Below are frequently asked questions and answers about the coZEV 2040 Ambition Statement. If you have any additional questions not covered here, please don’t hesitate to reach out to the Aspen Institute’s coZEV facilitation team by sending us an email to

Note that shipping companies are referred to as “carriers” and the term “cargo owner” is used for beneficial cargo owners that utilize ocean freight services.

What is coZEV and what is its role?

In 2020, the Aspen Institute worked in collaboration with and input from numerous cargo owner companies to develop coZEV, Cargo Owners for Zero Emission Vessels. coZEV is a platform for climate-forward companies to work with one another — and others in the supply chain when appropriate—to develop initiatives to advance maritime decarbonization. The first public action of the coZEV initiative is the release of this 2040 Ambition Statement.

The aim of coZEV is to be nimble, ambitious, action-focused, and as light-on-process as possible, focused on providing cargo owner companies with concrete opportunities to drive decarbonization of the maritime sector. Companies that participate in a project of the initiative are not required to formally join as a standing member nor commit to future actions of the initiative. coZEV brings companies together around shared interests.

Who are the organizers of coZEV? Where does the funding come from?

The Aspen Institute’s Shipping Decarbonization Initiative developed coZEV with cargo owner input and serves as its secretariat. Philanthropic resources to support coZEV are provided by the ClimateWorks Foundation. coZEV also benefits from advice and support from the following expert founding not-for-profit partners: Clean Air Task Force, Environmental Defense Fund, Ocean Conservancy, and University College London Energy Institute. Other valued partners include the Global Maritime Forum, c40 Cities, ESP Advisors, Rocky Mountain Institute, and Pillsbury Winthrop Shaw Pittman, among others.

Is coZEV duplicative of existing efforts? Are there international treaties or other efforts that address this need? Will coZEV work with others?

coZEV is unique in its role and function. There is currently no treaty or other collaborative effort specifically designed to provide opportunities for cargo owners to signal customer demand and high ambition for zero carbon shipping. coZEV is focused on harnessing cargo owner leadership in climate action and responding to their specific shipping decarbonization concerns by creating high-ambition collaborative projects tailored to their interests.

Collaboration is a priority for the Aspen Institute and the coZEV network. There are several important existing initiatives that organize industry players across various parts of the shipping value chain in support of shipping decarbonization, including the Getting to Zero Coalition. The work of coZEV complements these existing efforts. The shipping industry’s cargo owner customers are essential catalyzers of action, but they cannot enact the change needed alone. Engagement across the value chain, with other experts, and policymakers is essential.

Did cargo owners need to become “members” of coZEV to sign onto this statement?

By becoming signatories to the coZEV 2040 Ambition Statement, specific companies have shown leadership among peers on the topic of maritime decarbonization. However, there is currently no requirement to become a member of a standing group or otherwise commit to future actions of the coZEV initiative.

Why zero-carbon fuels? Why not just use fossil fuels more efficiently?

Studies from Llyod’s Register and UCL/UMAS have demonstrated that while many technical and operational efficiency measures are currently available and should be deployed, they are not enough. Operational and technical efficiency measures can at most provide a 50% carbon intensity reduction for fossil powered shipping, not nearly enough to fully decarbonize the sector in line with Paris Agreement goals. Therefore, a full scale transition to zero emission fuels and technologies ‒ combined with maximum feasible use of efficiency measures ‒ is necessary. Given the predicted long arc of this transition, the pace of change must accelerate quickly.

Are there really zero-carbon fuels? What does the coZEV 2040 Ambition Statement mean by zero-carbon and lifecycle emissions? What does the statement say about LNG and hydrogen-derived fuels?

The coZEV 2040 Ambition Statement defines zero-carbon fuels as:

  • Zero-carbon fuels are those that have zero or near-zero greenhouse gas emissions (not only CO2) on a lifecycle basis. Lifecycle emissions, often termed in shipping “well-to-wake” emissions, take into account the emissions of a fuel at all stages of its harvest, production, and use for propulsion and auxiliary power. Analyzing emissions from a lifecycle perspective ensures that all the potential impacts to the environment and human society are taken into account.
  • Acceptable zero-carbon fuels are those that are sufficiently scalable (individually or in combination) to decarbonize the entire shipping industry. A 2020 Llyod’s Register and UCL/UMAS study — Techno-economic assessment of zero carbon fuels — discusses the scalability concerns of some maritime fuels due to limited production potential and competition for their use that will lead to supply constraints. Addressing safety and land use concerns regarding potential zero-carbon fuels is also noted as important. Land use concerns, competition with human food supply, and ecosystem damage from production relate in particular to some categories of biofuels. A focus on safety is relevant for all potential new fuels and technologies, but a specific discussion of toxicity and other impacts of ammonia as an alternative shipping fuel is found below.
  • Importantly, the statement also calls for establishment of globally recognized standards for zero-carbon shipping fuels, as have been developed for sustainable aviation fuels.

While this general definition keeps the door option to a variety of potential fuel and technology types, the definition cautions against fuels and technologies that experts have indicated will offer no or only very modest greenhouse gas reduction potential and will be costly to retrofit for use with zero-carbon fuels. In particular, the definition echoes the concerns regarding LNG (particularly fossil-LNG) that have been expressed by the World Bank and other prominent organizations.

