Lesson 3 of 9 · about 16 minutes
Zoning Districts, Overlays and Size Tiers
You'll be able to
- Build a use table that allows, conditions or prohibits energy facilities by district
- Explain what Idaho Code 67-6511 requires of an overlay district
- Classify a project into Tier 1, 2 or 3 using size, acreage, transmission and parcel triggers
- Apply an aggregation rule to a project split into pieces
Plan policy says where energy facilities should and should not go. The zoning ordinance makes it law in three layers: a use table by district, overlay zones for special places, and a size classification that decides how hard the review is. Jeff's energy facilities chapter does all three. This lesson walks through each with Owlcreek County numbers.
The use table
Every Idaho zoning code has some version of a table listing uses down the side and districts across the top. Each cell says permitted, conditional or prohibited. If commercial solar, wind and battery storage are not listed at all, staff may classify them as "similar to" a listed use, a gap the data center zoning lesson explains in detail. The first job is to list them.
| Use | Agricultural | Rural residential | Light industrial | Heavy industrial |
|---|---|---|---|---|
| Tier 1 on-site system (50 kW or less, serves the parcel) | Permitted (administrative) | Permitted (administrative) | Permitted | Permitted |
| Tier 2 solar or wind (over 50 kW to 25 MW) | Conditional, never on Class I or II soils | Prohibited | Conditional | Conditional |
| Tier 3 solar or wind (over 25 MW, or other trigger) | Prohibited unless an agricultural support use serving mainly the host parcel | Prohibited | Conditional | Conditional |
| Battery storage, 5 to 20 MWh | Prohibited | Prohibited | Conditional, fire district approval | Conditional |
| Battery storage over 20 MWh or over 5 acres | Prohibited | Prohibited | Prohibited | Conditional, fire district approval |
| Standalone substation for export projects | Prohibited | Prohibited | Conditional | Conditional |
That table is adapted from Jeff's chapter. Its effect is plain: commercial export generation stays off the farm zone and out of residential areas, and large batteries go only to heavy industrial land. Jeff's draft required an agricultural support finding for Tier 3 wind and solar in agricultural zones, "a finding that commercial export projects cannot satisfy." That is a prohibition written as a condition. Say so in the table. Honest drafting is easier to defend than a test designed to fail.
Two state laws bracket what a county can do to agricultural land. Idaho Code 67-6529 says county planning powers cannot deprive an owner of the full and complete use of agricultural land for producing agricultural products. Commercial power generation is not agricultural production, and the Legislature itself treats solar and wind as non-agricultural uses in the Agricultural Protection Area Act (67-9710(4)). But a genuine agrivoltaic project, crops or grazing under raised panels with production records, sits closer to the line. Jeff's chapter exempts agrivoltaics only where crops are the primary use, verified by annual production data. Keep that exemption narrow and measurable.
Overlay districts
An overlay draws a map line and adds rules inside it, without changing the base zoning. Typical energy overlays: a buffer around a town, a canyon rim or scenic corridor, a strip along a main canal, an airport approach. Idaho Code 67-6511 adds two requirements: overlay standards must be "clear and objective," and they must not amount to a regulatory taking.
Clear and objective means a surveyor or a staffer can apply them and get the same answer. "No energy facilities within 2 miles of the Dunmore city limits" passes. "Energy facilities shall not detract from the rural character of the Dunmore area" does not. Jeff's package is full of the first kind (setbacks in feet, noise in decibels) and has a few of the second kind (community character as an "independently sufficient" ground for denial). The first kind holds up better, and lesson 9 comes back to why.
Tiers by size
A tier system scales review to impact. A rooftop array on a dairy barn should not need what a 300 MW export plant needs. Jeff's chapter sets three tiers, and the triggers are the strongest part of the draft because they look at more than megawatts.
| Tier | Thresholds | Review | Financial assurance |
|---|---|---|---|
| 1, on-site | 50 kW or less AND 2 acres or less AND no off-site transmission; mainly on-site use | Administrative, staff decision within 30 days | None |
| 2, medium | Over 50 kW to 25 MW AND 2 to 160 acres AND no new off-site line over 5 miles | Conditional use permit, one public hearing | Bond at 150% of verified removal cost |
| 3, large | Any ONE of: over 25 MW; over 160 acres; new line over 5 miles in the county; easements or leases on 10 or more parcels; aggregation over any threshold | Conditional use permit, county-commissioned impact assessment paid by the applicant, two hearings, board decision | Trust fund at 150% of verified removal and restoration cost |
The 10-parcel trigger is clever. A project that needs leases from ten landowners is, by definition, a project reshaping a neighborhood, whatever its megawatt rating. The transmission trigger catches projects that look small at the panel field but string new lines across the county.
Jeff's chapter also classifies data centers by electrical load, treating load as equal to generation capacity, with any data center over 1 MW or 100,000 gallons of water a day falling under the chapter. That ties the two halves of the problem together: the large load and the generation built to serve it.
