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[Episode #184] – EROI of RE

Do renewable energy sources generate enough energy ‘profit’ to make them worth continued investment? And is any energy profit large enough to run our modern world, as renewables displace fossil fuels?

Some skeptics of the energy transition have claimed that renewables can’t run our world because the net energy they deliver to society is too low. They make this argument drawing from past data for the Energy Returned on Investment (or EROI) for various fuels, which showed high EROIs for extracting fossil fuels, and low EROIs for very early generations of wind and solar technology. However, the historical EROI literature has been plagued with methodological inconsistencies so how reliable is this legacy data for guiding modern outlooks?

In a new paper we discuss in today’s episode, a group of researchers has cleaned up and rectified recent EROI data so that the various fuels can be compared on an apples-to-apples basis. Their new results paint a very different picture from the old literature.

Not only do renewables have sufficiently high EROIs to power our society, they are much higher than the EROIs of the fossil fuels they are replacing! In fact, these results suggest that only through the energy transition can we maintain a functioning society.

To walk us through this new paper, its lead researcher, Dr. David Murphy, an environmental scientist at St. Lawrence University in New York, returns to the show.

In addition to reviewing the results of this new paper, we’ll also talk about some of the other mistaken arguments that are frequently made against the energy transition, and explain why they are wrong.

Geek rating: 9


[Episode #54] – Resource Limitations

How do we know at what level our consumption is sustainable, and when we’re in planetary overshoot? How do we quantify what the planet’s capacity is to meet human demands, and how much of that capacity is renewable, and how much of it is just being permanently depleted? And once we had a way to quantify that, what would we do with that information? Would we use it to inform our actions and avert overpopulation and disaster? Would we ignore it at our peril? Or would reality just unfold in some messy fashion along a default path somewhere in between? Is a deliberate transition to a sustainable energy system even possible?

Our guest in this episode created a scientific methodology called “ecological footprint analysis,” a kind of ecological accounting, to inform policymakers about our resource demands on the world as compared with Earth’s ability to meet those demands. Earth Overshoot Day, which the Global Footprint Network calculates every year, arrived on August 2, meaning “that in seven months, we emitted more carbon than the oceans and forest can absorb in a year, we caught more fish, felled more trees, harvested more, and consumed more water than the Earth was able to produce in the same period.” After listening to this discussion, you’ll never quite think of energy transition the same way again.

Geek rating: 2


[Episode #42] – Can Renewables Power the World?

Is the net energy of renewables high enough to actually power human civilization? Or will replacing fossil fuels prove too difficult on an energetic basis? What is the state of the art in net energy analysis, and can biophysical economics yet prove to be policy relevant, and not just an arcane field of study that only interests academics? What’s the trajectory of EROI for various fuels, and what’s the right way to compare them?

If you’ve heard that the net energy of renewables is too low to run society, and that as a result energy transition is destined to fail…then you need to listen to this interview with net energy researcher Rembrandt Koppelaar and check out his new research. His findings will probably surprise you.

Geek rating: 8