Substation vs. transmission line: why do developers care?
General information, not a substitute for the advice of an attorney.
Short answer: A transmission line carries high-voltage power over long distances, and transformers at substations raise or lower voltage (EIA). Developers want land near lines and substations, because the grid connection is a large part of project cost (Penn State Extension).
What is the difference?
High-voltage transmission lines carry electricity over long distances, and distribution lines carry lower-voltage power to homes and businesses (EIA). Transformers at substations step voltage up or down for each stage of the trip (EIA).
- ERCOT's transmission plans include new and upgraded 345 kV and 138 kV lines and conversions of 69 kV lines to 138 kV (Texas Reliability Entity).
- On April 24, 2025, the PUC approved the first 765 kV transmission projects in Texas (Texas Reliability Entity).
- Texas rules define distributed generation as 10 MW or less, connected at less than 60 kV (16 Tex. Admin. Code § 25.211).
Why does a substation with room matter?
Solar developers look for land with easy access to high-voltage lines near substations, and that connection is a large part of the cost of solar development (Penn State Extension). See how close to power lines land needs to be.
A line on or near your land may not have room for a new project. While in a queue, proposed projects are studied for their effects on the grid, and some need broader grid upgrades to fit (U.S. Department of Energy). In most of Texas, that process runs through ERCOT (ERCOT). Only those studies show whether a given line or substation can take the project.
What is a gen-tie line?
Power from a solar site must reach high-voltage lines, by trench or by pole (Penn State Extension). The line a project builds to the grid is often called a generation tie line, or gen-tie. It ends at the point of interconnection, where the utility's conductors meet the generator's and ownership changes (Oncor).
A gen-tie may cross land that has no panels on it, and that land needs an easement. Solar leases can allow substations, power lines, and roads on the property (National Agricultural Law Center). A new utility transmission line is a different case; see Texas transmission line easements.
Questions to ask
- Which substation or line will the project connect to, and how far away is it?
- Has an interconnection study been done, and what did it find?
- Will a gen-tie or project substation sit on my land? Where, and how wide is the easement?
- Is the gen-tie easement paid separately, and does it end when the lease ends?
General information from the sources linked above, not legal, tax, or financial advice.
Sources and helpful links
- EIA eia.gov
- Penn State Extension extension.psu.edu
- Texas Reliability Entity texasre.org
- 16 Tex. Admin. Code § 25.211 law.cornell.edu
- U.S. Department of Energy energy.gov
- ERCOT ercot.com
- Oncor preglobal.oncor.com
- National Agricultural Law Center nationalaglawcenter.org
More official contacts and resources: Helpful links.