ERCOT Generator Interconnection
How a solar, storage, or hybrid project moves from a RIOO-IS application to commercial operations on the Texas grid, and what that means for diligence, timelines, and risk.
ERCOT is not a FERC-style queue
ERCOT's generation interconnection process is not a classic FERC Order No. 2003-style serial queue with network-upgrade cost allocation and deliverability rights. Underwriting assumptions from PJM, MISO, or CAISO need to be adjusted.
Not a FERC queue
Each project moves through the process on its own. Congestion and staff capacity can create queue-like crunch points, but there is no formal queue with position-based rights. The monthly Generator Interconnection Status (GIS) Report is where the public sees project status.
Connect and Manage
Generation is connected and then managed through real-time congestion management. FIS studies ensure reliability. They are not intended to ensure deliverability or freedom from curtailment.
Driveway vs highway
Interconnection studies cover the "driveway", meaning the facilities needed to connect safely. Broader system upgrades (the "highway") go through the Regional Planning Group (RPG) planning process, not the interconnection study.
A public monthly report of interconnection milestones and trends. It is not a study stage.
The detailed, TSP-led study package that follows screening: steady-state, short-circuit, dynamic/transient stability, and facility study.
Three different regimes
Planning Guide 5.2.1 applies to new or modified Generation Resources, ESRs, or SOGs of 1 MW or more. Aggregate nameplate decides large vs small. Large Loads follow a separate set of rules.
Large generation
- Studies: SSS → FIS → Reactive → QSA
- Agreement: SGIA with the transmission TSP
- Separate modification rules apply
- This is the path shown in the main flowchart below
Small generation
- No SSS/FIS package like large gen
- TDSP System Impact Study
- Fully executed DSP/TSP interconnection agreement (or attestation)
- Financial security for distribution upgrades and operational-limitation confirmations
- Then ERCOT Approval to Submit Model Information
Large Load interconnection
- Separate regime: Large Load Interconnection or Modification (evolving Batch Zero process)
- Certain loads also appear in the QSA
- Not the same as the GIM generation path. Keep it on its own branch.
- Co-located load at a hybrid site needs both lenses. ERCOT provides separate coordination templates for co-located loads under 75 MW.
From application to commercial operations
Click any step to see what happens there and which documents it needs. Colors show the handbook stages: Stage 1 Stage 2 Stage 3
Stage 1 Step 1: GIM / GINR application
The Interconnecting Entity submits a Generator Interconnection or Modification (GIM), often still called a GINR, through RIOO-IS. It pays the Generation Interconnection Fee and receives an INR ID (yrINRxxxx). ERCOT reviews completeness, typically within 10 Business Days. Proposed large-gen COD must be at least 15 months after submission (PG 5.2.2).
- GIM/GINR application in RIOO-IS
- Generation Interconnection Fee (ACH/credit card per Fee Schedule)
- Lone Star Infrastructure Protection Act attestation (PG §8 Att. D)
- INR number assignment
Stage 1 Step 2: Security Screening Study
ERCOT runs a high-level steady-state screening (power flow / transfer) for the proposed POI and MW. It shows how much of the proposed generation can operate alongside other known generation in the area before significant transmission additions may be needed. It also screens for SSR study needs and SSO risk. ERCOT is allowed 90 days and may waive the SSS at its discretion.
- Security Screening Study report (posted to IE via RIOO)
- SSR vulnerability indication / Credible Single Contingency radial-to-series-capacitor count
Stage 1 Step 3: Full Interconnection Study
Within 180 days of SSS results, the IE must request FIS (dates, proof of site control, FIS-level data, fees) or the GIM is considered withdrawn. ERCOT designates a lead TSP, and the kickoff starts a 60-day clock to agree on scope. FIS covers steady-state, short-circuit, dynamic/transient stability, and facility study. SSR is scoped alongside FIS but is not part of it.
- FIS change request + Proof of Site Control
- Resource Registration data at FIS level (dynamic models / model quality tests)
- FIS Application Fee (ERCOT); FIS Scope / Study Agreement with TSP(s)
- DOD Siting Clearinghouse declaration (PG §8 Att. C) where applicable
- Reports: steady-state, short-circuit, dynamics, facility study; SSR study (separate)
- Optional ERCOT Economic Study if Tx costs expected >$25M
Stage 1 Step 4: SGIA + NTP + security
After the final FIS elements are complete and posted, the IE and TSP may execute the SGIA. ERCOT is not a party. The SGIA generally must be signed within 180 days of FIS completion or the GIM may be cancelled. Notice to Proceed and financial security for interconnection facilities are the key commercial milestones.
- SGIA (current form for SGIAs executed on/after Jan 1, 2026), or other public financially binding IA
- TSP notice of Notice to Proceed + financial security
- Semiannual Declaration of Resource Data Accuracy (PG §8 Att. A) once FIS requested
Stage 1 Step 5: Planning Guide 6.9
Meeting PG 6.9 (signed SGIA, NTP, financial security, air permits / water declarations as applicable, required data) qualifies the project for planning models, QSA eligibility, and the Protocol 16.5 operational-standards review.
