What is the best way to feed back into the grid?

[Weldrite]

I'm fairly new at all this but I'm starting to think about feeding power back into the grid.  I don't want to make money or really save money, but if I can make it myself I would be that much happier. 

I would like to use my garden tractor to power the whole setup. It's running a 8hp diesel engine which comes out to about a 12hp gas motor.  I would have the generator set up to run off the extra pulley on the tractors crank like a old school belt drive set up.

My question is how should I make the power?  Generate AC? DC then trough a inverter to AC so it is more consistent?  The generator will be tied to the grid do I need to worry about fluctuations?  What is my best plan of attack?

I know it's a lot of questions but it' something I would love to learn more about. 

Thanks for the help.

[sawguy21]

What is your reasoning to feed the grid? If you are planning to feed your incoming line it will only go as far as the transformer on the pole. Don't do this without consulting with the utility company, they get real cranky if a lineman gets zapped while working on a line that is supposed to be dead in a power outage. If you want to supply the neighbors during an emergency, you will need a separate line that ties into a manual transfer switch in their house. Your tractor drive generator would have very limited capacity.

[Bart May]

Feeding back into the Grid in not as easy as we are led to believe.
I've thought about this allot and ask my Engineering Friends in the power business.
I also hold a Degree Electrical Engineering.
 
While true Power companies are required and have meters that will run backward to take power from homeowners. At the end of the day feeding the Grid is like Solar Power. Not economically practical for the average home owner today. Your looking at an initial investment of around $50K. With replacement cost in about 5 to 10 years. 

Your exactly right in asking questions about the fluctuation. If you placed an 120V inverter to you power feed and your power feed is 125V guess which way power will flow?  Toward the inverter and probably smoke!

The inverter voltage will always have to be greater than the line voltage to run the meter back wards .If not there will have to be some circuitry that breaks the connected between the two. Also Very Important the inverter will have to be in Phase Synchronization with the line power.

All in all considering what we pay to the power companies it pretty dang handy utility. At a reasonable cost. 

The smartest thing we can do is cut your electric consumption as much as possible.
Like installing LED lights. I use a wood boiler to heat my hot water, I've even looked at Air Conditioners that could run off my wood boiler.

Save Your Generator for emergencies outage. It you ran it 7x24 it would last but a year or two and what would the gasoline cost Ya?. 

[Weldrite]

Thanks for the replies.  I'm well aware that it may not be cost affective but if I can source most of the parts for little to no  money over time I think it would be a fun project.

I know when tied to the grid you need some type of switch so if the grid looses power it would trip and disconnect the generator so you would not zap anyone doing a repair on the line.  Does anyone know what type of switch this is or what they are called?

The way I would address the cost of fuel is by running the engine off waste veggie oil and that I can get for free. But still are not sure what type of power I should be generating?

Thanks

[red oaks lumber]

generate ac ,i would skip wanting to feed the grid. time you pay for the transmission lines to the grid and the monthly meter fee it won't even be close to cost effective. maybe just powering your own needs might work. when its all said and done you will save what? $300/ year

[caver]

Your utility would have to allow net metering or you would have to go
guerrilla (look up "solar guerrilla"). You would need a unit to synchronize with the grid which may be built into the  inverter you also need unless you generate A/C.

[Weldrite]

I guess I should have stated that I am hooked to the grid right now.  My house is all electric, heat, well, hot water, and my bill can be upwards of $450 in the winter with the wood stove going.  The house is well insulated with one floor and no basement and about 1600 square feet with the heated garage.

We do run net metering and I would not have to go "guerrilla".  As long as you notify the electric co. and are inspected to be safe they have no problem with you feeding back in.

I'm just hitting a stumbling block as to what the individual components are that I need and what they are called?  I don't want to eliminate my bill (that would be nice) but just bring it down some and put the WVO to good use.

Thanks for the info.

[logwalker]

You are looking at an Intertie system. Look at something like this for a start.

http://www.affordable-solar.com/grid-tie-kits.htm

[Hilltop366]

The restaurant down the hill from me uses their used fryer oil in their furnace, just a different way to use the oil and still save $$.

I don't know anything about the process of burning the oil in the furnace but if you can gear up a hot water boiler to run off the fryer oil you could use it for heat and hot water and save a bundle, I know on my house with two adults and one child when I am running my wood boiler and turn off the electric water heater my power bill is $40 to $50 a month the small water heater alone adds $50 per month to the power bill. The reason I am suggesting this over a generator is a oil hot water boiler is made to run a lot for many years with very little trouble and low cost repairs compared to most generators. Also I'm not sure about the effiency rate of a diesel generator of turning the oil in to electricity then into heat but I am quite sure it can't come close to a well tuned boiler. I suppose that both could be used but you would reduce your usage on the generator by about 5-8 times so it should last much longer as well, just think how much cheaper a furnace oil burner and circulator pump is compared to a diesel engine. I got 6 oil burners in use on various buildings and spend an average of about $10 per year on repairs and $100 on a tuneup (most of the $100 is labour around $20 for parts). Now if the price of oil would stop going up I would all set!

Cheers and good luck on your project.

[Weldrite]

Logwalker and Hilltop thanks very much that was just the type of info/ideas I needed to continue/expand my plans.

Thanks

[James P.]

Hello before even doing much research on how to do it. You should ask your power supplier if you can. I had a 100kw generator and wasn't going to use its full capacity. I thought I might be able to sell my extra to them. I was told they don't buy electric made from fuel run generators. Its either solar, wind and water powered and that was that. Might not seem fair but thats what I was told.
I agree , if electric is used like a kitchen faucet. you shut it off when not in need and be mindful of it money trickling down the drain. Its a bargain compared to everything else.

