best off grid electricity ROI

I was just thinking about this the other day.  There is a lot of excitement for solar and wind power.  But my general thinking is that nothing beats micro hydro.  And this would be a form of hydro that has a near zero impact on fish habitat:  diversion of water in an area that has no fish, or partial diversion of water that does have fish habitat (less than 5%).  Maybe nothing more than the type of micro hydro that floats on the water with a paddle wheel.

If my guess is correct, microhydro could have an ROI 20 times greater than solar or wind.  And it isn't just about the money, but also about the materials used:  less materials uses is better.

I'm hoping that somebody here has a great deal more knowledge about this sort of thing than me.

Anybody?

Easiest and cheapest if you have a reliable source of running water.  if not you are SOL.  Land with running water is expensive, at least much more so than dry property.

I just had the privilege of taking a look at a microhydro setup at a farm community in NoCal where I will be living and working this season.

Their setup diverts water out of a holding pond when the pond is full and drains it into a stream. A pipe brings a moderately-sized volume of water down a fairly small drop, about 15ft of head, and spins a single turbine. It can only be used when the pond is ready to overflow, otherwise the pond will dry up too early in the summer to be of use for other important yields (like swimming). The number of amp hours they get out of the turbine is much less than from their solar setup, but it fills a gap to top off the batteries once in a while when it's raining.

If you don't have a large volume of water, you need a lot of drop. If you don't have a lot of drop, you need a large volume of water. (Large volume on a homestead scale, though, not on the scale of a giant reservoir.) As I understand it, multiple turbines in a row don't increase power generation much, if at all, since each turbine slows and churns the water, making the one that follows less efficient.

I've thought a lot about this, and tend to agree that microhydro is the way to go if available.  Of course, in the strive for redundancy, why not have solar and wind too?

The major issue with microhydro is having the water of course.

That said, as permaculturists, we know it's really not that hard to build ponds high up on the landscape.

I've even thought that rather than using solar and wind to make electricity stored in leaky batteries that have to be replaced every few years, it might make more sense over a lifetime to use that energy to pump water upwards and store the energy as gravitational potential rather than chemical inside a battery.

A simple stirling engine might be a good way to pump water uphill to store in a microhydro pond--You have a solar absorptive pipe with one-way valves all along its length, and concentrate sunlight along it. The water heats up and expands and pushes itself through the successive valves. When it gets to the holding pond you just have to make a simple condenser or let it cool down naturally, and then you can hold that water uphill (minus evaporation, unless you keep it in a tank) until you need to run it back down to make some electricity. It's probably more efficient than solar PV, and less toxic too.

Of course, you STILL have to have water to begin with. And having water to begin with will probably get more difficult in my bioregion as the climate changes and our broken system of getting our water from the Hetch Hetchy breaks more. But it can be the same water held for fire control or for dry season irrigation or other emergencies, so that's a help at least.

Kerrick wrote:
A simple stirling engine might be a good way to pump water uphill to store in a microhydro pond--You have a solar absorptive pipe with one-way valves all along its length, and concentrate sunlight along it.

What you have described isn't a stirling and might (I very much doubt) work only if you can alternately heat and cool the pipe.  As described this is not a practical idea, sorry.  If you have a link to the design you're talking about please post it.

Really? I'd be interested to hear more about why it doesn't work; it was described to me matter-of-factly by one of my design teachers. I don't know the proper name for it, or if it has a proper name. It doesn't seem to me that you would need to cool the pipe alternately along its length--letting a section of pipe cool off every few feet or so shouldn't be hard either, though.

This, I think, is a small-scale prototype with only one valve: It uses an actual stirling engine to drive a piston, so it's different from what was described to me.

And here is a description of a multi-tank system that uses the same principles (I know that just because a patent is filed on something doesn't mean it works): http://www.patentstorm.us/patents/5511954/description.html

It's the same principle that's used to circulate water in a solar water heater--the hot water expands and forces its way along a pipe, drawing cold water in after it.

Hot water flowing like you describe is more like a thermosiphon than a Stirling engine.

