Two things make the the low cost possible:
- The use of a low cost China import grid-tie inverter.
- The glut of low low cost PV modules on the market right now.
The inverter comes in at about $0.35 a peak watt, and PV modules can can had in the $1 per peak watt area (plus some expensive shipping). With some homemade mounts and a few odds and ends it will probably all come in under $2 per watt. The recent US average for commercially installed grid-tie systems in the US is $6.80 per watt (from Solar Today) -- so, this is a substantial saving.
|Ken's 500 watt PV system|
The only real fly in the ointment is that the inverter is not UL approved for grid-tied operation. But, it does have the anti-island feature, so it shuts down automatically if the utility grid goes down. This is basically a bootleg system.
Even though the system is simple, there is some know-how involved in putting it together correctly, but Ken's blog entry goes through all this.
|The Ningbo Sun 600G -- other sizes available.|
Of course, you won't get net-metering with this system, so if the system is producing more power than your house is using at a given time, you won't get credit for the power that goes out to the grid. But, with a small system like this, that won't happen very often.
So, if you want to save a few bucks on your electric bill and a half a ton of CO2 emissions, this offers a way to do it.
All the details on Ken's system on his blog...
Ken is, of course, aware of the bootleg nature of this system, and is interested in hearing what people think of the whole idea -- pro and con. Probably best to leave comments on Ken's blog to keep everything in one place.
There are some commercial systems in the works that may offer a way to buy these kind of plug and play systems down at the local Home Depot with all the approvals -- some listed here...
If the low budget and significant saving are appealing, but you are hesitant about the whole bootleg thing, bear in mind that there are a lot of small solar heating projects that come in well under $0.10 per peak watt :)