[solidwoods]

Your electric company can tell you exactly what is required (be sitting down when they tell you).

If you feel you have lower than market rate surplus electric maybe look at sending it to another family use.  Or set it up to send to another person.
jim

[maple flats]

Check with your utility. They only buy solar and wind because there are laws requiring them to until a certain % of their power comes from alternative sources. They do not want it but must by law. I would be very surprised if they would buy or even accept your hook up feed. If they would you will need an intertie inverter that will put the power going out in perfect sinc with the grid. This equipment is not cheap and you would likely need an even cheaper source than used veg oil. Even if free it will cost you to either convert to bio diesel or even well filtered straight veg oil. I suggest you just do it for yourself. If your gen capacity was much larger and fuel was free it might be a go. The part about the law I speak of is NYS law but I think most areas have similar, I do not think it is fed law.

[Qweaver]

You would have to have enough free fuel to run your generator full time to make this practical.   Even then the noise and maintenance may not be what you'd like to live with.  I have a Lincoln weld and power 7500 watt generator that I use when we lose power and I'm really ready to turn it off when the power comes back on.  Plus it uses about 8 gallons a day.  Pretty expensive.

[Fla._Deadheader]

Simplest way is, use an Induction motor. Over speed it by 100 or so RPM's, and you feed CURRENT back through the meter. Perfect if you have a water turbine. There will be no need to match power Co. juice.  IF the power goes off, your system will automatically stop generating power, UNLESS you have built up magnetism in your windings.

  This is NOT legal, unless your power company says to do it. You MUST have a visible air gap disconnect, so there is ABSOLUTELY no chance to feed the grid.

  You asked for the best way to do this, BUT, it's a good way to use it in your house, if you make the proper connections, and NOT feed it back to the grid. It WILL cut your power consumption by a considerable amount, and it WILL equal the price you pay for KWH. 

[Nantahala Forest Products]

As stated in the previous post a grid-tie induction generator would be a good option. With a 8hp diesel engine you could probably use a 5hp induction motor connected to your diesel engine. IMOA your best option would be to gear setup so that your engine runs at peak fuel efficiency and over spins the induction motor about 100 rpm above its rpm rating.

I am assuming that since you want to grid-tie to your electrical company service you plan on selling the extra electricity produced back to them? If you are that is fine but you will need to contact them to see if they will allow it. Since you are using diesel to generate the extra electricity I think it will be at your utility companies discretion if they will let you. If you were using renewables investor owned utilities are mandated to buy back electricity from customers but I don't think cooperatives are required to.

If they will allow you to connect to their grid then they will come out and inspect your system this is primarily for safety concerns. For example if you are feeding the extra power you produce back into the grid and had a ice storm which knocked out the electricity. The utility company wouldn't want send out some poor person to be electrocuted with the power you might be feeding in to the grid. But, the great thing about the type of induction generator I am referring to is that it uses the grid's power to excite the generator. So, if the grid loses power the induction generator will also stop producing electricity.

When I checked Georgia Power's website they were paying 17 cents per kwh for green energy!
Best of luck to you and just Google grid-tie induction generator to learn more on this subject by the way these setups are less efficient usually around 70%. 

[Al_Smith]

First of all you have to have it in phase with the incoming power off the grid .It can be done with an induction motor which once synced is ran up above slip speed of the motor .At that point it becomes an induction generator . Keep in mind it takes syncrascopes ,a good governor on the prime mover and a good coupling to kick the engine in on time.Not cheap nor all that simple .

All well  and good but not so simple .Unless you had a huge and I mean huge generator with a gigantic diesel prime mover you cannot generate even your own power cheaper than the utility company let alone sell it for a profit .That little 12 HP diesel isn't enough to make a drop in the bucket .

When gas was 2 bucks a gallon I ran my little 5 KVA gasoline generator because we were without power for 4 days on account of the biggest ice storm in 50 years .I figured it was right at 30 cents  per KW /hour .Kinda self defeating  because the power company was 7.5 cents per .Kept the blower going on the wood stove ,water pump,TV and computor ,lights so it worked out .

[scsmith42]

First of all you have to have it in phase with the incoming power off the grid .It can be done with an induction motor which once synced is ran up above slip speed of the motor .At that point it becomes an induction generator . Keep in mind it takes syncrascopes ,a good governor on the prime mover and a good coupling to kick the engine in on time.Not cheap nor all that simple .

All well  and good but not so simple .Unless you had a huge and I mean huge generator with a gigantic diesel prime mover you cannot generate even your own power cheaper than the utility company let alone sell it for a profit .That little 12 HP diesel isn't enough to make a drop in the bucket .

When gas was 2 bucks a gallon I ran my little 5 KVA gasoline generator because we were without power for 4 days on account of the biggest ice storm in 50 years .I figured it was right at 30 cents  per KW /hour .Kinda self defeating  because the power company was 7.5 cents per .Kept the blower going on the wood stove ,water pump,TV and computor ,lights so it worked out .

+1.  Well stated Al.

[submarinesailor]

And above all else......You MUST have an IEEE rated automatic disconnect that the local company can talk to.  You do not want to be powering the line/grid while they are working on it. A good way to kill some linemen out there that you may not know is there.

For the life of me, I can't remember the IEEE standard number.  Scott do you recall it?

Bruce

[scsmith42]

And above all else......You MUST have an IEEE rated automatic disconnect that the local company can talk to.  You do not want to be powering the line/grid while they are working on it. A good way to kill some linemen out there that you may not know is there.

For the life of me, I can't remember the IEEE standard number.  Scott do you recall it?

Bruce

Automatic disconnects fall under ANSI/IEEE Standards C37.90.1 and 929-2000.