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There are several hard problems in wind turbine design. One is that, for large wind machines, wind speed may vary considerably across different parts of the blade area. This produces huge stresses in the blade system. Aircraft propellers and hubs don't have that problem, so technology borrowed from aircraft props didn't quite work. That's been solved, but it took years to get past it.

A basic problem, one which this new design doesn't solve, is overspeed protection. Wind turbines above toy size must be able to deal with high wind conditions safely. Some turn sideways; some turn upwards; some feather the props. Brakes aren't enough. There's no way to feather or turn this new design. Even small turbines need, and have, overspeed protection.

There are lots of wind machine designs that more or less work in a small size, but don't scale up to the point where they're worth building. There's a square law; double the blade length and get four times the energy out. So big turbines beat out little ones, once ths scaling problems are solved. Wind turbine size has been creeping up since the 1970s, from about 50KW to a few megawatts.

A 1.5 MW unit was built in the 1940s, but it suffered a bearing failure within a year, then a loss of blade accident which threw a blade 700 feet. Only in the past decade have reliable wind machines in that size range been produced in quantity. With 2800 of their 1.5MW units installed, General Electric can be said to have solved that scaling problem.

The big machines aren't simple. They have active yaw control, active pitch control, hydraulic brakes, AC to DC to AC variable frequency conversion, and lightning protection. But, at last, they work.

So these guys are going to beat that with a little tin model that looks like something used to spin a sign in a used car lot. Right.

[CrazyJim1 wrote:] I also thought that if a house has its own batteries, it could last through blackouts, and with solar powers, offset some of the power costs of the house.

For solar charging of your laptop: http://www.realgoods.com/renew/shop/product.cfm/dp /1000/sd/1006/ts/3415278

They also have solar battery rechargers and rechargable batteries for the GPS unit.

I would think the key to what you want is something with plenty of memory for storing the village locations and, perhaps more importantly, the routes to access them.

Also, some reading material might be useful depending on where you plan on going. (http://www.amazon.com/exec/obidos/tg/detail/-/006 0011602/qid=1121378747/sr=8-1/ref=pd_bbs_ur_1/103- 2873278-2601459?v=glance&s=books&n=507846). Usually includes when the local rebels prefer to lay their mines, how to bribe your way out of various situations without actually offerring to bribe anyone, etc...

Unclear what he's measuring with, but it it's a typical DVM, the voltages and currents are peak values, not average. If he's getting good sine waves out, multiply by 0.707. For worse waveforms, the value is lower. He's probably getting under 300 watts out, which seems about right for the machine he's built.

What's making this work is rare-earth magnets. The field strengths you get today from rare-earth magnets are so high that even this simple design will sort of work. But good designs with rare-earth magnets do far better.

What's scary is that his turbine has a wooden hub and no overspeed protection. Most wind turbines are built to feather or turn sideways ot the wind in overspeed conditions. This thing will probably throw a blade in a big storm.

Real Goods will sell you a 3KW watt wind turbine for $5000, or a 400 watt unit for $900. So spending $700 on magnets alone to build your own is not a win. Real Goods units deliver more power from a 4' rotor than this guy gets from a 17' rotor, and they tilt to a safe position in high winds.

It looks real enough to me, but not cost-effective.

Unclear what he's measuring with, but it it's a typical DVM, the voltages and currents are peak values, not average. If he's getting good sine waves out, multiply by 0.707. For worse waveforms, the value is lower. He's probably getting under 300 watts out, which seems about right for the machine he's built.

What's making this work is rare-earth magnets. The field strengths you get today from rare-earth magnets are so high that even this simple design will sort of work. But good designs with rare-earth magnets do far better.

What's scary is that his turbine has a wooden hub and no overspeed protection. Most wind turbines are built to feather or turn sideways ot the wind in overspeed conditions. This thing will probably throw a blade in a big storm.

Real Goods will sell you a 3KW watt wind turbine for $5000, or a 400 watt unit for $900. So spending $700 on magnets alone to build your own is not a win. Real Goods units deliver more power from a 4' rotor than this guy gets from a 17' rotor, and they tilt to a safe position in high winds.

