First Carbon, Second Harvest

How an integrated biorefinery uses carbon can greatly affect its carbon life cycle, and profitability.

Here’s why, and how.

So, your integrated biorefinery project is coming along great. Then comes the carbon lifecyle analysis — the horde of critics shouting about “indirect land use change” — somehow, your project, which you think reduces carbon emission, is criticized as a polluter.

It’s a common tale. Especially if you’ve been looking at palm oil or corn — or anywhere near a forested area.

So here’s something you can do about it. Take the pledge that the first carbon harvested off your proposed feedstock plantation will be used for biobased applications, rather than to generate fuel or power.

Here’s why this is important. When you first harvest a forest or other biomass, you take all that carbon that’s been sequestered — if you use the “first cut” for energy or fuels, that carbon is released.

Now, in the world of renewables, that’s not a terrible thing. Because that carbon will eventually be reabsorbed by your next crop. But you will have what critics call a “carbon debt” for some time between first cut and regrowth of that biomass. It could last a season, could last for years, depending on how fast the biomass regenerates. Plus, you’ve used carbon for energy to plant, fertilize, harvest and transport the biomass.

All of which can exacerbate your “carbon budget” — and drive your friends in the environmental community crazy.

But here’s an option. Take that first harvest and dedicate it to biobased materials. For example, organic acids (for example, acetic acid, succinic acid, or adipic acid) that are used for biobased applications like plastics, paints, lacquers, coatings or nylon. Those uses of carbon are generally quite stable — you will have sequestered carbon for the long-term, inside a chair, a roof, a coating of paint, or in the hundreds of uses for nylon and other polymers.

Now, you have radically reduced your “carbon debt”, because no carbon is released in the form of combustion exhaust. If you have renewable, biobased energy used throughout your process for system energy, transport, harvest and fertilizer, you might even be “carbon neutral” at this stage.

From here, the biomass you have harvested for your first crop of biobased applications — well, that will regenerate. But, instead of reabsorbing carbon that was previously emitted from the combustion of your first crop — it will be absorbing carbon from the atmosphere (for example, CO2 emitted by fossil fuels). In this stage of your activity, you will become, briefly, carbon negative.

Ultimately, when you convert that second harvest to energy for power or fuels, the carbon from your biomass will be released, and you will return to some small net use of carbon, or carbon-neutrality — depending on the biofriendliness of your overall process and logistics.

But — as you can see — the cycle varies from carbon-negative to carbon-neutral, instead of carbon-neutral to carbon-positive. And it will be enormously more environmentally-friendly than a competing fossil fuel project.

In fact, you can use biobased applications to “tune” the carbon lifecycle of your refinery. For example, if you would like to achieve a better carbon profile, then dedicate the first two harvests of biomass to biobased materials. Or three, or four. You get the idea.

The more you use the long-term carbon storage that biobased materials offer — the more carbon-friendly your project will become. You may also find that, selling $5 chemicals initially instead of $3 fuels, you get a pretty good tailwind in terms of your economics.

The bottom line? Don’t mind critics who snicker when you talk about making biobased materials and chemicals in the near term, and fuels later. They might scoff at your plans — because what they see are small markets — and may become suspicious that your process economics may never work for fuels.

But you’ll know better. Triple bottom-line economics means looking at social, environmental and economic sustainability. After all, if money is the only object in life, why not just deal drugs or work as a arms trader? Your venture is something more important — it’s an integrated biorefinery — which uses the unique economic and carbon advantages of biobased materials and chemicals to your advantage.

The secret lies not only in the choice of feedstock, but in the way you cycle your harvests and product runs.

First carbon? Sequester it into biobased products — you’ll like the economics, you’ll love the environmental friendliness. You might also make some new friends amongst those who have become increasingly skeptical about biobased industry in recent years.

It’s all in the feedstocks.