roof space, no land, no legal right to decide how things are done - you are dependent on paying for centralised services, and hence on wage slavery.