‘A role model’: how Seville is turning leftover oranges into electricity | Renewable energy – About Your Online Magazine


IIn the spring, the air in Seville is sweet with the aroma of azahar, orange blossom, but the 5.7 million kilograms of bitter fruit that the city’s 48,000 trees deposit on the streets in winter are a danger to pedestrians and a pain head to the city cleaning department.

Now, a scheme has been launched to produce a totally different type of juice than unwanted oranges: electricity. The southern Spanish city initiated a pilot scheme to use the methane produced while the fruit fermented to generate clean electricity.

The initial scheme launched by Emasesa, the municipal water company, will use 35 tons of fruit to generate clean energy to operate one of the city’s water purification plants. The oranges will go to an existing facility that already generates electricity from organic matter. As the oranges ferment, the captured methane will be used to drive the generator.

“We hope to be able to recycle all oranges in the city soon,” said Benigno López, head of Emasesa’s environment department. For that, he estimates that the city would need to invest around € 250,000.

“The juice is a fructose composed of very short carbon chains and the energy performance of these carbon chains during the fermentation process is very high,” he said. “It’s not just about saving money. Oranges are a problem for the city and we are generating added value with garbage. “

Ripe oranges taken from the trees in the gardens of the Real Alcazar.
Ripe oranges in the gardens of the Real Alcazar. The city employs around 200 people to collect the fruit. Photography: robertharding / Alamy

Although the goal now is to use energy to operate the water purification plants, the final plan is to put the surplus electricity back on the grid. The team behind the project argues that, given the large amount of fruit that would go to landfills or be used as fertilizer, the potential is enormous. They say tests have shown that 1,000 kg will produce 50 kWh, enough to supply electricity to five homes for a day, and estimate that if all oranges in the city were recycled and the energy returned to the grid, 73,000 homes could be supplied.

“Emasesa is now a model to follow Spain for sustainability and the fight against climate change, ”said Juan Espadas Cejas, mayor of Seville, at a press conference at the launch of the project.

“The new investment is directed mainly at water purification plants, which consume almost 40% of the energy needed to supply the city with drinking water and sanitation,” he said.

“This project will help us achieve our goals for reducing emissions, energy self-sufficiency and circular economy.”

The oranges look nice on the tree, but when they fall and are crushed under the wheels of the cars, the streets are sticky with juice and black with flies. The city employs around 200 people to collect the fruit.

Bitter oranges, originally from Asia, were introduced by the Arabs about 1,000 years ago and have adapted well to the climate of southern Spain.

A house in the Santa Cruz neighborhood, with orange trees outside.
A house in the Santa Cruz neighborhood. Most of the fruit is exported to Britain to make marmalade. Photograph: Santiago Urquijo / Getty Images

“They took root here, are resistant to pollution and have adapted well to the region,” said Fernando Mora Figueroa, head of the city’s parks department. “People say that the city of Seville is the largest orange grove in the world.”

The region produces about 15,000 tonnes of oranges, but the Spaniards do not eat them and most of the region’s fruit is exported to Britain, where it is made into jam. Sevillian oranges are also the main ingredient in Cointreau and Grand Marnier.

The origin of the marmalade is surrounded by myths and legends. Some link it to British copper miners working for Rio Tinto in neighboring Huelva, the same miners who founded the first Spanish football team, Recreativo de Huelva, in the late 19th century.

However, a handwritten recipe for jam dated 1683 was found at Dunrobin castle in Sutherland in the Scottish Highlands. Legend has it that a ship carrying oranges from Spain took refuge in the port of Dundee and local confectionery maker James Keiller was the first to find a use for the fruit, which otherwise would not be edible. This may be a myth, but in 1797 Keiller produced the first commercial brand of jelly.

Paula Fonseca