admin answers:

Hi Yves, I’m sure there are many websites that can give you better answers so try google too, Yahoo is limited. If you look on ebay you will see lots of permanent magnet 24 volt DC motors for use in scooters, I use one of these, the 250watt model, to power a 12 volt sound system, it can deliver 10 amps at 15 volts. For a wind genny you may have to put gearing between to get the right rpm.
I don’t know if you plan to use a voltage regulator, but if you only intend to use a blocking diode, the best one is a Schottky type, there is a cheap twin 15A schottky from Maplins under £2. I use both 15A diodes in parallel so they won’t get hot & need a heatsink.
The Schottky diode has a voltage drop of just 0.2 volt, I think you put the decimal place wrong
For wind generators the recommended battery charging voltage is 13.8Vmax so 14V with the diode. Car alternators usually produce about 15 volts minus 0.6V for the rectifier, so charge at 14.4 volts. Rutland voltage regulators for wind gennies operate at 13.8volts to stop the battery over-charging.
I don’t know why charging voltages are not the same for a car and a wind genny battery, I’m inclined to think any voltage from 13.8 to 14.4 is ok.
Batteries can deliver a huge current possibly causing burns and starting a fire, so it’s essential to put a fuse in the circuit, right next to the +ve terminal is best.
Good websites are Magnificent Revolution & Cambridge Green Tech

admin answers:

Axial Flux Alternator

The axial flux alternator (sometimes called a generator), is the heart to many diy wind turbine projects. While a small permanent magnet, D.C. Motor, such as the Ametek 30, makes for a very quick and simple project assembly, these motors are becoming very difficult to find and quite expensive. Ebay is loaded with people selling D.C. Motors for home wind turbine projects, that simply will NOT work, due to the extremely high RPMs required to get any usable output. Thus a homemade axial flux alternator may be your best alternative.
What is an Axial Flux Alternator?

A permanent magnet alternator generates power by passing magnets past a group of coils of wire. The magnetic field that surrounds a magnet is call it’s flux. Axial Flux simply means the lines of magnetic flux that past through the coils of wire, travel along the “axis” of the turning motion. The other type of magnetic flux in an alternator is called RADIAL FLUX and it occurs when the flux occurs “around” the magnet. Pictures are worth a thousand words:

Radial Flux

Axial Flux Alternator

In the left picture, the yellow disk is the stator. The two bluish plates rotate, along the horizontal axis, past the stationary stator. In the image to the right, the stator is on the case. The rotor, on the axis, rotates “inside” the stator. This guide by Hugh Piggott describes the process in good detail – How Axial Flux Alternators Work

Overview of the Complete Process – Building an Axial Flux Alternator

In February 2001, Hugh Piggott created a guide for building a permanent magnet generator (PMG) (alternator), after being commissioned by the British government. This guide remains in the public domain and provides an excellent overview of the complete process. You can build a PMG from these plans, though these instructions continue to be improved upon. The PDF document can be downloaded here: PMG Manual

This manual describes how to build a ‘permanent magnet generator’ (PMG). We can
also call it an ‘alternator’, because it generates alternating current (AC). Continued…

admin answers:

The most important thing is to have LOTS and LOTS of money.

If you are a billionaire, that would be a good start.

admin answers:

Hey Michael, Ben is correct about the vertical type turbines. The reason none of the power companies use them, is because they are horribly inefficient. Most of the energy absorbed by the downwind blade is used forcine the upwind blade back into position for the next cycle, and very little is left to produce power. Typically, this type of wind turbine, called a Darrieus Rotor, is about 5 to 8 % efficient, meaning less than 1/15th of the winds power is converted into useable torque, or electricity, and the rest is just wasted churning the blade around in the wind. Horizontal units, and in particular the 2 or 3 blade units generally operate at about 30 to 35 % efficiency, or about 6 times more efficient than a comperably sized Darrieus Rotor. The smaller home sized units like ours have a tail that constantly turns the unit to face the wind regardless of where it is coming from. Older farm type turbines with 12 or 15 blades on them usually worked this way too. That type of turbine, with the multitude of wide flat blades were almost never used for electrcity generation, they were also not very efficient. In most cases, they were used to pump water, and in that way what was needed more than efficiency was low wind start up torque. The large multiple blades worked better for this, but tended to stall out in higher winds. Electrical generating wind turbines work much better in high winds and at high RPM’s, so fewer blades is ideal for this.

