Alternative Fuels for Military Applications

By James T. Bartis & Lawrence Van Bibber, RAND Corporation

The U.S. military has expressed interest in being early users of alternative fuels in their tactical weapon systems. Doing so would supplement the services’ use of gasohol and biodiesel in administrative and other nondeployable vehicles. Each of the services has established programs geared toward reducing dependence on the use of fossil fuels in tactical weapon systems, such as aircraft, combat ships and vehicles, and supporting equipment.

If the services are indeed to use alternative fuels in tactical weapon systems, these fuels must be able to substitute for one or more of the three petroleum-based distillate fuels that currently support the majority of military operations. From the perspective of technical viability, a number of alternative fuels can meet this requirement. But uncertainties remain regarding their commercial viability–namely, how much these fuels will cost and what impact they may have on the environment, particularly in terms of greenhouse gas emissions.

RAND examined economic viability, technical readiness for commercial production, lifecycle greenhouse gas emissions, and approaches that could be used to reduce those emissions.

Key findings:

Opportunities to Produce Alternative Fuels with Lower Greenhouse Gas Emissions

Fischer-Tropsch fuels are the most promising near-term options for meeting the Department of Defense’s needs cleanly and affordably.

• For biomass-derived FT fuels, the biomass feedstock must be produced in a sustainable manner; specifically, its production should not be based on practices that lead to sizable emissions due to direct or indirect changes in land use. If this is achieved, lifecycle greenhouse gas emissions can be near zero.
• For coal-derived FT fuels, carbon dioxide emissions at the FT fuel production facility must be captured and sequestered. If this is achieved, lifecycle emissions can be in line with those of petroleum-derived fuels.
• For FT fuels derived from a mixture of coal and biomass, carbon dioxide capture and sequestration must be implemented. The biomass must also be produced in a sustainable manner. If this is achieved, lifecycle emissions can be less than half those of petroleum-derived fuels. In particular, a feedstock consisting of a 60/40 coal/biomass blend (by energy) should yield alternative fuels with lifecycle greenhouse gas emissions that are close to zero.

It is highly uncertain whether appreciable amounts of hydrotreated renewable oils can be affordably and cleanly produced within the United States or abroad.

Nuclear, solar, and wind energy technologies may offer important benefits in the production of military, as well as civilian, alternative fuels. But the beneficial hydrogen derived from nuclear, solar, and wind energy technologies is not an economically viable option over the near-to mid-term.

The Military Utility of Forward-Based Alternative Fuel Production

Concepts that have been proposed for forward-operations-based alternative fuel production do not offer a military advantage.

Goals and Progress of the Military Departments

Defense Department goals for alternative fuels in tactical weapon systems should be based on potential national benefits, since the use of alternative, rather than petroleum-derived, fuels offers no direct military benefits.

Current efforts by the services to test and certify alternative fuels are far outpacing commercial development.

If the Department of Defense continues to support the development of technology to produce alternative fuels, it should consider consolidating and strengthening management and shifting support to longer-term goals.

• The Defense Department’s current R & D efforts are overly focused on short-term gains, foregoing the work required for long-term progress.
• Improved management of the alternative fuel R & D program is key to success.

To cost-effectively promote early industrial production of alternative fuels, the Department of Defense needs extended contracting authority for fuel purchases.

The Prospects for Commercial Production

Within the United States, the prospects for commercial production of alternative fuels that have military applications remain highly uncertain, especially over the next decade.

Conclusion

The RAND investigation was limited to alternative fuels, as opposed to the whole of energy use across the Department of Defense. But this study can be placed within the broader context of an overall energy strategy for the U.S. military. The RAND team’s finding that the use of alternative fuels offers the armed services no direct military benefit is consistent with top-level findings of recent studies on military energy issues by the Defense Science Board and the JASON Defense Advisory Group: In short, the military is best served by efforts directed at using energy more efficiently in weapon systems and at military installations. In this regard, the services’ energy programs are clearly, and appropriately, placing the greatest emphasis on measures that would increase the efficiency of energy use.