Carbon In, Carbon Out

What does it mean when an energy source is carbon neutral? Does using it still emit carbon dioxide into the atmosphere? What are some examples of carbon neutral sources of energy? Are all renewable sources carbon neutral? You’ve already learned about molten-salt reactors as a possible new source of energy. In this post, we’ll take a look at some new developments in the renewable energy sector.


Biomass is a by-product of the agricultural industry. Let’s say you are a corn farmer and you’ve just harvested your crop. Selling the kernels is how you make money, but what happens to the husks and leaves and stalks? The traditional method is to burn the leftovers on the field. But what if we were able to harness the energy within the corn plant to produce electricity? As a global society, we produce enough biomass to potentially power our cities. And by combining biomass with other sources of renewable energy (such as solar, wind, and hydroelectric), we can create a fossil fuel independent future!

Carbon Neutral

The carbon cycle describes the recycling for carbon between plants and animals. Photosynthesis takes carbon dioxide from the atmosphere and using an enzyme called RUBISCO, builds glucose (C6H12O6). When animals eat plants, they use the glucose to produce cellular energy (ATP) while breathing out CO2 from their lungs back into the atmosphere. As you can see, the CO2 emitted is equal to the CO2 absorbed and thus, carbon neutrality is established between photosynthesis and cellular respiration.


Using biomass is quite similar to the carbon cycle. While the combustion part is different (fire instead of cells), it is a carbon neutral process. Decomposing organic material produces combustible methane. Public transportation systems, cars, and houses use this methane to produce heat and electricity, emitting CO2 as a by-product into the atmosphere. Crops around the world are able to use the CO2 to grow.

Renewable Energy Future

Renewable energy isn’t just confined to sun, wind, and water, as you can see. Today, technology has made it possible to use all sorts of organic materials as biomass, including algae! Some scientists have even thought of using the oil droplets inside of diatoms as a fuels source. Unfortunately, all these new methods don’t produce enough combustible product, plus it’s expensive. But as coal becomes more expensive, we will inevitably transition to renewable sources of energy.