The C3 Fund is accepting applications from September 30 through 5:00 p.m. ET on December 31, 2026. Each application identifies two things: 1. the investment window, which is the type of financing you are requesting, and 2. the project category, which describes the qualified project the financing will support.

Each investment window is a financial product designed to remove a common financing barrier, with its own terms, eligibility criteria, and underwriting standards. There are five project categories, and an investment window is not limited to one of them. MCEC considers both the window and the project in its review, because the type of project affects how the financing is structured. Please review the investment windows and qualified projects below, then apply through the C3 Fund application.

MCEC staff will hold an informational webinar on September 29 at 10:00 AM with a walkthrough of the C3 Fund, the four investment windows, and the application.

MCEC reserves the right to adjust the investment windows at any time if required by law or at its discretion after the application period closes. 

Investment Window 1 (IW1) provides short-term bridge loans for predevelopment and early construction expenses. Proceeds cover the upfront costs project sponsors face at a stage when private lenders are typically reluctant to engage. IW1 helps sponsors maintain momentum without waiting months to close permanent financing or tax equity deals.

IW1 is built for projects that have a defined scope and a repayment source already in view, such as tax equity, permanent debt, a construction-to-permanent conversion, project sale proceeds, or federal tax credit proceeds. IW1 can fund multiple projects in one bridge loan, but the use of proceeds should be aligned with the projects and are typically structured as one disbursement at closing.

Investment Window 3 (IW3) provides grant funding for early-stage analysis: the work that turns a clean energy concept into a project ready for financing. Many projects never reach the financing stage because feasibility analysis, engineering studies, design, financial modeling, and permitting are too expensive to fund out of pocket and too early to attract project capital.

Preference is given to qualified projects that benefit low- to moderate-income households or underserved communities, sponsored by organizations that do not have the staff, funding, or technical expertise to carry out this work on their own. Typical applicants include nonprofits, local governments, housing authorities, schools, and other community-serving institutions. MCEC gives priority to applications that show both the community benefit and the need for grant support. Applicants that can fund predevelopment work themselves are generally better served by Investment Window 1 or 2, where these costs are eligible uses.

Core eligible activities include feasibility studies, energy audits, technical and engineering analysis, energy modeling and load analysis, schematic and preliminary design, financial modeling and capital stack development, and resource assessment and siting analysis.

To some extent permitting fees and environmental review, interconnection study deposits are allowable with documented justification. IW3 typically does not fund construction or equipment costs, subscriber acquisition, or work already funded by another grant for the same scope. Because this work comes before a project is ready for construction, strong applications show a clear implementation plan, a reasonable approach to funding the project if feasibility is confirmed, site control or a credible path to it, and capable project leadership.

There is one C3 Fund application for all four investment windows. It opens with a short set of eligibility questions, then asks which type of investment you are seeking: bridge loan, line of credit, feasibility grant, or term financing. Your answer determines which questions you see next, so you only complete the sections that apply to your request.

You may apply to more than one investment window. Each request requires its own application. If you are not sure which window fits, the application includes an option to request a conversation with MCEC staff instead.

What Happens After You Apply?
MCEC conducts a preliminary review of every submission and will contact every applicant with the outcome of that review. If your application advances, we will send a list of the documents we need and provide access to MCEC’s secure data room, where you can upload the requested documents. You do not need to gather those documents before you apply.