I recently saw a production small scale Stirling generator that makes something like 10kW of power, but it was about $10k.

The concept of Stirling/fluidyne engines and pumps are cool, but I have yet to see a really good one.

Yes, hydro is good if the flow is there. Wind is second in quality, but many more sites have wind. I am looking at co-generation of heat and electricity for a cold climate site... would like a wood stove to heat the place and run a steam engine to power a generator.

mekennedy1313 wrote:Land with running water is expensive, at least much more so than dry property.

I've been reading the Keyline books. It sounds like setting up dams near the top of a watershed is a significant investment, but not nearly so pricey as buying land where concentrated water flows naturally and consistently.

Yeomans (the son) put them up for free recently, to promote his own book:

Soil and Health Library

Kerrick wrote:
Really? I'd be interested to hear more about why it doesn't work; it was described to me matter-of-factly by one of my design teachers. I don't know the proper name for it, or if it has a proper name. It doesn't seem to me that you would need to cool the pipe alternately along its length--letting a section of pipe cool off every few feet or so shouldn't be hard either, though.

Here's a site that shows the design

http://www.linux-host.org/energy/sstirling.htm
http://www.fieldlines.com/story/2004/12/9/41413/0938

Its not just a heated pipe, a little more complex than that.  It's what is known as a liquid piston stirling and it MUST have a cold chamber as well as a hot chamber.  It doesn't work just on thermal expansion and density gradients like solar water heaters.  This does work but if you look at the 2nd link what you described was just the pipe on the right, you also need the "motor" which has a hot side and a cold side as on the left of the diagram.  I have built these with my students as high school science experiments which is why I knew your description was neither a stirling nor would it work.  This is a hot air motor, at the top right above the blue lines in link 2 is air which is what needs to be alternately heated and cooled, not the water.

Thanks for the diagrams, much clearer now.

I've always seen those described as "fluidyne pumps" rather than "liquid Striling."

tamo42 wrote:
Thanks for the diagrams, much clearer now.

I've always seen those described as "fluidyne pumps" rather than "liquid Striling."

Same thing, type either into google and this is what pops up.

I think Kerrick's pipe-and-valves pump would work if the valves were tight enough, but there would be very little throughput.  it isn't a thermosiphon, though, because it isn't driven by convection, it's driven by the change in volume of the whole mass of water in the pipe.

it might work better to add a large pressure tank with an air bladder to the system since the volume of a gas will change so much more than a liquid with changes in temperature.

tel wrote:
I think Kerrick's pipe-and-valves pump would work if the valves were tight enough, but there would be very little throughput.  it isn't a thermosiphon, though, because it isn't driven by convection, it's driven by the change in volume of the whole mass of water in the pipe.

it might work better to add a large pressure tank with an air bladder to the system since the volume of a gas will change so much more than a liquid with changes in temperature.

It would work only until the initial water in the pipe boiled out.  With no cooling there would be no contraction to pull more water through the lower 1-way valve.  The vapour pressure of the steam would hold the water out until heating stopped and contraction began.  Small amounts might seep in during heating but would become steam. Not a good strategy for pumping water.

mekennedy1313 wrote:
It would work only until the initial water in the pipe boiled out.  With no cooling there would be no contraction to pull more water through the lower 1-way valve.  The vapour pressure of the steam would hold the water out until heating stopped and contraction began.  Small amounts might seep in during heating but would become steam. Not a good strategy for pumping water.

there's no boiling.  no steam.  it's just the daily fluctuation of ambient air temperature heating and cooling the water, and maybe a little extra solar gain if the pipe is exposed to the sun.

I don't think anybody has suggested that this is a great way to pump a lot of water, but I do think it might be a simple way to pump a little bit of water without any energy input after construction.

the warmer the water is to begin with, the more it will expand or contract given a particular change in temperature.  from 0 to 45 Celsius you're looking at roughly 1% increase in volume, but from 45 to 90 Celsius, it's closer to 2.5% increase in volume.  again, not going to pump much unless the volume in your pipe is very large.

adding an air bladder in a rigid container to the system means you're going to get much greater changes in volume.  the volume of a gas at constant pressure (just atmospheric pressure if it's at the top of the system) is directly proportional to its absolute temperature, so for the same 45 degree Celsius change, you've now got about a 16.5% change in volume.  that's just 16.5% of the air bladder and not all the water, but still quite a bit better than the water alone.

again, we're talking about pretty small volumes of water, but I believe the theory is sound.

