How to Calculate the PCF of My Vertical Farm in openLCA?

Question

Hi everyone,

I am calculating the Product Carbon Footprint (PCF) for my Vertical Farm in Dubai and need guidance on integrating primary data into openLCA.

System boundaries: Cradle-to-Gate

Key Data Available:

1. Energy Consumption:

   • 12 months of electricity data (daily/monthly values).
   • Partial renewable energy input (unclear how much is allocated to the farm).
   • Dubai’s grid emission factor: 0.4041 kg CO₂-eq/kWh (DEWA, climatiq.io).
   • How can I integrate this specific emission factor into openLCA?

2. Water Use:

   • NFT hydroponic system (defined water volumes in channels/tanks).
   • Water replenishment per cycle.

3. Production Data:

   • Crop breakdown (lettuce, baby leaves, microgreens) with yield per cycle.

4. Materials & Infrastructure:

   • LED lighting, HVAC, pumps, fertilizers (N, P, K values known).
   • Grow media, NFT channels (mainly PVC).

5. Container as Facility Structure:

   • Repurposed 40-ft shipping containers converted into clean rooms.
   • I plan to use openLCA secondary data for containers, but since they are not newly produced, should I modify the approach?

Questions:

1. Best way to integrate primary data into openLCA for an accurate PCF?

   • Should I create a custom process for energy use or rely on existing LCIA data?
   • How to correctly model the renewable energy contribution?
   • How to include Dubai’s specific electricity emission factor (0.4041 kg CO₂-eq/kWh)?

2. Handling the container as part of the LCA:

   • Can I use openLCA’s standard data for a 40-ft container, even though it is repurposed?
   • Should I instead define a custom process for refurbishing the container?

Any insights would be greatly appreciated!

Answer 1

Hi, loads of question, here some answers:

Best way to integrate primary data into openLCA for an accurate PCF?

To integrate primary data into openLCA, create a custom process with the product flow representing your product. Then, include the relevant carbon dioxide elementary flows in the output (or input, in case of uptake) with the appropriate values according to your PCF results. Ensure that the selected elementary flows are assessed using the LCIA method you apply. In the downstream processes, link your product flow to the respective provider.  In our method package, we now have the ISO 14067 compliant IPCC method as well as in ecoinvent 3.11, there is also now a IPCC 2021 incl. biogenic carbon uptake.

Should I create a custom process for energy use or rely on existing LCIA data?

Yes, build your own process if a PCF is present for the production of energy as described above. It depends on the level of accuracy you need.

How to correctly model the renewable energy contribution? How to include Dubai’s specific electricity emission factor (0.4041 kg CO₂-eq/kWh)?

 If using primary data, create a custom process where the energy flow is modeled with their respective carbon dioxide emissions. If you use renewable energy, enter the respective PCF value as described above.

Can I use openLCA’s standard data for a 40-ft container, even though it is repurposed?

openLCA is just the software. To what database are you referring? Please have a look in a respective PCR for vertical farms. If it is repurposed, you could you the cut-off approach hypothetically.

Should I instead define a custom process for refurbishing the container? Yes, if the repurposing process significantly alters the environmental footprint of the container, it is recommended to create a custom process. This should include material inputs, refurbishing energy consumption, and any emissions related to the refurbishment process.

Hope this helps