Grid-Tie Power Systems

The terms grid-tie, grid connected, grid intertied, and net metering all loosely refer to a power generating system (solar, wind, hydro-electric, or other) that is somehow connected to the electrical power distribution network ("the grid") in a way that allows the system to feed electricity into the grid. This is a long-winded explanation for "spin your meter backwards", which seems to be a common, and often misleading, phrase these days.

There are good reasons for owning a grid-tie system for your home or business, but except in rare cases, economy isn't one of them. Don't even consider grid-tie if your main objective is to save money on your power bill. Tax incentives can make a major impact on the installed cost of your system, but it could take years to pay back your initial equipment investment. That situation may change if electricity costs rise dramatically or solar costs drop, but for now, grid-tie systems have to be seen as a long-term investment before you get a return. To lower your power bill, it is much more cost-effective to save or conserve energy by upgrading doors, windows, insulation. Buy energy-efficient appliances and lighting, and make an effort to waste less power. Buy a Kill-a-Watt Meter for just $38 to find out exactly how much energy your appliances use.

What about the good reasons? If you are in an area where grid power is present but unreliable, a grid-assist with battery backup system might be a smart choice. This system typically has a modest-sized array that stores electricity in batteries for daily use. The solar array normally powers the system through battery storage, and the grid is used to supplement the solar array during cloudy days or during heavy electrical demand. Electrical power is always available without interruption for computers, refrigeration, lighting, etc. This type of setup is primarily an off-grid solar system that makes use of the grid as a backup power source. Some of these systems can also be connected with a diesel generator, to handle larger loads during long-term grid outages. Solar panels + inverter + charge controller + batteries = working system.

Another choice would be for emergency, standby, or backup power. This system differs from the one just mentioned because it does not use a solar array or any other energy collection source. It simply consists of batteries and power inverter. The grid keeps the batteries charged. When the grid goes down, the inverter is instantly activated and your home is running on battery power without interruption. This system can be designed to carry you through short to moderate outages if your power usage is conservative. The main distinction to this system is that it does not produce energy in any way, and it is the least expensive type of system. Batteries + inverter = working system.

Probably the best reason to own a grid-tie system is because it eases the load on the power grid and reduces our national consumption of finite energy sources. By producing your own clean electricity you are doing a good thing for our planet and mankind. There is much talk about a "smart grid" where all of the grid-tie systems in the USA would be monitored through the internet, giving utilities better control of their energy resources. Some of that technology is available today, though widespread implementation of smart grid is still in the future. But it is very important to know that most grid-tie systems stop working when the grid is down. That means during a power outage, your home will be without power of any kind and your solar panels will be useless until the grid is energized again. I find this to be a peculiar irony. The primary advantage to a straight grid-tie system is it's simplicity: solar panels + grid-tie inverter = working system.

Important note: Although I sell the components to construct grid-tie systems, it is not my specialty. In most states, connecting your power system to the grid requires approval from your utility, permits, and an electrician licensed in your state. There may be other requirements. This makes the project generally less "handyman friendly", and it would probably be wise to employ an experienced local electrician to do the installation for you.

Another possibility would be to use a modular system like Enphase for your grid-tie array. Enphase uses one micro inverter for each solar panel, making the entire installation very easy and eliminating the need for potentially dangerous, high-voltage DC circuits. A homeowner can successfully install an Enphase system, needing an electrician only for the final grid connection. Enphase also provides a convenient way to get a ballpark idea of grid-tie costs. A single solar panel and inverter is rated to provide 26 killowatt/hours of electricity per month, at $1200 cost. Look at your monthly electric bill and check your killowatt/hour consumption for that month. Divide that number by 26 to find out how many panels it will take to make the same amount of power you bought from the electric company for that month.

On this page I list a small sample of grid-tie equipment for comparison purposes. Many more items are available... please inquire if you don't see what you want. I even have solar roofing products! I will attempt to match or beat prices on genuine quotes from other dealers.

Enphase is a great way to begin your grid-interactive system. There is a separate micro-inverter for each solar panel. I offer a modular package that includes one 175 watt Sharp solar module, one Enphase micro inverter, Unirac roof mounting system and hardware, and the Enphase branch circuit install kit. One branch circuit kit will support up to 15 inverter/solar panel pairs. This single-panel system will provide up to 26 killowatt/hours of power under standard operating conditions (your conditions may vary). Since the system is modular, more solar panel/inverter pairs can be added easily to increase output. If you want to start with a large array, let me quote a complete system price for you, with shipping costs included. This is about as simple as solar can get! The Envoy communications gateway is easily installed to connect your system with the internet so you can monitor your energy production from any internet-connected computer. Envoy comes with a one-year subscription to the Enlighten website, which is required for viewing data.

Enphase website informational videos are HERE
ENPHASE GRID-TIE KIT includes:

1 Sharp NE-175U1 175 watt solar module
1 Enphase Micro Inverter 240 VAC for MC3 cables
1 Enphase Install Kit, AC Branch Circuit 240
1 UniRac 96" Solar Mount Rail (1)
4 UniRac 310068, Serrated L feet, Single
4 UniRac 320173 "D" End Clamp (1) Bronze
1 Lay-in Ground Lug with Stainless Screw (1)

ENPHASE KIT ..... $1200
ADDITIONAL ENPHASE INVERTERS ..... $200
ENVOY COMMUNICATION GATEWAY ..... $365
6' AC EXTENSION CABLE ..... $65
12' AC EXTENSION CABLE ..... $95
ADDITIONAL SHARP 175 WATT PANEL ..... $679

Other Enphase packages are available, so call for more information!