If you look back to Kerricks original "stirling" post it speaks of "concentrating" sunlight on the pipe but not of cooling it.  That would eventually result in steam.  Your statement of more ambient fluctuations would result in a minor flow but I would think too small to be useful in any manner unless you had a bloody big pipe.  For example 1L of water at 4 celsius, the temperature with the highest density as water expands below and above this (which is why ice floats), expands by 28mL if heated to 80 celsius.  This is hardly what could be achieved by "ambient" fluctuations.  A temperature fluctuation of night cool to day high of 10 cel to 30 celsius only results in expansion of 3mL.  If you don't believe this I invite you to look up the coefficient of thermal expansion for water and do your own calculations.  It will pump theoretically but in practical terms it is a useless amount.

I think we're finally on the same page.  I used water's coefficient of thermal expansion to come up with the 1% and 2.5% figures I mentioned in my previous post.  Kerrick was mistaken in calling it a Stirling engine, but it could work, even if only barely.  if it were to boil, though, it would work slightly better.  if all the water in the pipe turned to vapor and most of it evacuated under the surface of a holding pond, you would be left with a vacuum when the sun goes down.  into that vacuum goes more water from the bottom end.  the maximum volume pumped in one cycle would be the volume of the pipe.  still not much water, but potentially a useful amount.

anyhow, we're descending into minutia.  I'm not suggesting anybody go to the trouble of building something like this because I don't think it would be worth the effort, but if they did, I think it would move a little water.

there are flowing wells in our area..in laws property had a well and we have thought of putting one down for our pond..if we can find a spring.

we would like to get one with enough pressure to bring up a pipe and give us a drop  to the pond..and we HOPE to be able to put some type of hydro on it if we can do this..in the next year or so.

do you know how much drop we would have to have to turn a water wheel..? Do you know where we can get more info on this..our son really believes that this is the BEST source of alternative elec for Michigan..as we already have the pond..and would really love to have the flowing water..nearly all of our neighbors have artesian wells...so it is feasible here.

based on info at http://www.theotherpowercompany.ca/Hydro.html , a truly practical micro-hydro setup needs at least 10 feet of 'head' / change in elevation to work with.

However, where Artesian wells are concerned, you can actually achieve more 'head' than a  simple change in elevation contributes ... because water emerges from an Artesian well already 'pressurized'.  It sounds like you need to explore the drilling of a well in hopes of hitting an Artesian vein.  If you can come up with 5 psi of Artesian well pressure this is equal to a 10ft change in elevation !

One very important piece of physics on wind vs. water:

Water is about a thousand times as dense as air, and doesn't compress significantly, so that a comparable rate of flow, and a comparable size of turbine, can produce drastically more electricity.

On the other hand, there are some details of electrochemistry (water is more corrosive than air...) and geology (as noted above, wind is more widely distributed) that can also be important considerations...

Paul,

I've two comments on off grid-electricity and ROI.

1- ROI is a capitalist idea  -why not think in terms of most sustainable primarily and secondarily, the effective electrical yearly cycle?  ROI can be fudged so many ways such that sustainable technology just isn't financially feasible ( without taking into pollution and the long term -7 generations -view). The quicker one leaves the paradigm of fear and greed built into capitalist terms, the quicker one can be free of the current mainstream system of voluntary slavery.

2-the storage of electrical energy is the real choke point of off grid electricity. Batteries must be replaced very 10 to 15 years  -this is significant!!!  in the long term view (7 generations), battery storage of electricity is not very sustainable. 

The only truly sustainable electric storage method I am aware of is a very large water reservoir at a high altitude, a micro-hyrdo generator, and a lower water reservoir at a low altitude.  -so whether you generate the initial electricity via solar panels or not, I recommend the "two reservoir" method of storing enery.

