[tog] UPS for my House / Off Grid System

Noel Bourke cros13 at cros13.net
Thu Apr 16 13:43:08 CEST 2015

If you are going grid-connected (and you have no other option on your
budget) you are going to be feeding power back into the grid, whether it's
metered or not. The meter is free.
The system can run when the grid power is down if you get an additional
automatic transfer switch.

For €4,000 you can just about pay for a basic setup of 4kw of panels and a
inverter, if you do most of the labor yourself.
There is no way you can fit a battery system of any reasonable capacity (2
Kwh+) for that kind of money, even the cheapest sunny boy all-in-one
inverter and battery system starts at €5,500 excl. the panels.
A DIY system for the same capacity would cost more and involve a lot more
risk with the system design.

All this will be a lot more feasible next year when hopefully the feed-in
tariffs will be reintroduced. Up to last year you could sell power to the
grid at 9c/kWh during the day and buy it back at night at 7.4c/kWh.

Monitoring your usage is step one:

On 16 April 2015 at 11:40, Kieran O'Sullivan <whoiskieran at gmail.com> wrote:

> Hi
> Firstly thanks for all the replies.
> My budget would be no more than 4,000.  I was not actually planning to
> sell power back to the grid I have heard of this system but it sounds like
> a lot of trouble.
> I agree insulation is a better option and already have that, but this has
> more of a "nerd value" more interested in doing it and it might save some
> money but also might be able to help other people do it.
> Thanks for all the links I will send a report back in about 2 weeks or so
> with my findings.
> On 16 April 2015 at 09:31, Daniel Cussen <dan at post.com> wrote:
>> I have worked with wind, solar and diesel generation systems.
>> You have not really stated your aims or objectives. Also a budget
>> would be helpful.
>> If you aim is to save money insulation and energy reduction is
>> probably a much better value proposition.
>> One key metric is how many years until it breaks even, and what is the
>> life of the system. If you cannot calculate that then you are not
>> basing your decisions on facts but marketing bull.
>> In my opinion most home scale wind is not great quality, can be noisy,
>> and as said would have safety/insurance problems. Any wind system I
>> have seen has broken and been fixed a few times. If it is high up that
>> means cranes or a tilt over system.
>> Batteries are very expensive and not a good idea when mains
>> electricity is available. The numbers just do not stack up.
>> Solar Electric (PV) panels are very low maintenance but they are very
>> expensive initially and don't give out much energy to power anything
>> substantial. they would be fine for say LED lighting, TV, but they
>> won't ever power water heating, washing machine, kettle. A 50W panel
>> would give out something like 10W during daytime on an average Irish
>> day. That said is there anyone home during daytime, and what is your
>> energy draw during the middle of the day?
>> One system I saw installed, was a small wind turbine that connected
>> directly to a the electricity wiring in the home. This used no
>> batteries and had it's own inverter. Basically while the wind blew it
>> helped reduce you electricity bill. It needed no batteries and was
>> fairly self contained. However putting up a pole, turbine and
>> connecting it to your fuse board is still a big job.
>> The SEAI is the independent government body that gives advice, and
>> real world numbers for these systems, but for a start what is the
>> energy rating of your home?
>> http://www.seai.ie/Renewables/Renewable_Energy_for_the_Homeowner/
>> Grants, subsidy and hype are a big part of the industry.
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> --
> ===========================================================================
> "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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