Help
The In My Backyard (IMBY) tool's step-by-step instructions will walk you through the process of creating estimates of your solar photovoltaic (PV) electricity production. However, if you have questions or need additional help, see detailed instructions for the:
Find U.S. Address
Follow the steps below to enter your information in IMBY's location tab.
Step 1. Enter your location.
Type your street address in the field. You may enter a full address with city and state (e.g., 15013 Denver West Parkway, Golden, CO) or ZIP code (e.g., 15013 Denver West Parkway, 80401). When you are done, click the Find button. The map will zoom in to your location. You are also able to change that location by editing it in the left navigation column.
Choose a System
Follow the steps below to use IMBY's Solar Electricity Estimator.
Step 1. Choose a System
Choose your system's size by dragging one of the template icons from the left navigation column onto your map and lay it on the area you plan to use for your system.
Once the icon is dragged onto the map, it will create a blue box with orange circles in the corners to represent your system and indicate the basic land-use required for the system you have selected.
The template icons have set sizes (4kW-100kW) to start you off. However, when you modify the shape of your system, the size of your system will be automatically adjusted in the System Inputs Size field (see the left navigation column) to match the new area you have created. Note: Systems with size greater than 100.0 kW may provide inaccurate results.
IMBY can estimate the production you can expect from a PV array or wind turbine, but it cannot tell you if such a system is right for you. To learn more about choosing, sizing, and siting such systems see the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy's small PV array system website.
Step 2. Modify the shape of your system.
You can zoom your location using the zoom tool on the upper left of the map. Push the + button to zoom in and the - button to zoom out.
To move your system, click and hold on to the orange circle in the center. To modify the shape your system, click any of the orange circles and hold to drag it to your desired position. As you move the brighter orange circle, you will notice that new dimmer orange circles will appear between the brighter ones. Any of the orange circles are moveable so you can truly customize your system.
If you make a mistake and need to start over, click the Delete button at the top left of the map. Select a new System Type and begin again.
For single system sites, make sure you delete your system prior to adding a new one or you will create a second system that is included in your system total.
Finally, if you plan to have multiple systems on a site, you can add additional systems within a mile of your original system. Please keep in mind that each system added needs to be clicked on and selected for deletion.
Step 3. Adjust the inputs.
Based on the location and size of the array you draw, IMBY will calculate suggested inputs for your PV electricity production estimate. When creating these estimates, IMBY assumes you are installing a fixed-tilt PV array. If you want to use a different array type, you'll need to use the PVWatts™ calculator.
Please note the System Type is defaulted to be Residential, but a Commercial System option is available.
If you know your system differs from the suggested inputs, you can adjust them. To do so, click in the appropriate field and type in your information. Most of the field titles provide additional information about each field when you hover over it. Learn more about derating, tilt angle, and azimuth angle.
Clicking the Option button beside the Derating input field expands its parameters to include: PV module nameplate DC rating, Inverter and Transformer, Mismatch, Diodes and Connections, DC Wiring, AC Wiring, Soiling, System Availability, Shading, and Age.
The Data year field allows you to choose the year of solar data that IMBY uses to create a production estimate. By choosing a specific year, you can compare your system's output with your actual load profile for a given year.
The Electric rate field is populated with a default value of $0.09/kWh. You can change the value to reflect your known rate.
Step 4. Estimate your production.
When you are satisfied with your inputs, click the Run button. IMBY will calculate your estimated electricity production.
Payback Section
The Payback section displays in the center of the Solar Simulation Results pop-up window. This section shows the values used to estimate the payback for this system.
The PV payback algorithm uses a variety of economic inputs to determine how long it will take for you to make enough money to break-even on the cost of the PV system. These values are only estimates and should not be used as actual values. The payback value represents the "simple payback" and assumes no net-metering. This means that it assumes that all of the electricity at the location is used, and nothing is sold back to grid.
Initial Cost ($/Wdc)
This value presents a general estimate of the cost of installing PV. The value is dollars per watt ($/W), and is computed from a list of known PV installations and their cost.
Initial Cost ($)
The initial cost represents the initial total cost you would pay for this PV installation. This value is computed by multiplying the size of your PV system with the cost per watt defined above. The Initial Cost can be broken down further by clicking the Option button and editing Modules, Inverters, Mounting Equipment, and Installation Labor fields.
Rebates ($)
The per-watt rebate rate specified below may be less if local incentives are available. The rebates used here are taken from the Database of State Incentives for Renewables & Efficiency (DSIRE). Your System Type is important to this value because Residential and Commercial systems have different values.
Tax Credits ($)
Each tax-credit for your location is selected from the Database of State Incentives for Renewables & Efficiency (DSIRE) and is aggregated to present one value here. This value includes local, state, and Federal tax credits. Your System Type is important to this value because Residential and Commercial systems have different values.
After Incentives ($)
The "cost after incentives" represents the subtraction of the selected PV incentives from the initial cost of the system.
Payback
This value estimates the number of years it might take to recoup the cost of this PV system. This value considers the general operating and maintenance costs and the annual electricity production of the PV system to determine the number of years until enough money is made from the system to equal the initial system cost. However, this value does not consider the amount of monthly electric bill savings you may find from this PV system.
System Outputs Section
The System Outputs section displays in the center of the Solar Simulation Results pop-up window. This section shows the amount of electricity (kWh) generated each month by your system and is translated into the dollar amount represented by those values.
Load Section
The Load section displays on the right of the Solar Simulation Results pop-up window. Follow the steps below to compare your electricity consumption with your estimated solar electricity production.
Step 1. Select a load profile.
You can choose to use a sample load profile for your area or your own custom load profile.
Use a sample load (A. Use a residential load profile). To use a sample load, select an option from the drop-down box. The 4kW-system sample load profiles are based on data for a 1,800-ft2, three-bedroom, two-story residential home. The differences among the sample profiles are due only to climate difference among locations.
- Upload a custom load (B. Upload a load profile). To upload your own custom load profile, click the Browse button to select for your custom profile document. This document must contain your profile information in comma-separated value (CSV) format and should have city, state as first entry. See the Help link for more information.
Step 2. Run load profile.
Click the Run button to see your results.
Step 3. Review your results.
Your results will be loaded into the top of the Solar Simulation Results as two new tabs: Load and Generation and Utility Bill.
Load and Generation. The top chart shows a 19-day snapshot of your system generation compared with your site load. The bottom chart is your annually estimated generation and load. To zoom in on any part of either chart, click and drag to highlight your dates of interest.
Load Duration Curve. Your load duration curve is shown if you click the Show Duration Curve button found within the Load and Generation Help section. This chart shows the 8760 hours of load during the year (Load) and is sorted from highest load to lowest load. This is compared with a sorted load profile after the PV production has have been taken into account (Reduced Load). Any power that is less than zero is excess electricity and sold back into the utility grid.
- Utility Bill. This bar-graph shows estimates of both your monthly electric bill (in blue - based on the load profile you chose) and your electric bill after PV has been installed (in red). You can change the electric rate above to modify the graph.
Step 4. Export your results.
Click the Export Results button to save your results as a CVS file for your spreadsheet program.
