How can one grid tie a generator

[wantfreeenergy]

I am wanting to get a generator and modify it to the GEET setup. I would also like to be able to hook it up to my house and tie it into the grid so I can spin my meter backwards.

I don't know much but as much as I do know, one is able to do this with solar panels. I am also aware that if the power goes out from the elec co I need a way to stop supplying elec to the grid so the linesmen stay safe.

Is anyone doing this. Or can someone explain to me what is needed to shut off my mains supply when the elec co power goes out but keep my house running?

thanks

[dutchdivco]

How about,.....

calling up the utility company and ASKING them? I know they are "the enemy", at least to many people, but they are the experts, its their linesman you'll fry if you don't do it right, etc. If your paranoid use a payphone, and don't give em your name. Jim

[rickoff]

I am wanting to get a generator and modify it to the GEET setup. I would also like to be able to hook it up to my house and tie it into the grid so I can spin my meter backwards.

The best info that I have seen on this subject is in a booklet put out by Eagle Research, called Reverse Your Electric Meter Legally. It is well worth the $14 price. Basically, the method uses an induction motor (IM)as a generator to directly produce household usable power, and any excess power that you do not utilize will flow out to the grid, thus causing your meter to run backwards. Safety circuits are included in the book to stop supplying power to the grid when the circuit senses a grid outage. You can pick up a used induction motor quite inexpensively - perhaps even free, and the book will tell you where to look for one. Most induction motors get scrapped when the "start" windings burn out, but the "run" windings are all you need, and these seldom go bad. When you turn an induction motor with a drive belt that is driven by your engine, just a bit over the IM's rated rpm, it becomes an excellent generator, and delivers the voltage rated on its tag. The amount of amperage capability depends on the size of the IM. A four pole IM rated at 1800 rpm synchronous speed will usually develop its rated hp at about 1745 rpm, which is 55 rpm less than the rating. Here's the sweet stuff: To turn the same IM into a generator of the same hp rating, you only need to increase the rpm's to about 1855! That's just 55 rpm above the synchrounous rating, and a total rpm increase of just 3%. You don't need to spin it up any faster than that, and doing so would just cause the IM to heat up. You can run it continuously at 1855 rpm, as a generator, with no heat problem. And the output is so simple. You plug the IM into any receptacle in your house that has the same voltage and frequency rating, and that's it! Of course you'd leave it switched off until the IM is brought up to operating speed. The larger the IM that you can drive in this manner, the better it will be, of course. You can drive a 10 hp IM up to synchronus speed with just 1 hp from the shaft of a drive engine, so if you are using a 3 to 5 hp gas engine at well under full power, and using drive pulley ratios to triple the output speed at the IM, your gas engine will work nicely, and economically, at an idle speed of between 615 and 620 rpm. If you fuel your GEET equipped engine with waste oil and water, your energy cost will be just about nothing, and the electric company will end up paying you for power you create while you are sleeping.

Here's a link to the book that I mentioned above. I have had one for quite some time, and it is excellent - tells you everything you will need to know about the subject, and all the protective and switching circuits are included. Reverse Your Electric Meter, Legally! [4901.99.00.503] - $14.00 : Eagle-Research Store

Best regards to you,

Rick

[theremart]

Great advice Rick,

I would also recommend this Yahoo group.

wastewatts : Sustainable Technology Discussion Group

They have all kinds of methods of alternative energy put in practice. One of the moderators is off grid, and they know what it takes to get that way.

The laws are different for different states, so good to do your research BEFORE contacting the electric company.

Also I find it helps to talk to those who have already done it.

Peace

[jibbguy]

The large and expensive microprocessor-controlled "energy controller and management" systems used with large solar and wind arrays to sell-back power usually do it by first converting to DC, then inverting back to 60 Hz AC (or with higher-current systems, sometimes using a DC motor-to-alternator setup.. As i recall around 10KW there is a cost break in the efficiencies of inverter vs. motor/alternator).

This is because if your gen's cycles are not Phase- and Frequency- Locked to the grid, the power company won't pay you; and will force you off "their" grid. And of course many renewable methods of generating your own power such as wind or water-wheels have varying RPM's; which virtually require an output that must be first converted to DC than back to A 60 Hz / 230 VAC (or some other common multiple V RMS; usually 3-phase).

