Join Zero Emission Maritime Buyers Alliance


The Zero Emission Maritime Buyers Alliance (ZEMBA) is a first-of-its-kind buyers group within the maritime sector with the mission to accelerate commercial deployment of zero-emission (ZE) shipping, enable economies of scale, and help cargo owners maximize emissions reduction beyond what any one freight buyer could accomplish alone. Through demand aggregation and a competitive forward procurement process, ZEMBA members will gain early access to ZE shipping services not currently available and build confidence among the rest of the maritime value chain that sufficient demand for ZE solutions exists to stimulate additional investment.

In September 2023, over 20 ZEMBA members announced a first-of-its-kind Request for Proposals (RfP) for ZE shipping services to be delivered in 2025. Through this RfP, ZEMBA members are seeking ocean shipping services powered by zero-emission fuels for 600,000 twenty-foot containers (TEUs) over a three year period.

ZEMBA is an initiative of Cargo Owners for Zero Emission Vessels (coZEV) and facilitated by the Aspen Institute Energy & Environment Program


ZEMBA is focused on catalyzing a market for new ZE fuels that are not yet available. Therefore, for the RfP, ZEMBA has developed a multifaceted ZE fuels criteria.

To help guide bidders, ZEMBA is using the following definitions for ZE fuels which qualify under the RfP.

  • “Zero Emission” fuels have the potential to achieve GHG (CO2, CH4 and N2O) emission reductions equal to or greater than 90% when compared to the reference fuel (LSFO-R). The methodology for the calculation of the Well-to Wake “WtW” GHG emissions life-cycle assessment (LCA) value will be based on the IMO LCA Guidelines*. The units will be gCO2(eq)/MJ of fuel.
  • “Zero Emission” fuels shall be derived from sustainable and/or waste, residual, or byproduct feedstock sources including hydrogen and captured CO2. Fuel suppliers must be certified to a relevant sustainability standard by an independent certification body accredited to one of the following sustainability standard holders: the Roundtable on Sustainable Biomaterials (RSB), the International Sustainability and Carbon Certification (ISCC) or another standard holder recognized by the European Commission.
  • “Zero Emission” fuels, including any relevant feedstocks (e.g., hydrogen), shall be produced using renewable energy or another non-fossil, low-carbon energy source.
  • “Zero Emission” fuels must be sufficiently scalable to make a meaningful contribution to the decarbonization of the maritime shipping industry as determined by ZEMBA and must have safety concerns addressed.

As ZE fuel technologies advance and the availability of green fuels increases, we anticipate strengthening the emissions reduction requirements for ZEMBA in subsequent RfP rounds.

*Contained in IMO Resolution MEPC376(80)


ZEMBA’s RfP is a forward procurement process because today, ZE fuels that meet ZEMBA’s GHG emissions reduction requirements are not available at the scale needed to meet ZEMBA’s demand. Through this RfP process, ZEMBA aims to kickstart the market for these fuels, helping to facilitate new or expanded partnerships across the maritime value chain in order to fulfill the requirements of this RfP, and prepare for future rounds with higher demand.

By working together, ZEMBA members are building confidence and appetite for investment in ZE fuels and technologies across the maritime value chain.
ZEMBA welcomes the submission of both individual carrier bids and consortium bids, as needed to fulfill ZEMBA’s volume goal. By forming a consortium, carriers can leverage synergies in fuel procurement and realize economies of scale, leading to competitive pricing. Furthermore, this collaborative approach accelerates the shift towards zero-emission shipping and fosters a shared commitment to this goal.

For potential bidders interested in gaining more information specifically about the RfP, please email For general questions about ZEMBA, including joining as a member, please email

ZEMBA will make subsequent announcements in the coming months.