It looks real enough to me, but not cost-effective.

Silicon Valley has already done its part. Inverters are available for around a dollar a watt, produce good AC waveforms (early units output square waves, causing excessive heating in inductive loads), will synch to and intertie with the power grid, and work reliably.

In California, there are huge tax incentives, the power company has to buy power back from solar installations at retail rates, and adding solar won't increase your property taxes.

And still nobody does it. You have to pave the roofs of the world with solar panels. In fact, solar power production in California dropped slightly during the 1990s. Wind power is way up. But wind power is not a home solution. As Real Goods puts it, "We generally advise that a good, year-round wind turbine site isn't a place that you'd want to live. It takes average wind speeds of 8 to 9 mph and up, to make a really good site. That's honestly more wind than most folks are comfortable living with."

Don't worry about it too much. When the price of oil doubles, we'll see more solar panels.

Counties in California are prohibited from increasing your property tax assessment due to the added value of installed solar equipment.

And, from a more authoritative source,

Summary: According to the California Revenue and Taxation Code, section 73, when assessing property for property tax purposes, active solar energy systems installed between January 1, 1999 and January 1, 2006 are not subject to property taxes. Active solar energy system means a system that uses solar devices, which are thermally isolated from living space or any other area where the energy is used, to provide for the collection, storage, or distribution of solar energy. Active solar energy system does not include solar swimming pool heaters or hot tub heaters. Active solar energy systems may be used for any of the following: domestic, recreational, therapeutic, or service water heating; space conditioning; production of electricity; process heat; and solar mechanical energy.

They say they have four solar panels. Suppose they're Shell Solar SP150 units. Four of those would about cover a truck. You'd get about 600 watts in bright sunlight, about a tenth of what they need to move the truck at all. They might get 5KWH per day, or 18 MJ, if they're lucky. One gallon of gasoline is about 100 MJ. So they're getting no more than 1/5 of a gallon of gas equivalent per day.

With batteries, you'd get about 80% of that energy out of storage. Electrolyzing hydrogen and then burning it is less efficient. Probably a lot less efficient.

They're pushing a pickup truck around, so they'd get maybe 15-20MPG. So it looks like they can drive maybe two miles on the flat on a good day.

Of course, if you park it all week, you can go maybe ten miles on the weekend.

With super-light cars and ultra-expensive gallium arsenide photocells, things look better. But no way is putting some solar panels in a pickup truck ever going to accomplish much. The energy just isn't there.

• Abstract - The commercial feasibility of small scale solar ORC for distributed generation and CHP is demonstrated. This has been achieved with an exergy analysis of over 150 commercially available solar hot water collectors, a survey of candidate working fluids and by adapting rotary refrigeration compressors to run in reverse direction as expanders/asynchronous generators. A computer code combining the results of these sub-studies has demonstrated that self-stabilisation close to optimum conditions for given irradiance may be possible without electronic feedback control. The principle obstacles encountered included oil migration, face and tip sealing problems and low expansion ratios.

If you want solar powered water pumps, they're commercially available. A complete kit, including solar panels, is $1,697. But they're not really cost-effective. Windmill pumps still outperform solar, and newer pumps will work at low wind speeds.

• Abstract - The commercial feasibility of small scale solar ORC for distributed generation and CHP is demonstrated. This has been achieved with an exergy analysis of over 150 commercially available solar hot water collectors, a survey of candidate working fluids and by adapting rotary refrigeration compressors to run in reverse direction as expanders/asynchronous generators. A computer code combining the results of these sub-studies has demonstrated that self-stabilisation close to optimum conditions for given irradiance may be possible without electronic feedback control. The principle obstacles encountered included oil migration, face and tip sealing problems and low expansion ratios.

If you want solar powered water pumps, they're commercially available. A complete kit, including solar panels, is $1,697. But they're not really cost-effective. Windmill pumps still outperform solar, and newer pumps will work at low wind speeds.

