off grid garage

moonlighting

i have a standalone shed/garage in the countryside. if i was to get an esb connection it would cost about 1700 euro. my other option is to go off grid.
i know it would cost more but would like to get some info on the possibly of it working.
the garage would need a constant supply for around 100 watts for the security system and backup lighting. average usage when iam there would be around 300 to 400 watts.
the odd time i might need to use power tools which could be over 1000watts but not that often.
iam thinking of a wind turbine 1000w model (seem to have decent winds in my area)
electric solar panels iam not sure about a second wind turbine would be better.
to store the energy is there any decent batteries or any alternatives out there at the moment. thats my biggest concern
also to save money i would install the system myself so just the cost of buying the goods.
so theres my delema esb or off grid
would love to tackle the off grid idea if its anyway feasible.

quentingargan

You're right to identify batteries as the key issue. Fork lift batteries for example are "deep cycle" but designed to be recharged each night. That seldom happens off grid, and few batteries are designed for running along half empty for long periods. I am currently trying a new type of battery on our house that has carbon fibre mesh around the plates to prevent sulphation - will have to wait and see if they last the pace. But other solar / wind batteries such as Sonnenschein / Rolls are extremely expensive (a lot more than your €1700 ESB connection..)

It is possible to go off grid using wind, but if I was doing it again, I would go for a combination of wind and solar PV - they complement each other quite well across the seasons in Ireland, and solar PV is coming down dramatically in price. I'm planning to add 1kw of these to our current 2.5kw turbine for our own house.

100W baseload is very high for an off grid system. I would work on getting that down. Use LED floodlights and motion sensors rather than leaving any permanent lighting. A 1kw turbine on most sites will struggle to deliver an average of more than about 150w by the time battery losses etc are factored in.

Also, note that off grid turbines usually often work a lot less efficiently than grid tied ones because they don't have MPPT tracking (maximum power point). The turbine in grid tied systems is dynamically loaded as it speeds up, whereas most battery systems just hold the turbine at whatever the battery voltage is. I've been working on solutions to this that use grid tied inverters for off-grid use, but it is expensive, and only for larger sites.

It is do-able, but your budget will be a lot more than the ESB installation cost. However, hopefully your battery replacement costs will be a lot less than your monthly bills would have been, and it is nice to have turbine, PVs etc., and get your energy from an independent source...

Poor Uncle Tom

There's also the cost of a planning application. There are provisions for putting 1 wind turbine within the curtilage of a dwelling house but from what you say there is not any dwelling house with the stand alone garage.

moonlighting

thanks for the advice guys. i guess the best way would be to get an esb connection and hook up the renewable energies up to main board. does that sell back feature work yet where the excess electricity being generated from the renewables offsets your esb bill.

quentingargan

moonlighting wrote: »

thanks for the advice guys. i guess the best way would be to get an esb connection and hook up the renewable energies up to main board. does that sell back feature work yet where the excess electricity being generated from the renewables offsets your esb bill.

Yes, but only if the ESB account is residential. The reason for this (apparently) is a complication to do with charging VAT. So it may be that your shed is eligible. The feed in tariff is 9c plus a 10c supplement for the first 3,000 units for five years. That is a lot cost effective than batteries unless a grid connection is prohibitive.

Paarse Krokodil

One might be able to procure a stand-alone off the grid solar charge controller with a MPPT tracker but for wind I havn't seen thse

If you're able to get the 100W down to something more reasonable off the grid might still be worth doing. It might work grand in the summer with a decent number of batteries but you're not going to generate 2.4KWh a day on a quiet frosty winter's day so things will start cutting out then.

quentingargan

Paarse Krokodil wrote: »

One might be able to procure a stand-alone off the grid solar charge controller with a MPPT tracker but for wind I havn't seen thse

There is one small wind turbine in the UK with a battery MPPT charger, but there are also a couple of ways I have worked on to provide MPPT charging for larger turbines, though that bit is probably a bit off topic (and expensive for this application).

However, you are quite right to highlight the fact that the output of wind turbines when connected directly to batteries is severely hampered by the fact that the energy loading on the blades cannot be modified to suit the blade characteristics. You harvest no energy until the generator gets to battery voltage, and then you load the generator in a very random fashion above that speed.