Analysis of Pathways to Reach Net Zero Naval Operations by 2050

With the backdrop of net-zero emissions as an essential element of national security, this study undertook an analytical approach to evaluate current Department of the Navy (DON) emissions and understand energy needs to support mission readiness while reducing emissions over time.

May 1, 2023

Naval Postgraduate School, Monterey, CA

An overview of U.S. Department of Defense and federal government energy consumption from fiscal years 1975 to 2018. (Image: Naval Postgraduate School)

This report is based on a broad study of strategies for the Department of the Navy (DON) to achieve net zero global emissions by 2050 to comply with recent Executive Orders and goals set out for the Department of Defense (DOD) and the DON (Melillo, 2022). In January 2021, Executive Order 14008 called for a government-wide approach for meeting climate related challenges in the U.S. and set goals for agencies. In December 2021, Executive Order 14057 set the specific goal of net zero emissions from overall federal operations, including DOD, by 2050 and a 65 percent emissions reduction by 2030.

These are challenging targets for the DOD: 2019 data shows that the DOD consumed 682 trillion BTUs, which represents up to 77 percent of federal government energy use. The Navy uses fuel for jets, vehicles, ships, ground equipment, and for generating electricity for forces in the field and for powering operations at Navy installations. Fuel is required for mission readiness and fuel demand depends on operational needs and the tempo of operations. Depending on the year, up to 75 percent of that energy use is operational; for the DON, that means ships and aircraft – two of the most difficult sectors to decarbonize, both in the military and in the private sector.

With the backdrop of net zero emissions as an essential element of national security, this study undertook an analytical approach to evaluate current DON emissions and to understand energy needs to support mission readiness. In this report, researchers present current and proposed low-carbon energy sources as possible pathways for shifting DON to net zero by 2050 with models presenting four pathway options. The research leverages existing net zero strategies and findings developed by the public and private sectors and identifies challenges and gaps to advance future research and analysis to further emissions reduction by the DON.

The relationship of climate change to national security is well-documented. Most recently, the DON opened its climate strategy, Climate Action 2030, with the statement Noting that the climate threat for the DON is existential, the strategy acknowledges increased instability across the globe while simultaneously affecting the DON’s ability to respond. Moreover, most DON installations are coastal and sea level rise will test the ability for these installations to continue to meet their missions. Furthermore, the DOD has found that climate change is reshaping the geostrategic, operations and tactical environments with significant implications for U.S. national security and defense.

As a destabilizing force, climate change demands new missions of the DOD and DON and can alter the operational environment (Department of Defense [DOD Adaptation], 2021). Climate change exacerbates existing threats, especially in vulnerable parts of the world where the Navy and Marine Corps are called upon for Humanitarian Aid and Disaster Response (HADR) missions and may experience increased conflict from resource competition or scarcity and environmental changes. Impacts of climate change also are felt at installations which affect key warfighting capabilities. It is within this context that the Navy Climate Strategy sets mitigation measures to reduce the impact and speed of climate change by reducing emissions of greenhouse gases (GHG) or taking steps to remove carbon dioxide from the atmosphere. Accelerating these efforts would help to modernize Naval forces and reduce costs and operational vulnerabilities related to fossil fuel-based energy.

This work was performed by Kristin Flecher, Marina Less, Brandon Naylor and Jonathan Lussier for the Naval Postgraduate School. For more information, download the Technical Support Package (free white paper) here under the Vehicles and Robotics category. NPS-2098