Solar power in Pennsylvania currently provides less than 1% of the state's electricity, but there are many policies in place to regulate and incentivize its use. Pennsylvania mandates the use of solar power through a renewable portfolio standard, which requires a percentage of electricity from each providers to come from solar, and net metering, which compensates small-scale solar generation through net metering. By 2021, Pennsylvania is required to have 0.5% of its electricity from solar. Solar power could theoretically provide over 30% of the state's electricity, but growth in solar generation has slowed due to a reduction in solar grants and the low price of solar energy credits.
When you install your solar system, 30% of your project expenses apply toward a credit to offset any taxes you owe that year. This federal tax credit is a major incentive to go solar, but it is being phased out by 2022.
Most people are eligible to claim this credit (you must owe federal taxes to be eligible).