First post here, so go easy on me

Options
DDuffeeInc
DDuffeeInc Registered Users Posts: 12 ✭
in Solar Beginners Corner #1
Hello, this is my first post on this forum. I am an electrical contractor so the solar side of things really intrigues me. From what I can see now they have a solar setup that is grid tied through some type of inversion or power box. Such as SMA or Sonny Boy. Is this correct?

Also I am contemplating setting up a system on a building of ours for usage and the knowledge of how they install and work. We have a building that has a large roof with a 2-12 pitch. There is absolutely zero shade over the roof so the amount of sun would be maximum on the panels. From the looks of things we might have to slightly angle the panels to the South for peak usage but I still have to study on that. The building is a metal building with a metal roof. The amount of usable surface we could mount on is around 14,000 sq feet.

The utility bill on this place is $700 per month so we would want to install a large enough system that would make a sizeable dent in the bill. I am thinking $20,000 would be a start at looking at one. This would be before rebates of any type.

I have ordered a few books and plan on going about this slowly and hopefully get a correct install. The electrical end calculations we have covered, the panels, hardware and power box we will have to research and look over what our best options and calculations would be.

I have heard alot of people use the Kyocera 135W panels. Is this a good start? With a grid tied system can you add another power box and more panels later? I know with the grid system you have to have a box which prevents islanding. Also we plan on installing a Skystream 600 sometimes this mid year along with the PV system.

I have always felt of you do not know anything, ask. Input is really appreciated here. Also let me say I really like the dialogue, language and general attitude of this forum. Looks to me like the "egos" are kept in check and the attitudes are left "at the door". I plan on becoming a frequent visitor here and hope to gain useful knowledge about what I feel is a up and coming industry that has no way to go but up.

Thanks for you time...David
· Share on Twitter

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Options
    Re: First post here, so go easy on me

    Welcome David.

    The box you're asking after is a grid tie inverter. They all have the anti-islanding function built-in. You can look over a selection of them and some "sample" systems here: http://www.solar-electric.com/gridtiesolar.html

    It will give you some idea what you're in for. How large a system you can install is not as dependent on your roof space (which you apparently have plenty of) as on your existing electrical feed and utility requirements. I suggest you contact them first to see if they accommodate grid tie applications and what requirements they have. It would be a good first step.

    Kyocera makes fine panels, but it usually comes down to cost per Watt. Sometimes you get better deals buying whole pallets of panels like the Evergreen. Look over some of the selection here: http://www.solar-electric.com/hiposopa.html

    P.S.: You'll find the Skystream is a waste of money. Read this thread: http://forum.solar-electric.com/showthread.php?t=4981&highlight=skystream
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #3
    Options
    Re: First post here, so go easy on me

    We do have some sticky threads that show how to design and install a system:

    Illustration of 8 KW (DC) GT Solar PV System Install for Residence in Urban Area

    And a thread with a whole bunch of links and posts about solar and conservation:

    Working Thread for Solar Beginner Post/FAQ

    Regarding Grid Tied systems--They are getting pretty cost effective to install--on the order of cost of power (or even less) in California and other high power cost states...

    However, much of the $$$ of Grid Tied solar depends on your state and local power companies rules and regulations.

    For residential customers, it can be pretty straight forward--1 Year Net Metering--Basically you "sell" your power to the utility at retail during the day (perhaps flat rate or Time of Use) and buy it back at the same rate at night (or less, if you have time of use billing).

    However, for commercial customers, it can get a bunch more complex and, at times, even cost you more than not having solar...

    In many locations (at least in California), we have "reservation" charges which are based on the top 15 minutes of power usage (or power sales from solar) which accounts for ~1/2 of the electric bill. And the other 1/2 is kWH/Dollar pricing... So, it is possible with solar to send your peak/reservation charges higher and you get very low pay back with the actual kWH charges:

    A couple of News Articles...

    So--The basic power concept is pretty simple... Mount the solar panels on racks (ground or roof), connect the 200-600 VDC wiring to Grid Tied Inverters which take the DC power from the solar panels into inverters which take the maximum power available from the solar panels (Pmp=Vmp*Imp) and convert it into 240 / 208 single or three phase power...

    The inverters follow the AC wave form from the utility and push current into the AC lines (power factor = 1.0). If the AC utility power fails, there is now voltage (or correct frequency) and the GT inverter shuts down for safety.

    The AC power generated is simply shared with the utility power... If you have more loads than solar power, the utility will supply some of the energy. If the solar power is greater than the load, the power will be pushed out to the utility for use elsewhere in the local grid.

    For all the world, the Utility grid looks like a giant AC battery and the GT inverter is simply "recharging" the grid (pretty much like a car alternator/electrical/battery system).

    The solar power can turn the utility power meter backwards, or the utility may meter you separately (there are several different methods that depend on the exact tariff rules for your installation).

    So, while it will be very interesting for you to learn about the hardware/wiring requirements--You also need to learn about your local regulatory environment so that you have happy customers.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter

Categories