new build wanting to be off grid. advice and opinions please.

[paikese]

Or given the contentious nature of the subject perhaps that should read "opinions and more opinions please..."

Hello, to start with.

I have been lurking gently for a couple of years but have never been in a position to ask a sensible question.
Now I think I am.

We are about to start building our new house here in Estonia. Northern Europe for those who are unsure... We want to be as self reliant as possible regarding energy and also want to be free of the chore of wood burning stoves. That in itself might upset some, all I can say is that for the last seven years we have chopped and hauled 10+ cubic meters a year for all cooking and heating needs and we just want electricity. Switches to flick with no axe work or muddy boots involved. Apologies to all those who like wood burners.

Grid-tie in Estonia is problematic in that by law the only utility company in the country would own all your home-produced electricity as soon as you connect to the grid. By law you would lease your equipment to them (at a price they set) and they would sell the electricity back to you (at a price they set).

That's the background to wanting to be off-grid.

The plot is about 2 Ha and at least 1 km from the nearest forest. (Estonia is basically one big forest with some bogs and a few fields. We own a field!)

I have been measuring wind speed on the plot for a little over a year. Average wind speed in m/s was just under 3 m/s. Measured at a height of 9 m. I am not entirely convinced about this figure as the meteorological tv reports always showed higher speeds than I was getting so I want to check the calibration of the anemometer and that figure might well change when I do. Probably upwards. The Estonian average for the area we are planning to build in is actually closer to 6 m/s. But I have no idea what height this is measured at.
At this point I am sticking to the lower figure to avoid disappointment.

We have outline planning permission for a mast and turbine hight of 30 m. That's ground level to blade tip of the blade that's at the top of it's revolution. We can site the mast up to 30 m away from the house which is 7.5 metres at the roof ridge.

Energy needs. My worst case scenario guesstimate is 2000 kwh per month. 1500 kwh is probably closer to the mark but I would rather overestimate energy needs and underestimate available wind. Just to avoid disappointment. The new build is 530 m2. Straw bale walls and ground heat pump under floor heating and hot water. Well insulated roof.

I would like want 3 phase available in my workshop for a small metal lathe and a small wood lathe. I want to be able to run a 170 amp 240v welder without problems. (just in case some are unaware, 240v AC is the norm in Europe, it's one phase and neutral of a three phase supply as far as I am aware.)
Battery storage is only an issue in as much as "how many can I afford..."

Question 1 then...

Realistically, do I have a fighting chance of being able to power my house based on the figures I have set out and the available real world knowledge that I am aware several forum members possess?

And for a bonus point if the answer to 1 was yes....... Do any of the multitude of self build plans fit the figures above? I actually have 3 options in my mind all provided by long term members of this forum.

I am looking to pick the brains of those who have done it and are doing it and am more than ready to answer all relevant questions.

The caveat to all the above is that the average wind speed might well be higher than I have quoted. I cannot do any calibration until next weekend so I am going with the lower figure for now.

Go on then, hurt me.
 

[scoraigwind]

There's a difference between 3 m/s and 6 m/s.  According to my estimation, one of my design homebrew 4.2 m machines could produce about 67 kWh per month on a 3 m/s site (so you would need about 22 of them), or if the wind is 6 m/s average then you could expect 400 kWh and you could get by with only 4 turbines.    Or just two, at 6 metre diameter.

You also should allow for some losses in the battery but the above is not a very exact calculation anyway, just a ballpark thing.

Maybe you can get some help from Criss and Madis? http://scoraigwind.co.uk/?p=1002

I would recommend you tackle the project as a process rather than as a single thing.  if you start for instance with a 3 metre machine or suchlike and get it up on a sturdy tower, then you will begin to produce energy, and you will get a sense for how much of a resource you have got, and make a plan for what to do next.

[Flux]

I agree with Hugh, wind speed is critical. At 3m/s it is not realistically viable.

If you have a field in the middle of a forrest then your measured figures at 9m may be right. If you can get a tower 10m taller than the surrounding trees then you may see a very drastic increase in wind speed and it might be possible. Hopw high you can go may be the critical factor.

There is probably a good case for trying one small machine ( say  3m) and get it as high as you can and use that to get more meaningful results. Normal met office wind speed is measured at 9 or so metres but you need figures at the height you expect to run your turbine.

Flux

[paikese]

Criss and Madis look to be about 15-20 km away! I will be getting in touch with them. Thanks for the pointer.

Flux, sorry I think you mis-read my post concerning the forest, we are actually in quite a forest-free area, nearest tree line is 1 km ish away. But maybe you did get that. Not so important I guess. Knowing what height the meteorological readings are taken over here would be quite useful. A little more research is called for.

[TomW]

If you already have power on site you might consider doing the off grid process in chapters or chunks. Start with a big enough inverter to cover anticipated needs and then add to the system as you discover what works.

Kind of what we do. About 30% off grid and enough to get by if they quit selling electricity or it goes away. We could survive on what we make but luxuries tend to be power hungry.

Just another angle.

Tom

[birdhouse]

paikese-
i'm in the states, so did the calcs on your new home size.  it's around 5700 sqft.  that's HUGE!! 

do you have many children? or does this size include your shop space that is needed for your income? 

anything is doable, just depends on how deep your pockets are.  just some rough calcs show you would need to spend around 25,000 to 40,000 USD on a battery bank to be able to pull 60-70 KWH per day.  then there's charging it.  i would guess you'd want around 5,000-10,000 watts of solar and at least two sizable wind turbines and a quality generator to keep you batteries topped off. 

just a wild guess- you could drop 100-140k USD and could have a huge system that could potentially meet your requirments.  there's a lot of ins and outs to save/spend more money.  the more work you can do the better.   

conservation is the best money spent!  straw bale should give you good insulation in the walls.  even if you could drop you consumption to 1000KWH a month, your system could be substantially smaller!   

have you read here http://builditsolar.com/ there are great plans to preheat water with solar, and solar air heaters as well.  these designs seem to be the best bang for the buck for being off grid.  basically using the sun for more than just creating electricity. 

adam