Blowing Up the BTU Myth: Why Ethanol Deserves a Second Look

By DahVeed Montané

What if everything you thought you knew about engine fuel efficiency was based on a myth? A persistent illusion, driven not by physics, but by petroleum industry propaganda? That's the argument being made by ethanol advocates who say it's time we stop comparing fuels by how much heat they give off, and start looking at how much work they actually do.

I recently sat down with three experts to uncover why ethanol is so misunderstood and what that means for America's fuel future. Joining me were David Blume, author of Alcohol Can Be A Gas!, Marc Rauch, co-founder of The Auto Channel and author of The Ethanol Papers, and Dean Harlow, president of Ricardo plc at the time they developed the EBDI engine.

What Is the BTU Myth?

For decades, we've been told that gasoline and diesel are better fuels because they contain more energy, measured in British Thermal Units (BTUs)—the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. But experts like Blume say this flips the truth on its head.

"The BTU rating of a fuel is almost meaningless unless you're using it to boil water," Blume once quipped. "In an internal combustion engine, it's the combustion profile, not the heat profile, that matters."

Blume explains that while petroleum fuels do have a higher BTU content, their combustion profiles—a term that encompasses factors like flame front speed, pressure curve, and expansion characteristics—are generally slower and less efficient. Compared to ethanol, gasoline explodes too slowly and inefficiently to effectively convert its chemical potential into useful mechanical work. Diesel, while delivering high torque, burns more slowly and at much higher temperatures, leading to greater heat loss, more soot and emissions, and a heavier engine design to handle the pressure—none of which are required in an ethanol-optimized system. In contrast, ethanol burns cleaner, cooler, and more completely. That means more of its energy gets turned into actual motion, not wasted heat.

To prove the point, Blume compares equal-BTU quantities of gasoline, wood, and dynamite—demonstrating how drastically different their real-world impact can be depending on how fast they release their energy.

"BTUs measure heat, not work," I said. "Even a campfire has tons of BTUs, but it won’t move your car an inch. What matters is converting chemical energy into motion."

Rather than lower heat energy being a disadvantage, cooler operation is the holy grail of engine design. Ethanol engines run significantly cooler—so cool, in fact, that they can use a smaller radiator, or in some cases, even eliminate the need for liquid cooling altogether through air-cooling systems. Cooler combustion means less wear and tear, lower maintenance costs, and longer engine life—a triple win for durability, sustainability, and cost. Add to that the lower price of ethanol at the pump, and you've got a compelling case.

Marc Rauch: The Man on a Mission

Marc Rauch has driven hundreds of vehicles across the country, testing various ethanol-gasoline blends. His conclusion? Ethanol consistently delivers better performance, lower emissions, and a lower price at the pump than gasoline—benefits that align perfectly with the FillUps mission of making fuel more affordable and less polluting.

"The BTU argument is a distraction," says Rauch. "It sounds scientific, but it's actually a gimmick created by the oil industry. They want people to think ethanol is weaker or less efficient. In reality, ethanol often outperforms gasoline in both power and mileage."

Rauch’s research shows that ethanol has a higher octane rating than gasoline, which means it resists knocking in high-compression engines. That allows engine designers to get more torque and horsepower from ethanol than from gasoline—if the engine is optimized for it.

"Most ethanol tests are rigged," he says. "They just pour ethanol into a gas engine and say, 'Look, it doesn't work as well!' That’s like putting diesel in a gasoline car and blaming diesel. It’s nonsense."

The Physics of Work vs. Heat

Let’s take a step back. In science, work is measured in joules, and power (the rate of work) in watts. An internal combustion engine converts the chemical energy of fuel into mechanical work. But that process is full of energy losses, especially in the form of heat.

Brake Thermal Efficiency (BTE) is often cited to measure how efficiently an engine converts heat into work—but this metric fundamentally misses the point. Internal combustion engines don’t run on heat; they run on the rapid expansion of gases created by the controlled explosion of fuel. The relevant question isn’t how much heat is released, but how much chemical energy is directly converted into mechanical motion. Ethanol excels in this regard, especially when engines are designed to take advantage of its fast flame front and high compression tolerance. If an engine isn’t optimized for ethanol, it’s the engine—not the fuel—that’s underperforming.

