[tog] UPS for my House / Off Grid System

Noel Bourke cros13 at cros13.net
Wed Apr 15 23:42:28 CEST 2015

So there are a number of issues that might impact your plan:

1. Since 31st of December there is no feed-in tariff so any spare power you
don't store will be given to the grid *for free*. A situation unique in the

2. If you don't draw enough power from the grid, you will be hit with a
low-usage surcharge of 66c/day as a nice solid F*ck You from the
electricity grid for giving it free energy.

3. The energy you give the grid is not offset against the energy you draw
at night (because apparently net metering leads to communism)

4. Any equipment like that in a grid connected system needs to be certified
under the irish standards.
A DIY system will find it difficult to meet that requirement, especially
since *none* of the commercial systems have been certified.

But if you fit the battery system after the export meter is fitted what
they don't know won't hurt them.

The cheapest system is SMA's:

Of the current systems on the market Bosch has the best (UK launch due next

However Tesla are due to announce a new battery energy storage system the
end of this month that's expected to halve the cost tpre kWh of the Bosch

There are rumors that a 230v system would be sold in the UK starting early
next year.

Or you could go the route of using an immersun to heat water with the spare
PV power. Some people have also buried heating elements in the ground to
waste energy to get below the low-usage surcharge.


On 15 April 2015 at 20:45, Kieran O'Sullivan <whoiskieran at gmail.com> wrote:

> Hi All
> I am looking to build a off-grid system for my home.  In reality it would
> be more like a UPS, which sits between the main power line and the house.
> My plan is to try and feed in wind and solar energy to the system so that I
> can save money and the environment.
> If anyone has built such as system can you let me know.
> The UPS would power the house and would be charged by the wind/solar
> system during the day, and at night I would consume the power once the
> power got too low it would switch back to the main power.
> Also if anyone thinks this is unworkable let me know.
> I am not sure if wind-mills can be set-up in urban settings putting it on
> the roof might work but may not be high enough.
> --
> ===========================================================================
> "When I give food to the poor, they call me a saint. When I ask why the
> poor have no food, they call me a communist."  Hélder Câmara
> "We must always take sides. Neutrality helps the oppressor, never the
> victim. Silence encourages the tormentor, never the tormented." (Elie
> Wiesel )
> "Act your way into a feeling don’t feel your way into Action" (Gandhi)
> "When I say 'free', I mean 'free': free from bond, of chain or command:
> to go where you will, even to Mordor, Saruman, if you desire. "
> Gandalf, paraphrasing the choice between Free and Non-free software.
> Kieran O'Sullivan
> 66 Edenmore Avenue Raheny Dublin 5
> Mobile: +353(0)876187680
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