Sr. Accounts Payable Specialist

General Summary

The Sr. AP Specialist is responsible for the accurate, timely, and compliant processing of vendor invoices, with a strong focus on purchase order (PO) matching, project‑based accounting, and grant‑funded expenditures. This role serves as a subject‑matter expert for complex AP transactions, supports month‑end close activities, and partners closely with Procurement, Project Management, and Grants teams to ensure financial accuracy and compliance with internal controls and external regulations.

Why GTI Energy?

GTI Energy is where complex energy challenges meet bold solutions. With expertise in energy research, technology development, and business innovation, partners across every sector trust us to build and demonstrate solutions for better-performing energy systems. Guided by systems thinking, collaboration, and innovation, we are focused on driving progress that matters for people everywhere.

Being part of the GTI Energy team means being surrounded by people that are passionate and purpose driven, empowered to continuously learn, ask hard questions, and leverage their knowledge and experience to drive toward a greater purpose.

We offer generous benefits, competitive salaries, opportunities for professional growth and career advancement. We prioritize and maintain a respectful culture, and we ensure reasonable accommodation is made to enable individuals with disabilities to perform the essential functions of their role.

Work Location

The position will be based in the Chicagoland area at the GTI Energy Headquarters. We offer a hybrid/core work week, where employees are remote Mondays and Fridays, and required to be on-site Tuesday through Thursday.

Key Primary Responsibilities

Accounts Payable Operations

* Perform end to end processing of vendor invoices, including high volume and complex transactions

* Execute 2 way and 3-way PO matching (invoice, PO, and receipt), investigating and resolving variances related to pricing, quantity, and terms

* Ensure invoices are properly coded to general ledger accounts, projects, cost centers, and grants

* Review and validate supporting documentation to ensure compliance with company policies and audit standards

* Process weekly or biweekly payment runs (ACH, wire, check)

Project & Grant Accounting

* Accurately allocate expenses to capital projects, operational projects, and grant funded initiatives

* Ensure invoice charges align with approved project budgets, funding sources, and grant agreements

* Monitor allowable vs. unallowable costs under grant regulations and funding requirements

* Support grant reporting, audits, and reconciliations, including preparation of documentation for internal and external auditors

* Coordinate with Project Managers and Grants Administrators to resolve discrepancies and ensure timely cost recognition

Compliance & Controls

* Maintain strict adherence to internal controls, segregation of duties, and approval workflows

* Assist with month end, quarter end, and year end close, including accruals and AP reconciliations

* Support internal and external audits by providing detailed documentation and responding to inquiries

* Ensure compliance with GAAP and applicable grant and regulatory requirements

Vendor & Internal Stakeholder Support

* Serve as a primary point of contact for vendors regarding PO related questions and payment issues

* Collaborate with Procurement/Purchasing on vendor setup, PO accuracy, and contract compliance

* Provide guidance and training to junior AP staff on PO matching, project coding, and best practices

* Identify opportunities to improve AP processes, automation, and reporting

* Perform other duties as assigned

Required Knowledge, Skills, Abilities, and Other Characteristics

* Demonstrated expertise in PO‑based invoicing and 3‑way matching

* Hands‑on experience with project accounting and grant‑funded expenses

* Strong knowledge of AP controls, invoice auditing, and expense allocation

* Proficiency with ERP systems; preferably Deltek Costpoint (e.g., Oracle, SAP, Workday, Net Suite, or similar) and advanced Excel skills

* Excellent analytical, organizational, and problem‑solving abilities

* Strong communication skills with…