Philosophy vs Science: The Church Tried That Too and Lost, Dr. Bardi

My colleague Ugo Bardi wrote a rebuttal to my recent post in which I explained why the EROI of renewable energy remains lower than that for fossil fuels.

Bardi’s post Is the Energy Return of Renewables Really Higher than that of Fossil Fuels? A Rebuttal to Art Berman’s Criticism presents no data and is, therefore, little more than a philosophic rejection of science. The Catholic Church tried that for several centuries before losing its futile battle.

Bardi reveals his failure to understand the mechanics of EROI (energy returned on energy invested) in this, the core of his rebuttal.

“And here is the point of the discussion: you can measure the energy embedded in a barrel of oil and compare it to the energy embedded in a lithium battery. But the battery will dissipate that energy in the form of electric power at more than 90% efficiency. To obtain the same amount of work from the oil contained in the barrel, you have to go through a series of steps, including transporting, processing, refining, more transporting, and finally burning it inside a thermal engine that, typically, has an efficiency of about 30%. Not all energies are created equal!”

EROI is the ratio of the total energy output divided by the total energy input over the life cycle of an energy source. The efficiency of a lithium battery is not a measure of its EROI because it is not a measure of either its energy output or input but rather its conversion rate. His argument ignores the energy required extract, ship, manufacture and distribute its components.

In the interest of  pedantic generosity, however, I will take Bardi’s statement at face value and show why it is hopelessly wrong even though it is irrelevant to any honest discussion of EROI.

The output of a standard Tesla lithium ion battery is about 13.5 kWh. A standard barrel of oil contains approximately 1,700 kWh of work. If we use Bardi’s 90% efficiency for a battery and 30% efficiency for a barrel of oil, the battery delivers 12.2 kWh and the barrel of oil, 510 kWh. Oil wins.

Bardi is in effect arguing that a battery–a storage device–is a better source of energy than the electricity that it stores. At the same time, he is ignoring the energy cost to generate the electricity and the energy cost to build the battery. That is outside of the realm of reason and science.

I am not arguing in favor of oil or fossil fuels. Quite the contrary, as I said in my original post,

“I favor a future society that is based largely on renewable energy. That society will look very different that what we know today. Substituting renewables for fossil fuels is not a solution without greatly curtailing our total energy consumption. That’s what the physics indicates will happen in a renewable future. I suggest that we stop trying to make renewables look like something that are not and cannot be, and just learn to live with them as they are.”

I am arguing in favor of the truth based on the facts that we have today. Those facts indicate that the EROI of renewable energy is lower than of fossil fuels.

That is not a win for fossil fuels but rather a reflection on of how difficult it will be for humans in a renewable energy-based future. Pretending it is otherwise is simply not helpful.