FAQs on the Citrus Oils LCA

Q: The title of the LCA is “Life Cycle Assessment – Renewable and Sustainable Citrus Oils.”  How are citrus oils renewable and sustainable?  

A: The Cradle-to-Cradle LCA for Citrus Oils demonstrates that essential oils derived from citrus have an extremely small carbon footprint, or in other words, a low potential to contribute to global warming. The citrus crop is harvested every year and is fully renewable.  In addition, utilizing the peel for citrus oils is a sustainable practice and does not consume a human food crop.

Carbon dioxide that was absorbed as the orange grew (embedded carbon) ultimately returns to the atmosphere, and thus there is no net release of fossil-based carbon, only biobased-carbon, in the form of carbon dioxide (carbon neutral) as the cycle of growth and harvest is sustained.

Q: Did the findings show environmental benefits when using citrus oils instead of petroleum-based products?

A: Yes, the overall results indicate that citrus oils are more environmentally benign and sustainable when compared to petroleum-based counterparts.

Q: Why is the term closed-loop cycle used in the LCA?

A: Citrus oils are unique in that the building blocks (carbon dioxide and water) come from the environment through photosynthesis and most uses return the carbon to the environment.  This closed-loop cycle allows the LCA to track these building blocks from their origin in nature to their return to the environment or “cradle-to-cradle”.  This holistic approach demonstrates the carbon neutrality associated with renewable citrus oils.

Q: How does a cradle-to-cradle study differ from a cradle-to-gate study?

A: A cradle-to-gate study usually ends at the producer’s gate and may include transportation to the receiving organization’s gate.  This cradle-to-cradle LCA includes the commercial and consumer use phase and follows the fate of the citrus oils and ultimate return to the environment as carbon dioxide and water where the cycle of growth and harvest can be sustained.

Q: Were the carbon footprints of the major citrus products determined?

A: Yes, the LCA calculated the carbon footprints of orange juice, cold pressed orange oil, 5-fold orange oil, orange terpenes, citrus terpenes (d-limonene) and citrus-based cattle feed.  They can be found in Tables 6.1 and 6.6.

Q: What methodology was used for the carbon footprinting of citrus oils?

A: This LCA was carried out using the Carbon Trust’s PAS 2050 Specification.  The output of an LCA carried out using the PAS 2050 methodology is a carbon footprint measured in CO2-eqivalents.

Q: Does the cradle-to-gate study end at the processor’s door or the receiving organization’s door? 

A: The PAS 2050 methodology specifies that distribution of the final product to the organization that will incorporate the ingredient into a new product includes the environmental impact of transporting the product to that organization.  Therefore, the gate was set at the receiving organizations gate instead of the citrus processor’s gate as this complies with PAS 2050.  The cradle-to-gate information ending at the processor’s gate is calculated in the sensitivity analysis section of the report.

Q: Was allocation based on mass or economy?

A: The PAS 2050 methodology specifies that allocation must be based on economic value of the products and co-products.  The products with the most economic value are the primary reasons for growing and processing citrus.  This is the approach typically used in LCA and is the most appropriate allocation method for use in this study.

Q: What methodology was used for the impact assessment of citrus oils?

A: The Building for Environmental and Economic Sustainability (BEES) impact assessment methodology was used.  The BEES methodology covers a broad range of environmental, health, and energy categories that meet the International Standards Organization (ISO) requirements and is used by the USDA for assessing biobased products for the Federal BioPreferred Program.  The BEES methodology was used for the following reasons:

BEES has adopted the U.S. EPA-developed Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI), a set of peer-reviewed U.S.-based LCA methods;

BEES addresses a comprehensive set of impacts to meet ISO’s requirements for a range of impact categories; and

The BEES framework and impact categories are used for other government programs, such as the USDA’s BioPreferred program.

Q:  Is the LCA based only on citrus grown in Florida?

A: The geographic boundaries of the LCA cover citrus oils produced from oranges grown in the U.S. and Brazil. The data collected and used in the LCA covers greater than 80 percent of the processing industry and, as a result, the study can be considered representative for the industry.

Q: Why is the LCA based only on oranges?

A: Approximately 33 percent of all citrus fruit is processed with orange having a dominant 80 percent share.

Q:  What functional unit was used?

A: The functional unit is 1,000 kilograms of each of the citrus oils products which include cold pressed orange oil, 5-fold orange oil, orange terpenes, and citrus terpenes (d-limonene).  All other associated products (orange juice and citrus-based cattle feed) have been normalized to 1,000 kilograms of their own products respectively.

Q: Does this LCA include the carbon sequestered in the wood of the roots, trunks and branches citrus trees?

A: Carbon sequestered from the atmosphere into the wood of the roots, trunk and branches has been excluded from the study because sequestration beyond the 100-year point is not expected.

Q: How was the data collected?

A: To ensure representative product systems, data collection questionnaires were prepared and distributed to the appropriate growers and processors to collect the primary data. The data used represent the production during a representative 12 month period.

Q: How was data collected for petroleum-based products?

A: The study used data from the US LCI, Ecoinvent 2.2 and Plastics Europe databases for the petroleum-based counterparts.

Q: Does the data collected for the LCA represent current data?

A: “Data represent the situation for the most recent 12-month period for which data are available.  Typically this was for the financial year 2009 or the 2008-2009 growing season.

Q: Can the results be related to everyday activities?

A: Yes, this is called normalization.

The difference between producing and using 1,000 kg of d-limonene and naphtha amounts to 2,159 miles driven in a car which is approximately the distance from Ontario in California to Orlando in Florida.

The difference between using 1,000 kg d-limonene and perchloroethylene amounts to 26,000 miles which is almost 2.5 times the average mileage of a car in a year.

On a larger scale, if 1,000,000 kg d-limonene per year were used to replace 1,000,000 kg of acetone, it would be equal to taking approximately 1,188 cars off the road per year.

Q: Was a sensitivity analysis performed?

A: Yes, the following parameters were investigated in the sensitivity analysis:

  • Calculation of the carbon footprint excluding transport to the end user of cirtus oils (classic cradle-to-gate assessment);
  • Reducing or substituting fertilizer use when growing the oranges;
  • Landfilling of orange peel instead of using it for citrus oil and cattle feed production; and
  • Use of a different impact assessment methodology (Impact 2002+).

The Citrus Oils LCA seeks to improve and foster life cycle thinking.  Society places a high value on reducing greenhouse gases.  Customers in the value chain are starting to ask suppliers for information that will allow them to not only choose products manufactured using less energy intensive processes, but also for information to use when developing the carbon footprint profile of their own products.

Carbon Footprints for Citrus Oils:  The carbon footprints of citrus oils in this LCA are measured as a cumulative aggregation of this metric through the cradle-to-gate value chain and is expressed as carbon dioxide equivalents (CO2-eq).  The cradle-to-gate ends when the product arrives at the receiving organization’s door or ‘gate’.  For citrus agriculture, this includes the upstream processes that produce the raw materials used for growing through the steps of crop production; i.e., planting, fertilizing, watering, and harvesting.  For citrus processing, this includes downstream processes of transportation to processors, pressing, distillation, folding and packaging.  The carbon footprints for citrus oils are presented in a format specified in the ISO 14040 Standard.