Small scale hydro

[Triassic]

I have a stream, it runs all year round. I’m thinking small scale hydro.
 

Do I need permission? If so, from whom?

 

Can anyone recommend any  good sources of information?

[ProDave]

The important thing is not so much the flow but the fall.  Ours only has a fall of about 1.5 metres across our plot.

 

In Scotland you are supposed to get an extraction licence from SEPA even though 100% of what you extract goes straight back in again.

 

[joe90]

I was fascinated with Dick Strawbridge and his water wheel in Cornwall, yes I too always wanted a stream to be able to “try” to generate lekky.

 

here is @ “blast from the past “

 

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5510

Edited Saturday at 11:02 by joe90

[joe90]

Thinking back I remember Dick was lucky to find an 80-1 gearbox to drive his alternator but they have losses (and are expensive or impossible to find, ) my thoughts were to use a chain drive (fewer losses than gearboxes). He also ran his house lighting on 12 volt from the alternator but that required up rated wiring and my thoughts were to use an inverter and use 240 volt on standard lighting cable. 

[SteamyTea]

Yes you need a license.

You also need a decent mass flow rate. It is the kg of water flowing over the turbine that is important.

Then there is a lot of formula about rotational speed.

 

Unless you have a few tonnes an hour passing at 5 m/s, put a solar panel in its place.

Edited Saturday at 12:01 by SteamyTea

[ProDave]

I did my own experiments a couple of years back. By catching the water as high up and piping it down to the end of my land I got just over a metre head but low flow rate due to small pipe used (what i had)  I calculated it should generate about 12W, yes that is nothing, and my attempt at a water wheel to catch it using just scrap I had, and trying to use a dc motor as a generator, most of that 12W was lost in mechanical losses.

 

To do something useful, I would need about 100 metres of much larger pipe, and just the cost of buying that would make the payback time way too long,  even if I could generate 100W that would be 2.4kWh per day saving about 50p per day, or £180 per year. even ignoring when the flow is too low in the summer and in flood in winter (and would have to be lifted out to avoid self destruction)

 

I do have an old washing machine direct drive motor that might make a low RPM direct drive generator so would avoid gearing losses and I might give that a try some time, but unless I can source at about 100 metres of some decent diameter pipe at next to nothing it's a non starter.

[joe90]

10 minutes ago, SteamyTea said:

put a solar panel in its place.

Unless batteries are used lighting cannot be run on a solar panel 🤷‍♂️. Don’t get me wrong I am sure the figures don’t stack up for most but as a “project” to play with I find it fascinating 

[SteamyTea]

4 minutes ago, joe90 said:

Don’t get me wrong I am sure the figures don’t stack up for most but as a “project” to play with I find it fascinating

I find doing things without moving parts best. Why I have added more secondary glazing.

Door glass and an opening window this time. I have enough plastic sheet left to do one more window. I have 3 windows that are the escape route in case of fire.

I do have a door between porch and living room which I will do as well.

I am sold on triple glazing now.

Edited Saturday at 12:12 by SteamyTea

[joe90]

4 minutes ago, ProDave said:

I did my own experiments a couple of years back.

Yes I remember, chances of height and flow rate being sufficient are very slim for most I guess 

[Triassic]

Thanks for all the interesting and informative replies. Sounds like solar is the way to go, mind you shading is a problem as the site is in a valley bottom.

 

Cheap Solar suggestions anyone? It’s for a Scout campsite after all…..! 

[Marvin]

Been there, got the tee shirt.  Main problem is an uneven supply of rain over the year. Watermills were first invented in the 4th century and it was not long before mill ponds came into being to try and regulate the supply...

[Marvin]

Hi @Triassic

 

Re Solar.  Fixed on site or mobile?

 

What you want it to serve? (lights? computor, kettle??)

 

What amount of storage do you expect to need (storage?)

[SteamyTea]

5 hours ago, Triassic said:

Scout campsite

Can you design a system for showers.  That is probably the biggest energy usage.

A combination of solar thermal, PV and heat pump.

 

Or, get them to build a fire with a large pot over it, just like Baden Powell did in Africa.

It can be lit by rubbing Boy Scouts knees together.

 

 

Image for illustrative purposes only, not to scale.

[Roger440]

10 hours ago, joe90 said:

Yes I remember, chances of height and flow rate being sufficient are very slim for most I guess 

 

I reckon ive got about 8 meteres of head, on a stream that runs about 9 months of the year. Kris harbours youtube channel is useful. Which would suggest i could get to circa 750watts, which at 24 hours a day for say 7 months would be rather useful.

 

However, if you want to do it legit, its an approvals nightmare. For no sensible reason as Dave observes.

 

 

[saveasteading]

38 minutes ago, Roger440 said:

For no sensible reason 

Except that it may be a very bad thing to build a dam that might fail, or a river diversion that might hasten water flow.

I think it's sensible to check, although tiny spillways are obv not going to be a problem.   But how would you define the cutoff?

[Trw144]

Following with interest, we have a spring near our plot so a pretty constant flow of water, and also an old man-made reservoir (think it was something to do with fire safety for some war time munitions factories, and has circa 500,000 litre held). We have decent head (probably 15m-20m) but not necessarily a large flow rate. At some point when I have time I need to empty the reservoir and see how quickly it refills. 

[SteamyTea]

1 minute ago, Trw144 said:

We have decent head (probably 15m-20m) but not necessarily a large flow rate

MGH

Where M is mass flow rate kg.m^-1.s^-1

G is gravitational constant 9.81 m.s^-2

H is head height in metres, m

 

So say you want a 2 kW generator.

 

2000 [W] = M x 9.81 [m.s^-2]  x 15 [m]

 

2000 / 9.81 x 15 = 15 kg.s^-1

 

With a 500,000 litre store you can generate for 33,333 seconds, or 9 hours.

[Roger440]

11 hours ago, saveasteading said:

Except that it may be a very bad thing to build a dam that might fail, or a river diversion that might hasten water flow.

I think it's sensible to check, although tiny spillways are obv not going to be a problem.   But how would you define the cutoff?

 

No dam required. Sure, if you start building proper dams, thats a different situation.

 

All i want to do is run a pipe parallel to the stream from a pre existing pool at the highest point.

 

Maybe there should be a middle ground? As it is, its just to hard for the power available. Cheaper just to continue burning oil.

[Trw144]

22 hours ago, SteamyTea said:

MGH

Where M is mass flow rate kg.m^-1.s^-1

G is gravitational constant 9.81 m.s^-2

H is head height in metres, m

 

So say you want a 2 kW generator.

 

2000 [W] = M x 9.81 [m.s^-2]  x 15 [m]

 

2000 / 9.81 x 15 = 15 kg.s^-1

 

With a 500,000 litre store you can generate for 33,333 seconds, or 9 hours.

Yes, pretty much where I got to hence needing to know how quickly it refills. I'd settle for 500w if it's constant