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  # 2034433 12-Jun-2018 14:24
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elbrownos:

 

frankv:

 

The downside of hydro electricity is that there's a lot *less* recreational facilities for whitewater kayaking and rafting and tramping. And, in the North Island, a lot of either productive pastures or forest drowned. And, as you point out, loss of habitat for some species which depends on fast-running water. These species, of course, contribute to NZ's reputation as the only place where a whole lot of unique wildlife can be seen, which is of course a major attraction for tourists.

 

I wonder about the economics; is a billion dollar dam better than 50,000 homes set up for solar?

 

 

 

 

They submerged two of the world's largest geysers under Lake Ohakuri in 1961.

 

I wonder if the geysers would still be there if we drained the lake.

 

https://en.wikipedia.org/wiki/Lake_Ohakuri

 

 

Then, easy, now never


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  # 2034625 12-Jun-2018 21:04
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Aredwood: Solar is not going to provide large scale electricity generation in NZ. Simply because peak demand is early mornings, and winter evenings. So solar doesn't reduce the amount of generation capacity that you need to build.

 

I am not sure if I agree with this.  I would suggest that as solar technology becomes cheaper in a country the output of solar power can hit a point where it must be stored and released over a period of time using grid storage techniques.





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  # 2034771 13-Jun-2018 08:36
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TwoSeven:

 

I would suggest that as solar technology becomes cheaper in a country the output of solar power can hit a point where it must be stored and released over a period of time using grid storage techniques.

 

 

I think large scale storage at a reasonable cost is a key issue.  While solar panels are getting cheaper, storage isn't really.

 

Years ago Vanadium Redox Batteries looked promising, but the energy density of that technology has peaked at a not very impressive figure.

 

Perhaps energy density doesn't matter that much for grid scale storage, but it does for domestic storage. 

 

 





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  # 2034778 13-Jun-2018 08:47
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MikeAqua:

 

I think large scale storage at a reasonable cost is a key issue.  While solar panels are getting cheaper, storage isn't really.

 

Years ago Vanadium Redox Batteries looked promising, but the energy density of that technology has peaked at a not very impressive figure.

 

Perhaps energy density doesn't matter that much for grid scale storage, but it does for domestic storage. 

 

 

It's hard to believe that any form of electrical battery could give the scale of storage required for the national grid.

 

How about combining solar with hydro and using excess PV power to pump water back up into hydro lakes?  They do this for a thermal station in Wales


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  # 2034782 13-Jun-2018 09:02
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shk292:

 

MikeAqua:

 

I think large scale storage at a reasonable cost is a key issue.  While solar panels are getting cheaper, storage isn't really.

 

Years ago Vanadium Redox Batteries looked promising, but the energy density of that technology has peaked at a not very impressive figure.

 

Perhaps energy density doesn't matter that much for grid scale storage, but it does for domestic storage. 

 

 

It's hard to believe that any form of electrical battery could give the scale of storage required for the national grid.

 

How about combining solar with hydro and using excess PV power to pump water back up into hydro lakes?  They do this for a thermal station in Wales

 

 

See here..... The Electric Mountain

 

It is actually a net-user of electricity, but does the time-shifting and can respond to peaks.


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  # 2035929 13-Jun-2018 12:39
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shk292:

 

It's hard to believe that any form of electrical battery could give the scale of storage required for the national grid.

 

 

ISTR that a battery is being used at one of the Auck substations to supply power at peak times, being recharged at off-peak, due to the power supply lines being maxed out.

 

And something similar but larger scale in Victoria, Aus.

 

And in Puerto Rico (popn 3.3M): "Already Tesla batteries are "live and delivering power" at 662 locations, Elon Musk tweeted Wednesday. " [https://hardware.slashdot.org/story/18/04/20/2254242/can-teslas-batteries-power-puerto-rico]

 

It seems that the key thing is to NOT have storage on the scale required for the national grid, but to have micro-grids with distributed storage.

 

 


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  # 2036293 14-Jun-2018 00:45

huckster:

 

shk292:

 

MikeAqua:

 

I think large scale storage at a reasonable cost is a key issue.  While solar panels are getting cheaper, storage isn't really.

 

Years ago Vanadium Redox Batteries looked promising, but the energy density of that technology has peaked at a not very impressive figure.

 

Perhaps energy density doesn't matter that much for grid scale storage, but it does for domestic storage. 

