How Do We Measure CO₂ From Biofuels?

Written By Teacher: Elizabeth Ward

My name is Elizabeth Ward. I am a former Early Childhood, Elementary, and English as a Foreign Language educator. I have taught third grade Science and Social Studies as well as Kindergarten in both urban and rural Oklahoma public schools. I taught online EFL to students of all ages in China for four years. I also have experience in curriculum development and content design for teachers in the physical and digital classroom. As a former teacher I have a passion for supporting teachers and making their jobs easier. I currently live in the greater Houston area with my husband and four dogs. 

Biofuels and bioenergy can help reduce carbon emissions, but their net impact depends on how we measure the full lifecycle, including land-use changes and production processes. Understanding these emissions is critical for evaluating their role in climate solutions. This topic allows students to explore the complexities of carbon accounting and the trade-offs in adopting bioenergy. Middle school and high school students may enjoy learning about biogas through this video or biofuels with this interactive map and chart.

Written By: MIT Environmental Solutions Initiative

The MIT Climate Change Engagement Program, a part of MIT Climate HQ, provides the public with nonpartisan, easy-to-understand, and scientifically-grounded information on climate change and its solutions.

Organic materials like corn, soybeans, or wood can be turned into energy, either by refining them to produce liquid “biofuels,” or by burning them for heat, which can then be used to produce electricity. 

Is this a “carbon-neutral” alternative to coal and gas power—one that doesn’t add climate-warming carbon dioxide (CO2) to the atmosphere? Some scientists and policymakers think so, because plants recycle carbon. When burned, plants release carbon, but they also take up carbon from the air when they regrow. This cycle means the overall carbon impact is, at least hypothetically, neutral.

“If you do that in a neat loop, all the carbon that we are generating from burning biomass is going to be sequestered again,” says Angelo Gurgel, a research scientist at the MIT Joint Program on the Science and Policy of Global Change.

In practice, that loop is rarely neat, and measuring the carbon impact of bioenergy is complex. Crops used for bioenergy must be continually replanted to stay “carbon-neutral.” Some, like trees, take decades to regrow, so harvesting biomass can outpace replanting.