DARPA Heat-to-Electricity RFI (DARPA-SS-27-01)

Executive Summary

DARPA's Defense Sciences Office is asking for information on solid-state devices that turn heat directly into electricity with no moving parts. Companies, universities and labs may respond. Responses are due 4:00 p.m. ET November 23, 2026; SAM.gov lists 11:00 a.m. ET, so plan for the earlier time.

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This is a Request for Information, so it carries no funding and no award. DARPA says the RFI is for "information and new program planning purposes" and will "inform potential program(s) in this area." In BW&CO's experience, DARPA RFIs like this one often lead to funding, either as a new program solicitation or as seedling awards through the DSO Office-wide BAA (HR001126S0015), and DARPA typically funds seedling-type projects at about $1 million per project (BW&CO estimate, not a posted DARPA figure). A strong response puts your technology and team in front of the program manager who is shaping that next step.

Solicitation at a Glance

• Agency: Defense Advanced Research Projects Agency (DARPA), Defense Sciences Office (DSO)
• Opportunity: Solid-State Energy Conversion from Heat to Electricity, Request for Information (RFI)
• Number: DARPA-SS-27-01
• Award Vehicle: None. This is an RFI and "does not constitute a formal solicitation for proposals."
• Funding: No posted amount. DARPA "will not provide reimbursement for costs incurred in responding to this RFI." Possible follow-on route: DSO Office-wide BAA HR001126S0015 (no posted award amounts).
• Technology Maturity: Any. "DARPA welcomes responses on low-TRL concepts and mature technologies."
• Due Date: 4:00 p.m. (Eastern) on November 23, 2026 per the RFI document; the SAM.gov notice lists 11:00 a.m. ET. Submit by 11:00 a.m. ET to be safe.

Think your company qualifies? Talk with BW&CO before the November 23, 2026 deadline.

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What Is the DARPA Solid-State Heat-to-Electricity RFI?

DARPA-SS-27-01 is a Defense Sciences Office request for information on "the current state of the art and technological limitations of solid-state direct thermal-to-electric energy conversion technologies." DARPA defines solid-state energy conversion as systems that turn a temperature differential directly into electricity "without utilizing mechanical moving parts (e.g., pistons, turbines, or rotary alternators)." The RFI names thermoelectric generators (TEGs), thermionic energy converters (TECs), thermophotovoltaic (TPV) converters, alkali metal thermal-to-electric (AMTEC) converters and hybrid architectures. It is "intentionally use-case and heat-source agnostic," so DARPA wants to hear from a wide range of approaches.

What Problem Is DARPA Trying to Solve?

Most power today comes from mechanical heat engines. DARPA notes these reach more than 50% efficiency at utility scale but only "15-25% in the tactical (kilowatts, kW) power ranges," and they bring friction, seal wear, vibration and heavy maintenance. Solid-state converters avoid moving parts, yet realized efficiencies "have remained stubbornly low, on the order of 3-7% for thermoelectric devices and 5-15% for thermionic systems." DARPA wants to know whether recent advances in nanomaterials, microfabrication, high-temperature ceramics, wide-bandgap semiconductors and radiative engineering can push solid-state efficiency much closer to the Carnot limit.

Priority Capability Areas: What DARPA Is Looking For

• Current capability: The most efficient solid-state converters realizable today, with the operating point (hot side temperature, cold side temperature and power output), efficiency calculation method, temperature limits and size, weight and power (SWaP).
• Technology potential: Quantitative evidence that current barriers can be overcome and how much performance could improve.
• Applications: Use cases that would benefit most, the pain points of current solutions, and the efficiency, power or SWaP thresholds that would make a solid-state system "the clear favorite."
• Thermionic advances: Microfabricated spacers for micron-scale gaps, and low or tunable work function emitter materials that allow cooler operation.
• Hybrid and AMTEC approaches: Thermionic/thermophotovoltaic hybrids and faster screening for adverse material interactions in AMTEC systems.
• Terrestrial and space use: Systems with cold sides near 300 K for ground use, and systems with higher cold-side temperatures that "may enable efficient radiative cooling for space systems."

Why Respond to an RFI? How DARPA RFIs Turn Into Funding

DARPA pays nothing for RFI responses, and the RFI states that responses "do not bind DARPA to any further actions related to this topic." So why spend time on one? In BW&CO's experience, a DARPA RFI is often the first public step toward new funding in that technical area. The RFI itself says the information "will inform the potential for future DARPA programs in this area."

• New program solicitations: In BW&CO's experience, DSO RFIs often come before a program announcement or BAA on the same topic. DARPA has not promised a program here, and responding "is not required to propose to a subsequent solicitation (if any)."
• DSO seedling awards: The DSO Office-wide BAA (HR001126S0015) accepts executive summaries and abstracts "on a rolling basis until August 27, 2027, at 4:00 PM." DARPA describes awards under that BAA as efforts that "often serve as valuable foundational 'seedlings' for future DSO programs." Its first thrust area is "Materials, Manufacturing, and Energy Systems."
• Typical seedling size: In BW&CO's experience, DARPA typically funds seedling-type projects at about $1 million per project. This is a BW&CO estimate, not a posted DARPA figure; the DSO BAA does not post award amounts.
• Visibility with the program manager: The RFI lists Mike McDonald, Program Manager, DARPA/DSO, as point of contact. A clear, quantitative response helps the program office understand what your team can do before any solicitation is written.

See BW&CO's breakdown of the DARPA DSO Office-wide BAA for how that follow-on route works.

