What counts as substantial completion on a solar construction loan

Every credit agreement defines substantial completion differently, but the lenders who've closed a few dozen utility-scale deals all end up asking the same underlying question: is the plant built enough to stop being a construction risk and start being an operating asset. That line matters because it usually triggers a draw release, a change in the interest rate margin, or the start of the debt service reserve requirement. Get the definition wrong, or trust a number you can't verify, and you've released money against a milestone that wasn't actually met.

Substantial completion vs. mechanical completion vs. COD

These three terms get used loosely on site calls, and that looseness costs people money.

Mechanical completion usually means the physical installation is done: racking set, modules mounted, DC and AC wiring run, inverters and transformers in place. No energization required. It's a construction-contract term, defined in the EPC agreement, and it's the first checkpoint an owner's engineer signs off on.

Substantial completion is a step further and it's the one that shows up in loan documents. It typically requires mechanical completion plus successful completion of commissioning tests, interconnection to the grid (or at least the ability to), and often a punch list capped at an agreed dollar value or item count. Some credit agreements tie it to achieving a percentage of nameplate capacity on a performance test. Others tie it to the EPC's own certificate under the construction contract, cross-referenced against the independent engineer's concurrence.

Commercial Operation Date (COD) is the furthest milestone. It generally means the plant has permission to operate from the interconnecting utility, has executed any required power purchase agreement obligations, and is delivering energy commercially. COD is when construction risk fully converts to operating risk, and it's usually the trigger for conversion from a construction loan to a term loan, or for tax equity to fund.

So the order on a typical draw schedule runs: mechanical completion, substantial completion, COD. A plant can hit substantial completion and still be weeks or months from COD if the interconnection utility hasn't issued permission to operate, or if a final performance test hasn't run.

Why lenders can't take the EPC's word for it

The EPC has every incentive to call a milestone early. Substantial completion often releases a draw, starts the clock on liquidated damages exposure flipping in their favor, or marks the point where they stop carrying as much schedule risk. None of that makes the self-report dishonest, exactly, but it does make it a number worth checking before it's attached to a wire transfer.

The usual check is a site visit from the owner's engineer or the lender's independent engineer, walking the array with a punch list and a tape measure. That works, but it's slow to schedule, expensive per visit, and gives you one snapshot. If the milestone definition in your credit agreement references a specific count, a specific number of tables racked, modules mounted, inverters energized, you're relying on whatever the EPC's construction manager reported that week, confirmed (maybe) by a field visit that happened some days or weeks before or after the actual count changed.

What a verified count settles

The practical question a lender needs answered before releasing a substantial completion draw is simple: does the as-built match what the draw schedule says should be built. Not the EPC's percentage, not the construction manager's verbal update on a Friday call, a count of modules, tables, and inverters on site, measured against the interconnection design and the drawdown schedule.

That's the gap Solar Panel Counting is built to close: a counted inventory of modules, tables, and inverters at the site, pulled from very high resolution imagery on a quarterly cadence, so you can check an as-built count against what the draw schedule or interconnection agreement calls for, without waiting on the EPC's own percent-installed number or scheduling a field visit every time a milestone comes up for sign-off.

If your next draw request hinges on a module count you can't independently confirm, that's worth fixing before the funds move, not after.