New Zealand Power (from Don't Vote Labour)

[Jantar]

What about using the excess generated wind power to pump water back up the dam systems? I expect that would have poor efficiency at this stage but would be better than just throwing it away.

This is called Pump Storage, and it is very efficient. It only works though when the hydro station has a lake both above and below it. If it has a river below then it would quickly empty the river, like in a few seconds, unless the river is one that flows uphill. The only place in New Zealand where there is a lake both above and below a hydro station is at Tokaanu, and this could be used for a small amount of pumped storage. Lake Rotoaira at the top is very small, so it would still only be effective for a few hours, like overnight.

Another potential site is the neck between Hawea and Wanaka, if we could ever get the conservation order removed from Wanaka.

...but if climate change is as real a problem as it seems (sounds like a safe bet, the howls of denial are now only coming from the fringes) then it isn't better.

A seperate debate, but the howls of denial are now coming from most of the scientific community. Its the political and greeny community who keep trying to tell us the debate is over.

We seem to have lost our ability to execute large-scale planned change, what with the recent-ish shift to more libertarian ideals in the west. Unfortunately some problems do require more intelligence than a simple market mechanism can bring to bear. More unfortunately we don't have any suitably states-person like government options to deal with the problem either!

Oh, so true. As any engineer or scientist will tell you, "The laws of physics and the laws of economics are incompatible with each other."

[Pixie]

Why not. The US have. Part of their dessert is radioactive due US nuke testing years ago.

Trifle or instant pudding?

[davereid]

Can be efficiently made from Sugar beets, wood chips etc etc and requires no adaption for cars upto a a certain % so whay the hell can't some spoddy little engineer (sAsLEX, not you!!) make it work for energy supplies. Oh shit oil and petrolium industry lobbying politicicans!!

So true. In fact the petrol engine was developed from Mr. Ottos original engine which was designed to run on ethanol.

Mr. Diesels engine was also developed to run on biofuel - the original design used peanut oil.

And ethanol has a "big brother", brewed using a process very similar to making Gin, called N-Butanol.

N-Butanol will go straight in your V8, without modification to the car. It can also be shipped and distributed via existing fuel pumps. Its just not economic while petrol is so cheap and plentiful as it is now.

Diesels are popular for power generation, simply because they are very good at it. Relatively easy to start and stop. Easy to run over a wide load range while still keeping to 50hz, and still very cheap to run.

Good diesels will make a kw/hr of energy using about 1/2 cup of diesel/peanut oil/tallow. And when you don't need it any more, turn it off and go home.

I was involved with the installation of a (30Mw?) diesel generator at Henderson Field in the Solomon Is. years ago. I was very impressed by just how simple it was, and how efficient.

[Pixie]

Better monitoring of power will also help maintain frequencies in times of high load.

AU is looking at each house having a little black box that allows an advanced form of ripple control so that the supplies/somone can turn off certain things such as appliance circuits but leave lighting etc to avoid blackouts

Turn off everything in every household that described themselves as environmentalists at the last census.That should save some power

[Pixie]

I understand that if only the smallest nuclear plant was built it would too big for NZ's needs. Is that correct Jantar or K14?

The ones in submarines were pretty compact

[Pixie]

Can be efficiently made from Sugar beets, wood chips etc etc and requires no adaption for cars upto a a certain % so whay the hell can't some spoddy little engineer (sAsLEX, not you!!) make it work for energy supplies. Oh shit oil and petrolium industry lobbying politicicans!!

I'm a convert to biofuels.Apart from the relative carbon neutrality myth that keeps the hippies quiet,you also get an added benefit that the conversion of food crops to fuel crops and the associated global starvation,will reduce the earth's human population and that will reduce the world's power needs.
A win win situation.

[k14]

Diesels are popular for power generation, simply because they are very good at it. Relatively easy to start and stop. Easy to run over a wide load range while still keeping to 50hz, and still very cheap to run.

Good diesels will make a kw/hr of energy using about 1/2 cup of diesel/peanut oil/tallow. And when you don't need it any more, turn it off and go home.

We do have a diesel power station, Whirinaki. It is owned by the crown and installed for peaking. It is however very expensive compared to other forms of generation per MW. In the vacinity of $200 per Mwhr as opposed to say thermal around $40 to $50.

Surely something around 360MW would be sustainable?
IRIS Westinghouse et al 360 PWR Pre-certification 2010

I mean what is the minimum NI load?

Even 360MW would be pushing it. As we speak, the 2nd largest generator in NZ (Otahuhu-395MW) is turned off cause the load is not sufficient to support such a big unit. It is quite common for one of the big CCGT's in the north island to be off around the christmas new year period and even some long weekends (easter, labour weekend) because the demand isn't big enough.

Maybe in 10 years time when the base demand has increased, then NZ could support a 300ish MW nuke. But no chance now. Although in saying that, it would probably take 10 to 20 years to develop and build one.

[sAsLEX]

The ones in submarines were pretty compact

Yeah not really designed for power generation though, they ramp them up and down fairly regularly which leads to poisoning of the reactor and stuff like that so they only have a shortish life span

[Jantar]

And contributing to the very high running costs.