Furthermore, the definition points to hydrogen and hydrogen-derived shipping fuels (e.g., liquid hydrogen and ammonia) as offering a potential economically viable pathway for zero-emission shipping from a lifecycle perspective that meet our other criteria as well, without closing the door to future fuel and technology innovation. When produced with zero-carbon energy, hydrogen-derived fuels are as near to zero carbon as can be achieved from a lifecycle perspective. A 2019 study by Lloyd’s Register and UCL/UMAS — Fuel Production cost estimates and assumptions — provides more information on the lifecycle emissions of different fuels.

The zero-carbon definition in the footnote of the ambition statement was written jointly by cargo owner companies and not-for-profit experts as a way to clarify general criteria for appropriate “zero-carbon” fuels without constraining future flexibility to include or exclude specific fuel types as innovation unfolds and as experts learn more about the pros and cons of various fuels.

What about the safety and other environmental concerns surrounding ammonia?

E-ammonia (ammonia made with renewable energy) is attracting particular interest as a future alternative to fossil fuel for shipping for its ability to avoid carbon emissions from a lifecycle perspective, be produced at vast scale, and at potentially competitive prices, particularly where adequately supported by policy. However, there are important questions remaining about its safe onboard use and bunkering, non-carbon pollutants that may need to be mitigated (including NOx and N20, a greenhouse gas), and concerns about clean up protocols in the event of marine spills. The results of studies underway on these matters are eagerly anticipated, as is the creation of appropriate international and domestic fuel standards and regulatory updates to address concerns. These will help society determine the appropriateness of e-ammonia as a potential cornerstone zero-carbon fuel for shipping decarbonization.

What about other fuel types like:


Wind assist technology is a powerful new/ancient additional efficiency measure to reduce the use of fuel during transoceanic voyages. While wind as a primary propulsion system is possible for some routes on some vessel types, it isn’t a viable global decarbonization solution on its own for all of shipping. Widespread use of wind assist to bolster the efficient use of all fuels has exciting potential for the future. Furthermore, wind power (along with other renewable energy sources, like solar) can also be used to generate power as a feedstock for the production of zero-carbon fuels such as e-hydrogen.


Methanol is an easy to deploy and relatively inexpensive fuel for lowering net carbon emissions. Its formulation requires carbon and in order to become at (or near) net zero carbon, those carbon sources must be either low-emission biofuels or direct air capture. Bio-based methanol may play a transition role as companies begin adapting their procurement in favor of zero-carbon shipping and seek to lower their shipping emissions immediately. However, there are long term sustainability concerns with any bio-based shipping fuels because of potential land use concerns, supply limitations, and anticipated competition from other sectors seeking to use biofuels (e.g., aviation). Methanol made with carbon captured from the air is currently expensive, but could offer economically viable opportunities in the future as direct air capture technologies advance and come to scale.


Nuclear power can be used as a feedstock for hydrogen production, and there is also work being done to develop new nuclear-powered marine propulsion technologies. The ambition statement does not weigh in on the acceptability of either. Instead, the statement emphasizes the requirement that any shipping fuels of the future must address society’s safety and other social and environmental concerns.

Will these fuels cost more, and what impact will this have on cargo owners?

It is generally understood that zero-carbon fuels may cost more than fossil fuels in the early years, until there is sufficient policy support to close the cost gap and large-scale deployment of those fuels to achieve economies of scale.

Signatories to the coZEV 2040 Ambition Statement are not at this time committing to purchase specific volumes of freight moved by specific types of fuels at specific price points. Instead, they are signaling that they want a competitive and economically viable marketplace for zero-carbon freight to form, that they are interested in working with other cargo owners and actors across the value chain to be able to participate in that marketplace, and that policy support will be essential to achieving success in the long run. Cargo owners will continue to make independent procurement decisions as this energy transition in shipping unfolds.

What is a green shipping corridor and how can cargo owners get involved?

According to a 2021 report by the Getting to Zero Coalition, green corridors are defined as "a shipping route between two major port hubs (including intermediary stopovers) on which the technological, economic, and regulatory feasibility of the operation of zero-emissions ships is catalysed through public and private actions." Other aspects of green corridors that have been identified by thought leaders include, but are not limited to, concerted efforts at emission reduction and the commercial operation of the first vessels powered by fuels that emit zero or near-zero greenhouse gases on a lifecycle basis. They are voluntary in nature, and can be coalitions of industry-only, government-only, or public-private actors working in collaboration. To be successful, they require both fleet and land-side solutions. The concept of green corridors were featured prominently during discussions at COP26, including through the Clydebank Declaration.

In January 2022, the ports and cities of Shanghai and Los Angeles announced their intention to work together with cross-industry partners, including coZEV, to establish a green shipping corridor along this route, one of the busiest container shipping routes in the world. For more information on this route, see our Initiatives page.

Through coZEV, the Aspen Institute Shipping Decarbonization Initiative will offer multinational companies that rely on maritime shipping opportunities to contribute to the development and implementation of new green corridor projects, including the Shanghai - Los Angeles initiative.

For more information, or if you're a cargo owner company who wants to get involved with the Los Angeles - Shanghai green corridor development, please reach out.