The problem with running an induction motor backwards as an AC gen above the RPM rating is that the frequency would increase above 60 Hz too... This is usually not a problem if it varies a bit for your house-hold use; but is a major stumbling block for selling-back power.

The power utility companies are only doing this because they are forced to by State laws. They don't like doing it (it costs them money, in more ways than one lol), and will use any quality-control excuse they can against you.

However, if you have a steady 60 Hz output already regulated at the desired voltage level, you can phase-lock to the grid fairly easily with a relatively small and low-cost device.

[Matthew Jones]

If all fails for sending current back to the grid you can purchase a A back up generator switch and use the grid for the backup. This is perfectly legal and will save you money right away.
People like Guardian and Kohler make "Whole house switch's" that sits between your meter and the input.

The thing about selling energy back to the grid is tricky. The laws vary from state to state, but not only does your generator have to be certified as a clean power producer but the manner in which you drive it will have to certified as well. They only have to buy GREEN energy by law. And depending on how thats worded in the law, it may only be from certian power sources, IE solar. wind, hydroelectric via running water or tidal movement.

If its a internal combustion engine the power company will / may says it can't be considered green energy because of the exhaust, clean or not. They will require you to get your fuel and exhuast tested. Depending on the local laws that might cost more than its worth. You might have to test regularly and have the abilty to report emisions on demand at anytime. Also maintian power lisenses and insurance.

But you can power your own home under most conditions with anything you like as long as it fits within certian emmision standards. Backup generator that run either on petroleum or natural gas all have well set standards for emmisions. They also might require onsite testing depending on the state.

Best of luck to ya.
Matt

[rickoff]

To clear up some common misconceptions:

The first common misconception regarding induction motors used as generators is that you must spin an induction motor (IM) backwards to generate electricity. In fact, you can generate electricity while rotating the motor forward or backwards, but it is generally a better idea to spin it up in the forward rotation that it was designed to operate in. An IM only becomes a generator when it is driven faster than it normally wants to go when used as a motor. At full load, when used as a motor, an IM rated for 1800 rpm synchronous speed will be operating around 1746 rpm. If you use an external device (such as a gas or steam engine or turbine) to spin the IM faster than 1746 rpm, the IM will use less and less Grid power. When the speed reaches 1800 rpm, the IM uses no power at all. Driving it above 1800 rpm, the IM begins to generate electric power, and at 1855 rpm it generates the full amount of power that it would ordinarily use from the Grid as a motor.

The second popular misconception is that it is difficult to maintain the frequency of a grid-tied IM at 60 Hz while using it as a generator. In fact, the IM will not act as a generator unless it receives an outside frequency signal. Plugged in to a household electrical receptacle, the IM receives its outside frequency signal from the 60 hz Grid power sine wave. When you overdrive the IM above synchronous speed, it begins to generate electricity, as noted in the previous paragraph above. As speed increases, voltage and amperage will rise, but the frequency will stay phase-locked to the Grid frequency. If you suddenly lose Grid power, or if you throw a switch to disconnect from the grid, you lose the 60 hz sine wave signal and the IM will quit generating electricity. Whatever caused the Grid to go down will also drain all the power from your generator.

A third popular misconception about using an IM as a generator is that it poses a danger to a lineman working to restore power after a power outage. As just stated, in the last sentence of the prior paragraph, the IM quits generating power when the Grid sine signal is lost. The only "problems" that you face during an outage are:
1. The IM generator continues to be driven while generating no electricity, so your drive engine would be wasting fuel.
2. If your drive engine runs out of fuel during an outage, or if you switch it off to save fuel, the IM will try to operate as a motor when the Grid power is restored. If the IM is equipped with capactive start, it will start and run just fine, but it will be consuming power from the Grid. If you are only using the "run" windings of a 4-pole IM (that's all you need for generating electricity) then you will probably fry the windings when power is restored.
These problems are easily solved by applying the use of simple and inexpensive circuits that you can build, and which are fully explained in the manual that I referenced in post #3 of this thread. The simplest solution of all, of course, is to manually throw a Grid disconnect switch when the power goes out, and then kill your drive engine. In this case, you would need to be at home to do this whenever a power interruption occurs. By using some simple circuits, as outlined in the manual, you can accomplish this automatically. And if you prefer to have your IM continuously generate power, even during an outage, this is also easily accomplished by using another simple circuit that will self-excite the IM with a 60 hz sine wave to keep it functioning while disconnected from the Grid during the power outage period. In that case, when Grid power is restored, your self-exciter circuitry would turn off and the IM would automatically reconnect to the Grid.