[sAsLEX]

And contributing to the very high running costs.

In general aren't Nukes cheap to "run" but its the construction and de-construction that ramps up the cost? Like the UK at the moment decommissioning all its old Nuke plants and buying Nuke power from France ......

[davereid]

We do have a diesel power station, Whirinaki. It is owned by the crown and installed for peaking. It is however very expensive compared to other forms of generation per MW. In the vacinity of $200 per Mwhr as opposed to say thermal around $40 to $50.

Yes, I was comparing diesels to wind generators, not to thermal stations. Whirinaki is a open cycle gas turbine, so its not really particularly efficient.

In fact, although I am sure your costs for Whirinaki are correct, it possibly tells us more about the cost of the fuel than anything else.

A conventional steam turbine power plant struggles to be 35% efficient. But it is an external combustion engine, so it will burn any old rubbish you can find, or you can use a bit of uranium to heat up the steam. ie low cost power, just a bit tricky to turn on and off.

A gas turbine is a little more efficient, but not much. And it needs to be fed a better class of fuel. But its easy to start and stop.

A combined cycle plant can reach about 60% efficiency. Thats is good as it gets really, but it needs good fuel, and it has a steam component as well, so you can't just tur the key and go hoe at the end of the day.

But diesels (reciprocating piston type) are second in efficiency to the combined cycle plant, and are better than the standard gas turbine. Plus, you can turn em on and off, with a minumum of fuss, and as long as you are happy to starve the third world, they are happy to run on home made fuel.

The other great thing about diesels, is you can just build em where you want the power. Put one under the Skytower, and Aucklands got 80Mw on tap, without a single powerline.

IMHO ...

#1 = Hydro. A great way to make power, but often needs a lot of infrastructure to transport the energy, not a limitless amount of rivers to be used, and currently seen as bad for the birds and native trout.

#2 = Thermal. Really good if the fuel is plentiful and cheap, ie geothermal or cheap coal/oil/gas. But getting harder to find cheap anything. And if fossil fuel powered seen as the enemy.

#3 = Nuclear. But not popular here due to twitter and tweet, and as prviously pointed out, what do you do with all the waste heat when all the load is turned off. Not easy to keep turning 'em on and off!

#4 = Solar. Not really a way of generating electricity at all. But can make a useful contribution by way of water heating at site, etc. Photovoltaics are crap and should be banned.

#5 = Wind. Not really very good at making power 24/7. Not cheap. Possibly very pollutant if visual effect counts for anything and lifecycle cost correctly accounted for.

#6 = Tidal etc. Experimental.. do we want the beach cluttered up with this shit ? If we stop water flowing through Cook Strait will we slow the rotation of the earth down, squash fish and scare dolphins ?

[Bullitt]

Maybe this is a stupid question but what happens if too much electricity is generated. Does it just get wasted or does it start blowing things up or what?

Maybe its because all the powerlines are full

[RiderInBlack]

Could not something be done using the Cowshed Poo Ponds? Got ta be a fair bit of energy tied up in those. Surely the methane from those would at least power the milking shed and the farm?

[k14]

Maybe this is a stupid question but what happens if too much electricity is generated. Does it just get wasted or does it start blowing things up or what?

Maybe its because all the powerlines are full

Nope not a silly question at all.

The overall body that sees all of NZ has power 24/7 is transpower. Now they have 2 control rooms (one in Hamilton and one in Wgtn) that are manned 24/7. The guys there are constantly monitoring the power demand and sending out instructions every 5 minutes to power stations (known as a dispatch instruction) telling them to increase or decrease their output as the demand does the same.

Now in between these five minute periods there is what's known as a frequency keeper in each of the islands. They are just following the frequency on a clock or graph to ensure that 50hz is maintained. At the moment its very unlikely that the frequency is bang on 50hz. Quite possibly 49.98 or 50.02hz. This is natural and the frequency is always oscillating from anywhere between 50.1 and 49.9 hz quite happily. When you turn on a light in your house, the generator closest to your house isn't able to instantly supply the power. So the stored energy in the power lines will drop its frequency ever so slightly for say 1/100th of a second, to cover the added load of your light. Then in that 1/100th of a second the generator can sense that the frequency has dropped slightly so increases its output to compensate and everyone is all happy

Now we could go to the extreme case scenario of either a big chunk of generation or a big chunk of load tripping off. So if a big power station (ie Otahuhu 395MW) tripped off all of a sudden there would be a ~400MW shortfall of generation. The frequency would rapidly deplete to as low as 49hz and then other power stations would respond and try build the frequency slowly back up to its nominal 50hz. If the opposite happened and a large load tripped then the frequency goes high and generators have special protection to trip and try get back to 50hz.

So in essence, it is very hard to generate too much electricity. It can only be done when a large load source trips off. While this is a possibility it is pretty much never going to happen to a level where the end user will notice. I hope this is sufficient?

[sAsLEX]

Does that answer your question?

What he meant to say that too much generation will increase the frequency, was it not K14?.... nice edit......



So say we were down one station from New Plymouth closing and this winter the cook straight cable shits itself....... and say Stratford trips...... how long would I be without KB for? After all the other power stations trip in a cascade....