A solar developer can screen a parcel for flood zone, slope, wetlands, and zoning in minutes — and get a binary answer on most of it. Either the land clears the filter or it doesn't. Substation proximity doesn't work that way. It doesn't kill a deal outright. It changes what the deal is worth, and it does that quietly, folded into the economics before the offer reaches you.
The distance to the nearest substation is one of the first numbers a developer calculates. For most landowners, it's one they've never looked up.
How Developers Use Distance to Screen Land
Solar developers pull substation location data from HIFLD — the Homeland Infrastructure Foundation-Level Data maintained by CISA — and run it as one of the first layers in site screening. The distance from a parcel to the nearest substation gets flagged early because it feeds directly into the cost model. A bad number there ends the evaluation before anything else gets checked.
There's no official cutoff that applies across the industry, but the informal thresholds are consistent enough to be useful:
| Distance to nearest substation | Typical developer interpretation |
|---|---|
| Under 1 mile | High priority — minimal gen-tie cost, fast site feasibility |
| 1–3 miles | Workable — standard interconnection study; may require line extension |
| 3–5 miles | Viable but marginal — gen-tie cost starts compressing project economics |
| Over 5 miles | Usually passed over — interconnection cost often exceeds the project's tolerance |
How strictly a developer applies these varies with project scale. A 200 MW utility-scale project can absorb a longer distance and amortize the gen-tie cost across more megawatts. A 5 MW community solar project can't — the same mile of transmission line represents a much larger share of total project cost. The thresholds above are most reliable for projects in the 20–100 MW range, which is where most rural solar development happens.
What the Gen-Tie Line Actually Costs
When a project isn't close enough to connect to the grid at the nearest substation, the developer has to build its own line from the project boundary to the point of interconnection. That line is called a generation tie line, or gen-tie — privately funded, privately owned, and entirely the developer's cost.
Construction runs roughly $1 million per mile for a standard single-circuit 115 kV line, based on EIA benchmarks. That's the flatlands figure; mountainous terrain or complicated right-of-way negotiations push it higher. Five miles of gen-tie through agricultural Indiana costs less than three miles across wooded western Virginia.
The gen-tie is one piece of total interconnection cost. Add substation upgrades and utility study fees, and Lawrence Berkeley National Laboratory's interconnection cost research puts the average for utility-scale solar at around $250/kW — roughly double what it was a decade ago, as queue backlogs have grown and network upgrade requirements have increased. For a 100 MW project, that's approximately $25 million in grid-related costs before construction starts. A 5-mile gen-tie adds another $5 million. Where does that $5 million go? Mostly, it comes out of what the developer can offer for the land.
How Distance Flows Into the Lease Offer
Developers build their project economics from the revenue side backward — projected power sales over a 25-year term, minus every cost between the land and a working project. The lease payment is what's left after the required return is satisfied. It's the last number in the model, not the first.
That structure is why grid proximity shapes the offer more than solar irradiance does in most markets. Irradiance varies less than interconnection cost across the regions where solar is actively developed. Interconnection cost can swing by millions on a single distance variable, and that swing compresses directly into the lease.
On a 100 MW project with a 500-acre footprint, every $5 million increase in interconnection cost works out to roughly a $200/acre/year reduction in the maximum sustainable lease rate. That's not a rounding error — solar land lease rates across the US span $500 to $2,000/acre/year in active markets. Two hundred dollars moves an offer from competitive to something a landowner will hesitate to accept without understanding why.
When a developer presents a lower number, they rarely explain the line items. You'll hear about "grid access constraints" or "project economics" — technically accurate, but it doesn't tell you that $5 million of the gap is a gen-tie that a neighboring parcel two miles closer to the substation doesn't need.
Distribution Lines vs. Transmission Lines
One thing that trips people up: substation proximity isn't the same as having a power line near the property. What matters is what kind of line, and whether it can serve the size of project the land supports.
Transmission lines run at high voltage — 115 kV, 230 kV, 500 kV — carrying power long distances between substations. Utility-scale solar projects, generally 10 MW and above, connect at the transmission level. That means a transmission substation needs to be within reasonable distance, not just any overhead line.
Distribution lines are lower-voltage, typically 4 kV to 34.5 kV, running power from substations out to homes and businesses. Smaller solar projects — most community solar at 5 MW or under — can connect at the distribution level, which is cheaper and faster than transmission interconnection. For those projects, proximity to a three-phase distribution line (within roughly 0.2 to 0.5 miles) matters more than the substation distance.
Whether the distinction is relevant to your parcel comes down to acreage. A 50-acre parcel can realistically host 5 to 7 MW — you're likely in distribution territory. At 300 acres, you're in utility-scale range, and the substation question becomes the right question to ask.
What Substation Capacity Adds to the Picture
A substation 1.5 miles away doesn't help much if it's already running near its capacity limit. When a substation is full, the utility can't accept new power injections without upgrading the transformer bank or the transmission lines feeding it — and those upgrade costs fall on whoever is trying to connect.
This is why a parcel 2 miles from a congested substation can end up with higher interconnection costs than one 4 miles from a substation with available headroom. The developer only finds out which situation they're in after running an interconnection study — a formal technical review required by the ISO or utility that determines what grid upgrades, if any, the new project triggers. FERC Order 2023, which reformed the interconnection process with compliance deadlines through 2024, adjusted cost allocation rules. Developers still bear the cost of network upgrades their project requires, but how those costs get shared when multiple projects trigger the same upgrade has changed.
The interconnection study is also why developers use option periods rather than committing directly to a lease. The two-to-five-year option window exists to absorb the study timeline. A developer going quiet after signing isn't necessarily backing out — they may be waiting on results that determine whether the substation math works at all.
How to Look Up the Distance
HIFLD's national electric substation dataset is publicly accessible at catalog.data.gov/dataset/electric-substations, with location coordinates, voltage class, and ownership for substations across the US. Google Maps satellite view works for a rough estimate — follow the large lattice transmission towers from the parcel and see where they terminate. Most utility service territory maps, available on utility websites, show substation locations for their coverage area.
None of these sources give capacity data. You can find where a substation is; you can't easily find how much room it has left. That's what the interconnection study surfaces. But knowing the distance is where any serious parcel evaluation starts, and most landowners — and many land buyers — skip it entirely.
Sunnyplans includes substation distance as a primary filter applied to every parcel it indexes — so the grid proximity question is already answered before you spend time evaluating anything else.