A fourth popular misconception is that it is difficult, illegal, or expensive to tie to the electrical Grid. If you "hard wire" your generator to your household electrical circuitry then you will come under local and state electrical codes, which must be obeyed. There is, however, nothing difficult, illegal, or expensive, about plugging an IM into a household receptacle, or in overdriving the IM to generate electricity. A typical household already has several IM's plugged into receptacles, and are used to run fans or appliances. Any one of these IM's, or a separate IM, can be overdriven to generate power, and any power that is generated can immediately be used by you to reduce power drawn from the Grid, and to reduce your electric bill. During times when little or none of the generated power is being used, your electric meter will actually begin to turn bacwards. If you monitor your meter readings, you can generate only enough power during a month so that your meter reading only moves ahead a relatively small amount, thus resulting in a monthly charge of only a few dollars. Here in Maine, there is a monthly minimum charge of about 10 to 12 dollars just for remaining connected to the Grid, even if your meter reading is unchanged, but that's still quite affordable for having Grid back-up available at all times. There can be days when your meter is actually reversed beyond the last reading recorded by the electric company, but that's okay - it's like banking power into the Grid which you can draw out and use another day. You simply monitor your power generation and usage to obtain the desired end results - a low meter reading at the end of each monthly usage period.

In the case where you want to actually generate enough power to be able to have the electric company pay you for the excess production, you would have to do a little more than mentioned above, but it doesn't have to be complicated. If you want the power company to purchase excess power that you generate, they will prefer that you have two one-way meters - one to meter incoming power, and the other to meter power sent to the grid. If you go that route, you will pay about 10 cents per kwh for incoming Grid power, and the power company will pay you about 2 cents per kwh for the excess power sent to the Grid. The 2 cents represents what the power company refers to as their "avoided cost." What most people don't realize, is that you don't have to go that route. US and Canadian law clearly states that if a customer is feeding less than 100 kwh to the Grid, the metering option is the choice of the customer, not the utility. The customer may elect to keep their single meter and arrange a contract of "net-billing." Under the net-billing choice, your meter continues to run both forward and backward, and the net-billing amount is the difference betwwen kwh used and kwh generated. If you use less power than you generate, the power company pays you their "avoided cost" rate of 2 cents per kwh for the excess. Now that's the same that they would pay you if two meters were used. The difference, though, is that net-metering and net-billing is more advantageous to the customer (and that's you). That's because you are able to bank excess power to the Grid, and then draw upon it at no price differential during each monthly period. A much better deal, and it's your legal right.
If you live in the USA, your rights are spelled out in Section 292 of the Public Utilities Regulatory Policy Act (PURPA) laws. Obviously, it is to your benefit to become familiar with those rights, because the electric company will not inform you of them.

Best wishes to all,

Rick

[jibbguy]

@Rickoff: Yes, i suppose i was skimming your earlier post.. me bad

I was of course referring to running it backwards as a gen "off-grid" and not over-driving it as a gen with the house mains synced (two separate entities as you well point out).

Came across this doc which down on page 8 shows the energy curve for over-driving; apparently according to this it must be kept close to the "118%" range for best efficiency:

http://www.freescale.com/files/product/doc/AN1930.pdf

________________

Here is in a very interesting and up-lifting application of the former (off-grid use) that i came across:

http://www.palangthai.org/docs/HKTmi...dro19Feb06.pdf

A village in Thailand is using a commercial centrifugal pump and induction motor backwards as a turbine-generator for communal power (1.5 kW up to 3 kW). I've got a friend in the mountains of W-VA who is going to do this soon (he has a beautiful stream running through his camp grounds properly with over 7 meters of fall over a 100 m distance; i hope to get some pics and results when he's completed it next Spring

[rickoff]

@Rickoff: I was of course referring to running it backwards as a gen "off-grid" and not over-driving it as a gen with the house mains synced (two separate entities as you well point out).

