What kinds are there?
The most common method is solar panels, but now Tesla’s got solar roofing tiles.
How much do they cost?
It differs depending on who’s installing them (Solar Panels Plus here in Hampton Roads offers them at $2.99 per watt installed), but the national average cost can be as high as $7-9 per watt with solar panels. Most roofs have a total of around 5 kW, which is $35,000 to $40,000, but the prices vary depending on where you live, how much your local power company compensates, and how much of your roof you want to cover. The Tesla roof costs $77,000, and that covers around half of your house (I based Tesla’s price quote on our own home size, so the price varies here too).
What is a payback period and how long does it last?
The payback period is a number of years where your solar panels will generate enough power to “pay back” your initial installation cost. It lasts an average of ten to twelve years.

A Tesla roof is said to be able to last into infinity.  So, I would say it depends on what you build the rest of your home from.
How does Dominion accommodate for houses with solar panels if I choose to stay on the grid?
That’s pretty simple, actually. If your house is using more electricity than your solar power is producing, then Dominion will charge you for the energy it provides to your house. If your solar power produces more than you use, the extra energy will be used by Dominion (put in another house) and you will get money from them based on how much energy they “took” from you.
Solar power is great for your forever home and the best investment for your electrical bill! We suggest it wholeheartedly if you plan on living in your current home for a long time.