Micro hydro electric power generation

[Carey]

Although the gutter hydro system seems like a win-win, a hydro turbine that would run on that low of a head x volume would give you a very low monthly generation yield....
If your head pressure was at 12 ft (that would be the distance from the downspout to a ground mounted turbine on a typical one story house on 4' piers)
and you had a roof area of 1500 sq feet
and the rain was 12" for a month
you would have 1,500 cubic feet of water a month, or 11,220 gallons
if this was a constant 24hr a day rain for the whole month, you would have a consistent 1/4 gpm flow, or 0.03 cu ft/min, or 0.00055 ft3/sec
output 'p' = gravity (32 ft/s) x head (12') x flow (.00055ft3/sec) {x efficiency} = 0.21 kW at 100% efficiency....
probably enough for LED lighting, but not much more (and only if you had a consistent rain and 100% efficiency...our fluctuating rains would give you far less most of the time....maybe easier to kick around a soccer ball!

here is a link to a handy USAID brochere:
http://www.energytoolbox.org/gcre/mod_4/...opower.pdf

[Hunt Stoddard]

You don't need a huge amount of water if you have sufficient head. In California, we have a system from Harris hydro with 80 ft. head that only require a small amount of water which then goes through a small orifice jet that turns the turbine. The house has very moderate energy needs. Of course, more consumption would mean either larger volume or even more head. Unless you're on VERY steep land, large head means having the water source on someone else's property, and a fairly large pipe going down to your generating station. And then either your generating station is close to your house, or you're going to need to boost the volt up substantially in order to get it to your house without significant loss, which means high voltage lines, safety, etc. So there's lots to consider.

[Hunt Stoddard]

Actually, one of the very first things I thought of flying into Hilo and seeing all those streams pouring into the ocean was "micro hydro"..

[Carey]

Hunt, after the Honolii Hydro EIS went to the Supreme Court in the early 1990's, Hawaii has not done anything further with public hydroelectric generation...which really does limit our choices of truly green, sustainable & long laster power generation facilities..

Added( Hydro plants on this island are within the "micro-hydro' label, as they are all fariry low generation facilities...when you think of hydro generation...)

I still think that the modeling question was blown out of proportion for the EIS, and that the real fear of changing sediment loads on the Honolii was made mute with the drastic change in the agriculture of the Honolii watershed during the 1990's from intensive sugar cane cropping to forestry... as far as I know, there has been no outcry about the sediment load change from that shift...so....was it a real concern or a NIMBY?

[bystander]

There's an inn in Hilo that has hydro power, only 4KW though.

http://www.waterfall.net/hydro-electric-facility.htm

[Carey]

As I stated earlier, the main 2 roadblocks for private use would be if there was any need for a grubbing or grading permit within the riparian zone (this would be most significant in penstock/weir const.), and wether you had the have the flow volume for the application you need....which is the problem in Puna!

[David M]

A fascinating subject. I was all excited about it when we first bought our property as a year round stream runs along one boundary. Unfortunately, not enough natural head/flow plus the distance to the house. Maintainance is an issue to be aware. A neighbor, but on one of the larger streams has a nice system that has been in place for years except for some recent upgrades. In spite of living on a remote 100 acres, someone has been messing with his intakes the past couple of weeks. Debris in the line is also a problem requiring period checks and cleaning. The inn previously mentioned has had a number of maintainance issues over the years, at times having to really solely on generator backup. Another off grid friend who is upstream from the inn spent considerable time and effort in evaluating micro hydro as he is on awesome head/flow, but eventually he reasoned that at his age (almost 80) getting down to the area and back up was gonna be a problem at some point - he opted for more PV panels. Another couple we know in Pepeekeo area had their system replaced after the original made an unplanned trip downstream one rainy season. Even knowing all above, I sometimes look wistfully at our stream.

David

Ninole Resident
Please visit vacation.ninolehawaii.com

[kalakoa]

Apparently I'm not the only one who's considered catchment-fed micro-hydro -- seems pretty ideal as a supplement to a PV array.

In my particular case, I've got at least 10-15' of drop between the spouts and the back of the property; I haven't penciled out the cost/benefit to see if the pipe is worth it, so it may end up more "science experiment" than "practical source".

[David M]

quote:

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Originally posted by kalakoa

Apparently I'm not the only one who's considered catchment-fed micro-hydro -- seems pretty ideal as a supplement to a PV array.

In my particular case, I've got at least 10-15' of drop between the spouts and the back of the property; I haven't penciled out the cost/benefit to see if the pipe is worth it, so it may end up more "science experiment" than "practical source".

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In my version, it flows from the catchment tank at the top of the property, makes electricity at the bottom (50ft drop over 500 ft) and is returned to top of the hill providing a constant flow. If only a way to pump it back up and have a substantial net gain.

David

Ninole Resident
Please visit vacation.ninolehawaii.com

[Royall]

[quote]
In my version, it flows from the catchment tank at the top of the property, makes electricity at the bottom (50ft drop over 500 ft) and is returned to top of the hill providing a constant flow. If only a way to pump it back up and have a substantial net gain.

David [quote]

David, why not put in a ram pump? I looked into for Dave when I was working up at their property. Very simple, easily built and maintained. Lots of info on the web and Gee.... look at all the free time you have on your hands!!! LOL


Royall

Hale O Na Mea Pa`ani