High Voltage Direct Current (HVDC) Interconnection
High Voltage Direct Current (HVDC) transmission offers advantages over AC in applications such as long-distance power transfer, stable AC interconnections, low short-circuit interties, and long underground links. SPP evaluates HVDC project requests, and both its regional expansion and the growing need for advanced HVDC technologies to support power exchange with other ISO/RTOs underscore the strategic importance of HVDC. Effective July 23, 2025, under the revised Attachment O of the SPP Tariff, the SPP HVDC Interconnection department established a new process with five stages: interconnection request, feasibility studies, planning studies, design studies, and interconnection agreement.
- Interconnection Request – Submission of the project request and execution of the HVDC Interconnection Agreement.
- Feasibility Studies – initial technical assessment.
- Planning Studies – detailed reliability and system impact evaluation.
- Design Studies – technical specifications and facility design requirements.
- Interconnection Agreement – final contractual arrangement.
The SPP HVDC interconnection process allows planners and developers to submit new HVDC projects into SPP’s sequential process for validation, study, analysis, and ultimately, execution of a HVDC Interconnection Agreement. These webpages provide guidelines to assist with submitting HVDC interconnection requests to SPP’s transmission system.
The following approved documents can help HVDC interconnection customers navigate the SPP HVDC process.
- SPP HVDC Interconnection Request Form
- SPP HVDC Interconnection Study Agreement
- SPP HVDC Attestation Statement for Site Control
- SPP HVDC Interconnection Study Deposit Refund Form
- SPP HVDC Interconnection IRS W-9 Form
- SPP HVDC Planning Manual
- SPP HVDC Interconnection Agreement
Should you have an immediate need that is not addressed on this site, please submit a request via SPP's Request Management System or HVDC_Planning@spp.org