Rules by state

Solar and battery interconnection rules in Colorado

Colorado interconnection procedures (Rules 3850 to 3859). Every threshold below was read out of the document linked at the bottom of this page, and the same rules answer the free screening check.

Who this binds: investor owned utilities, electric cooperatives. A utility outside that list sets its own terms, so confirm who serves the address first.

Check a Colorado address free
How the size is measured

kW AC. Colorado reviews an interconnection request on the combined nameplate ratings of systems accounting for their export capacity and energy storage operating mode, using actual simultaneous performance AC ratings. Where storage output is limited by a power control system, a relay or another agreed on site limiting element, only the capacity designed to inject into the system is used in the screens.

Size bands and what each one obliges

Level 1, the 25 kW inverter process Size 0 to 25 kW

A certified inverter based resource no larger than 25 kW AC, which may be paired with a non exporting storage system no larger than 25 kW AC. Colorado publishes an insurance table and the answer for an inverter based system below 1 MW is no insurance at all.

  • Certified inverter based equipment
  • No liability insurance required for inverter based systems below 1 MW
Level 2, fast track Size 25.001 to 5000 kW

Above 25 kW AC, with eligibility by line voltage from 500 kW below 5 kV up to 5 MW at 30 to 69 kV where the site is within 2.5 circuit miles of a substation and on a mainline. All synchronous and induction machines must be no larger than 2 MW regardless of location.

  • Application fee set in the utility interconnection tariff, which must be cost based
Level 3, study process Size 5000.001 kW and above

Everything not eligible for the smaller levels. Above 5 MW an inverter based system requires $2,000,000 liability insurance per occurrence.

  • $2,000,000 liability insurance for an inverter based system above 5 MW
  • Studies at applicant cost

The screens that decide it

Ask the utility this, before you sell it

  1. What is this customer average annual electricity consumption? Colorado caps the resource at 120 percent of it, and at no more than the customer service entrance capacity.
  2. What is the application fee in your interconnection tariff? Colorado publishes the fee structure but delegates the amounts to each utility, which must show they are cost based.
  3. For a cooperative, have you reduced or waived the insurance requirements, and what net metering size do you allow? Colorado cooperatives may do both.
  4. What is the line section annual peak load here, and where are the automatic sectionalizing devices? A fuse does not bound a line section in Colorado.

Worth knowing before you quote

Colorado publishes the clearest insurance table of the western states, and for ordinary residential and small commercial solar the published answer is zero: inverter based systems below 1 MW require no insurance. Non inverter machines step from $500,000 above 50 kW to $3,000,000 above 5 MW. Colorado uses 87.5 percent as the short circuit interrupting capability limit, not the 90 percent used in Arizona and Oregon. Net metering caps the resource at 120 percent of average annual consumption, and at 200 percent of expected consumption for a benefiting meter on a multi unit property.

Utility programs we have read in Colorado

Source

Colorado Public Utilities Commission interconnection rules, 4 CCR 723-3 Rules 3850 to 3859, adopted by Decision C21-0298 in Proceeding 19R-0654E, with net metering sizing at Rule 3664

Read and recorded 2026-09-12. The rule states that it largely tracks the 2013 amended version of the federal 2006 Small Generator Interconnection Procedures, the only state read that says so in its own text. Cooperatives are bound to the interconnection standards by statute but may reduce or waive the insurance requirements and set their own net metering sizes. Municipal utilities are outside it. The interconnection rules moved from the old Rules 3665 to 3670, which are now reserved; a citation to Rule 3667 for Colorado interconnection is stale.

What to do with this

Check a real address

The rules below are the general case. Run the free check to see which utility serves a specific address, which tier the system lands in, and what to ask.

Run the free check
Installers: keep the answer with the job

GridProjeX holds the project from here, with every value tied to the document it came from and the utility and permit tracks run to permission to operate.

How it works for installers
Utilities: see what applicants are told

The same published rules your applicants read here are the ones your queue sees. GridProjeX is the record both sides work from.

How it works for utilities

Also from CivyxIQ, if they fit what you already do: SolarProjeX for running the crews and the jobs, and Solar Home so the homeowner can follow their own project. Neither is needed to use the checker.