Our Research: The Oil Climate Index (OCI)

A first-of-its-kind, open-source analytic tool that offers a fully transparent method to analyze greenhouse gas (GHG) emissions differences between oil and gas resources over time.  By assessing the life-cycle carbon footprints of (soon to be over 100) global oil and gas resources, stakeholders can identify where in the value chain the largest emissions occur and advance innovations that make the deepest cuts in emissions. 



A brief history of the OCI


  • Gordon initiates the OCI with partners from Stanford University and the University of Calgary


  • OCI Version 1.0 is launched, modeling 30 global oils (5% of global oil production)

  • Gordon and her team find nearly an order of magnitude difference in per-barrel GHGs among oil producers and a similar range among oil refiners


  • OCI Version 2.0 is launched, modeling 75 global oils (30% of global oil production)

  • Gordon and her team confirm the results from 2015 for their larger sample of oils

  • The OCI begins to be cited widely in national and international energy policy (examples: the Congressional legislation, Know Your Oil Act; China’s ban on high-sulfur petroleum imports from the U.S.)


  • OCI Version 2.5 is launched, the International Energy Agency’s methane emission estimates are added to the model


  • OCI Version 3.0 will be launched, including 40 global gas resources


OCI’s underlying models

Three GHG-emission-estimation models are aggregated to create the Oil-Climate Index:

  1. OPGEE (the Oil Production Greenhouse Gas Emissions Estimator) was developed by Adam Brandt and his colleagues at Stanford University

  2. PRELIM (the Petroleum Refinery Life-Cycle Inventory Model) estimates midstream refining GHG emissions from the refinery inlet to the outlet, as well as refined petroleum product yields. PRELIM was developed by Joule Bergerson and her colleagues at the University of Calgary.

  3. OPEM (the Oil Products Emissions Module) estimates downstream GHG emissions (from the refinery outlet) that result from the transport and end use of all oil products from a given crude. OPEM was developed by Deborah Gordon, Eugene Tan, Jonathan Koomey, and Jeffrey Feldman.

Model outputs are standardized by converting them into the same functional units, or metrics, so emission results can be summed. The index estimates GHG emissions based on these functional units: per barrel of crude produced, according to the energy content of all final petroleum products (in megajoules), and per dollar value of all petroleum products sold. Read more about the underlying models

OCI data inputs

The models that underpin the OCI require consistent, comparable, and verifiable open-source data on crude oils. This includes oil assays (analyses of predetermined data measuring a crude oil's chemical and physical characteristics) that are reported out in a specified format, upstream field-level operating specifications, midstream refining process input requirements, and downstream transport and end-use data.

In creating the Oil-Climate Index, we went through an intensive process to obtain data on the 75 oils. We used hundreds of academic sources, technical documents, and reports from industry news to identify data. Oils were selected based on their geographic, geologic, chemical, and physical diversity. But the final arbiter of the 75 global oils selected was data availability. There were oils that we would have selected save for the lack of transparent data. Read more about the methodology.

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Collaboration with NASA Carbon Monitoring System Science Program

Gordon is a stakeholder of NASA’s Carbon Monitoring Science Program. Watch Gordon’s talk on how NASA is incorporated into current and future versions of the Oil Climate Index.

Deborah Gordon, Principal investigator of the Oil Climate Project, with Edil Sepulveda, Applications Coordinator for NASA Carbon Monitoring System.

Deborah Gordon, Principal investigator of the Oil Climate Project, with Edil Sepulveda, Applications Coordinator for NASA Carbon Monitoring System.


Using the OCI

New to the OCI? Watch these demonstration videos to see how the OCI can be used to answer important questions about the oil supply chain

There’s No Standard Barrel of Oil

Conducting GHG Checks and Balances

How does the OCI estimate GHG emissions through the oil supply chain?

How accurate is emission reporting in the oil sector?

Revisiting the Keystone Pipeline

Advancing Low Carbon Energy

Who bears climate responsibility for the heaviest oils?
How can the oil industry innovate to reduce GHG emissions?