- Signed SGIA + NTP + financial security (or MOU/EC letter)
- TCEQ air-permit documentation (or none required)
- Declaration of Adequate Water Supplies (wind/PV/battery ESS exempt per Att. B)
- Planning Model column data
Stage 1 Step 6: Reactive Study & Protocol 16.5
The IE completes the Reactive Study. ERCOT determines compliance with operational standards under Protocol 16.5 and has 90 days from PG 6.9 to do so. If SSR mitigation is required, it must be ready before Initial Synchronization.
- Reactive Study
- Protocol 16.5 Compliance with Operational Standards determination
- SSR mitigation (if required)
Stage 1 Step 7: Quarterly Stability Assessment
The QSA determines whether a project is eligible for Initial Synchronization in a given quarter. Prerequisites are due by fixed calendar deadlines. Missing a deadline means the project cannot synchronize in that three-month window.
- QSA inclusion prerequisites package
- QSA checklist (ERCOT)
Stage 2 Step 8: Registration & Modeling
Register as a Resource Entity, complete RIOO resource data through Full Registration (targeted ~120 days before the desired PLD), and coordinate the Network Operations Model through the Production Load Date. Set up EPS meters, ESI IDs, and telemetry/ICCP with the QSE and TSP.
- Market Participant Agreement; RE Application for Registration
- Managed Capacity Declaration; citizenship/ownership attestations; CEGE/CEGS LSIPA reporting
- Resource Registration Glossary data (Full Registration)
- NOMCRs (TSP); EPS meter design / cutover; GENMAP verification; ICCP point list
Stage 3 Step 9: Part 1 · Energize
Part 1 of the New Generator Commissioning Checklist: energize the Resource Entity's equipment, coordinating with the TSP at the POI.
- Commissioning Plan Template
- New Generator Commissioning Checklist Part 1
Stage 3 Step 10: Part 2 · Sync → Part 3 · Commission
Part 2 is Initial Synchronization with the required performance tests. QSA, SSR (if required), and operational-standards compliance must be satisfied first. Part 3 is the Request to Commission a Resource, which leads to commercial operations and INR status 'Operational'.
- Checklist Parts 2 and 3
- Test artifacts: IRR curtailment, reactive capability, VSS, AVR, PFR, PSS (as applicable)
- As-built dynamic models for IBRs prior to commissioning
- Weather preparedness declarations when required
The three official stages
The Resource Interconnection Handbook groups the process into three stages. Stage 1 holds most of the study and commercial work.
Interconnection Request Application → QSA
- GIM/GINR in RIOO-IS, fee, INR ID
- Security Screening Study (SSS)
- FIS request, scope agreement, FIS studies
- SGIA, Notice to Proceed, financial security
- Planning Guide 6.9, Reactive Study, Protocol 16.5 review
- Quarterly Stability Assessment (QSA)
Registration and Modeling
- Register as Resource Entity (if not already)
- RIOO resource data through Full Registration (handbook targets ~120 days before desired PLD)
- Network Operations Model via Production Load Date (PLD)
- EPS meters, ESI IDs, telemetry/ICCP with QSE and TSP
Energization, Synchronization & Commissioning
- Part 1 Energization
- Part 2 Initial Synchronization with performance tests
- Part 3 Request to Commission a Resource (commercial operations)
- QSA, SSR (if required), and operational standards must be satisfied before synchronization
| Actor | Stage 1 · Request → QSA | Stage 2 · Registration & Modeling | Stage 3 · Energize → Commission |
|---|---|---|---|
| IE / RE | Submits GIM, fees, site control, FIS data; signs FIS Scope Agreement and SGIA; posts NTP + security; meets PG 6.9; completes Reactive Study | RE registration, MPA, Full Registration data, Managed Capacity Declaration, attestations | Commissioning Plan; submits Checklist Parts 1–3; as-built dynamic models (IBRs) |
| TSP / TDSP | Lead TSP runs FIS elements (and SSR if required); designs interconnection facilities; executes SGIA; posts NTP/security to RIOO | Submits NOMCRs; EPS metering design / cutover; POI telemetry | Coordinates POI energization |
| ERCOT | Completeness review; runs SSS; designates lead TSP; reviews FIS/SSR; Economic Study if >$25M; PG 6.9 and 16.5 review; runs QSA | Network Operations Model build to PLD; GENMAP verification | Approves energization, synchronization, and commissioning; INR status → Operational |
| QSE | — | ICCP point list, telemetry setup | Takes part in commissioning tests and checklist; SCED telemetry; outage scheduling |
Key actors
Interconnecting Entity
The developer or applicant. Starts the GIM in RIOO-IS, pays fees, provides site control and resource data, funds TSP studies, negotiates the SGIA, and drives milestones. May or may not become the eventual RE.
Resource Entity
Registers with ERCOT and owns or controls the Generation Resource, ESR, and/or Load Resource. Responsible for registration data, telemetry coordination through the QSE, and commissioning checklist submittals.