The really large utility sized turbines you see that have no tail are either fixed to face one direction where the wind is almost always blowing from, like along the coast, or they have a small anemometer on top that senses the winds direction, and a computer uses a small gear motor to physically turn the unit to face the wind if necessary. These are typical in the midwest. Darrieus Rotors, and their close cousin, the Savonius Rotor, are really neat looking devices, and they are great for small garden pond pumps or outdoor garden lighting, but they are ill equipped to produce enough power to run even a household refrigerator. There is a great article at the American Wind Energy Associations website written by Mick Sagrillo about this, if you want to learn more, check it out. Mick is considered by many in the renewable energy world to be the modern day guru on wind power. Take care Micheal, Rudydoo

admin answers:

Sounds like a cool project… I’d love to try out some ideas too, but haven’t yet.

There’s a boom in “residential wind turbines” and related literature. This link:
http://www.squidoo.com/residentialwindturbine
gives a good summary of what’s commercially available, but about 1/3 down the page is a do-it yourself section with supporting references that might give you a good start.

Same site lists a “Earth4Energy DIY Wind Generator” for around $200. Probably a good start just for learning, then you can scale up as interest & budget allows.

Good luck & be safe!

admin answers:

Solar panels currently being manufactured, have a design life of 20+ years.

Home-size wind turbines have a wide range of design lives. The turbine life is influenced by conditions of use — high winds, ice on the blades, etc.

I would recommend that you purchase your home-scale wind turbine from a seller who offers a guarantee to repair or replace the unit if it fails under normal use. A 5-year or 10-year guarantee period would be ideal.

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admin answers:

There is no such thing as a device that can generate energy from nothing. So called perpetual machines are announced every few years with great fanfare but they always turn out to be frauds (or in rare cases honest but careless mistakes).

You can generate electricity from a ‘free’ source like sunlight or tides or wind or waves or geothermal heat, but you can’t generate electricity from nothing. To do so violates one of the fundamental laws of physics, the conservation of mass and energy.

Very convincing sales copy can make you believe in such devices. For instance, I remember reading a few years back about a ‘Genesis’ energy generation system that used a catalyst to split water into hydrogen and oxygen while using just a tiny bit of energy; then the hydrogen and oxygen were used to generate electricity through a fuel cell, and almost all the electricity produced was available, only a tiny bit was needed to split more water. This is malarkey and anyone with some basic physics knowledge will know it’s impossible, but it didn’t stop the company from claiming it had over 100 reputable scientists on its staff or board of directors. A good way to get some start-up money – sell some stocks to uninformed investors, then cash out before the house of cards collapses.

admin answers:

Excellent question from someone who obviously has a functional grasp of economics. You didn’t vote Obama, did you? (Oh you hater, you! You must be racist, too!)

If we would have just allowed the ill-managed lenders to get into real trouble and not interfere with them in the form of our ridiculous bail outs, the recession would have been far shallower that it is now going to turn out to be. It’s like getting the flu. Don’t medicate yourself – just get the nasty fever, feel like crap, then get over it.

Now the car manufacturers will be on the dole. We will reward their stupid management practices and ludicrous wages with free money. I say we let them take a dump. Like there’s not a rich investment group out there who would not come swooping in with bucket loads of money to buy Ford at fire sale prices? You’d have the UAW under control again, wages back to where reality resides, and a more competitive product too.

And if a car factory flat out closes, then the goverment can do something actually beneficial for green needs and turn these car factories into wind generator factories, solar panel manufacturers, etc. You want energy independence? Start there!

This bailing everyone out because things didn’t work is childish. I cannot believe how stupid this country has become. It’s like a parent of a teen who just keeps buying his idiot kid a new car every time he wraps it around another tree. Instead of making the kid ride a bike or bus, he just enables him to continue in the bad decision making by throwing more money at the problem.

admin answers:

May the New Year usher in loads of luck and happiness to you! Unlike Gulf countries, where they issue 2-year renewable visas, the European countries issue employment visas which are considerably longer. Who knows, if they like you and your work, they may even offer you citizenship (like the US) after spending a few years in Denmark.

admin answers:

Most tread mills as well as other equipment employs private labeled motors. These motors are manufactured by a motor manufacturer and have the treadmills manufacturer part number placed on them. This is done so that you have to pay the top dollar for a replacement motor from the treadmill company instead of getting one off the open market for a tenth of the price.
I doubt the manufacturer will even tell you much about these motors since the less you know about their motors the more likely you are to buy one from them and they make a handsome profit.
If you can get these treadmills cheap enough you can part them out and sell the parts on Ebay and make a handsome profit. You can have your motors for free!

admin answers:

To make an electrical generator, you need to have a length of wound copper wire rotating inside a magnetic field (refer to elementary physics).

