Dave Slade Chemical Engineer on why liquid fuels are so valuable to humanity

About this episode

Vance interviews Dave Slade, a chemical engineer at Renewable Energy Group who calls himself a "chemical engineering hippie," about the real-world mechanics and economics of biodiesel, renewable fuel policy, and why liquid fuels remain irreplaceable for heavy transport and the developing world. Slade traces his personal path from idealistic 1980s chemical-engineering student who couldn't stomach going into petroleum, through a decade of odd jobs and teaching, back to a PhD studying hydrogen and battery chemistry, and finally into biodiesel from waste oils and fats. He explains the federal Renewable Fuel Standard and RIN credit trading system (started under George W. Bush), pushes back on the idea that ethanol/biodiesel are net energy losers, and lands a sharp critique of "indirect land use change" (ILUC) penalties — calling the practice of blaming U.S. crop-based fuel for hypothetical rainforest deforestation elsewhere "imaginary" once an idea takes root in policy. He and Vance riff on why Europe drives diesel and the U.S. doesn't (fuel economy incentives vs. cheap gas), why modern diesel exhaust can be cleaner than intake air, and the core physics argument for the episode's theme: liquid fuels have such extreme energy density that no current battery technology can replace them for trucking, aviation, or shipping — batteries are roughly 15x heavier per unit of energy. Slade argues nuclear is safe and valuable but slow to build, wind and solar are excellent for "base load" but can't meet sudden peak demand, and that policymakers chasing a "one size fits all" electrification push ignore basic thermodynamics. He predicts roughly a 40-year horizon before the grid becomes majority-renewable, with liquid renewable fuels bridging the gap — especially in off-grid regions of the developing world where self-sufficient fuel tanks beat fragile electric grids.

“Liquid fuels contain an amazing amount of energy in a very small, portable, transportable package... people have no sense of how energy dense and amazing and revolutionary liquid fuels are.”

“This is a federal program, once again it was started by George W. Bush. It's the renewable fuel standard, the EPA's Renewable Fuel Standard Program... refiners and importers of petroleum... have to acquire so many of these credits, these RINs.”

“Used cooking oil restaurants, had to pay someone to come pick it up because it was a waste... Now because of biodiesel, they have to lock it up because people will steal it from behind the restaurant.”

Key moments

• ~2%: Origin story — chose academia over the 1980s petroleum-industry default because "I just wasn't ideologically able to do that."
• ~26%: Waste cooking oil going from something restaurants paid to dump to something people now steal, because biodiesel created a market for it.
• ~40%: The "indirect land use change" (ILUC) critique — Slade calls it an "imaginary" penalty that got baked into EU/California policy and is now hard to uproot.
• ~48%: The liquid-fuels-changed-the-world riff — whale oil to gasoline, and why nobody appreciates energy density until they think about it.
• ~57%: Batteries are ~15x heavier per unit energy than liquid fuel — the core physical argument against full electrification of heavy transport.
• ~63%: 40-year prediction for grid decarbonization, with liquid renewable fuels filling the gap for trucking, aviation, and off-grid heating.
• ~93%: "What's available today versus what can you maybe do in 10 years" — Slade's closing point that supply, not demand, is the constraint on biofuel expansion right now.

Notable quotes

“Liquid fuels contain an amazing amount of energy in a very small, portable, transportable package... there would be no aircraft without liquid fuels ever.”

“This land use change stuff is actually, is imaginary... once an idea gets root, it's really hard to uproot it.”

“It's about 15 times heavier per unit energy than liquid fuels... it doesn't make sense to do electricity, everything.”

“Now because of biodiesel, they have to lock it up because people will steal it from behind the restaurant.”