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Hook a generator to the house Answered

What is needed to hook a generator up to the house and basicall only have to buy what energy the genrator does not create? I have a free fuel source from time to time and was wanting to take advantage of it.?


A Google search should get you decent information.

For example, under "home generators" the first page had this discussion which is a decent overview. The section on "transfer switch" discusses how a backup generator is wired in to avoid interfering with the utility mains.

What you're describing is similar to the way home solar or microhydro systems work -- they provide partial power while still receiving utility power. The power electronics needed to support that (and to prevent the local generator from feeding back onto the mains out of phase) is about US$1000, as I understand it. Search for "home solar" or "microhydroelectric" for more details.

What i have is a endless supply of yellow grease or waste kitchen oil and a small dieseal generator.

I am a plumber by trade but will haveto hire a electricain to wire everything , but was wondering if nothing else is therea kind of "check valve " so to speak that would allow me to tie in my generator to the house a nd use the grid for suppliment?

The utlity company here has a "power purchase" program , but they are primarely aimed at solar and wind , but will consider any renewable source on the application.

The challenge is that they either want engineered drawings for application(not happening) or a unit already installed to look at and review(much cheaper) if possible.

No matterwhat if icould make this work i would simply run the generator while at home duirng the heavy load days and should be able to successfully support teh majority of my electrcial needs off the grid and if accepted i would possibly be able to credit my acount enough to have a neautral power bill.

Sorry i shoudl have been more clear as to my needs earlier.


Yes, indeed! "Check valve" is a good description of the device. The technical term is a "utility interconnect" or a "grid-tie" inverter. Most home generator systems (solar, wind, microhydro) produce DC directly, so the grid-tie is a DC-to-AC inverter with power electronics to ensure that the output AC is in phase with the utility mains.

If your generator produces AC, you may need to do a bit more research (an electrician licensed and qualified to install home generator systems should be able to help) to find a grid-tie device without the inverter.

Thanks i figured there had to be a way to do it. I do plan on hiring a electrician to complete the task properly.

Note that grid-ties run a couple of thousand dollars (US), and this is not something you get to skimp on, as your utility company has final say (and a bigger pair of wire cutters than you do ;->). If your generator is enough to supply 100% of your power, you could go with the much cheaper transfer switch, and just stay off-grid.

In any event, very cool project!

You will need a diesel engine first. Second you will need to process the grease through filtering and a chemical process to make it usable as a fuel. The process to convert to a fuel will end up costing more than a dollar a gallon. Once you get all that accomplished, then you must have a method of assuring you do not send power INTO the grid during a power outage. This is because men are working on the electrical wires and your generator will BACKFEED into the transformers and re-energize them. The workers may touch a wire a mile from your house--- thinking it is de-activated-- but actually it has thousands of volts on it (because of your generator). This would kill or injure the workman. That is why they want to inspect your setup and get engineering drawings. I suggest you forget sending the electricity into the mains unless you can really do it right. Consider using the electricity for your own use... and the waste heat to heat your house. That would be accomplishing quite a bit.

Well i disagree with the processing. I currently filter the devil out of the grease i have a nd insure it is heated to around 145 degrees to become close to the same viscosity as diesel . This works well so far .

I do agree however about insuring the proepr equipment is used to disconnect from the grid. That is very dnagerous and i know i have read folks getting arrested for it more than once.

Just FYI: There are commercial products which use a natural-gas powered engine both to run a generator (selling excess power back to the grid) and to provide heat for the house (taking advantage of the engine's waste heat). VERY efficient, though in northern climates they may need to be supplemented by another small heater during the winter. I was seriously tempted to install one, but at the time I was replacing my system they were available only for forced-hot-air systems, and I wanted to keep my existing hot-water loops.

What's your fuel and hw much cash do you hae to spend?