Gasoline/diesel/etc. Generators run basically like your car’s engine, but instead of turning wheels, it uses the motion to rotate the wire inside the magnetic field, producing electricity. Remember, energy can’t be created or destroyed. The chemical potential energy in your combustible fuel is being converted to kinetic energy, which is being converted into electrical energy.

A wind turbine is more “free” in that you don’t have to go out and buy drums of oil to make your electricity. But it works on the same principle, but in this case, it’s the turbine blades catching the wind that spins the copper loop, creating electricity.

As far as your batteries go, you may be able to store it there, but to charge any battery, from AA to car, you need the correct circuit and voltage, or nothing will happen. So you probably can’t use your batteries. But if you can, all that you an do is store the potential energy there, and use it at a later time.

But if you just want to play with making a generator, try this:

First, you need to choose the energy source that you want to convert into electricity. You can use a stationary bicycle, a water wheel, wind turbine, a bored child willing to do some menial work on a set of gears, or virtually anything else with a rotating axle. You do have to choose the source, because as I said – you can’t get energy from nothing.

Take that copper wire that I talked about, and make that loop that I also talked about, but leave two ends free (you need that to form the electric circuit). The larger the number of turns in the loop, the more electricity you can generate for the same amount of rotation. Kind of like an electric pulley system, to use a bad analogy.

Take your loop, and connect it to your energy source. You need to be able to rotate the loop end-over-end, without twisting the two connecting wires about each other, because if they do, you’ll get a short circuit, and boom, it’s done. One way to successfully accomplish this is to connect one wire to the rotating axle and the other wire to a conducting “brush” that maintains contact with a second conductor.

Make sure that you’ve sufficiently supported the loop so that it’s out of the way of any moving parts of the energy source (such as your legs and the pedals if you pay a seven year old to ride a bicycle that never goes anywhere – give them one of those hand-held video games, they’ll never notice). To make sure that you get this right, you may need to reinforce your loop with plastic or another light (but sturdy) material.

Grab some magnets (permanent magnets), and arrange them around the loop so that the loop can rotate freely between them. Take care to ensure that you arrange the magnets to maximize the field strength. One good and simple method is to make the south end of one magnet face the north end of another.

Stick the two conductors on your energy source to a battery, circuit, chainsaw, whatever it is that you want to drive. Again, you need to keep your wires separate to avoid a short circuit, so you’ll need to use some kind of brush mechanism again, or whatever more clever thing that you can come up with that I haven’t considered.

Poke the kid and get him to start peddling, or release your turbine to the wind, whatever you want. The amount of energy that you get from your turbine will depend on the efficiency of its construction, materials used, and how much mechanical energy us put in to drive it and spin the turbine itself (a faster peddling kid will give you more electricity than a slower one).

Run with it. A home-built turbine is unlikely to provide your house with any really useful power, unless you’ve really taken some time, money, and thought into it (which is possible). But you might run some simple things from your standard knock-off generator, such as perhaps basement lighting, that kind of thing.

admin answers:

You will not be able to manufacture solar power cells in your own home.

See this link for solar cells.

Http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGLR_enGB241GB243&q=solar+cells

That is like trying to manufacture a CPU in your own home, you cannot make the semi conductors.
You need a clean factory and millions of pounds worth of equipment for that.

See this link for do it yourself wind turbine.

