DETERMINING SOLAR ENERGY OUTPUT AND SAVINGS:One of the most important questions you’ll have when you’re considering PV power is how much your system will cost and how much it will save you. A good place to start is to understand how much electricity you currently use. You can do this by looking at your electricity bills for the past year or by contacting your utility company. This will give you a baseline so you know how much electric energy you’re using now and how much you’ll be able to offset by installing a PV system.
An Example of Solar Energy Output and Savings;
Your energy savings with a PV system can be estimated by multiplying the energy in kilowatt-hours (kWh) that your system might produce each year by the electric energy rate charged by your utility company. The chart below shows the estimated annual energy savings from a small (2kW) and a large (4 kw) system to illustrate a range of savings based on four different electric rates.
PV SYSTEM ESTIMATED ANNUAL UTILITY ELECTRIC ENERGY RATE SIZE OR Kw ENERGY $0.08/kwh $0.10/kwh $0.12/kwh $0.14 2.0 kW 2300 kWh $184.00 230.00 276.00 322.00 4.0 kW 4600 kWh $368.00 460.00 552.00 644.00
THE QUESTION WILL THEN BE HOW LARGE A SYSTEM YOU WANT TO INSTALL. The larger the system, the more electricity you’ll be able to generate, but at a higher up-front cost. You should consider four factors when choosing a system: your energy needs, the amount of the energy you can generate, whether you want a battery backup system, and the system costs. What you should remember is that no matter what system you choose, the actual output will vary due to environmental and system fluctuations. Ask your PV provider how much electricity your system will produce each year and how that compares with the amount of electricity you typically use each year. A GOOD RULE OF THUMB: If you’re installing a roof-mounted system, the tilt and orientation of your roof will affect your system’s output. For example, in New York, a 30 degree roof tilt facing south produces the greatest output, while an east facing roof with the same tilt will enerate 19% less electricity.
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