Eligibility Requirements and Participation

• Who may respond: DARPA "appreciates responses from all capable and qualified sources, including, but not limited to, universities, university-affiliated research centers (UARC), Federally Funded Research and Development Centers (FFRDC), private or public companies, and Government research laboratories."
• No prerequisite: Responding is voluntary and is not required to propose to any later solicitation.
• Follow-on BAA limits: The DSO Office-wide BAA is narrower. It states that FFRDCs, UARCs and "Government Entities to include National Laboratories are not eligible to propose to this solicitation."
• Classification: Responses must be unclassified. Mark any proprietary page with a label such as "Proprietary" or "Company Proprietary."

How to Apply

• Format: 12-point font, single-spaced, single-sided, 8.5 by 11-inch paper with 1-inch margins, in MS Word or Adobe PDF.
• Cover sheet (1 page): Response title and technical point of contact name, organization, phone and email.
• Technical description (5 pages): Address one, several or all of the three questions (current capability, technology potential, applications). Include models, test data and current TRL where you can.
• Bibliography/references (2 pages): Supporting literature for your claims.
• Prior research and capabilities (1 page): Relevant prior research, experimental capabilities and publications.
• Graphic overview slide (optional): One PowerPoint slide, "optional but highly encouraged."
• Submit: Email the response to DARPA-SS-27-01@darpa.mil. Send questions to the same address; DARPA warns that emails sent directly to the program manager "may result in a delayed response or no response at all." DARPA "encourages respondents to respond early."

What Happens After You Submit?

• No acknowledgment required: DARPA "is under no obligation to acknowledge receipt" or give feedback.
• Who reads it: Submissions may be reviewed by DARPA and other Government partners, FFRDCs and Scientific, Engineering and Technical Assistance (SETA) support contractors.
• Program planning: DARPA uses the responses to judge whether a future program makes sense. Watch SAM.gov and darpa.mil for any related solicitation or proposers day.
• Parallel route: If your concept fits DSO's interests now, you can submit an executive summary or abstract to the DSO Office-wide BAA, which reviews submissions on a rolling basis.

Is This Opportunity a Good Fit for Your Company?

This RFI fits teams that build or study thermoelectric materials, thermionic emitters, thermophotovoltaic cells and emitters, AMTEC components or hybrid converters, and that can back their claims with numbers. It also fits companies with a defense or space use case where a quiet, low-maintenance power source would change the mission, such as tactical power, remote sensors or spacecraft. If you have device data at a defined operating point, or a credible path to a large efficiency gain, a response is worth the effort. If your work is an incremental tweak to a commercial product, DARPA is less likely to see it as a program driver.

How BW&CO Can Help

BW&CO has helped deep-tech and dual-use founders secure more than $350M in non-dilutive funding. For DARPA RFIs like the Solid-State Heat-to-Electricity RFI, we help you:

• Position for follow-on funding: Shape the response so it sets up a later DSO BAA submission or program proposal.
• Frame the technical case: Turn your data into the operating point, efficiency and SWaP numbers DARPA asked for.
• Define the use case: Connect your technology to defense and space applications with clear performance thresholds.
• Manage proprietary content: Decide what to share and how to mark it in an unclassified response.
• Plan the DSO BAA path: Draft an executive summary or abstract for the DSO Office-wide BAA when the timing is right.

Plan Your DARPA Heat-to-Electricity RFI Response

Frequently Asked Questions

Does the DARPA-SS-27-01 RFI provide funding?

No. It is a Request for Information issued "solely for information and new program planning purposes." There is no posted amount and DARPA "will not provide reimbursement for costs incurred in responding to this RFI."

Why should my company respond to an RFI that offers no money?

In BW&CO's experience, DARPA RFIs often turn into funding, either through a new program solicitation or through seedling awards under the DSO Office-wide BAA. The RFI states it will "inform the potential for future DARPA programs in this area." DARPA has not promised a program, but a strong response helps the program office understand your capabilities early.

How much could a follow-on DARPA seedling award be worth?

In BW&CO's experience, DARPA typically funds seedling-type projects at about $1 million per project. This is a BW&CO estimate, not a posted DARPA figure. Neither this RFI nor the DSO Office-wide BAA posts award amounts.

When are responses due?

The RFI document says responses are accepted "Until 4:00 p.m. (Eastern) on November 23, 2026." The SAM.gov notice lists a response time of 11:00 a.m. ET on the same day, so plan to submit by 11:00 a.m. ET. DARPA encourages early responses.

Which technologies are in scope?

Any system that converts a temperature differential directly into electricity without mechanical moving parts. The RFI names thermoelectric, thermionic, thermophotovoltaic and AMTEC converters plus hybrid architectures, and it is "intentionally use-case and heat-source agnostic."

Who can respond?

DARPA invites "all capable and qualified sources," including universities, UARCs, FFRDCs, private or public companies and Government research laboratories.

Does my technology need to be mature?

No. "DARPA welcomes responses on low-TRL concepts and mature technologies." You should state the current TRL of demonstrated performance and your projected improvements.

Do I have to respond to the RFI to compete for later funding?

No. Submission "is voluntary and is not required to propose to a subsequent solicitation (if any) on this research topic." You can also submit to the DSO Office-wide BAA (HR001126S0015) on a rolling basis until August 27, 2027, at 4:00 PM ET, though FFRDCs, UARCs and national laboratories are not eligible to propose under that BAA.

Can I include proprietary information?

DARPA asks for non-proprietary information "to the maximum extent possible." If you include proprietary content, label each such page "Proprietary" or "Company Proprietary." Do not include classified information.

Can BW&CO help with a DARPA Solid-State Heat-to-Electricity RFI response?

Yes. BW&CO helps teams shape RFI responses that present their data clearly and position them for follow-on DARPA funding, including a DSO Office-wide BAA submission. Book a call with our team.

Source: SAM.gov: DARPA-SS-27-01 Solid-State Energy Conversion from Heat to Electricity RFI