The CI Challenge
‍
Here's a challenge - try opening up nearly any ag-related publication, news article, or press release, spend 30 seconds scanning the headlines, and see if you can stumble across the term “carbon intensity”.  

Perhaps its context is tied to a hot-topic pipeline project being proposed in your county. Maybe it is related to a lucrative conservation program being rolled out by a local ag retailer. It may have started as a simple search, but the next thing you know, there’s complex tax codes being thrown around, contracts being discussed which are full of fine print, and more buzzwords than a regenerative agriculture conference.

It's easy to get caught up in the complexity of a relatively novel conversation. And quickly, this challenge has become a chore. But it doesn't have to be complex and confusing if you have a handy guide to help unpack the nuances and discover the tangible opportunities just underneath the “CI surface”.

So bookmark this guide, and the next time you stumble across CI and are in need of a reference, we’ll be there to help  

A Simplified Efficiency Metric

Let’s start at the very beginning. Broadly speaking, carbon intensity is synonymous with carbon footprint. It has a particular emphasis on efficiency per unit of output, and when we’re trying to simplify the conversation, it's really just an efficiency metric. Input vs output. How many emissions went into production of a widget across its lifecycle and what was the final yield. And the more you can limit inputs or maximize output, the better your score will be.

Luckily, it's a wildly versatile metric as carbon intensity (CI) can be measured for many different units of economic production, including kilowatt hours, bushels of corn, or gallons of ethanol.

What is G.R.E.E.T. Methodology

You can think of CI scoring methodologies (aka the way you calculate CI) almost like you would think about a financial Credit Score. If you went to a bank seeking a loan, you'd likely see your credit score as 2-3 different numbers. Why the difference? Simply put, its because the primary credit reporting agencies all utilize slightly different methods when calculating your score.

The same can be said for CI.

When it comes to generating a CI score, there are several different methodologies available for calculating a value, but one that stands above the rest in US Agricultural Production.Argonne National Laboratory out of Illinois has developed the Greenhouse gasses, Regulated Emissions, and Energy use in Technologies Model. This is a robust, comprehensive tool that was developed to evaluate and estimate consumption of energy, generation of air pollutants, greenhouse gas emissions, and water use for energy systems, vehicle technologies, fuels, and products. This approach creates a full life cycle analysis, illustrating the total environmental impact of each process. With the help of this methodology, the fuels a farmer’s grain is refined into can be effectively and accurately scored.

CI Scoring for Feedstocks

CI Scoring for bio-based fuels isn’t limited to what occurs at the physical location of the processing plant.

Feedstocks, or the raw materials used to produce the biofuels, contribute a significant amount to the total CI of a gallon of biofuel. In the case of ethanol that is produced from corn, roughly 40% of the total CI comes from the feedstock. To accurately measure and report the CI of feedstocks, the Feedstock Carbon Intensity Calculator (FD-CIC) can be used. The FD-CIC is an evolution of the GREET model that takes a granular approach to estimate farm-level CI of individual products and practices used to grow corn, soybeans, sorghum, or rice.

The FD-CIC includes emissions of upstream processes for manufacturing agricultural inputs to on-farm production practices. This a full lifecycle of feedstock production, also known as “cradle-to-farm-gate activities”. A significant amount of data is needed to fill out the FD-CIC to calculate the CI per a bushel of corn. This enables users to accurately compare the efficiencies of farmers, grains, and oilseeds that are produced across the United States.

Connecting CI from the Biofuel Plant to the Farmgate

A measurement is only valuable if it's actionable. With that in mind, a common need exists throughout the biofuel industry to further understand what the CI is for the corn that is grown in the sourcing geography of each ethanol plant. The answer varies tremendously with climate, geography, yearly growing conditions, and with each unique farming practice, so where should an ethanol stakeholder start when seeking to connect farmgate CI to Ethanol CI? These are legitimate considerations, however, for the sake of simplicity and education, let’s start by looking at the default values within the FD-CIC and evaluating how these standard inputs contribute to the CI for a bushel of corn. With any luck, a first time user can utilize these notes to guide their own user defined scoring and understand where their final score is coming from.

Figure 1: FD-CIC Flowchart