At this geographic location, in order to generate 20,000 kW of electricity per year, you would need a 16 kW photovoltaic system installed.

Cost Analysis
Using a typical photovoltaic installed cost of $7.50/Watt (this cost can vary depending on many variables specific to your site), the total installed cost of this system should be approximately $120,000.00.

Business Energy Investment Tax Credit (ITC) $36,000.00
The credit is equal to 30% of expenditures, with no maximum credit. Eligible solar energy property includes equipment that uses solar energy to generate electricity, to heat or cool (or provide hot water for use in) a structure, or to provide solar process heat. Hybrid solar lighting systems, which use solar energy to illuminate the inside of a structure using fiber-optic distributed sunlight, are eligible. Passive solar systems and solar pool-heating systems are not eligible.
Tax credit for this system is likely to be $36,000.00

Modified Accelerated Cost-Recovery System (MACRS) $24,000.00
The MACRS allows a corporation to depreciate the cost of the solar panels and associated equipment and installation in five years.
The depreciated cost per year of this system is $24,000.00

Pennsylvania Sunshine Solar Rebate Program (small businesses 3 to 200 kW) $24,002.50
The program is set up to provide rebates that decline over time as certain benchmarks, or "steps", of installed capacity are reached. The residential and small business portions are assigned separate incentive schedules for PV rebates, but the schedules are combined for solar thermal installations. Each small business PV step contains 5 megawatts (MW) of installed capacity. Currently, the small business portion of this program is in step 2. The rebate for this system is estimated to be $24,002.50

Pennsylvania SRECs $6,260.00
The SREC program provides a means for Solar Renewable Energy Certificates (SRECs) to be created on behalf of the solar owner and sold to electric suppliers to meet their solar RPS requirement. All electric suppliers are required to use the SREC program to show compliance with this part of the State's Renewable Portfolio Standard. SRECs are designed to provide solar owners with an economic incentive to investing in solar electric systems which improve the electric distribution grid. They represent the renewable attributes from your solar facility, bundled in minimum denominations of one megawatt hour of production. In addition to it's own state, Pennsylvania solar panel systems can sell their SRECs to Washington, DC, Ohio and North Carolina.
It is estimated that this photovoltaic system would generate approximately $6,260.00 per year (assumes rate of $313.00/mW).

How many years to pay the photovoltaic system

Original Cost of System: 120,000.00

End of Year 1 Savings:
Investment Tax Credit: $36,000.00
MACRS: $24,000.00
State Rebate: $24,002.50
SRECs: $6,260.00
Energy Savings: $1,940.00
Remaining System Cost: $27,797.50

End of Year 2 Savings:
MACRS: $24,000.00
SRECs: $6,260.00
Energy Savings: $1,940.00
Remaining System Cost: $0.00