The experts agree that ethanol engines run cooler, which is usually seen as a weakness in BTU comparisons, but is actually a strength. Cool engines last longer, need less maintenance, and produce fewer emissions.

And What About Diesel?

Diesel is often lauded for its torque and fuel economy, but at a steep cost. Ultra-low sulfur diesel (ULSD) may have improved tailpipe emissions over older diesel formulations, but it still produces dark exhaust plumes, contributes to ground-level ozone, and leaves toxic residues in soil and sea. Meanwhile, diesel fuel is significantly more expensive than ethanol—and its engines are notoriously heavy, hot-running, and expensive to maintain.

Ethanol-optimized engines have demonstrated equivalent torque and horsepower when properly configured, without the pollution and price tag. Plus, ethanol’s fast flame front and cleaner combustion allow for quicker starts and smoother operation under load—ideal for agricultural, industrial, and freight applications.

From Brazil to the Backyard

Brazil has for decades run millions of vehicles on E100 hydrous ethanol—essentially 190-proof vodka with a denaturant added for tax purposes. They’ve proven it works, and works well. Their flex-fuel vehicles switch seamlessly between E100 and gasoline blends. One reason this works? Ethanol absorbs small amounts of water, so when it's used as the dominant fuel, water separation isn't a problem. Fuel tanks are also designed to pick up fuel from the bottom, where water settles.

“There’s no reason we can’t do that here,” says Marc Rauch. “We just need to stop believing lies and start redesigning engines for the fuel we want to use.” Ricardo plc did just that in 2010, designing the EBDI engine—an ethanol-boosted direct injection platform. As Dean Harlow, president of Ricardo at the time, put it: their ethanol-optimized engine demonstrated “the performance of a diesel, at the cost of ethanol.”

The Real Metric: Torque and Horsepower

If you want to know how well a fuel performs, look at torque and horsepower—the actual work being done. Ethanol-optimized engines, using proper compression ratios, better air-fuel mixtures, and vaporization techniques, can exceed diesel efficiency by as much as 22%.

Tractors, race cars, and freight truck engines already demonstrate this. For example, Scania operates ethanol-engine trucks in European logistics fleets, proving that E100 can reliably power long-haul transport vehicles. Dedicated E100 harvesters in Brazilian sugarcane fields also show that ethanol can handle rugged, high-demand applications in agriculture. It was the exclusive fuel for the IndyCar Series for nearly a decade, where high power and fast combustion matter most.

Fueling the Shift: The YNOT Vision

Heat energy is a great metric for steam engines and other external combustion engines like nuclear or coal-fired power plants, where the goal is to generate heat to boil water and turn turbines. But internal combustion engines work differently—they convert chemical energy directly into mechanical motion through the rapid expansion of gases. Judging ethanol by its heat output is like judging a hammer by how hot it gets instead of how well it drives a nail.

What would happen if we judged fuels not by their heat energy potential but by how much useful mechanical work they produce in real engines?

That’s the first goal of our YNOT project: to develop engines optimized for E100, starting with farm tractor engines. This will reduce the cost of farming, the environmental impact, and the price of fuel for farmers and others. Instead of burning imported oil, we’ll be growing our own fuel from winter wheat and sorghum in Florida—crops that also provide valuable animal feed or biomass energy.

Green Light for Ethanol!

Green means go—and it’s time for ethanol to accelerate out of the myths and into the fast lane of America's energy future.

Heat doesn’t move your vehicle. Work does. And the sooner we stop comparing fuels by their heating value and start comparing them by their real-world output, the sooner we’ll realize ethanol’s full potential.

Ethanol isn’t just ready for the road—it’s already at the intersection, engine running, waiting for us to hit the gas.

It’s not about BTUs. It’s about truth, torque, and transformation.

DahVeed Montané is an entrepreneur, renewable fuel educator, and founder of FillUps, a vertically integrated fuel provider aiming to reimagine fuel for a regenerative future, and its project YNOT, which aims to redesign engines to match.

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