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Hobbyist Renewable Energy?
vossman77 writes "I was looking into renewable energy from a hobbyist perspective, maybe generating a few watts of solar or wind power, just to reduce my electric bill. But upon further review, I found out that I need a special grid-tied AC inverter that shuts off when the grid turns off (for worker safety reasons) and makes the current in-phase with the grid. These two additional features, over the cheap inverters sold at department store, make the cost upwards of $2000, but support more watts than I need. While this is fine for large-scale projects, it is out of range for a small scale hobbyist. A Google search came with some home-brew hacks at best. So, are there any Slashdotters out there doing small-scale renewable energy projects with grid-tied systems? What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?"
which is totally what she said
You can try converting parts of your house to 12 or 24 volt, which would negate the need for expensive inverters and whatnot. All you'd need is a simple charging circuit for a battery (could be as simple as a diode) and then feed the 12/24 volt lights straight off it.
Feed the need: Digitaladdiction.net
If your house isn't worth $2000 then go a head jury rig something (that would probably cause your house to burn down and void your insurance to boot). Else stop screwing around, pay the $2000 and get the parts you need to do this sort of work.
Electricity is a dangerous thing, jury rigging solutions is not an option when your safety is at risk. The device is $2000 because it must pass safety, UL, and a whole host of standards so it doesn't you know kill you or blow up the local transformer when somthing goes wrong.
I imagine anything you want to hook up to the grid will need to be regulated, approved and expensive. So, the alternative is a power source large enough for a single task, like running your computer, and a hefty UPS to carry you through shady spots. Plus an automatic switch over to grid power for when your batteries run down.
If going green was cheap, fossil fuels would die out on their own without incentives and subsidies.
I would also think long and hard about criminal liability for the death or injury to utility workers who get killed because his system was backfeeding the power grid.
Those transformers on the poles work just as well when operated backwards, stepping the 120V output from your inverter up to the 7-13 kV distribution level. Unless your inverter has enough "smarts" to isolate itself from the grid in the absence of utility power, your system will attempt to power up your part of the utility network, resulting in a severely overloaded inverter (with resultant blown fuses/smoke/fire) at the best, or a serious hazard to lineworkers at the worst.
People HAVE been sued when lineworkers are killed/injured by improperly installed generators or PV systems that resulted in backfeed. Prosecution for criminally negligent homicide is also a possibility, especially if the prosecution can prove that you KNEW of the need for automatic isolation, but failed to provide it in order to save a buck.
In short, use properly designed equipment, installed according to manufacturer's instructions (and get the proper permits/inspections as required), or stick with a completely isolated low voltage DC system.
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How many city electric workers are going to agree to touch your electricity when they see some homebrew box rigged up to your breaker? I'm guessing that whatever you attach to your city's power grid has to be approved and licensed, and has to meet local electric code requirements. That probably kills most homebrew solutions.
if it doesn't seem so hard to you, then post some actual answers other than claiming it's not worth your intellectual super power
I got the impression that the author was looking more for alternative ways to use the power than "homebrew grid tie-in". For example, I used to run the vent fan on my greenhouse based on solar power. When the sun went down or when it was cloudy (i.e., when you didn't want the fan running), it'd stop. I'd imagine something like that would be nice for an attic fan setup, too.
Think of things in your house that you really don't need to run on grid power -- nonessential items. Perhaps, since this is just for a hobby, you could create a single dedicated socket that you don't use all the time that provides your renewable power to household devices. Your power could be fed into a battery, which would then be fed into a cheap store inverter. You'd want it to be on a switch so that your inverter doesn't run nonstop and drain your batteries, of course. You would, of course, have to have a battery back for such a solution.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
> Because, let's be clear here: we're talking about generating lethal
> amounts of power and driving it into wiring that goes into other
> people's houses and into systems that other people are maintaining.
This is the key part. I'm as Libertarian as they come but a power grid implies a need for some sort of standards and real enforcement of same. Forget the legal implications for a minute, do YOU want to kill your lineman? Then don't conduct unannounced experiments on the production power network. Ya got three choices here:
1. Man up and buy the commerical, TESTED AND CERTIFIED product for that key interconnection point.
2. Build a test grid, do your R&D and produce a TESTED AND CERTIFIED product of your own.
3. Restrict your alternative power experiments to those that do not require an interconnect to the grid.
Democrat delenda est
More seriously, you can collect wind and use the power for things in your garage or shop. Maybe switch one common light circuit in your house. Forget the grid tie until you are ready for the red tape that goes with it. I will be at the Make Fair in San Mateo this weekend with my Savonius Windmill and its power generating / inverter setup. I currently charge two Golf Cart batteries which have 120 Amp hours and use the power for my shop light, shop vac, and garage door opener when there is a black out. I will be wiring my family room with a transfer switch to use the power next. This room is generally two CFL bulbs and the 42" TV.
This is exactly why you want to buy a real isolating inverter and not try to make your own.
If the failure is isolated to your circuit from the power company (like if the transformer at your pole fails), then your circuit would never detect that the grid power went down if your home power system is producing enough power to feed the grid -- since your home system is tied directly to the grid, it would also be powering your 24AC transformer so would never see the grid side go down.
So, when the lineman goes to fix your transformer, he's dealing with a live circuit from your house.
Real isolation inverters look at the waveform and frequency to determine if the grid is offline.
Use solar energy to heat some form of heat store (anything from a lump of rock to a phase change material) that will heat your house overnight.
Be creative, but stay off the grid unless you have a UL approved connection!