Well, perhaps it's not generally applicable enough to be considered a "solution" so let's call it a "solar consideration" instead.

Anyway, although I was disappointed when Real Goods became part of Gaiam, they at least still have a decent selection of solar power devices, some of which (as I understand it) can power your laptop directly. Under the right conditions, this would easily allow you to keep the system powered for many more hours than the typical laptop battery would provide (although, for DVD watching, the darker environment that may be desired for viewing would be counterproductive for watching on solar power).

Anyway, just something to think about, and certainly Real Goods is not the only source of such items. I recently bought a small solar battery recharger from Silicon Solar, for example, and some of the products in their catalog would probably be workable for this too.

(Many caveats apply, of course, including the size/portability/convenience of the solar power device.)

It is indeed a shame that more interest in this technology doesn't exist. The lack of responses to this article is pretty disappointing, especially since I would think /.ers would be one of the main supporters. Doubling the output of cells is a definite improvement.

I remember reading somewhere (IIRC one of the Real Goods Source Books) that had the phrase similar to "Solar Panels will never become widely accepted until they are available from your local Home Depot." This definitely rings true. Aside from the solar powered walkway lights (total garbage), they have very little to offer there. Solar Cells need to be cheaper and more powerful if people are going to use them.

It's good to see that progress is being made, though, as this article describes. Perhaps one day it will indeed become practical to use solar panels. Until then, we're stuck with calculators.

Bats would normally eat those mosquitos... just install a bat house on your property.

Jack Rabbit Submersible Hydro Generator

No Pipes or Dams! Power from any Fast-Running Stream or Tidal Flow!

The Jack Rabbit is a special low-speed alternator mounted in a heavy-duty, oil-filled, cast aluminum housing with triple shaft seals. Orginally designed for towing behind seismic sleds for oil exploration, this marine-duty unit is ideal for home power generation near a reasonably fast-moving stream. In a 9 mph stream (slow jog) the Jack Rabbit produces about 2,400 watt-hours daily. Ina 6 mph stream (brisk walk) it produces over 1,500 watt-hours. The 12.5" propeller requires 13" of water depth. A rock or timber venturi can often be constructed to increase stream speed and power output.

Jack Rabbit Submersible Hydro Generator neat stuff

This thing is the only applicable product that I've ever seen.

Seriously, almost any solution will cost more than conservation. Not only can you have a smaller generator, but you won't need as many batteries to store energy for peak periods.

Check out real goods and other suppliers. Good lighting, gas-powered hot water heaters, fridges and cooking... there are lots of nice appliances that can reduce your reliance on electricity.

As for generation- keep your options open. It may not be legal for you to install a micro-hydro generator, and solar or wind might be cheaper.

Real Goods sells renewable energy sources, books on design and installation, and planning and installation services.

How do I plan on getting solar power in the middle of the night? First, reduce your electricity needs after dark. 12 V DC lighting, avoid large appliance usage, surf the net on the laptop instead of the desktop, etc. Next, get a rack of these Solar Gel Batteries. Store excess energy during the day, burn it up at night. No problem.

Am I going to do this on my current house? No. It's far too energy-inefficient to even bother with. My next house? Might go with a solar intertie system. House after that? Grid-free living. Have a plan.

Real Goods has a pretty good page with information about rechargable batteries.

I use this one to recharge the batteries for my MP3/CD player in the car. They make a bigger one that will recharge 8 D cells in a day (depending on ambient sunlight, of course.)

I on the other hand have basically one device that uses batteries: my Olympus C-5050Z digital camera. And unlike some who may pull their camera out for vacations, birthday parties, and the occasional group shot, I use my almost every day. I've exhibited my photographs, maintain two photo blogs (jetcityorange.blogspot.com & www.jetcityorange.com/photos), and see every problem as a photo waiting to be taken.

