High head hydro

[TomG]

I've a couple of friends who are getting a farm on Norway, and there is a stream on the plot of land they're looking at. The drop from the highest to the lowest water is about 300 m, but I'm struggling to find any turbines which could deal with that sort of head. I don't know about the flow rates yet, since they're not living there, but from the map, there's at least 1sq.km of watershed flowing into the stream, and there's a lake at the top. The lowest precipitation is about 40mm/month, and my maths says that that gives about 15 litres/sec of flow.

I'm pretty sure there's plenty of power available there, it's just a matter of the cost of the installation. So I thought I'd tap the wealth of experience around here, and get suggestions  Might it be better to just use 40m of head, with a couple-of-kilowatt turbine? Would the piping and turbine for 300m be extortionate?

Thanks in advance!

Tom

[ghurd]

Yikes!

Pressure in a static water column is roughly 1 bar per 10 meters.

At 300m, that's 435PSI.

An online calculator shows 44KW of power available at 100% efficiency.

Again, Yikes!

I don't know much about it, but that's an awful lot of pressure.

Sounds dangerous.

G-

[TomG]

Yep, "yikes" is about right  Given that they didn't pick the site for its hydro potential, it's pretty amazing.

44KW actually matches what I'd worked out, which is nice. And that's in the "dry" season.

Don't worry, I'm not recommending that they weld something together and try squirting that across it! They were definitely looking at a built turbine. And I'm increasingly leaning towards a small, (relatively!) cheap install, using maybe 30m of head and a few litres/sec of flow. Enough to power their house, and with a nice short payback time. Then, if they want to invest in a huge installation later, they'll have the data to do it properly.

[fabricator]

I would imagine there is probably some kind of permitting process to go through, unless the watershed, lake and stream are all entirely on private property.

[hydrosun]

The other part of the equation is deciding how much power is needed. Why go to all the expense of a high head hydro if there isn't any need for that much power. I run my house including heating with a heat pump with 1 kw continuous. So 33 meters and 6 liters/sec should give that much. The advantage of a larger output would be able to meet peak loads without batteries and inverter. I do everything with a 2 kw inverter so I never use more than that at peak. So they can look at peak loads to decide the size of the hydro needed. The 300 meter system would need steel pipe on it's lower section. The highest head I've worked on had about 100 meters head. We were worried about the final hoses to individual nozzles at that pressure.

I'd love to have the problem of too much power.

Chris

[herbnz]

Hi

I operate a pelton wheel at 130 metre head . No great drama pipes are readily available to handle that presure approx 200psi. If i was given the choose there I would use at least use 100 metres and pipe size and jet to take a small quanity of water to suit needs. The disadvantage of low heads is the greater water flows that need bigger more costly pipe also on a running front there is much more rubbish to filter/screen off. Also wheels are much smaller dia and therefore total turbine should cost less.

Herb

[tecker]

With a lot of drop you may consider adapting a post hole auger and the right sized pvc pipe .that way the upper and lower bearing has a dry mount as well as the genset .Lay  pipe the horizontal length twice the size of the auger size and set an inlet the size of the auger .

[Ungrounded Lightning Rod]

With a run that long I'd especially worry about what happens if the water freezes in the pipe.  Not too likely if the flow keeps up.  But if something restricts it to a trickle things could get far too interesting for my tastes.

Don't forget you have to support the weight of the water in the pipe, too.

[Simen]

It's the Norwegian Water Resources and Energy Directorate (NVE) that manages those permits here in Norway.: http://nve.no/en/ Check the 'Licensing' in the menu for the permit process. If you can read Norwegian, there's loads of more detailed info there...

I think one have to apply for a permit (or at least a review) regardless to the size of the plant, due to all the considerations one have to make to the area (environment, pollution, cultural heritage, mining, roads, sea fishing, agriculture). For smaller power plants, (0,1-10MW) it's not certain that one needs a permit, but it have to be evaluated anyway.

All this implies that one grid-ties the plant...

For putting a tube in the creek that wouldn't disturb the flow and having a small homemade 12-48V generator at the end, i couldn't find any rules...

[fritzblitz]

Hello,

I know a company in austria which makes small turbines as I know up to 100 KW,

try : pico-wasserkraftwerk,may be there is a solution!

[esux]

I built a micro hydro, buying a Pelton in Italy.

I know that sells Pelton and Turgi

They are built very well!

http://www.flickr.com/photos/peltonturgo/

[TomG]

Yeah, ice is a problem I haven't entirely got my head around yet. Apparently they can expect a meter of snow to sit through most of the winter, so I guess the frost-line will be pretty deep. More cost there.:-/

[TomG]

Well, if they're grid-tying it, that spare power is income  But I see your point. Sadly, that's another unknown factor - they're not living in the place yet. It has a couple of woodburning stoves, but it's a big house in a cold country! It's a farm, so I imagine there'd be a lot of places that dumploads would be useful, rather than just wasted. And if they're running some farm-type equipment on electric, the peak loads could be pretty big.

Thanks for the input - lots to think about!

[TomG]

That's a handy link: thanks! I haven't entirely decided on the grid-tie vs offgrid choice yet. I think gridtie would be simpler and cheaper (apart from the paperwork!) but I don't know how many powercuts they should expect up there. If they're frequent, the cost of a battery bank could quickly start looking like a reasonable price to pay...

I'll urge them to start putting out feelers to the NVE soon, just to get more info.

[Simen]

I guess that a proper approved grid-tied micro hydro would start at $15000 ++

A generator with a grid-tie-inverter wouldn't be approved here i think. We (Norway) take hydro power rather seriously here. Nearly all power production and usage here in Norway are from hydro plants, and more plants are under developement; most of them private. (The water-power potential here are currently 205,7TWh/year, and around 60% of this are developed.)

(A curiosity: There's a clause in the permission of power productions that says that a plant will be transferred to the goverment after 60 years in production. This is to ensure national power.)

Power cuts aren't that frequent here. It does sometimes happen when we get 3-6 feet of snow in a day... (Trees falling over the power lines etc. due to snow.)

As you said in another comment; there's always use for excess power on a farm, so a non-grid-tied plant would work just fine. On the other side; if there's some equipment on the farm that's critical, a grid-tie-plant with island-capabilities would seem the way to go...

Just to be curious; where is this place?

[TomG]

About 20km from Naustdal, if that means anything to you?