 

 

It's hard to believe that any form of electrical battery could give the scale of storage required for the national grid.

 

How about combining solar with hydro and using excess PV power to pump water back up into hydro lakes?  They do this for a thermal station in Wales

 

 

See here..... The Electric Mountain

 

It is actually a net-user of electricity, but does the time-shifting and can respond to peaks.

 

 

How do you get enough energy to reliably fill the hydro lake if there is overcast / rainy weather for multiple days in a row? Either you will still need to have a fossil fuel power station available, which will still cost big money to build and maintain, even if it only rarely gets used. Or you will need 10X as much solar, to account for solar only outputting approx 10% of its rated output on overcast days. And since people use more power on cold days, you will need even more solar again. And such a policy would encourage lots of diesel generation to be built. As diesel is the cheapest to build, and since it would only be rarely used, running costs are only a minor issue. Yet the whole point of renewable energy is not having to build more fossil fuel generation.

 

Most of the hydro lakes in NZ discharge into rivers or other hydro lakes. So you actually can't do pumped storage, as refilling 1 lake is simply removing water from a lower lake - so no gain in the total storage. And when the hydro station output is a river - no water available to be pumped back anyway. And in the case of lake Manapouri - it drains directly into the sea. So if you try to do pumped storage on that lake - you would be mixing seawater into a fresh water lake. Which would definitely destroy the ecosystems in that lake.

 

The Tesla batteries in Auckland and Alice springs are used mainly for providing reserve capacity. If a major power line or generator suddenly trips, causing an imbalance in the supply Vs the load, the Tesla batteries can instantly provide enough power to prevent a blackout. They only need to provide that power for 5 minutes or so. Enough time to restart the generator or transmission line / start-up other generation / switch off non essential loads etc. Wholesale power prices often spike to $1,000+ per unit during such short events. Which is how the battery owners make a profit. And since they don't happen that often, the batteries have a long life. Those economics are completely different, when you are trying to work with only 10c or so price difference between coal generated power, and solar power.

 

 

 

In the Auckland installation, The transformers in the Glen Innes substation don't quite have enough capacity to meet worst case winter peak demand, With that extra demand coming from the new state houses being built in that area. So the cost of the batteries is offset against avoiding the need to upgrade that substation. And Vector has found that average peak loads in established residential areas slowly decline over time. And they are banking on peak demand having declined again by the time that the Tesla batteries have worn out. It is also to avoid a rule that requires lines companies to deprecate most of their assets over 40 years. So it makes it very hard to justify spending money on new transformers etc, if they won't be used for the whole 40 years.But that peak demand modelling was done before EVs started appearing. EVs will actually increase peak demand, as people will arrive home in the evening, turn on the heaters, stove, lights, use hot water, and plug in their EVs to charge. So Vector will probably need the extra transformers anyway.

 

 






 
 
 
 


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  # 2036475 14-Jun-2018 12:30
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Aredwood:

 

How do you get enough energy to reliably fill the hydro lake if there is overcast / rainy weather for multiple days in a row?

 

 

On rainy days, the lake refills itself. ;)

 

 

And Vector has found that average peak loads in established residential areas slowly decline over time.

 

 

Hmmmm... that's counter-intuitive, at least for me. I'd have thought that over time, load would gradually increase as people get more appliances and bigger TVs, and as infill housing increases the number of people.  I wonder what's behind it... more efficient appliances, perhaps? Heatpumps instead of radiant heaters? Or maybe it's that people's lifestyles are changing, so they cook at home less, or at different times?

 

 


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  # 2036506 14-Jun-2018 13:12
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frankv:

 

Hmmmm... that's counter-intuitive, at least for me. I'd have thought that over time, load would gradually increase as people get more appliances and bigger TVs, and as infill housing increases the number of people.  I wonder what's behind it... more efficient appliances, perhaps? Heatpumps instead of radiant heaters? Or maybe it's that people's lifestyles are changing, so they cook at home less, or at different times?

 

 

I think you are on track with the appliances - especially the white-ware.

 

Also better HWCs.  Possibly changes in cooking patterns: more stove top, less oven, more BBQ.

 

Gradual penetration of gas into the market for cooking, hot water heating and space heating.

 

Solar water heating.

 

Improved insulation and glazing.





