2 - Design Your Project
Using the data you collected in the evaluation phase, you can produce an actual system design detailed enough to determine your costs and benefits more precisely.
Make a copy of the HAREI Generic Solar Install Template spreadsheet
The spreadsheet is a Google Sheet; it will be easiest if you have or create a Google account so that you can make a copy.
Select the menu 'File -> Make a copy...' - name your copy using your last name (or other project label of your choice) as the file name
Open the INSTRUCTIONS tab for details of how to fill in the sheet
Fill in the Panels and Inverters section with the number of panels you need. If you don't know, start with 30 and see how much power that gets you at the end of the sheet. You should check current prices
You can use the NREL System Advisor Model to explore design alternatives and how they trade off costs.
Design your mounting system
Most of our recent installations have used one of the mounting systems from IronRidge.
Find out if your town building inspector and/or fire chief are requiring roof pathways to the ridge. Some towns are adopting a National Fire Code regulations that will affect your layout see: Rules for Rooftop Solar
Go to the free online design assistant tool (you will need to create a free account)
The tool supports creating roof and ground mount designs
Costs will be up to 40% lower than those shown when you order with the HAREI discount.
Save the project in the design tool
Export the Bill of Materials from the tool, and copy each item into the Mounting section of the spreadsheet. We strongly suggest adding a few extra of each of the small parts like panel clamps and mounting bolts.
The tool will also help you produce drawings you will need when applying for permits.
If you are doing a roof mount, you can further refine your plan by making a copy of the Roof Grid Tool spreadsheet (created by HAREI member Rob Figler) to calculate specific positions for the flash feet (on which the rails are mounted).
Don't forget that you need feet near each end of each rail, and to comply with NH guidelines remember to stagger the flash feet distributing the load evenly across all the rafters unless you plan on a separate structural evaluation.
Contact HAREI to review your plan.
We will help you refine the plan, and help you prepare your order(s).
You will need to create a detailed Electrical Installation Plan with your electrician
We have detailed information to help with this in Wiring Your Solar Array
Determine applicable tax credits, rebates, and other returns. The spreadsheet will compute these for you.
For 2022 there is a Federal Income Tax credit for 26% of your total installed cost (keep all receipts for related expenses!).
This can include any costs for the project, including things like removing trees that would shade the array.
The New Hampshire Residential Small Renewable Electrical Generation Systems Rebate program: The NH rebate program has run out of funds, and is not accepting applications for the rebate at this time; we don't know when (or if) the legislature will renew funding.
For each megawatt (1000kwh) you generate, you create one Renewable Energy Certificate (REC), which can be sold at auction quarterly. Returns are variable; for this reason, we have not included REC revenue in our payback estimates - they're just gravy.