Government offer of *feed-in tariff of 60 cents per kilowatt hour (kWh)*

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Government offer of  *feed-in tariff of 60 cents per kilowatt hour (kWh)*

I'm a bit confused about the government offer of paying the owners of solar
photovoltaic (PV) systems  who put power back into the grid.

Is this at all possible in the real world?

When you consider the power losses within the cables and other
infrastructure on the electricity grid.

Does an array of solar photovoltaic generate *enough power* to feed any
*useful* energy back into the grid?

Re: Government offer of *feed-in tariff of 60 cents per kilowatt hour (kWh)*

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Depends what you mean by possible. In a world inhabited by beings with a
solid understanding of economics, no such scheme would ever be
constructed. However, we don't live in such a world. Instead we live in
a world where decisions are made based not on sound economics, but short
term political expediency. In such a world, yes, it's possible.

Though given your comments below, I suspect you meant technically.

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The grid isn't that inefficient.

But it doesn't matter anyway. Power you generate will likely be consumed
by people in the same street, and reduce the power that has to be
transmitted through the grid.


Re: Government offer of *feed-in tariff of 60 cents per kilowatt hour (kWh)*

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The power only has to go next door to find another consumer
so unless you're on the end of a 100km SPER line I'd say the
answer is yes.

Re: Government offer of *feed-in tariff of 60 cents per kilowatt hour (kWh)*

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Yes, it works. They will actually pay you, and you *can* efficiently put
power back into the grid.
Whether it makes actual economic sense overall is another matter entirely...
The scheme is likely not economically sustainable, grab it while you can.

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It's not that bad, the grid is actually quite efficient. The power you
generate will be used more by your neighbours rather than the rest of the
grid, so the losses are fairly minimal becuase their power is supplied

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Yes. A typical system of 1KW is a pretty decent amount of power, certainly
not insignificant. Most of it will be usable after various losses. If you
switch off your house power then most of that goes back into the grid to be
used by your neighbours.

It's all about averages and so forth.
Back of envelope:- If everyone had a 1KW system on their roof in Sydney for
example (1.5million people), that's 1.5GW of peak power available to the
grid as a whole, or roughly half of the snowy river hydro scheme output. And
that power is distributed near point loads, so it's comparatively quite

Nit-pickers go for your life...


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Re: Government offer of *feed-in tariff of 60 cents per kilowatt hour (kWh)*

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if there are consumers nearby without solar and using energy - it

Remember too - about the "feed in tarriff". in the QLD system, it is
only paid on power IN EXCESS of what you are using in your own home.
So if you are using 0w and generating 1kw - you will be paid the feed
in tariff on the 1kw x the number of hours it is generated.

If you are using 500w and generating the 1kw, you are paid 50% of the
feed in tariff PLUS saving the normal tariff of the 500w you are using
in your home.

If you are generating and using the same amount, then you are only
saving the normal tarriff, which is a LOT less than 60c (typically 17c
for domestic and half of that for off-peak hot water - if its actually
on at that time. :).

If you arent going to be home during the day, and can turn off all
appliances in the home during that time - including hot water systems,
and all things that use stand-by power -  you will get the full 60c.

You may be able to get away with turning the fridge off during some or
all of that time, if the insulation is good, no one will be home to
open it, and you don't have anything that is going to spoil at the
slightest drop in temp. (IE beer fridge in workshop) Whether this is
worthwhile compared to the savings is another matter.

As to your other question, if the power being generated isnt being
used, it isnt stored anywhere.

Its the same scenario as a generator running without load, or a better
analogy would be a battery that is not connected to anything.

With no load, the impedance of the power lines would just rise
slightly and the power from the solar system simply wouldn't flow into
the grid as there would be no load for it to flow into.  Whether the
solar system generates a slightly higher voltage than the mains
voltage - to get it to flow in and therefore "take priority" over the
mains, for  any load on the grid that is below the solar panel's full
output capacity - I don't know.

The inverter in the solar system might even just shut itself down,
until there was a load present ?

Re: Government offer of *feed-in tariff of 60 cents per kilowatt hour (kWh)*

On Sun, 24 Jan 2010 01:24:30 -0800 (PST), kreed

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Grid Tie Inverters push power back into the grid by raising thier own
voltage above the incoming mains, so that current flows back into the
If there is no grid voltage present, the Inverter shuts down.
Practice is called anti islanding, and is done for safety reasons, so
that if the electricity supply to your house is cut for any reason,
the internal wiring wont be live.

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