Other grid-tie systems generally combine the output of a large array of solar panels and sends that power to a special, centrally located inverter that manages the job of supplying electricity to your home and selling the surplus to the utility company. This usually requires working with very high voltage DC power, and this installation is often best left to the professional. The following systems are of the large array/single inverter type:

Select Grid Tie Systems These complete grid tie solar power systems include the highly efficient Kyocera KD210 solar panels and Solectria inverters. Each system includes required wiring, combiner box and breakers (if needed) and with or without IronRidge Solar Mount rail mounting system for rooftop installation. Inverters include UL Listed DC and AC disconnects. Ask your inspector is these are acceptable.
WSS Select Grid Tie System	Racks	DC Watts	Array Size PTC**	Price Per Watt	Monthly Output based on 5 hrs sun a day	# of Solar Panels	Inverter	Product Number	Price (April 2009)*
WSS Select 1470	Includes Racks	1,470	1,291	$5.50	up to 220.5kWh	7 Kyocera KD210	1 Solectria PVI1800	1214700	$8,001
WSS Select 1470	No Racks	1,470	1,291	$5.25	up to 220.5kWh	7 Kyocera KD210	1 Solectria PVI1800	1214701	$7,606
WSS Select 1680	Includes Racks	1,680	1,476	$5.34	up to 252kWh	8 Kyocera KD210	1 Solectria PVI1800	1216800	$8,830
WSS Select 1680	No Racks	1,680	1,476	$5.09	up to 252kWh	8 Kyocera KD210	1 Solectria PVI1800	1216801	$8,401
WSS Select 1890	Includes Racks	1,890	1,660	$5.21	up to 283.5kWh	9 Kyocera KD210	1 Solectria PVI1800	1217900	$9,670
WSS Select 1890	No Racks	1,890	1,660	$4.98	up to 283.5kWh	9 Kyocera KD210	1 Solectria PVI1800	1217901	$9,214
WSS Select 2100	Includes Racks	2,100	1,845	$5.13	up to 315kWh	10 Kyocera KD210	1 Solectria PVI1800	1221000	$10,568
WSS Select 2100	No Racks	2,100	1,845	$4.88	up to 315kWh	10 Kyocera KD210	1 Solectria PVI1800	1221001	$10,017
WSS Select 2520	Includes Racks	2,520	2,214	$5.02	up to 378kWh	12 Kyocera KD210	1 Solectria PVI3000	1225200	$12,234
WSS Select 2520	No Racks	2,520	2,214	$4.70	up to 378kWh	12 Kyocera KD210	1 Solectria PVI3000	1225201	$11,385
WSS Select 2940	Includes Racks	2,940	2,583	$4.92	up to 441kWh	14 Kyocera KD210	1 Solectria PVI3000	1229400	$13,956
WSS Select 2940	No Racks	2,940	2,583	$4.67	up to 441kWh	14 Kyocera KD210	1 Solectria PVI3000	1229401	$13,190
WSS Select 3150	Includes Racks	3,150	2,768	$4.89	up to 472.5kWh	15 Kyocera KD210	1 Solectria PVI3000	1231500	$14,862
WSS Select 3150	No Racks	3,150	2,768	$4.62	up to 472.5kWh	15 Kyocera KD210	1 Solectria PVI3000	1231501	$13,993
WSS Select 4620	Includes Racks	4,620	4,059	$4.88	up to 693kWh	22 Kyocera KD210	1 Solectria PVI5000	1246200	$21,731
WSS Select 4620	No Racks	4,620	4,059	$4.64	up to 693kWh	22 Kyocera KD210	1 Solectria PVI5000	1246201	$20,620
WSS Select 5040	Includes Racks	5,040	4,428	$4.84	up to 756kWh	24 Kyocera KD210	1 Solectria PVI5000	1250400	$23,533
WSS Select 5040	No Racks	5,040	4,428	$4.59	up to 756kWh	24 Kyocera KD210	1 Solectria PVI5000	1250401	$23,152
WSS Select 5460	Includes Racks	5,460	4,797	$4.75	up to 819kWh	26 Kyocera KD210	1 Solectria PVI5000	1254600	$24,990
WSS Select 5460	No Racks	5,460	4,797	$4.55	up to 819kWh	26 Kyocera KD210	1 Solectria PVI5000	1254601	$23,836
WSS Select 6300	Includes Racks	6,300	5,535	$4.92	up to 945kWh	30 Kyocera KD210	2 Solectria PVI3000	1263000	$29,952
WSS Select 6300	No Racks	6,300	5,535	$4.68	up to 945kWh	30 Kyocera KD210	2 Solectria PVI3000	1263001	$28,317
WSS Select 10080	Includes Racks	10,080	8,856	$4.82	up to 1,512kWh	48 Kyocera KD210	2 Solectria PVI5000	1210080	$46,808
WSS Select 10080	No Racks	10,080	8,856	$4.59	up to 1,512kWh	48 Kyocera KD210	2 Solectria PVI5000	1210081	$44,413
Please be aware that these prices may change rapidly. Call Voodoo Solar for current pricing *STC is Standard Test conditions or factory ratings. PTC is PV-USA Test Ratings which are closer to real world conditions. Your unique conditions will affect your system output.