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  # 2036507 14-Jun-2018 13:14
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frankv:

 

Hmmmm... that's counter-intuitive, at least for me. I'd have thought that over time, load would gradually increase as people get more appliances and bigger TVs, and as infill housing increases the number of people.  I wonder what's behind it... more efficient appliances, perhaps? Heatpumps instead of radiant heaters? Or maybe it's that people's lifestyles are changing, so they cook at home less, or at different times?

 

 

At a guess: LEDs vs incandescent lighting; LED TVs vs CRT/Plasma; heat pumps vs radiant heaters; newer houses with insulation; uptake of gas for heating and cooking in newer areas; use of tablets/phones instead of laptops/desktops


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  # 2038302 15-Jun-2018 13:31
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shk292:

 

frankv:

 

Hmmmm... that's counter-intuitive, at least for me. I'd have thought that over time, load would gradually increase as people get more appliances and bigger TVs, and as infill housing increases the number of people.  I wonder what's behind it... more efficient appliances, perhaps? Heatpumps instead of radiant heaters? Or maybe it's that people's lifestyles are changing, so they cook at home less, or at different times?

 

 

At a guess: LEDs vs incandescent lighting; LED TVs vs CRT/Plasma; heat pumps vs radiant heaters; newer houses with insulation; uptake of gas for heating and cooking in newer areas; use of tablets/phones instead of laptops/desktops

 

 

Vacuum cleaners are another one. Last year the EU lowered the maximum allowable power from 1600W to 900W. Apparently performance hasn't suffered. Presumably we will see a decrease in vacuum cleaner power here too.


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  # 2038396 15-Jun-2018 17:13
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elbrownos:

shk292:


frankv:


Hmmmm... that's counter-intuitive, at least for me. I'd have thought that over time, load would gradually increase as people get more appliances and bigger TVs, and as infill housing increases the number of people.  I wonder what's behind it... more efficient appliances, perhaps? Heatpumps instead of radiant heaters? Or maybe it's that people's lifestyles are changing, so they cook at home less, or at different times?



At a guess: LEDs vs incandescent lighting; LED TVs vs CRT/Plasma; heat pumps vs radiant heaters; newer houses with insulation; uptake of gas for heating and cooking in newer areas; use of tablets/phones instead of laptops/desktops



Vacuum cleaners are another one. Last year the EU lowered the maximum allowable power from 1600W to 900W. Apparently performance hasn't suffered. Presumably we will see a decrease in vacuum cleaner power here too.



Vacuum cleaner companies were designing motors that had less coils of copper wire in them. This both lowered manufacturing costs, and caused the motors to use more power. A win win for the manufacturer, as people think that more power is better. But those motors simply produced more heat, instead of outputting more mechanical energy.

I don't agree with the restriction though. Far better would have been an energy efficiency requirement for vacuum cleaners. So people could still buy a powerful vacuum cleaner if they wanted. Although I doubt that enough power would actually be used overall by vacuum cleaners to justify any rules regulating them.





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  # 2040333 19-Jun-2018 11:25
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Aredwood: . Although I doubt that enough power would actually be used overall by vacuum cleaners to justify any rules regulating them.

 

It's economy by 1000 cuts or one appliance at a time. Sure it makes next to no difference to your power bill but when you are talking about 250 million consumers (or there abouts) it will save megawatts across the EU. They'll being going through appliances one at a time a regulating out all the needless power inefficiency.


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  # 2040337 19-Jun-2018 11:40
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The talk about grid level solar storage in NZ isn't overly relevant yet, and may not ever be relevant. Hydro compliments solar (and wind) every well. When the sun is shining it reduces hydro demand so water is left in the dam and used later when the sun isn't shining. Pumping water uphill is only needed when your solar/wind production exceeds the load normally supplied by hydro. That is about 2600 MW during the day time at the moment, and it will be an amazing feat if we ever have that much solar given our weather. Pumping water uphill is very relevant in the UK because unlike NZ they don't have much hydro production to slow down in the first place.

 

The bigger problem we have is that our renewable production is a very long way away from our biggest cities and we can't transport power around the country efficiently. I was surprise to learn from the Transpower website that with Auckland running at max load and Huntly thermal off-line there is 300 MW of transmission losses. The conductors on our main pylons run at a temperature of 70deg C a max load!! We need some significant transmission upgrades and many of the public reports on the Transpower website talk about how they are going to overload this circuit or that circuit a little more to save upgrading it. Our generation, transmission and retail sections of the power supply system are a bit discombobulated at the moment.  


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