I also shoot multiple pictures in relatively quick succession. Charging the CCD and writing to the SmartMedia card is hard on batteries. I've found that Olympus' NiCads are great if expensive and un-recharagable. My first choice are Duracell Ultra's. Why? Cuz when I first starting shooting a digital camera 4 or 5 years ago (I'm on my 4th) I stumbled across a battery recharger that claims to "freshen" (their term) standard batteries. And it does! Not only do I get up to 5 cycles in my camera, my kids can get 2 or sometimes 3 in their Gameboys and CD players, which seem to be less demanding of batteries.

I got my battery recharger from Real Goods.

And of course, your mileage may vary.

Jerry

These devices emit the noise of an "angry male mosquito", and because only pregnant females bite, they're supposed to get scared away by the sound of an angry male. The thing is, according to the packaging on my device, there are over 1400 species of mosquito in the world, and this only works on about 500 of them. It doesn't scare all of them away - some of them it just makes not interested in biting. And of course, there are those 900 species that it has no effect on.

I've used my mosquito guard thingie all over the place - from the mountains in WA state (I live in Seattle and camp fairly often) to jungles in central america (where I've been on several occasions). It seems to work on most mosquitos I've run across, both in the flying-away sense (luckily, the horribly-toxic ones that live around my house), and in the not-biting sense (about 90% of the ones in Costa Rica). Others (like some I ran across while camping last weekend) seem completely unaffected.

It's a gamble. But if I figure it prevents me the annoyance of a few mosquito bites, it's worth carrying around.

Is there any way to take a reading of the power drawn by an electric device? For example, plug the device between the power outlet and the electric appliance you want to rate and then take the reading?

You need one of these my friend. Don't forget our chums at home power magazine for other energy related goodies and reviews.

These folks can answer all these questions and more where solar (off-the-grid) living is concerned (and then some).

Real Goods

Best of luck!

Ask and you shall receive:
White LED bulbs 120 vac
LED's last 10 times longer than compact fluorescents and 133 times longer than a typical incandescent. And energy savings are incredible. It would cost $772.20 to use one hundred 25 watt incandescents for 13 hours a day for one year compared to only $30.80 using these light-equivalent LEDs - a savings of $741.40. They only produce 3.4 BTUs/hr. compared to 85 for incandescents - no more heat problems. And they fit in standard recepticles, lamps, recessed cans, track lights, any place you would use a normal bulb. The 17 LED version replaces a 25 watt incandescent and uses only 1.7 watts. 9 LEDs in a n A-19 bulb - the same style as a typical incandescent (2 3/8 diameter). They look the same, have the same base, and replace a 25 watt incandescent while using less than .9 watts.
realgoods.com

You know what's better than stomping away like an animal on this contraption? Letting Mother Nature do the work for you by getting a solar panel for your laptop. Not only are they cheaper than this thing, but they don't involve looking like an idiot to passersby. I promise I'm not affiliated with this company. I just thought I'd provide an example so that you folks know what I'm talking about.

http://www.smarthome.com/9031.html or http://www.realgoods.com/shop/shop3.cfm?dv=3&dp=30 2&ts=1025344&kw=monitor

Check out http://www.realgoods.com/. They have a strong collection of books on alternative energy and construction materials. They are also a good source to purchase solar, hydro and other forms of alternative energy source equipment from.

They also host educational sessions but I have no firsthand experience with them.

Flickering is a lousy excuse : a good tube does not flicker because there is such thing call a "capacitor".

Check out the solar power module for laptops at Real Goods.

I don't have a laptop, and, therefore, don't have one of these, but here's what they say about it: "Output of 13.8 watts will run some models better than others. At a minimum it will triple your run time on the internal battery, or recharge in twice the time required by an AC plug." It doesn't support every laptop, but I think it may be worth checking out.

Real Goods ( www.realgoods.com) has a variety of solar panels, including one which powers a laptop, so is comparable to the unit featured in the above story. Price is $369.00

Real Goods ( www.realgoods.com) has a variety of solar panels, including one which powers a laptop, so is comparable to the unit featured in the above story. Price is $369.00

Real Goods and Jade Mountain, among others, have been selling these for several years now, for a wide range of laptops.