The link below is to an excellent article which provides insight into the principal three sources of federal funding for clean energy projects:
– grants (via challenges, as well as federal and state grant application programs – CleanFi has entered and won funds through several of these initiatives.  See HeroX.com for regular opportunities being announced)
– loans
– tax credits (NOTE: as of the date of this article, some of the IRA 2022 ITC initiatives, such as Direct Pay and Transferability, had not yet received IRS guidance.  We will post an update article here as soon as that information is released).
https://cleantechnica.com/2023/05/20/3-federal-funding-pools-every-industrial-project-developer-should-know-about/