This paper presents an alternative to the current use of gasoline and diesel for transportation in Barbados. By relying on experimental evidence, it shows that biomethane emanating from the combination of Sargassum seaweed that is found on the seashores of the country with wastewater from rum distillery production can be used to produce an alternative transportation fuel. If implemented successfully, this alternative combustion method can avoid as much as 1 million metric tons of CO2 emissions every year in the country. These findings have important implications for policymakers. First, they can contribute to the national objective of becoming fossil fuel free by 2030 and diversifying the energy matrix. Second, this alternative fuel can improve resilience to natural catastrophes, complementing the transition to renewables and diversification of the sector. Third, the impact on the tourism industry is expected to be high and positive, as the Sargassum seaweed has been declared a national emergency due to its prevalence on beach tourism spots.