Citrus City Electricity

1) Sustainability Problem

Energy: Urban energy consumption is a major contributor to global emissions, and so cities need to convert more of their energy grid over to renewable sources. While many renewable energy sources have inherent variability that limits grids’ ability to rely on them, energy from biomass offers some of the consistency strengths of fossil fuels that can help improve cities’ renewable energy portfolio while mitigating the reliability issues. Additionally, organic waste that would otherwise contribute to landfills could be used to reduce cities’ reliance on fossil fuels.

2) Technology Solution

Seville is using the orange waste from their iconic and plentiful orange trees to generate electricity in select water purification plants, with intentions to expand and give surplus electricity back to the grid. Initial studies found that 1,000kg of oranges could translate to 50 kWh, which could power five homes for a day. This is a really compelling opportunity to create value from waste while also reducing the city’s reliance on fossil fuels. Designing this energy source around a local resource also enables greater self-sufficiency in the city’s energy supply.

3) Stakeholders

A number of stakeholders will need to be engaged to drive this project forward:

  1. City Council: the city council oversees the waste collection of the oranges, and so would need to transition the process from disposal to utilization
  2. Purification Plant: currently, efforts are being directed toward water purification plants, which “consume almost 40% of the energy needed to provide the city with drinking water and sanitation”; these plants need to be engaged to convert their energy production over to biomass
  3. Grid Oversight: with longer-term plans to provide electricity back to the grid, project managers need to work with the grid to make sure this is done in an efficient way that maximizes the mutual benefits of the energy producers and the grid as a whole

4) Implementation

In order to roll out the program to convert urban orange waste into electricity one would need to:

  1. Align with stakeholders on the alternative energy source, the new use of this waste, and what measures might need to be in place to mitigate any drawbacks or risks
  2. Work with purification plants to install facilities that can generate electricity from organic waste
  3. Transition the waste collection processes from disposing of the waste to transporting it to the relevant facilities

Sources

  1. https://www.theguardian.com/environment/2021/feb/23/how-seville-is-turning-leftover-oranges-into-electricity
  2. https://www.haute-innovation.com/en/magazine/energy/electricity-from-oranges/

3 thoughts on “Citrus City Electricity

  1. #dh2733 Sounds like a win-win situation. Taking waste and turning it into clean energy. The oranges will go into an existing facility that already generates electricity from organic matter. You don’t have to create new infrastructure. The project has the potential to put back energy into the grid that could power 73,000 homes. What would be interesting to know is how the cost stacks up to other sustainable energy sources.

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  2. #nls2174 This was such a fun article to read. Since the City already employs 200 people simply to collect the oranges, perhaps there is opportunity to create green jobs–or rather, “orange jobs”. If the technology from Emasesa is implemented on a city-wide basis, perhaps the City could employ people to work at plants (not just the current water purification plants) to process the oranges, assist the process to collect the methane, and send energy back to the grid. This would add financial benefits to the sustainability benefits.

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  3. Is methane from fermentation clean though?… research is lacking in the WTE world, even if it is closed loop. The alternative is to use the oranges as fertilizer (or it goes to landfill).

    This is a great example of how sustainability is a trade off – methane production to achieved circular economy vs “cleaner” solutions (in my opinion) that generate waste.

    One thing that wasn’t talked about in the article is the amount of space/land needed to generate the 1000kg of fruit to produce the 50KWh of energy. Another trade off!

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