In most cities, you will be connected to your utility company and the Grid. There is usually a small monthly fee to be connected. Most utilities have a program called NET Metering. At night when your panels are not generating electricity, and you don't have a battery system connected, you will get your electricity from the utility company grid and your meter will reflect usage. During the daytime, when your system is generating electricity and you are not using it. you will send the electricity back to the grid. When that happens your meter will run backward. You will only be billed for the NET amount that was used. 

When you consider the savings on your electric bill, cash rebates, the Federal Tax Credit (Currently 30%), and accelerated depreciation, your return on investment could easily reach 20% or more.

The Federal Government provides a 30% solar tax credit for the total solar system installation. For example, a $25,000 total installation cost will give you a $7,500credit toward any income taxes you may owe. (That's a dollar-for-dollar deduction off taxes you owe, not a deduction from gross income). State and local incentives provide extra benefits. (Each state and municipality have different incentives, such as cashback, rebates, and tax incentives) 

The minimum you could expect for increased home value is the actual cost of the installed solar energy system. Some appraisers use a formula for valuing the solar system of between $4,500 - $5,500 per Kw installed. The Appraisal Journal shows a $20 increase in value for every $1 reduction in annual utility bills. No matter what formula is used, the value and desirability of a solar-equipped home will increase.