Request for Information (RFI): Phytomining for carbon-negative critical mineral supply chains | DE FOA 0002751

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The Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) issued this Request for Information (RFI), titled "Phytomining for carbon-negative critical mineral supply chains" (Funding Opportunity Number DE-FOA-0002751), to gather technical input that could shape a future ARPA-E research program. It is not a funding opportunity and it is not accepting applications for financial assistance, meaning there is no award amount, no expected awards, and no cooperative agreements being issued under this notice. Instead, ARPA-E is using the RFI to learn what transformative, practical technologies exist (or could be developed) to harvest high-value metals needed for clean energy technologies by using metal hyperaccumulator plants, with an emphasis on building domestic, low-carbon supply chains that avoid the environmental impacts and supply constraints associated with conventional mining and refining.

At a high level, the concept ARPA-E is exploring is phytomining: growing specialized plants that naturally take up and concentrate metals from soil, then harvesting the biomass and extracting the metals. The agency frames the desired end state as an economic and scalable approach that can operate on US land resources, particularly high-metal but non-arable lands such as ultramafic serpentine soils and mine tailings. The clean energy motivation is explicit: ARPA-E is looking for ways to produce critical minerals in forms that fit directly into battery and clean-energy manufacturing value chains, while minimizing greenhouse gas emissions and ideally achieving carbon-negative performance when evaluated using lifecycle analysis.

The RFI is organized around four interconnected technology areas. First, ARPA-E is seeking ideas on how to identify, domesticate, or develop hyperaccumulator species that are suitable for economically viable phytomining in the United States. This includes agronomic methods to improve plant performance and manageability, such as increasing biomass yields, controlling seed dispersal, and adapting species to US climates and soils. It also includes systems biology and related approaches to engineer or select for traits like faster growth, faster uptake, and the ability to accumulate metals in plant tissues and chemical forms that are easier to extract using low-carbon methods. ARPA-E highlights interest in perennial, high-biomass species (including trees) and plants that can thrive on marginal lands where conventional agriculture is not feasible.

Second, the agency is requesting input on methods to increase total metal uptake in hyperaccumulators at commercial scale. The focus here is on boosting how much metal can be captured per unit area without resorting to disruptive mining practices. Example directions include microbiome or rhizosphere engineering to increase metal solubility and availability to plants, and engineering plants to develop deeper or more effective root systems to access a larger pool of metals in the subsurface. ARPA-E encourages system-level approaches that integrate soil and root-zone manipulation, metal transport mechanisms within the plant, targeted accumulation in specific tissues or fluids (for example, saps), control over the chemical speciation of accumulated metals, and monitoring and analytical tools to measure and optimize the overall process.

Third, ARPA-E is looking for low-emissions, preferably carbon-negative extraction processes that can recover metals from harvested biomass while keeping the carbon captured in that biomass from being released back to the atmosphere. This category covers pre-treatment steps that could improve extraction yields (before or after drying), new metallurgical pathways that achieve high recovery and low impurity levels, and novel methods that directly yield metals in useful chemical forms. The RFI explicitly signals interest in integrated approaches that treat biomass in ways that both enable efficient metal recovery and retain or productively utilize biogenic carbon, including co-processing multiple biomass types, leveraging existing biomass processing infrastructure where possible, and designing recycling and recovery strategies that support circularity.

Fourth, ARPA-E wants concepts for producing high-value, high-purity metal products directly from phytomining that can feed into battery manufacturing and other clean-energy supply chains with minimal additional processing. In practice, this means shortening the conversion pathway from plant-derived material to a clean energy-relevant chemical form, reducing capital costs, energy use, and processing complexity. ARPA-E notes that many solutions may span multiple categories, such as a biological optimization strategy that simultaneously improves plant suitability for US conditions, increases biomass, increases uptake, and steers the metal into an extraction-friendly form.

ARPA-E provides an illustrative performance target using nickel as an example: the agency is interested in approaches that could reach at least 500 kg of nickel per hectare per year while delivering greater than 90 percent net greenhouse gas reduction compared to the state-of-the-art HPAL (high pressure acid leaching) process, assessed on a lifecycle basis. This target signals that ARPA-E is not only interested in proof-of-concept phytomining, but in concepts that can plausibly compete with industrial benchmarks on both production intensity and climate impact.

Administratively, the RFI was posted April 11, 2022, with responses due by 5:00 p.m. Eastern Time on May 26, 2022. Submissions were requested in PDF format via email to ARPA-E-RFI@hq.doe.gov. Eligibility is listed as unrestricted (open to any entity type, subject to any clarifications in the full text). The full RFI was made available through the ARPA-E funding opportunity portal at https://arpa-e-foa.energy.gov.

• The Department of Energy, Advanced Research Projects Agency Energy in the opportunity zone benefits, science and technology and other research and development sector is offering a public funding opportunity titled "Request for Information (RFI): Phytomining for carbon-negative critical mineral supply chains" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 81.135.
• This funding opportunity was created on Apr 11, 2022.
• Applicants must submit their applications by May 26, 2022 Reponses to this RFI should be submitted in PDF format to the email address ARPA-E-RFI@hq.doe.gov by 500 p.m. Eastern Time on 5/26/2022. For further instruction, please review the RFI in its entirety at https://apra-e-foa.energy.gov.. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Eligible applicants include: Unrestricted (i.e., open to any type of entity above), subject to any clarification in text field entitled Additional Information on Eligibility.

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