Http://www.scoraigwind.com/axialplans/index.htm

and this might help

http://www.google.com/search?sourceid=navclient&aq=t&ie=UTF-8&rlz=1T4GGLR_enGB241GB243&q=wind+generatore%2e

admin answers:

I still think that people are so ignorant when it comes to electric
cars they only think of one way to make them run and that’s batteries.
Its like you lost your mind and have no innovated ability to think of
more than one source of power. Every year people spend millions of
dollars to go to the gym they hop on bikes and treadmills and
ellipticals and pedal away for hours and then pay their gym for it.
Then they hop in their car and pay gas to ride home. The answer was
right in front of your face when you watched the Flintstones as a kid.
Do remember the car on the Flintstones. Hmm, not so stupid now is it?
Do remember how boats got across the ocean? Have you ever held your
hand outside the window and felt the power of the wind resistance
against your hand? The faster you went the more force you felt
pushing against your hand right. Have you noticed that the quality of
solar powered panel technology has increased tremendously in the last
twenty years. The quality of of generators and electric engines is
also there. Our government has manged to keep all of this from you
because they believe you are all ignorant and set in your ways. They
could make cars that run with out wheels but our government would
never allow it to be mass produced. If you had the means to build a
car that had electric generators that produced electricity via wind
power, Human power “recumbent bike pedals”, Solar power and maybe some
lithium batteries you would have a car that would go thousands of
miles without ever needing to be charged or fueled.
But will this ever be allowed. Its amazing that china and japan have
magnetic trains that never touch the track they actually float be we
never use that technology. Its no wonder they do not put any emphasis
on science. They want us to remain ignorant and in the dark. They want
you to keep forking all the billions of dollars in tax revenue. They
want the price of fuel to sky rocket because most of them own the
stock. The only way to overcome the greed is to take matters into our
own hands and break the grip of Fuel mongrels from ourselves by building
our own fuel free cars. I just showed you the way. Now all you have
to do is ” Just Do It!”
My method overcomes the perpetual energy law crap because you get extra energy, Via Human power and solar power! The sun is the source of unlimited free power and so what if you have to pedal your car for it to go long distances. I just saved you from getting fat as hell.
Source(s):
My brain!

admin answers:

I work primarily on Boeing products, so my answer is from that perspective.

Short answer: GTCP331

Commercial aircraft use an Auxiliary Power Unit (APU) that provides electrical power and pneumatic pressure. The electrical power can then be used to run the electrical pumps (ACMPs)to pressurize the hydraulic system.

There are also Ram Air Turbines (RATs) that deploy directly into the air stream. This “RAT” looks like a trolling motor you would see on a boat, the wind spins the propellers and generates hydraulic pressure. If you have pneumatics, you can use the Air Driven Pump (ADP) to get hydraulic pressure. If you have hydraulics, but no electric, you can use the Hydraulic Motor Generator (HMG) to get electrical power.

There are backup systems all over aircraft these days. Most of which are activated automatically in the event of a failure of another system. The crew may only get an annunciator light to inform them that a backup system has been activated. No further action necessary.

admin answers:

A wind turbine is basically an electric turbine on top of a stand and with blades attached.

I would recommend you salvage a motor from a small electrical device. If you can find a small fan, then you only need to put it on a stand of some sort to make a wind turbine because it all ready has a turbine and blades.

An electric generator is just an electric motor in reverse. So any device that has an electric motor can potentially be used to make a turbine.

admin answers:

It depends on a number of factors, including average wind speed for your area, and the turbine design.
Fill in your parameters here: http://www.reuk.co.uk/Calculate-kWh-Generated-by-Wind-Turbine.htm and it will give you an energy rating in kW-hr

admin answers:

The US motor industry has not been interested in quality since about 1935. They have been interested in the appearance of quality to promote sales.

Flint tools, the bow and arrow, the spear and the spear thrower, baskets, pottery, agriculture, domestication of animals, the needle and thread, the plough, bronze, glass windows, the magnetic compass, chimneys, the horse collar and the stirrup, the wheelbarrow, drilling for natural gas, paper money, two, three and four wheeled vehicles, the water and wind mill, steel, the steam engine, the steam road vehicle, the steam boat, virtually all musical instruments, electric telegraphy, iron ships, the kerosene lamp, the light bulb, the electric motor and generator, gasoline engines, the motor car, the motorcycle and the bicycle, mass production, photography, wireless telegraphy, aspirin, heroin, the steam turbine, the pressure lamp, the mantel lamp, multi-engined aircraft, radar, the digital computer, the flame ionisation detector, the atomic absorption spectrophotometer and the cavity magnetron are an insignificant fraction of significant inventions that were not invented in the USA.

