In the Albufera (València) region of Spain, rice has been farmed for nearly 500 years. Post-harvest flooding of rice fields has become an integral element of wetland refuge for migratory birds. The steady rise in the cost of purchased inputs is causing considerable economic stress to the viability of rice farming in this region. In 2011, it has been estimated the cost of purchased diesel accounted for about 15% of the gross revenue from grain sales. Setting aside about 1.6% of the 14,350-hectare paddy fields for the dedicated yearround cultivation of oleaginous microalgae appears to be sufficient for the entire annual need of diesel fuel. The isolated crude microalgal oil could be used directly in diesel farm equipment, with only minor modifications of the diesel engine required for the optimisation of performance and minimisation of the emission of pollutants. The net economic gain would be nearly €2 million annually.
Keywords: Albufera, diesel, economics, energy, microalgae, rice farming