No. You only need to provide your ZIP code. ZIP code is used to auto-populate both the default price and assumed emission rate for electricity. Providing your address is for informational purposes only and will be included on the report generated from your analysis.
Your discount rate depends on your value of a dollar saved in the future. See the user guide for additional details.
The study period the timeframe over which the analysis is completed. A common study period is the expected lifetime of the solar photovoltaic system. This is defaulted to 25 years because it is a common warranty for solar panels.
The default electricity data is the most recent average annual electricity costs per the Energy Information Administration (EIA).
Your rate schedule is available from your energy provider. It may be provided as part of your monthly electricity bill and/or available for download from the energy provider’s website.
If you cannot find your rate schedule, you can use the simple average electricity cost per kWh. Take the total cost of your electricity bill and divide by the total kWh of electricity you consumed. Electricity prices may vary over a year. It is recommended that you sum the last 12 months of costs and consumption to get an annual average price.
Yes, but you will need to find data for the system production and installation costs. A couple sources for cost data by state include LBL’s Tracking the Sun and EnergySage.
An SREC – solar renewable energy credit – is a certificate representing environmental impacts of solar energy. The value of the environmental impacts can be separated from the electricity generated and sold to energy providers that have requirements to purchase a certain amount of solar energy.
One source for SREC market data is SRECTrade: https://www.srectrade.com/markets/rps/srec/introduction
The economic calculations (life cycle costs, net savings, etc.) include the costs of installation, replacement, maintenance, electricity consumption, and residual value (resale value or disposal value) of the system at the end of the study period. The value of the system is assumed to depreciate linearly over its lifetime. The value of the environmental impacts (social cost of carbon) is NOT included.
AIRR is the adjusted internal rate of return. Internal rate of return (IRR) is the potential annual savings of the project after its costs. AIRR adjusts the IRR calculation to include reinvestment of the annual savings, which makes it a more accurate measure of returns.
GHG emissions are included for both operational and embodied emissions. Operational emissions come from electricity consumption from the electric grid. Electricity generation by a solar photovoltaic system offsets consumption from the electric grid and, therefore, reduces operational emissions by an equivalent amount. Embodied emissions are those associated with the solar photovoltaic system itself, which include both the initial installation of the solar panels, inverters, racking system, and monitoring system as well as any replacement of the individual equipment or complete system over the study period. The embodied emissions are “cradle-to-grave” in that they include all emissions from resource extraction and refining to manufacturing and transportation to installation and use to end of life (disposal or recycling).
The primary GHGs included in the emissions estimate are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Other emissions are included, such as sulfur hexafluoride (SF6).
Social cost of carbon is an estimate of damages from emitting an additional ton of carbon dioxide into the atmosphere.
The assumed social cost of carbon value is a constant $51/ton.