The USA from 1776 to about 1940 copied and technology from all round the world. Apart from some (not all) of the inventions by T. A Edison, and the inventions of A G Bell, de Forest, Edwin H Armstrong and a very few others the USA invented little of significance until about 1940.

admin answers:

* Americas Wind Energy Corporation (AWNE.OB) manufacturing and marketing of medium sized (500 – 1,000 megawatt (MW)) wind turbines for the North American market.
* Babcock & Brown Wind Partners (BBWPF.PK) An Australian based specialized investment fund focused on the wind energy generation sector
* Gamesa Corp. (GCTAF.PK) 18% of the world’s share of the wind turbine market. Based in Spain.
* Kore Holdings (KORH.PK) A power provider and marketer of alternative energy from wind farms, hydro and distributed power facilities.
* McKenzie Bay International Ltd. (MKBY.OB) Develops wind powered alternative energy systems.
* Mass Megawatts Wind Power Inc. (MMGW.OB) Develops prototype wind energy production equipment.
* NaiKun Wind Energy Group Inc. (NKW.V TSX Venture Exchange) Wind energy developer in the Haida Energy Field off the coast of British Columbia since 2001.
* Scottish Power plc (SPI) A leading developer and operator of renewable energy in both the UK and the US. It is one of the largest providers of wind energy in the US.
* Shear Wind Inc. (SWX.V Canadian Venture Exchange )Provider of wind-generated energy in Atlantic Canada.
* Sea Breeze Power Corp. (SBX.V Canadian Venture Exchange ) Developer of large-scale windfarms and underwater electricity transmission lines in British Columbia.
* Tower Tech Holdings Inc. (TWRT.OB) Involved in the engineering, manufacture, and sale of wind turbine extension towers and monopiles to the wind energy industry
* Vector Wind Energy Inc. (VWE.V Canadian Venture Exchange ) developer of wind energy projects in Canada.
* Vestas Wind Systems (VWSYF.PK) 34% of the world’s share of the wind turbine market. Based in Denmark.
* U.S. Wind Farming (USWF.PK) The federal court in Chicago entered a Final Judgment as to U.S. Wind Farming on October 20, 2006.
* Western Wind Energy (WNDEF.PK) Produces clean renewable electrical energy from over 500 wind turbine generators located in Tehachapi and San Gorgonio Pass (Palm Springs), California.

Here is an etf, exchange traded fund, PBW which invests in ALL of the following:
Here are the constituents of the WilderHill Clean Energy Index, with a brief description of each company, as of April 1st 2006. The index is the basis for the PowerShares WilderHill Clean Energy Portfolio ETF (PBW).

Renewable Energy Harvesting – 27% sector weight (10 stocks @2.7% each)

Distributed Energy, (DESC). Part solar, wind; mainly in DG, some H2: an integrator.
Emcore, (EMKR). Solar, 27% ultra-efficient PV cells, also makes LED products.
Evergreen (ESLR). Unique string-ribbon solar PV with efficient silicon-use.
Kyocera, (KYO). Solar PV, integrated manufacturer is doubling production.
MEMC, (WFR). Producer of the polysilicon needed in many crystalline solar PV cells.
Ormat, (ORA). Geothermal, works as well in recovered energy, biofuels.
SunPower, (SPWR). Solar, Efficient PV panels with all-rear-contact cells.
Cypress, (CY). (Parent firm of SPWR above, and owns the major block of their stock).
SunTech Power, (STP). Solar, fast-growing and major producer of PV is based in China.
Zoltek, (ZOLT). Wind, makes carbon fiber for wind blades and product ‘lightening’.

Power Delivery and Conservation – 26% sector weight (10 stocks @2.6% each)

American Superconductor, (AMSC). Superconductors, ‘no’-resistance 2G HTS wire.
American Power Conversion, (APCC). UPS, makes firm-power systems.
Cree, (CREE). LEDs, makes efficient lights, power-saving electronics.
Echelon, (ELON). Networking, for management of whole energy systems.
International Rectifier, (IRF). Efficiency-enabling electronics producer.
Itron, (ITRI). Monitoring, designs energy measurement and management systems.
Magnetek, (MAG). Makes solar inverters, wind power converters, power controllers.
Power Integration, (POWI). Energy savings, enables power conservation in IC chips.
SuperPower / Intermagnetics, (IMGC). Superconductors, and power transmission.
UQM Technologies, (UQM). Hybrid vehicle electrics; motor & power systems.

