I need to understand the components I need to tie solar panels into an existing AC powered house.

Here is what I want to do.  I live in South Central Texas and the sun is plentiful.  I would like to build a solar panel based system with batteries that can tie into my existing AC breaker panel.  Getting my meter to run backwards would be great but I would settle for running this small house with solar power.  Do I need an inverter to go from my battery bank to the breaker box?

Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,699 ✭✭✭✭✭
    edited April 2016 #2

    What are your goals?

    If you are looking to save money, a hybrid system (batteries but selling back to the grid) will cost more than buying from the grid! Won't save you money but you will have power if the grid goes down.

    A grid tied system (no batteries just pushes the electric you make into the system) will likely be close to cost effective and might save you some money.

    If you want either you will need an inverter but of different types. Both will require talks with your power company.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • BB.BB. Super Moderators, Administrators Posts: 32,235 admin
    Reviewing your loads (and monthly power bills, getting some sort of energy monitor like a TED and/or Kill-a-Watt type units) and then working on "extreme conservation" is usually the first steps.

    Beware that we are nearing the end of the first "golden age" of Grid Tied solar power systems... More and more, the billing plans which subsidized residential power customers with GT Solar power systems are slowly "going away" (Nevada's new billing plan pretty much stopped all GT solar installations in the state at this time).

    Once you have done the understanding the details of your energy needs and conservation, then looking at GT or Off Grid solar (or Hybrid solar--GT+Battery backed solar) would be your next logical step.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mvasmvas Registered Users Posts: 384 ✭✭✭
  • Marc KurthMarc Kurth Solar Expert Posts: 899 ✭✭✭✭
    edited December 2016 #5
    As Photowhit already said - is important to clearly understand your goals because a battery based system won't make sense from a strictly financial perspective. In fact, even straight grid tied systems are often very hard to justify because power is so cheap here.

    I do not know where you are located, but here in Bastrop, TX: I pay $0.10/kwh including connection charge and taxes. Without some form of taxpayer/ratepayer funded subsidy, the numbers for PV just don't look good.

    Of course many systems go in for "grid down" planning, simply wanting to be more self sufficient or other personal reasons. The biggest driver here is the very high cost of running new service to remote areas.

    Marc
    I always have more questions than answers. That's the nature of life.
  • solar_davesolar_dave Solar Expert Posts: 2,384 ✭✭✭✭
    Like everyone has said, conserve first, then upgrade your biggest consumers to more efficient units like AC units, refrigeration ...  These things will payback pretty fast.  

    At this point if you want to continue to chase solar, find out your utility net metering plan(s) and understand how they account for your power returned to the grid. Some do dollars and some store kWh with lots of restrictions.  With a hybrid system be prepared for the battery maintenance regime. Personally IMHO Grid tie makes the most sense usually but if your power is unreliable a hybrid could make sense.

    You really need to understand how a system is going to interact with the utility. That will get you some good estimates on the dollars and cents of it.  They can also clue you in on the attachment protocol that the code enforcement will require. 
  • mvasmvas Registered Users Posts: 384 ✭✭✭
    edited December 2016 #7
    Here is what I want to do.  I live in South Central Texas and the sun is plentiful.  I would like to build a solar panel based system with batteries that can tie into my existing AC breaker panel.  Getting my meter to run backwards would be great but I would settle for running this small house with solar power.  Do I need an inverter to go from my battery bank to the breaker box?
      Yes, you need an inverter to go from the Battery Bank, or Solar Panels, to the Main Service Panel.
      Question ... Are you going to install the PV System or are you going to pay licensed electrician to install a PV System?
      In my area, we are required to PASS an Electrical Inspection before the electric company will install the new meter that will "run backwards", ie one that calculates / measures our excess generated PV watts. The 2014 NEC, and soon the 2017 NEC, has many less than obvious PV System requirements that must be followed precisely. Do you have a copy of the 2014 National Electric Code and do you completely understand the requirements for installing a PV System? 
       Please consider the total / final cost of a PV System, the Solar Panels are just a fraction of the total cost.  A rough estimate for a Grid Tie (no battery) PV Array is about double the Watts. So a 5,000 Watt system will cost you about $10,000 for parts only, then add installation labor. Given 6 hours of Full Sunlight per day and a cost of 10 Cents per KWH then a rough Break-Even is about 10 Years = $10,000 /  ( 6 Hours/Day x 5 KW  * 10 Cents/KWH ). Adjust the formula, as needed. A PV+Battery system may take 15+ year to Break-Even.
Sign In or Register to comment.