Ethanol: The Original Solar Energy

Mother Nature has already given us an extraordinary solar panel that covers several hundred million acres of cropland in America’s breadbasket, where energy absorbed from the sun is stored for later use in a perfect battery: an ear of corn.
By Geoff Cooper | March 09, 2021

As policymakers, auto manufacturers, environmental groups and everyday Americans continue to look for ways to reduce the carbon impacts of our cars and trucks, it is often suggested that battery electric vehicles running on solar electricity are the “perfect solution.”

It’s true that an electric vehicle operating on solar power is a very low-carbon transportation option, offering greenhouse gas (GHG) emissions reductions of 90% or more compared to gasoline. But it’s also true that the 1 million battery electric vehicles on the road today represent just 0.4% of the total U.S. vehicle fleet. Further, photovoltaic solar panels generated just 1.7% of our nation’s electricity last year. So, it seems highly unlikely that solar-powered battery electric vehicles will be a dominant form of personal transportation on American roadways anytime soon.

But there’s another type of low-carbon solar energy that is available today in large quantities: ethanol. And it comes in liquid form, so it works extremely well in internal combustion engines and it can make use of the existing fuel distribution infrastructure.

Mother Nature has already given us an extraordinary solar panel that covers several hundred million acres of cropland in America’s breadbasket. According to scientists from NASA, the U.S. Department of Agriculture and nearly a dozen leading universities, “the Midwest region of the United States boasts more photosynthetic activity than any other spot on Earth.” The scientists noted that, in particular, “Corn plants are very productive in terms of assimilating carbon dioxide from the atmosphere” and converting it into carbohydrate energy.

That energy absorbed from the sun is stored in nature’s perfect battery: an ear of corn. Each “battery” is made up of about 800 to 1,000 tiny individual battery cells (you might know them as “kernels”) chock full of renewable energy. Indeed, America’s corn farmers are the original solar energy producers!

At the ethanol biorefinery, some of that solar energy is converted into renewable liquid fuel that powers our vehicles, some of it is turned into energy and protein that ultimately nourishes our bodies, and some of it is recaptured as biogenic carbon dioxide that is used in dozens of consumer and industrial applications.

And even after accounting for every bit of energy and all of the emissions associated with every step of the ethanol production process, today’s corn starch ethanol is shown to reduce GHG emissions by nearly 50% compared to gasoline, according to a recent study by scientists from Environmental Health & Engineering, some of whom are affiliated with Harvard University and Tufts University.

While a 50% reduction is impressive enough, corn ethanol is on its way to a 100% reduction, or “net zero” emissions. There are already meaningful volumes of cellulosic ethanol from corn kernel fiber being used in the California market today, and the Air Resources Board says that fuel offers a 70% to 80% GHG reduction compared to gasoline.

As for corn starch ethanol, proper accounting of soil carbon accumulation in corn fields will shrink its carbon footprint even further. And using biogas for thermal energy needs at the plant, or adopting carbon capture and sequestration technologies, could make corn ethanol carbon neutral—or even carbon negative.

And when you put E85 made from zero-carbon corn ethanol into a flex-fuel vehicle, you’ve got a transportation option that results in a smaller carbon footprint than most electric vehicles.

So, in the immortal words of George Harrison, “Here Comes the Sun” … and here comes low-carbon liquid solar energy.

Author: Geoff Cooper
President and CEO
Renewable Fuels Association