Energy Conversion – 18% sector weight (7 stocks @2.57% each)

Ballard Power, (BLDP). Mid-size fuel cells, makes mainly PEM FCs.
Capstone Turbines, (CPST). Micro-turbines 30-60 kW, may be flexible-fueled.
FuelCell Energy, (FCEL). Large fuel cells as stationary high-temp. Flex-fuel MCFCs.
Hydrogenics, (HYGS). Fuel cells and testing gear, H2 electrolysis, regenerative FCs.
Medis, (MDTL). Micro fuel cells, designed for liquid-fuels and a unique electrolyte.
Mechanical Technology, (MKTY). Small fuel cells, may compete with Li-Ion batteries.
Plug Power, (PLUG). Mid-sized fuel cells for distributed generation, home power.

Energy Storage – 16% sector weight (6 stocks @2.66% each)

Active Power, (ACPW). Flywheel power storage, a firm power alternative to batteries.
Energy Conversion Devices, (ENER). Very diversified: in batteries, solar PV, also H2 FCs.
Impco, (IMCO). Gaseous fuels, a manufacturer and integrator for cleaner-fuel vehicles.
Maxwell, (MXWL). Ultracapacitors, a battery alternative such as for hybrid vehicles.
Quantum Fuel, (QTWW). Hydrogen gas storage systems for cleaner-fuel vehicles.
Ultralife Batteries, (ULBI). Batteries, advanced lithium ion, polymer rechargeable.

Cleaner Fuels – 9% sector weight (5 stocks @1.8% each)

Air Products & Chemicals, (APD). Hydrogen, a supplier of many industrial gases.
BOC Group, (BOX). Hydrogen, a supplier of many industrial gases.
MGP, (MGPI). Biofuels, ethanol and fuel alcohol.
Pacific Ethanol, (PEIX). Aims to be a leading biofuels producer for Western U.S.
Praxair, (PX). Hydrogen, a supplier of many industrial gases.

Greener Utilities – 4% sector weight (2 stocks @2.0% each)

Idacorp, (IDA). Hydroelectric, Utility, mainly hydro; also some fuel cell research.
PPM Energy / Scottish Power, (SPI). Wind, Utility, PPM is growing wind power.

Source: PowerShares WilderHill Clean Energy Portfolio home page.

admin answers:

I own and install smaller wind generators.

I assume this is a model?

A small, 360 or 540 can electric motor from any hobby shop will be a good size to use, and only a few dollars.

The same hobby shop if it is at all useful will have various pulleys and propellors that can be fixed to the shaft. If you mount a very large (say 14 or 16″) diameter coarse pitch (8″ or more would be good) prop the motor will not require a lot of air flow in order to over come the ‘camming’ effect of a permanent magnet motor and start to turn it, it won’t go fast but if you set a finer pitch prop on it it will take heaps of wind just to get it turning, or might not produce any useful power at all.

The problem with the standard air screw is that it will have to be used backwards, but if you only have a few days left you can’t be choosy.

If you get a piece of wood about 14″ long, about 2″ x 2″ you could screw it standing up vertically to a large piece of ply, and having cut a 1/2″ groove across the top 2×2 face you can secure the motor to this by putting a nail or screw each side down about an inch and stretching a few ruber band across the motor, as many as needed – it will be rock solid if done right.

Then you can solder or plug on the two wires to the terminals of the motor and lead them to your multimeter and load (bulb, little motor whatever) and go and find some wind.

If the point of the project is to make a wind generator, i.e. Blow wind then the same thing will work, just apply a small current (say 6v one or two amps) to the motor and off it will go. You would be better off in that case by fitting a smaller prop, say 7×4 and see how that goes – it will rev so watch your fingers.

Again the hobby shop should have all you need.

Just type in wind generator to google and you will get about three years of info and reading. There is some really dodgy stuff out there – at the moment there are lots of scams from the look of it that even claim people are making 200 watt solar panels at home from scrap and a few dollars worth of stuff – yeah right………..

Good luck. 🙂

Start here:-http://www.otherpower.com/toymill.html
http://www.hydro.com.au/education/discovery/model/wtmodel.htm

admin answers:

Small places, like a remote house or an island, might have batteries. A large place, like a city, would be connected to a “Grid”, or electrical energy transmission system. If the wind stopped blowing, deep in the night, they would pull energy off the grid, from a nuclear plant, or coal-burning generation station, or hydroelectric project many miles away. A town on an island might have a large diesel generator.