Ensuring the Climate and Environmental Integrity of Alternative Fuels

Public and private investments in alternative fuelsmolecular
energy carriers with potentially lower net greenhouse gas emissions
than conventional fossil fuelsare rapidly expanding due to
their perceived decarbonization potential. However, alternative fuels
like hydrogen, ammonia, and methanol are not inherently “good”
simply because they can be produced with low-carbon methods. Their
climate and environmental impacts vary widely depending on how they
are produced, handled, and usedfactors that most assessments
fail to fully account for. This can result in poorly informed decision-making,
with overestimated benefits of deployment choices. In this Perspective,
we highlight potential environmental impacts from alternative fuel
value chains and provide an actionable guide for their responsible
deployment. Specifically, we provide a brief overview of alternative
fuel attributes, assess climate and air quality implications across
production, handling, and use, and discuss technological, political-economic,
social, and other environmental considerations for responsible deployment.
We recommend improvements to alternative fuel assessments and suggest
safeguards to maximize their climate and environmental integrity,
including best-in-class practices and enabling policies. Given the
urgency of achieving global climate goals, it is critical to ensure
that scaling up of alternative fuels adheres to sustainable practices
from the outset.