Okay, jibbguy, I see what you mean (or at least I think I do). By your use of the word, "backwards," you simply mean to refer to the IM generator as being in the opposite mode (generating electricity rather than using it). You didn't mean to imply that the IM generator was rotating backwards in relation to its normal rotation as a motor, right?

I only included the forward/backward explanation in my previous post so as to make it clear to readers that you don't have to spin an IM backwards, whether grid-tied or off-grid, to generate electricity. And no matter which direction you spin the IM, it will not generate electricity until driven past its rated synchronous speed.

Your WV friend would appear to be well situated for water driving an efficient water turbine to drive an IM generator. Not many people are fortunate enough to have such a resource in their back yard.

Best wishes to you,

Rick

[wantfreeenergy]

just use 2 IM's?

could one just use two IM's? If it only requires 1/2hp to spin a 5hp IM then could you just use a smaller IM to spin a larger one?

I also recall reading that an IM generator has a hard time starting another IM unless it's 1/10th the size of it.

So you could use a 3/4hp IM and spin a 5hp IM, but once the 5hp IM is generating could you just supply the 3/4hp IM with the 5hp IM's electricity? Essentially the 3/4hp will already be started and will require less electricity to keep it running?

just some ideas but has anyone else tried that

[sigzidfit]

Induction Motors as Generators and Grid Tie Info

Check out this link
Heat Engine Projects

Near the bottom of the page is some good practical information on this subject...including this link Induction Generator

Bottom line ... with the right capacitors, turning the motor at the right speed, makes good power.

Peace
PJ

[NZer]

Hydro

Hi rickoff,
Not sure if you still monitor this but I thought it would be worth a try to get some help on the subject.
I am in the process of setting up a grid tied induction motor run by a hydro turbine. I have a Irrigation dam with a maximum of 13 meters of head. I have calculated that on average 200 l/s can be maintained for 6 months a year. The problem i am faced with is getting the turbine RPM and subsequently the IM RPM constant as the lake level changes(only 3 meters or so as the lake area is large compared to the catchment area).

How does changes in IM RPM affect generation, how much variance can you have and how does this affect efficiency? Ive been told that as long as the IM i use has a larger rating than the theoretical power i can produce I wont be able to over rev it. I assume that with less flow due to a lower head the torque and therefore RPM would decrease......but only slightly as close to synchronous speed torque changes rapidly with a small change in RPM?


Any help would be much appreciated

[Jbignes5]

Yup and guess who did it first?

BEST AVAILABLE COP - Google Patent Search

This is the exact way that the power company does it rofl. Of course they do not want you to do this Because then they are only supplying the potential to your generator.

Tesla tried to show us that, as long as you have the potential or exciter signal all one needed to do was spin it faster on the converter or motor.

Replace the exciter in this patent and build the simple Generator that is in the upper right. Spin it faster then it is moving on it's own and you get both added together. Use a big enough version and walla plenty of power is available.

You need to follow this patent very closely and even the motors needs to be correct. If they are not then you won't get useful power to use. Just below the generator is the rotor of the generator to better show how they connected the pickup rings to the load circuit.

[kapierenundkopieren]

Hi guys! Here is a pdf that belongs in here and explains alot about how to generate power with asynchronous generators.

http://www.nbuv.gov.ua/e-journals/vn...8lpdhps_en.pdf

Hope it helps!

Does anyone know of an AC motor (generator) that would have permanent magnets in the rotor, so there is no need for excitation? Would that kind of generator produce more electric power than an induction generator? How much more, or what would be the main diferences?

Hope anyone will answer that...

