Two important references here for:
What is defined as an energy community?:
https://energycommunities.gov/energy-community-tax-credit-bonus/
If a project straddles an energy community, it will qualify if either 50% or more of the nameplate capacity or square footage of the project is within the energy community.
Map of Energy Communities:
Two important NOTES:
1- Brownfields are NOT shown in this map
2- US DoE Disclaimer: “The mapping tool may not be relied upon by taxpayers to substantiate a tax return position or for determining whether certain penalties apply and will not be used by the IRS for examination purposes. The mapping tool does not reflect the application of the law to a specific taxpayer’s situation, and the applicable Internal Revenue Code provisions ultimately control.”