arild jensen

5 cents per kilowatt hour is more than the cost of hydro-electric power at 3.5 cents per kilowatt hour published by our local power utility.
Unfortunately neither source represents what actual end users will pay. What is not indicated is the capital cost of the equipment involved in harvesting the solar power.

SES scrapped a whole bunch of Stirling engines from the California power project. Evidently their bean counters decided it was not cost effective to maintain. Instead they replaced the whole installation with PV arrays.

This does point out one of the problems with trying to transfer technology and scaling it up or down to suit.
When you are doing maintenance on one unit its no big deal but when you have 500 or 1000 to do its a major effort. Multiple crews, trucks and workshops not to mention an inventory of spare parts.
I located one company in Switzerland that made a wood stove with a stirling engine mounted on top. It only produced 1 kW but this is adequate for a single family domicile. When I queries them I was told they would not sell into North America; no reason give so draw your own conclusion.

Ray I usually spec DC chargers that can tolerate a wide voltage input. Then I discovered the manufacture had changed the spec so the same charger could handle Dc input as wellas widely fluctuating frequency. Hmmm? Then it dawned on me this was to accomodate the new breed of solar panels intended for grid tie as well as other types of generator sources. For European grid tie you need 230V @50Hz but their equipment is able to select either 50Hz or 60Hz still at 230V. To accomodate 120V equipment I find it easier to design in a stepdown transformer than deal with that idiocy of a center tapped neutral with the attendant unbalanced neutral current. In one job we ordered a 4kW transformer and it arrived de;overed docvkside in Floridqa for around $100

If you look at the lowtechmagazine you will see how the floating boat mills accomnodated river floods havi0ng water levels chaging by 10 - 20 feet
It is far safer to adjust wheel blade immersion where you are not fighting the force of the water.
Spillways are used to adjust water flow to modern turbines but then you get into expensive civil works construction. A floating undershot wheel is not as efficient but it is easier to regulate especially with electronic devices these days.

Marcos you are correct this is a simple elegant system. However keep in mind Ray intends to install this somewhere in the New England area and winter ice conditions would cause this configuration to stop working often.
This is a perrenial issue with you southern people. What works fine down south is not always suitable in more northerly climates.
That being said, We do have northern location hydro power dams that continue working right through the coldest winters.
Your research needs to be tempered with practical experience. < smile>
The thing about hydro power is the dearth of suitable sites. All the good ones are already taken. And the remainder have restrictions such as fish habitat protection or riparean water rights.
What is needed is fresh thinking on new techniques using sites with marginal conditions using conventional approaches.

Either approach would work ,- - - - depending. <smile>
The carpenter side kick ( Abrams ) in the long ago show 'This old house' bought a property with an existing old mill having a long shaft running the lenght of the building. He renovated it and produced wooden products. Those big wheels had tremendous torque so with proper gearing can deliver good speeds.
The suggestion of going direct AC instead of using a battery system has a few caveats. Water flow regulation is the prime issue. I worked for a company that designed equipment for Ontario Hydro. At one point they asked us to design a controller to regulate water flow to a remotely controlled turbine generator. Oh my did that get involved, ... and expensive.
For hybrid systems utilizing a mix of power sources a different approach is called for. We use such systems on board larger recreational boats. But this is not the usual approach used for many small off-grid installations.

Have a look at www.lowtechmagazine.com and find the articles on boat or ship mills. The point of this is to show just how much power is available even with zero or very low head. Our engineering people have got themselves into a mindset where only one approach is considered because it maximize profits for share holders. The reality is for almost 1500 years water power was the prime source to drive industry in Europe.
It was used elsewhere as well but the design and engineering was not as clearly documented nor as widespread in use.

Many of Europes's rivers do not provide sufficient head to power our modern style turbines unless you invest in multi million dollar construction of dams. Even so most of these rivers were crowded with mills grinding grain, cutting timber and powering looms making cloth and felt.

On the subject of generator use either permanently or as occasional back-up. By now most people have heard of the HONDAi generators.
Yamaha and a couple of other makers have by now copied the idea.
The generator adjust its speed dependent on load. Light load = slow speed, high load = fast speed. Not only does this save fuelbut also wear and tear on the engine. Running a conventionalconstantm speed genset at light loads is not only fuelinefficient but causes ssomething called "wet stacking" resulting in premature wear and glazed cylinder walls.
If your primary use is charging a battery, an even better approach is to get a DC genset. I built my first such generator back in 1965 before I even knew a name for it. My latest version has a diesel engine and can deliver 100 A @ 12V. Some clever bargain hunting meant it cost me $200 but realistically expect to pay closer to $1000 unless you are really good at bargain hunting like me. This is still less than what you would pay for a normal AC powered charger of equivalent capacity. 100A chargers typically cost $1500 new.
If you are willing to settle for a gasoline or propane fuelled genset and a taper charger instead of a 3 stage smart charger you can build one from scrap $200

Marcos Curiously my own information differs from yours. Because I worked in a naval design office I often had to extract fuel flow data for on board generators. When I bemoaned the lack of full BSFC curves and only got point data for 50% and 100% load data for various gensets the engineer informed me that most of their gensets had essentially linear curves between the two points. And if I was any sort of decent designer I would avoid selecting a genset that operated at less than 50% because of known service issues associated with this. And this also explains why we normally design in two gensets per yacht. Sometimes three.

I once found an article dealing with an experiment of building a paine pile in Siberia in winter conditions. Sadly I lost the link when my computer drive got trashed by malware.
The point being a large enough pile will insulate the fermentation process enough to allow the bacterial process to continue. Unfortunately scaling up the process takes it out of the realm of small backyard experiments.

Ray before you go down this road too far make a point of determining exactly how much power you actually need. Too do so ther are several power meters available for reasonable prices. At the low end a "kill-a-Watt" meter cost around $25 at amazon but is limited to 1800 watts instantaneous at 120V only.
Another instrument suited for single phase house panels with a center tapped neutral in the common 120/240V configuration is called TED5000 and cost abit more than$200
Other brands are available but I have no personal experience with them. Both instruments will gove you instantaneous measurements and accumulated watt hour totals per day week or month.
With accurate data in hand you can then assess what products or methods suit your situation best.