It's one storage method you can leave to your own 7th generation.

Please, if anyone knows of a chemical battery that does not need replacing within 700 years, please post it!!!  I want it!

A high-low two resevoir system, with some sort of natural replenishment for replacing water lost to evaporation would be very nice, I agree. However, many of us, perhaps most of us, don't have enough land that meets the topographical requirements to utilize such a system.

I'd love to have micro hydro of any form. Where we are located even if we had bought the section that the river, more like a creek,  runs through we would have faced bundles of red tape in order to get permission to use the water in any form of power generation. It's a wild and scenic rated stretch and impossible to do just about anything except look at it or catch fish in season and with the appropriate licence.


I agree that storage is the big bugaboo in alternative systems. Batteries were why the electric car never took off back in the early years of the twentieth century. The same problems exist today. My batteries look distressingly similar to the Exides that were used in some early electric cars.

Interestingly enough, to me at least, the early Bakers used a so called alkaline battery invented by Edison. It had lead plates and used acid; I'm not certain of exactly how they worked. Jay Leno has some of the original batteries in his 100 year old Baker. Apparently they wash them out every so often and refill. They still work today.

Micro-hydro definitely high ROI if the flow and head are there. 

2 gallons per minute of flow is about minimum for low-flow micro-hydro.  X60minutesX24hours =  2,880 gallons per day x 365 would be just over a million gallons a year.  Sounds like a lot of water right? 

OK - let's say you are in a rainy place like PNW, some places get 60+ inches of rain per year.  You would need about 30,000 sf of surface to catch a million gallons of water.  An asphalt road 30' wide 1000' long would do it.  Or 10 homes with 3,000sf of combined roof and driveways.  Then all you need is some head. 

In a peak oil retro-fit the suburbs scenario, any hilly neighborhood with asphalt roads (and driveways) in the PNW could be turned into micro-hydro bonanza.  Redirect the storm drain into ponds and install micro-hydro generators in sequence.

Regarding batteries for storage, I've used deep cycle, lead-acid "wet cells", sealed gel lead-acids, and Edison nickel-iron cells in both cars and houses. The lead-acids are over 99% recyclable, easy to find locally, easy to turn in for recycling, and relatively inexpensive. But the sealed gel cells can't leak, never need refilling with distilled water, never off-gas explosive gases, and are mechanically sturdier for vehicle applications. They cost slightly more than wet cells or AGMs (absorbed glass mat) but have 3 times the "cycle life" (number of available charge-discharge cycles for a given percent draw-down) and 98% charge eficiency.

The Edison cells use nickel and nickel oxide electrodes in a bath of potassium hydroxide with lithium hydroxide as a catalyst. They work well in very low temps, are lighter than lead-acids, and are sturdy but they have poor charge efficiency (about 70%), they are hard to find, and they cost a bundle unless you can find used ones cheap. You use them for about 10 years, then drain the electrolyte (which turns into potassium carbonate from reaction with CO2) and refill with fresh electrolyte. The diluted electrolyte makes a good potassium fertilizer on orchard trees, if needed.

You can find more details from the text and links on our web page at http://www.geopathfinder.com/9659 .

By the way, the BEST off-grid electricity is what you have available in your area! For us that's PV.

Bob Dahse.

Walk wrote:
Regarding batteries for storage, I've used deep cycle, lead-acid "wet cells", sealed gel lead-acids, and Edison nickel-iron cells in both cars and houses. The lead-acids are over 99% recyclable, easy to find locally, easy to turn in for recycling, and relatively inexpensive. But the sealed gel cells can't leak, never need refilling with distilled water, never off-gas explosive gases, and are mechanically sturdier for vehicle applications. They cost slightly more than wet cells or AGMs (absorbed glass mat) but have 3 times the "cycle life" (number of available charge-discharge cycles for a given percent draw-down) and 98% charge eficiency.

