Request for Information (RFI) on Active Substations with Flexible Large Power Transformers

The U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) has issued a Request for Information under DE-FOA-0003581 to explore opportunities in the development of active substations with flexible large power transformers. ARPA-E was established to advance transformative energy technologies that can improve the resilience, reliability, and security of the U.S. electric grid. This RFI does not constitute a funding opportunity announcement but rather seeks input to shape a potential future program. The program aims to accelerate the development of technologies that will reduce the cost, lead time, and size of substation components while enhancing their performance, modularity, and protection from cyber and physical threats. The scope of this request is broad, encompassing innovations in substation planning, design, commissioning, and manufacturing. ARPA-E is particularly interested in scalable and rapidly deployable solutions that address key challenges in large power transformer production and deployment. Example technologies include flexible hybrid transformers, solid-state transformers for high-voltage use, hybrid systems with integrated storage, and mobile substations for resilience management. Component-level areas of interest include dielectric and magnetic materials, winding insulation, bushings, and advanced thermal designs. System-level innovations such as modular transformer blocks and integrated power converters are also highlighted. The RFI seeks responses from a wide range of stakeholders, including engineers, manufacturers, developers, materials scientists, and energy storage experts. The agency expects respondents to share insights on where accelerated advancements are most needed and which technologies could yield the greatest impact. ARPA-E has also outlined areas outside the scope of interest, including non-substation-related technologies, low-level power electronics control, and semiconductor design and manufacturing. To guide submissions, ARPA-E has posed specific questions on substation technologies, modular designs, integration of energy storage, potential for compact or mobile substations, and strategies to reduce reliance on critical materials such as copper and grain-oriented electrical steel. Additional questions probe the role of hybrid transformers, the potential for additive manufacturing, and the feasibility of “substation in a box” concepts. Respondents are encouraged to provide technical insights, performance requirements, and challenges that could inform future funding decisions. Submissions must be in PDF format and emailed to ARPA-E-RFI@hq.doe.gov no later than September 22, 2025, at 5:00 PM Eastern Time. Emails should clearly state “<organization name> - Response to Active Substations with Flexible Large Power Transformers” in the subject line. The body of the email must include the respondent’s name, title, organization, organization type, email address, telephone number, and relevant areas of expertise. Responses should not exceed ten pages, must use 12-point font, and should avoid including proprietary or confidential information, as ARPA-E may use submitted material for program planning without attribution. Importantly, this RFI is purely for program development purposes and does not provide funding or compensation. Responses will not receive individual feedback, nor will ARPA-E release a compendium of submissions. However, the information gathered will directly influence the agency’s strategy in designing a new program to accelerate advancements in transformer technology and substation modernization. Respondents may be contacted for clarification, but otherwise, the process is limited to gathering expert feedback.