OT Electricity Generation

[Tim Streater]

Only if it's cost effective. Which is why I want answers to my set of Q.

[Dave Liquorice]

I should think less than 3km to the nearest 11kV.

This nearest line would be a small capacity one for the few scattered farms right at the top end of Teesdale. I don't know where the sub-station feeding this distribution is located. It may well be Barnard Castle but possibly Middleton-in-Teesdale, that would be 15km or so away.

[Dave Liquorice]

eh? Highest hydro FIT rate is 19.9p:

2kw 24/7 for a year > 365*24*2 =3D 17520kWHr @ =A30.199 =3D =A33486.48.

[<me9]

The largest Hydro scheme in England currently is Kielder, rated at a maximum of 12 MW.

The extraction of water at Riding Mill from the Kielder dam outflow to feed the Tyne/Tees/Derwent/Wiske takes an order of magnitude more power. Not a vast saver until you consider Kielder electricity is 24/7 and usage at Riding Mill is only in unusual circumstances.

[John Rumm]

ah, sorry was assuming it was the daft 38p they do for solar PV..

selling prices.

[David Hansen]

On Tue, 19 Oct 2010 22:42:47 +0100 (BST) someone who may be "Dave Liquorice" wrote this:-

The wind farm at Delabole, the first UK commercial wind farm, is 1.5km from the village, though the line may not be that long and I have no idea of its capacity. It used to have a maximum capacity of 4 MW. Its effect on the local electricity system was carefully measured and it stabilised the local electricity system, the operation of tap changers was much reduced.

The repowered Delabole , being commissioned at the moment, has a maximum capacity of 9.2 MW. No idea if any changes have been made to the connection to the rest of the electricity system.

So a 1MW hydro plant might be suitable to connect to a small 11 kV line. Certainly Scottish Hydro Electric has a number of sub 5 MW turbines in remote areas. I don't suppose they are connected by anything more beefy than a small 11 kV line of the sort which also feeds a few farms.

[David Hansen]

On Tue, 19 Oct 2010 20:26:59 +0100 someone who may be Roger Chapman wrote this:-

That is the name the publication is usually known as. Sorry if I credited you with more knowledge of the basic sources of information about electricity systems in the UK.

is the URL I gave, there is a clue at the end of that.

Still digging I see. This will be my last comment on this sub-thread, but if you wish to dig further so be it.

I was explaining how it is likely that hydro equivalent households are calculated, by pointing to how they are done for wind. There was no reason for me to provide a link to wind load factors, they are noting to do with hydro, I provided a link to hydro load factors.

[David Hansen]

On Tue, 19 Oct 2010 22:04:51 +0100 someone who may be andrew wrote this:-

No doubt the case if one is only considering one type of equipment. However, the Archimedean screw I linked to earlier means a whole new set of considerations. Vastly easier to make than a turbine and with no need to ensure dimensional accuracy to the same degree, but I imagine higher civil costs.

[Roger Chapman]

This from the man who is forever complaining about insults when someone points out his undoubted lack of intelligence!

You mean you are still trying to weasel your way out of a hole you dug for yourself.

And my comment was on the uninformative nature of the load factor information - viz:

""(3) Wind load factors can be found in Table 7.4."

Very informative as table 7.4 is securely hidden elsewhere."

Which you chose to dispute. No use now trying to move the goalposts.

[tim....]

How can you (or anybody) possibly make this claim when we STILL don't know how much it will cost to get rid of the waste material we have already stored, let alone that which we have yet to generate.

tim

[Tim Streater]

You don't need to get rid of it (unless you want to reprocess it for some reason). Just leave it alone.

The amount of high-level waste is not large. That's quite radioactive, but is composed of stuff with short half-lives. So after not many years (IIRC less than 50) it's less than half as radioactive as when you started with it.

The low-level waste (of which there is a lot more) is not particularly dangerous anyway.

[Nightjar]

...

We don't *know* the prices of anything in the future, but we can make informed estimates and for nuclear energy, the best estimate is that waste disposal will add 5% to the cost of generation.

Colin Bignell

[andrew]

Whether you can make a cheaper, comparably efficient, device doesn't alter the fact that if has to handle a greater mass of water to get the same power. So it tends to be more massive.

Pelton wheels are small, convert around 90% of the incoming kinetic energy to rotary motion and simple but they need a good head.

I fancy playing with a screw device in our weir but cannot see how it would trap a fraction of the flow let alone work at 90% conversion. Even if it were in a tube with minor losses around the periphery why should it get more out than a simple propeller type turbine in the same tube?

AJH

[Roger Chapman]

Both the Archimedes Screw Turbine and the Kaplan Turbine are supposed to work at a very low head. A quick google suggests that both can exceed

80% efficiency but I didn't find anything that gave a direct relationship between head and efficiency.

[andrew]

Yes I've seen a chart showing efficiencies and where the device sits on the head verses flow which suggests the Kaplan comes close to the pelton, isn't it fully submersed Kaplans at Dinorwig which I think reaches 70% overal conversion from electricity to elctricity which implies close to 90% mechanical conversion for each pass.

So if all the water is channeled down a tube what are the coinversion limits for a simple screw? and why would the archimdes screw do better?

AJH on claws

[The Natural Philosopher]

the same way wind people calculate costs when they have no idea how long the ghastly things will last, and calculate carbon reduction when they have no idea how much if any, given the total variability of the wind and the back up policy it entails, they will save (if any), or indeed calcualate the cost of removing the unsightly towers and foundations once its realised the things are of absolutely no value to anyone and a total eyesore, and the same way they calculate the cost of coal power, when no-one has any idea what regulations might be imposed some time in the future to deal with the (more radioactive than low level nuclear waste) coal ash..

Generally 15% of capital cost is put in for decommissioning: Fortunately these days stations are built to be taken apart, unlike e.g. Dounreay.

What is the cost of decommissioning a wind farm? Includig removing teh foundations?

And storing them somewhere no one will ever have to encounter the things ever again? Or at least for 5000 years...

[The Natural Philosopher]

Actually the fuel comes out for reprocessing, the low level shit gets taken away and stored - its relatively harmless: the reactor shell etc you fill with concrete and leave. If you are particularly bothered, make it a landfill site and build a mound over it. In 100 years it will be a useful place to put affordable housing.

Anything else you simply strip - gebnerators etc etc are all usable items, or recyclable

[David Hansen]

On Wed, 20 Oct 2010 14:09:38 +0100 someone who may be "tim...." wrote this:-

And when we know that the only way is up with the price of doing that.

[David Hansen]

On Wed, 20 Oct 2010 14:39:25 +0100 someone who may be Tim Streater wrote this:-

The existing waste... exists and something needs to be done with it.

Above ground dry storage is the best thing to do with the existing waste, with the nitirc acid turned into glass blocks and stored above ground.

However, the nuclear lobby doesn't want this reminder of our foolishness, it wants the waste out of sight and out of mind in a hole somewhere.

That does not mean we should create even more waste by building more nuclear power stations. Waste which is not created in the first place does not have to have anything done to it.

[Tim Streater]

So we do know what to do with it then, contrary to what you implied initially. Stored as glass blocks it would actually make a useful heat source.

Nuclear waste needn't actually be a problem. You're just quite happy to have a bogeyman to beat up the nuclear solution with.

Still, I suppose we could just go on creating CO2 waste instead, eh?