The Edison cells use nickel and nickel oxide electrodes in a bath of potassium hydroxide with lithium hydroxide as a catalyst. They work well in very low temps, are lighter than lead-acids, and are sturdy but they have poor charge efficiency (about 70%), they are hard to find, and they cost a bundle unless you can find used ones cheap. You use them for about 10 years, then drain the electrolyte (which turns into potassium carbonate from reaction with CO2) and refill with fresh electrolyte. The diluted electrolyte makes a good potassium fertilizer on orchard trees, if needed.

You can find more details from the text and links on our web page at http://www.geopathfinder.com/9659 .

By the way, the BEST off-grid electricity is what you have available in your area! For us that's PV.

Bob Dahse.

Wow, that's a nice explanation of batteries you've used.  Taught me a few things!  Thanks for that Bob!

I take issue with recommending gel cell batteries. They require different charging profiles than wet cell lead-acid or AGM batteries. They can not be fast charged. A standard battery charger can damage them. Ditto for charging off an automotive alternator unless a special regulator is used. To me they have more drawbacks than advantages. Not just my opinion...

Note: a sealed gel cell is NOT the same as a sealed AGM.

http://www.windsun.com/Batteries/Battery_FAQ.htm#Gelled electrolyte

http://www.batterystuff.com/tutorial_battery_gel_agm.html

http://www.vonwentzel.net/Battery/01.Type/index.html

AGM's are good performers. The big advantage to standard lead-acid flooded batteries id their cost per capacity.

Pardon me if I was reading this incorrectly, but I think the original thread dealt with return on investment. For only slightly more money than an AGM, a gel battery has three times as much cycle life. That's a pretty good ROI. And using a "standard charger" or "fast charger" isn't recommended for AGMs either. Both need voltage limitation, and since both are sealed, if you don't limit the voltage they'll be damaged by internal gas build-up. The only disadvantage I've found in gel cells, from using all three extensively (as well as various Ni-Cads, nickel metal hydrides, nickel-iron Edison cells from Edison, from Hungary, and from China, and several types of lithiums) is that gels have to be kept over -22F even if fully charged or they'll freeze.

The gels have been working great in our electric Porsche rebuild. For 4 times the money and half the weight I could have used lithiums, but that didn't fit our budget. Like AGMs, gels handle vibration well and don't off-gas. But AGMs will leak if punctured while gels can't. Finally AGMs cost more per watt-hour than wet cells and have the same cycle life, making them less advantageous than wet cells, not more (unless you add in their lack of gas-off and greater shock resistance). If you want extremely fast charging without damaging cells and greatly reducing cycle life, best to stick with either ultracapacitors or lithium nanoparticle iron-phosphate cells (A123 systems). Not just my opinion.....

Note: All battery chemistries and types have differences, making them better or worse in specific applications. That's part of why nobody agrees on what to use.

Twobirdstone -  I love the comment you made:
"The quicker one leaves the paradigm of fear and greed built into capitalist terms, the quicker one can be free of the current mainstream system of voluntary slavery.”

I find myself in the place you describe more often than I care to recall.

I see myself as an energy slave.  Wind, solar and the like are almost phantom technologies.  They will always be feasible next year.  In 2001 there were promises of thin film costing $1/watt next year.  Still we do not have it. 

I like the two reservoir system where one pumps water up high as a form of battery or storage of potential energy.  They presented this to my college physics class in 1981.  It captivated me as a young student. 

I have about 100 foot drop on my farm that could be a platform for such a system.  When I performed the feasibility analysis I needed an extremely high volume of water that was impractical.

A couple options that I have formulated are:
1) Using waste veggie oil WVO to power a converted diesel generator.  Depending on how much oil can be obtained and at what price this can be cost effective.  Maybe not sustainable but cost effective.
2) Another idea is to burn wood or biomass and run a steam engine / generator.    I have been advised that it requires continual maintenance.  But perhaps if it is just run for short periods to charge batteries it could work.  Also it can be dangerous.
For lack of personal drive I have backed off of this ideal but am so glad to see it being discussed.  Surely there is a way for us  to have personal energy freedom.
The main energy consumption  for us here in Nashville, TN is air conditioning.  We have a ground source heat pump (GSHP) that uses cool water from a sulfur water well and dumps into a pond.  This cuts electrical use a lot.  Maybe a super insulated and small house using  GSHP and a combination of the above. 
Energy independence is a worthy goal and one I have pursued for a long time.

