[Pundyburn Lynn]

Hello renewables experts! I[size=78%] wonder if anyone has the answers I'm looking for?[/size]
[/size]
[/size][size=78%]We're looking to develop an off-grid strawbale house, and the site we're currently considering has a powerful burn running down the perimeter.  The water only comes onto 'our' land (if we decide to buy) 150-200m up the hill.  Are there implications, or disadvantages to the turbine being so far from the batteries?  [/size]
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[/size][size=78%]Many thanks,[/size]
[/size][size=78%]Lynn[/size]

[Creagan]

If you are running a DC system, then voltage drop will be an issue over more than a few tens of metres.
However your description suggests that you are thinking of putting a turbine at the existing burn. Generally your inlet will be there, at about the highest altitude you can achieve. The turbine goes as low down as you can place it, connected to the inlet by a pipe. Power is directly related to head x flow rate.

[Pundyburn Lynn]

Why, thank you!  You've made it sound so simple!


Lynn

[Creagan]

A good ready-reckoner for calculating the output of a small hydro scheme is available on the Powerspout website. The Powerspout itself is a fairly low priced unit which looks quite user-friendly.
Try to work out your available flow rate and the vertical separation between your inlet and outlet, and you're good to go.
You may want to consider going down the FIT route for a bit of income too.

[cloddopper]

Marcus ( Mab )  on here has a hydro set up with a 60 foot head perhaps drop him a PM.

He is a well qualified registered electrician with all manner of useful info on off grid generation .

 You may need water authority permissions/ licenses  to extract and put the used water back in the stream .
 ( Sounds a bit daft but there are valid reasons if you think it through )  .

[mab]

hi, sorry - I've had no landline for most of a week    but it's back for now...


I think it's all been said already - that powerspout calculator is a good way to see how much power you may get.


if you have 150-200m of head then you can get a lot of power even from quite a small flow using a pelton wheel or turgo wheel (though I'm not clear if you mean 150m up or 150m away). I think Creagan has covered most of it, but I found that the single biggest expense for me was the penstock (pipe) to the turbine - so ideally you have a steep drop from the collection point to the turbine to keep the pipe short; although, with 150m+ of head you could get plenty of power even with a small cheap pipe (I ended up with 100m of 90mm pipe - about £450)

[Womble]

I think it's all been said already - that powerspout calculator is a good way to see how much power you may get.

So it turns out our wee burn is carrying just enough energy to light up an LED sign saying "Wooohooo!!". You know, I might do that anyway! 

[Pundyburn Lynn]

Mab - the powerspout website gives lots of good advice.  But it's the bit after the power generation that confuses me...  if a house is 150m from the powerspout, where should the battery bank go and what system (AC or DC) travels best over such a distance?
 
Thanks,
Lynn

[mab]

Hmm that's a tricky one...


electricity travels best at higher voltages, so for 150m I would want to go for high voltage transmission (doubling the voltage reduces the cable losses by a factor of four for a given cable size - or, to put in another way: doubling the voltage allows you to  1/2 the cable size).


AC or DC? well taking the question in isolation; if it's 3 phase AC you need 3 wires in the cable, whereas for single phase AC and for DC you need two so where there's a choice of 3ph vs DC I'd go for DC; But AC is easier to convert voltage so if you're generating at low voltage AC, you may want to stick with AC and use transformers to step the volts up for transmission and then step down at the other end.


But the final answer rather depends on what sort of generator and battery/system you go for (the following answers assume the generator operates at less than 230v AC - if the generator produces >230VAC then transmit the power at the higher generator voltage):-


1) an off-grid system with batteries where you're using the power from the batteries directly (i.e. not using an inverter):
Try to generate at high voltage or step up to high voltage for transmission back to the house, then step down to charge the batteries at the house.


2) an on-grid system: connect the generator to a grid-tie inverter at the generator and use a 230v a.c transmission line back to the house.


3) an off grid system with batteries using an inverter to supply loads in the house:
3A) If the hydro is the only source of power then I'd site the batteries & inverter at the generator (and you can use a low volts genny to charge the batteries directly) and transmit the power back to the house as 230v AC from the inverter.
3B) If you have other sources such as wind or solar (which are likely best sited in different locations than the hydro turbine) then I'd site the batteries and inverter and the central hub (house) but connect the hydro (and other remote sources) using grid tie inverters, transmitting at 230v AC (many of the good off-grid inverters will accept being back-fed by a grid-tie inverter). Although this option is getting more costly in terms of all the inverters and battery, etc.


hope that makes sense.