You've done the analysis. Solar pencils out at 350 kW on the rooftop, the PPA rate beats your retail tariff by 20%, and the 15-year cash flows clear the hurdle rate with room to spare. Your feasibility study says go. So why, six months later, is the project still sitting in someone's inbox?
Because feasibility studies answer the wrong question. They tell you whether a project could work. They don't tell you whether it will get built. And the gap between those two things is where the vast majority of onsite energy projects die. As we explored in why only 5% of viable onsite energy projects get built, the bottleneck is rarely economics. It's everything that comes after the economics check out.
A model doesn't have an interconnection queue
The single biggest source of post-feasibility delay is interconnection. Your model assumes the system connects to the grid on a certain date. The utility has other plans.
For mid-sized commercial systems, utilities often estimate 30 to 60 days for initial review, and another 60 to 120 days if a system impact study gets triggered. In practice, those timelines stretch further. According to Lawrence Berkeley National Laboratory's Queued Up report, the typical project built in 2023 took nearly five years from interconnection request to commercial operations, compared to less than two years in 2008. That data covers utility-scale, but the distributed generation queues aren't immune. Utilities like PG&E, National Grid, and Duke Energy are managing backlogs that stretch 60 to 90 days in certain queues, and California lawmakers have formally pressured the CPUC to enforce mandated timelines after repeated failures by PG&E and SCE.
Your feasibility study doesn't model any of this. It assumes a clean handoff that rarely exists. And here's what makes it worse: interconnection surprises don't just delay your project. They can change the project entirely. A utility may require expensive grid upgrades, cap your export capacity, or mandate a smaller system size. That 350 kW rooftop array in your study becomes a 240 kW system with a different return profile. By the time you find out, you've already spent months and internal capital getting to "yes."
Contracting friction kills momentum
Even when the interconnection path is clear, projects stall in contracting. A feasibility study produces a system size and a projected return. It doesn't produce a contract. And the distance between "this looks good" and a signed PPA or lease is longer than most buyers expect.
Scope misalignment is the most common culprit. The feasibility study might assume a 500 kW system, but the provider's proposal comes back at 380 kW after accounting for setback requirements, structural limitations, or updated utility rules. Now the economics shift and the internal champion has to re-justify the project to leadership. Or the study assumes a standard PPA, but the provider's contract includes escalator terms, insurance requirements, or performance guarantees that don't match what the buyer's legal team will accept. Each round of redlining adds weeks. Three rounds of redlining adds months. And somewhere around month four, the internal sponsor starts losing credibility with the CFO who approved the project based on a different set of numbers.
There's also a subtler version of this problem: the feasibility study and the provider's proposal aren't even measuring the same things. The study might quote an IRR based on year-one savings. The provider's proposal might use a different baseline, different rate escalation assumptions, or a different degradation curve. Both sides think they're aligned until they sit down to finalize terms and realize they've been talking past each other.
This is why competitive RFPs do more than lower your price. A structured procurement process forces scope clarity upfront. Without one, the contracting phase becomes a rolling negotiation where both sides discover misalignment in real time.
Nobody owns the project between "yes" and "built"
Feasibility studies are often commissioned by sustainability teams or energy managers. But the path from approval to construction touches procurement, legal, facilities, finance, and sometimes the C-suite. The person who championed the study rarely has the authority or bandwidth to drive every downstream step.
This is the ownership gap. The feasibility study gets handed off, and nobody picks it up with the same urgency. Facilities needs to schedule roof access. Legal needs to review the site license. Finance needs to confirm the accounting treatment. Insurance needs to evaluate the provider's coverage. Each of these is a small task, but none of them has a dedicated owner, and collectively they can stall a project for months.
The problem compounds when you're trying to do this across multiple sites. A single rooftop project is manageable, if painful. Ten projects across a portfolio, each with different utilities, different roof conditions, different local permitting requirements? Without a defined process and clear ownership at every stage, the second and third projects never get off the ground because everyone is still stuck on the first one.
As we covered in The Problem Isn't Economics. It's Bandwidth, for many buyers the total internal time spent on a project is only 4 to 5 hours. Everything else needs to happen outside their already-full calendars. When there's no clear execution owner and no process to follow, those hours never materialize.
Execution readiness is a different discipline than feasibility
A feasibility study is an analytical exercise. Execution is a project management exercise. They require different skills, different tools, and different organizational muscles. Treating a positive feasibility result as proof that a project is "ready" is like treating a business plan as proof that a company will succeed.
Execution readiness means asking a different set of questions before committing resources. Has the utility confirmed the interconnection timeline, or are you assuming one? Has the scope been validated against actual site conditions, not just satellite imagery and aerial measurements? Do you have a contracting framework that providers can respond to, or will every deal be negotiated from scratch? Is there a named owner for every phase between approval and commissioning? Has your legal team already reviewed a PPA template, or will that review happen for the first time after a provider submits terms?
These aren't peripheral concerns. They're the difference between a 6-month project timeline and an 18-month one. Most of the time added isn't construction. It's the dead space between decisions, the weeks spent waiting for internal reviews, utility responses, and contract revisions that nobody anticipated.
Buyers who build repeatably tend to do something specific: they treat onsite energy as a program, not a project. They standardize scopes, pre-negotiate contract templates, and create clear handoff points between internal teams. The feasibility study is an input to that program, not the starting gun.
