In spring, the air in Seville is sweet with the scent of azahar, orange blossom, but the 5.7m kilos of bitter fruit the city’s 48,000 trees deposit on the streets in winter are a hazard for pedestrians and a headache for the city’s cleaning department.
Now a scheme has been launched to produce an entirely different kind of juice from the unwanted oranges: electricity. The southern Spanish city has begun a pilot scheme to use the methane produced as the fruit ferments to generate clean electricity.
The initial scheme launched by Emasesa, the municipal water company, will use 35 tonnes of fruit to generate clean energy to run one of the city’s water purification plants. The oranges will go into an existing facility that already generates electricity from organic matter. As the oranges ferment, the methane captured will be used to drive the generator.
“We hope that soon we will be able to recycle all the city’s oranges,” said Benigno López, the head of Emasesa’s environmental department. To achieve this, he estimates the city would need to invest about €250,000.
“The juice is fructose made up of very short carbon chains and the energetic performance of these carbon chains during the fermentation process is very high,” he said. “It’s not just about saving money. The oranges are a problem for the city and we’re producing added value from waste.”