Closing the splitting loophole
The oldest trick in tiered codes is to cut a project into pieces just under the line. Jeff's aggregation rule treats projects as one if they are under common ownership, control or financing (including related entities), within 5 miles of each other, within 5 years of each other, and share transmission, roads, substations or interconnection. The county may also combine projects on substantial evidence of a common plan even if not all four factors are met.
Example: the Pell Flats split
Highline Solar LLC files for "Pell Flats 1," 22 MW on 150 acres. Eighteen months later, Pell Flats Two LLC, which shares Highline's managing member, files for 22 MW on 155 acres, 2.5 miles away, connecting to the same new substation.
- Common control: shared managing member. Yes.
- Distance: 2.5 miles, under 5. Yes.
- Timing: 18 months, under 5 years. Yes.
- Shared infrastructure: same substation. Yes.
- Combined size: 22 + 22 = 44 MW, over 25 MW. Combined acreage: 150 + 155 = 305 acres, over 160.
Result: one Tier 3 project. Under Jeff's reclassification clause, work on the expanded scope stops on written notice, a reclassification application is due within 60 days, and Tier 3 review must finish before work resumes. Without the rule, the county would have approved two Tier 2 projects with bonds, one hearing each and no impact assessment.
Common mix-ups
- Claim: A tier system is weaker than a ban. What the evidence shows: It depends on the table. Jeff's tiers, combined with district prohibitions and the soil rule, keep commercial export projects off farm ground entirely while letting farms add their own systems. The tiers decide how hard the review is where the use is allowed at all.
- Claim: A variance can let a prohibited use in. What the evidence shows: Idaho Code 67-6516 defines a variance as a modification of standards on lot size, setbacks, height and the size or placement of structures. It does not authorize a use the district prohibits. Say so expressly in the code anyway.
- Claim: If two projects have different LLC names, the county must treat them separately. What the evidence shows: Only if the code lacks an aggregation rule. Define related entities by ownership, control, financing and officers, and require each application to list related projects.
Reporting angle
- Request the use table and any staff interpretations classifying energy uses. Ask for the date and author of each interpretation.
- For each energy application, pull the Idaho Secretary of State business filings for the applicant and look for shared managers, registered agents and addresses with other applicants.
- Check the utility's interconnection queue position for the project, if public, to compare the megawatts there with the megawatts in the county application.
- Count the parcels in the lease area from the application map and the recorder's index of recorded lease memoranda.
Research angle
- Overlay standards requirement: Idaho Code 67-6511.
- Agricultural use limits: 67-6529 and 67-9710.
- Business entity records: Idaho Secretary of State business search.
- How conditional uses and variances differ: the conditional uses lesson and zoning and rezones lesson in the planning course.
Check yourself
1. What does Idaho Code 67-6511 require of overlay district standards?
The statute says overlay districts require clear and objective standards that must not amount to a regulatory taking under Idaho or federal law.
2. Under the tier rules adapted from Jeff's package, a 20 MW solar project on 140 acres needs a new 7-mile transmission line. Which tier?
Tier 3 is triggered by any one of its thresholds. A new transmission line exceeding 5 miles in the county is one of them, regardless of the 20 MW size.
3. Why does a tier system classify by the project 'as a whole, including all phases'?
Phasing is a common way to stay under thresholds. Counting all planned and reasonably foreseeable phases at the start closes it.
4. Two 20 MW projects are proposed 3 miles apart by related companies within two years, sharing one substation. Under the aggregation rule, how are they treated?
Common control, within 5 miles, within 5 years and shared infrastructure meet all four aggregation factors, so they combine into one 40 MW project above the 25 MW Tier 3 line.
5. What is a key difference between a prohibited use and a conditional use in a use table?
Conditional uses go through a permit process with findings. A prohibited use needs a rezone or code change first; a variance does not authorize a use the code prohibits.
Terms in this lesson
- Use table
- The part of a zoning ordinance listing which uses are permitted, conditional or prohibited in each district.
- Overlay district
- A mapped zone laid over the base districts that adds or changes standards for the land inside it.
- Tier
- A size class of energy facility that sets which review process and standards apply.
- Aggregation (anti-circumvention) rule
- A provision treating related projects as one for classification, so splitting a project cannot avoid a higher tier.
- Nameplate capacity
- The maximum rated output of a generator, in kilowatts or megawatts.
Sources
- Idaho Code 67-6511, Zoning ordinance (overlay districts, uniformity) checked 2026-10
- Idaho Code 67-6512, Special use permits, conditions, and procedures checked 2026-10
- Idaho Code 67-9710, Limitations on local regulations (APA Act) checked 2026-10
- Idaho Code 67-6529, Applicability to agricultural land checked 2026-10
- Idaho Code 67-6516, Variance checked 2026-10