The steam engine needs regular maintenance in oiling etc but it is almost all owner do-able as opposed to the servicing needed buy the infernal combustion engine.  They have the downside of being very expensive today.  Because they are high torque low speed they last upwards of 50-100 years.  A do-able technology if you have the up front $.

From what I have learned you only get continuous 125 watts if you have 100 gallons per minute at a 20 foot drop in a micro hydro. Very little energy but would be nice to help with solar or wind. I plan on building one before too long. I will post when I get the chance to do it.
I am thinking it will cost me about 1 K at my site to build it.
joe

The most important ROI is to reduce how much you need. The "build it solar" page has a great "half program" that is a good start in the right way of thinking if nothing else.

I have thought about what I have to have electric power for (besides this netbook... chosen, now that I think about it, for the low power processor)

- my heat is electric... I don't think it has to be,but that is house design.
        (I could live without if I had to, but its cheaper than gas here)
- light is one of the first things people want, I need it in the winter.
- food storage is the one must have, we only buy meat from farmers we know pasture feed 100%.
          (I have a son who reacts to store bought meat that has ever been fed anti-biotics, so
            we buy once a year)
- hot water. I have ours on a timer, but the one on "i will try" uses way less power as he only heats it enough for two quick showers a day. It comes on for a 2 to 3 hours to be ready for the morning shower then is off for the rest of the day. He uses only about 520w element (hand made) and super insulates (12 inches thick) it. He uses a dish washer with it's own heater however, which is probably not too off gridish, however if the dishes were washed at the same time of day as the showers are taken, it could be a non-issue. It would almost make it questionable if it would be better to use pv or solar hot water in this case. Solar hot water might be better for house warming.
- I use it for food prep, but could use propane or wood

So if I take as many loads off power as a I can, Solar could do a lot.
- I could run my freezer only daytime with a really low temp set and keep it full, using bottles of water if needed, reducing or eliminating the need for batteries.... some of those ice packs could keep a second chest freezer cold enough to use as a fridge.

Thats just one example, but it shows how lifestyle changes can make up for a lot of expensive hardware.

If you guys want Free Electricity, go here.
http://www.ncbookz.com/

I think everyone needs this info and no I"m not associated with him but man I wish I was.

High water volume or large drops may not be necessary after all!  Check this out- another "why didn't I think of that!" common sense idea!



http://www.youtube.com/watch?v=ta-bPT7DeJs&feature=related

If you have a little expertise and time to do it yourself, cost can be held down on the system using a simple but very ingenious vortex to drive a generator, and you have a plentiful supply of electricity.. no more than 1 meter of fall is needed .... 5 meter diameter pool will produce around 14 KW

http://www.zotloeterer.com/our_company_english.php
===================================================================================================================
Another, a Banki turbine, though not producing as much power, is simple to build... and not a great head of water is needed.. cheap to build...

1 -- http://www.boutiquepower.com.au/micro-hydro/crossflow_construction_guide.pdf

2 -- http://pdf.usaid.gov/pdf_docs/PNAAP285.pdf

Hello Paul

For zero impact on fish --- plus aerating the water--- and if you can do the labor, it can be a fairly inexpensive hydro system that needs no more than a meter of fall for 14KW of power, or more depending on size of your system...
www.zotloeteter.com

Whisper McCoy wrote:High water volume or large drops may not be necessary after all!  Check this out- another "why didn't I think of that!" common sense idea!

http://www.youtube.com/watch?v=ta-bPT7DeJs&feature=related

Here's a modern version of this same thing:

And some technical details:

1im not go at math but manage to builed . can you substitute pressure  insted of volume we have done this by a stream 6inch to 4inch to 3 you get idea. Or biger. Like i was saying no math guy