Qualified Scheduling Entity
Represents the Resource in the market. Handles ICCP/SCED telemetry and outage scheduling, and takes part in commissioning tests and the checklist process.
TSP / TDSP
The lead TSP runs the FIS, designs and builds interconnection facilities, executes the SGIA, and submits NOMCRs, EPS metering, and POI telemetry. For distribution-connected projects, DSP feasibility and the IA are critical.
ERCOT Resource Integration
Accepts the GIM, runs the SSS, designates the lead TSP, reviews FIS/SSR, runs the Economic Study (>$25M), administers RIOO, enforces PG 6.9 and QSA gates, sets the model PLD, approves commissioning, and publishes the GIS report.
Also involved: PUCT (regulatory oversight, e.g. SGIA form updates; Power Generation Company registration may be required for REs) and RPG / planning stakeholders (a separate path for broader transmission upgrades).
How long does it take?
ERCOT's own overall guidance excludes construction and supply-chain delays. Actual timelines vary widely with TSP study load, restudies after design changes, equipment lead times, and QSA quarter gates.
Approximate overall process. Source: ERCOT interconnection process presentation (Fernandes), Oct 28, 2024. Excludes construction/supply delays.
Approximate overall process. Source: same ERCOT presentation (Fernandes), Oct 28, 2024. Excludes construction/supply delays.
Resource Interconnection Handbook, Appendix I: GIM tabular timeline
These are ranges, not guarantees. The bars use a 0–300 day scale and show durations only, not a cumulative schedule (steps can overlap).
QSA synchronization eligibility calendar
Planning Guide 5.3.5 / Handbook. If you miss the prerequisite deadline, the project is not eligible to synchronize in that three-month window.
| Desired Initial Synchronization quarter | QSA prerequisites due by | QSA completion target |
|---|---|---|
| Jan – Mar | Prior Aug 1 | End of October |
| Apr – Jun | Prior Nov 1 | End of January |
| Jul – Sep | Prior Feb 1 | End of April |
| Oct – Dec | Prior May 1 | End of July |
Finance-relevant callouts
The points from the ERCOT process that most affect underwriting, diligence checklists, and closing conditions.
No deliverability guarantee
Under Connect and Manage, FIS covers reliability only. It does not guarantee market deliverability. Being interconnected does not mean being deliverable.
Congestion curtailment
Generation is managed through real-time congestion management. FIS is not intended to ensure freedom from curtailment. Model it in the revenue case.
Inactive → cancellation
Inactive status can remove a project from planning models and GIS capacity tallies. Transmission-connected projects can sit Inactive for up to 5 years before ERCOT may cancel.
Withdrawal / cancellation clocks
If FIS is not requested within 180 days of SSS results, the GIM is considered withdrawn. If the SGIA is not signed within 180 days of FIS completion, the GIM may be cancelled (exceptions exist).
Hybrids need dual INRs
Submit separate GIM/INR applications for each technology type (e.g., a solar INR plus a battery INR). ERCOT/TSP may hold one FIS kickoff and may use one SGIA that references both INRs.
New SGIA form
The new SGIA (Nov 6, 2025 form) applies to agreements executed on or after Jan 1, 2026. The pre-2026 form is only for amendments or restatements of earlier SGIAs (PUCT Project 58211).
Interconnection cost reporting
Under PG 5.2.8.4, TSPs began reporting monthly interconnection costs in Jan 2026. ERCOT includes them in GIS reporting and will publish an annual report starting Apr 2027.
SSO risk rule
Under PG 5.2.10, generators whose original SGIA is executed on or after Apr 1, 2026 face stricter radial-to-series-capacitor interconnection constraints.
Confidentiality flips at FIS
Large-gen project details stay Protected Information until FIS is requested (or the IE waives). After that, public GIS visibility and RPG-related disclosures apply under PG 5.2.3.
Key closing artifacts
Signed SGIA, TSP notice of NTP + financial security, and PG 6.9 status are the milestones that open planning-model and QSA eligibility. FIS posting also triggers the semiannual Declaration of Resource Data Accuracy.
Network upgrade cost signal
If interconnection transmission costs are expected to exceed $25M, ERCOT may run an optional Economic Study. The FIS facility study includes design, milestones, and cost estimates.
IBR model quality
Ride-through, NOGRR245, and IEEE 2800-related data obligations continue through the project's life in RIOO. Model quality and as-built dynamic models matter most for solar and storage.
Glossary
AVR
COD
DESR / DGR
DSP / TSP / TDSP
ESR
ESI ID
FIS
GIM
GINR
GIS
IA / SGIA
IBR / IRR
IE
INR
MIS
NOMCR
NTP
PFR
PLD
POI / POIB
PSS
QSA
QSE
RARF
RE
RIOO-IS / RIOO-RS
RPG
SGIA
SLF
SOG
SSO / SSR
SSS
VSS
No matching terms.
Sources & deep links
Useful handbook appendices (inside Handbook v1.95): D/E Large Gen Timelines · F/G Small Gen Timelines · H Small Gen Process Flowchart · I GIM Tabular Timeline. Process questions: [email protected]