Enphase has a good reputation. There is a micro inverter on each panel to convert from DC to AC which is the way to go on grid ties. One of the gotcha with PV power is that a shaded cell can impact the power production of the entire panel. If that shaded panel is connected to other panels, as they often are, the power production on the entire string of panels can be affected. Also, an under performing panel can also affect the entire string. Micro inverters prevent this from happening.
Flip side is that you cannot add batteries with these inverters. The system will
not provide back up power in a power outage.
A common default efficiency number is that you will get around 75% of the power produced by the panels at your outlets. Assuming five hours of power production, she would get 11,250 watts hours per day( 3000*5*.75) from 3,000 watts of power.
If she puts in more power generation that she consumes will the power company pay her or just take the power for free?
Check when she would get the rebate and verify the details. The Feds give, or used to give, 30% back but of course that was returned at tax time. NC gives back 35% when I do my taxes. This means I would want to do the installation at the end of the year since I have to come up with 100% of the money and I would want to minimized my time to get my money back via tax refunds. However, there is a catch in NC. NC will only pay back 50% of what you owe in state taxes towards a solar rebate. In other words, if I spent $10,000 on the PV system, NC would pay me back $3,500. However, if I owed $2,000 in NC taxes, they would only pay me $1,000 for the PV tax rebate. I can take up to either 5 or 7 years, I forget which, to get the full $3,500 but that means I have to make a loan payment, or be able to afford to have the money tied up for years, to get my full refund.
This website should have this sort of information or links to said info,
DSIRE: Database of Energy Efficiency, Renewable Energy Solar Incentives, Rebates, Programs, Policy
Later,
Dan