[chbot] 60 min of free power per day

[Mark Atherton]

Thank you Helmut,

No immediate plans to charge the platoon of Nissan Leafs from the one 
dangling light socket in the house, for 60mins !

Given the obviously available methods of energy storage within a house 
(hot water cylinder, electric storage heater), and the availability of 
low cost nighttime electricity, it became quite quickly obvious to me 
that the whole marketing ploy of electric-kiwi was rather clever. At 
first brush, it seems a brilliant deal; upon investigation it seems 
almost useless. Isn't that almost the definition of brilliant marketing ?

Regards, Mark

On 25/06/2017 8:01 PM, Helmut Walle wrote:
> Safety warning...
>
> A word of caution regarding this line of thought - and I am sure you 
> are more than aware of this, Mark, but it may warrant stating 
> explicitly: time is obviously limited. You have one hour to "download" 
> all the energy you can get, which appears tempting. But there clearly 
> is an incentive to draw a high current in this tariff.
> Now while the service fuse may be rated 60 A, surely many of the 
> downstream parts of the installation are not. This lies in the nature 
> of residential wiring work, which is there to provide electricity to 
> many places in the house, but the power available per socket is quite 
> limited. The current rating on any individual circuit will typically 
> be 10-20 A. All circuits should have appropriate over-current 
> protection. But there are some potential issues with this: any 
> electrical installation is subject to ageing. One thing that happens 
> is that connection points of any kind show a higher resistance over 
> time, which can be due to corrosion or loosening. The increased 
> resistance can lead to excessive heating under high load (high 
> current). One of the possible outcomes is a fire. But even moderate 
> heating that doesn't cause an outright fire can damage and degrade 
> insulation, which can in the long run again lead to a fire.
>
> Older houses in particular may be fraught with various issues 
> affecting the safety of their electrical wiring, which can be a 
> serious safety risk under very "normal" operating conditions that do 
> not even go anywhere near maxing out the current ratings.
>
> So this is something to keep in mind: when connecting higher loads or 
> drawing higher currents than before from the same installation, be 
> particularly careful and alert regarding these safety concerns.
>
> Kind regards,
>
> Helmut.
>
> On 25/06/2017 11:50 a.m., Mark Atherton wrote:
>> Hello All,
>>
>> Only just found about this energy company, and their offer of 60 min of
>> free off-peak electricity per day -
>> https://www.electrickiwi.co.nz/hour-of-power
>>
>> Haven't run-the-numbers yet to see if there are real savings to be had,
>> but figure this might make an interesting chocolate-fish-challenge for
>> the group.
>>
>> So the question is: how maximize the benefit of this kind of offer.
>>
>> So for a 60A service to a house, this is almost 14kW, and at $0.35 per
>> (daytime) unit, this could amount to just under $5 per day, if the
>> entire 60A could be consumed. This amounts to around $150 per month
>> possible savings.
>>
>> Obvious thing to turn on is the heater on the hot tank (3.5kW), which
>> would normally be heated at the night rate ($0.15 per unit), so only
>> $0.52 savings here.
>>
>> So, the problem looks like it converges on a need for daytime power, if
>> the higher saving is to be leveraged.
>>
>> Anyway, just a daft thought experiment.
>>
>> Comments welcome.
>>
>> -Mark
>>
>>
>>
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>
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