Dann

[rickoff]

Hi rickoff,
Not sure if you still monitor this but I thought it would be worth a try to get some help on the subject.
I am in the process of setting up a grid tied induction motor run by a hydro turbine. I have a Irrigation dam with a maximum of 13 meters of head. I have calculated that on average 200 l/s can be maintained for 6 months a year. The problem i am faced with is getting the turbine RPM and subsequently the IM RPM constant as the lake level changes(only 3 meters or so as the lake area is large compared to the catchment area).

How does changes in IM RPM affect generation, how much variance can you have and how does this affect efficiency? Ive been told that as long as the IM i use has a larger rating than the theoretical power i can produce I wont be able to over rev it. I assume that with less flow due to a lower head the torque and therefore RPM would decrease......but only slightly as close to synchronous speed torque changes rapidly with a small change in RPM?


Any help would be much appreciated

Hi NZer,

First off, I'm not quite sure, when you refer to a head of 13 meters, if you are referring to gross head or net head. The water delivery conveyance, or "penstock," if constructed at an angle down to the turbine (which more often than not is the case), will have a gross head that is somewhat more than the actual effective net head, which must take into account any flow losses due to angles, bends, pipe couplings, conveyance size, friction, etc.

Secondly, even if you have a true net head of 13 meters (about 43 feet), I would consider that a marginally acceptable water drop height. I had always considered a net head of at least 50 feet as being a rule of thumb requirement when choosing a site for a turbine installation. Since you say that the lake level can drop 3 meters, you would at times be left with only a 10 meter maximum head, which is quite a difference and may not be sufficient. Of course flow rate is also important, and can sometimes make up for inadequate drop height. You say you have an average flow rate of 200 liters per second, which would be a very good rate if accurate. Let's place this into a formula for determining the available power output that might reasonably be expected:


Power(kW)= Net Head (m) x Flow (litres/second)/200

Power = 10 x 200 lps / 200
Power = 10kw

This formula implies an overall efficiency of 50%, which takes into account both the turbine and generator efficiencies. Your actual efficiency may be a bit higher, as this formula is designed for a conservative estimate. So if you can derive 10kw power during low lake levels, and 13kw at peak level, that should more than meet your needs for power generation. Of course this would also depend upon your turbine's capability to drive a 10 to 15 kw generator, and you havent mentioned your turbine or generator specs. In any case, the possibility certainly exists at your site to provide not only enough power for your own needs, but for neighboring properties as well, along with the capability to either directly sell excess power to your electric utility, or reverse your electric meter for savings on your utility bill.

As far as generator rpm speed controlling goes, if using an induction motor (IM) for power generation, it is very important to maintain the rpm at the desired overdriven rate, as dropping to or below the synchronous rated rpm will produce no power. For example, and as I mentioned in post #3 of this thread, a four pole IM rated at 1800 rpm synchronous speed will usually develop its rated hp at about 1745 rpm, which is 55 rpm less than the rating. To turn the same IM into a generator of the same hp rating, you only need to increase the rpm's to about 1855. That's just 55 rpm above the synchrounous rating, and a total rpm increase of just 3%. You don't need to spin it up any faster than that, and doing so would just cause the IM to heat up. Staying at the high end of that 3% variable, in other words, is very important. 1855 rpm would be ideal. Above that causes overheating of the IM, and below that you lose generating capacity to the point where, at 1800 rpm or below, no power is generated. Maintaining a tight rpm range of say 1850 to 1855 rpm may prove to be very difficult under changing conditions of flow rate and head. There are three methods I can think of quickly that you might consider for ensuring fairly constant generator speed:

1. You could utilize a braking sytem between the turbine and generator to act as a speed governor and prevent the generator from rising above 1855 rpm. Obviously though, while this would be effective in preventing overly high rpm, it would not help in maintaining rpm at a level above 1800. I do like the idea of an rpm activated brake, and/or IM cutoff switch to be employed to prevent the possibility of IM damage from overheating.
2. Think about installing a water flow control valve to either automatically or manually control the drive speed of the turbine, and thus the driven speed of the IM. A manual valve will of course require frequent monitoring.
3. Consider employing a ram pump at the lake outflow to pump water to a holding tank at a higher elevation. This improves the net head, and also provides for a more constant head and flow rate.

Hope that helps, and best wishes to you,

Rick