Tuesday, 21 May, 2024 / Edition 8

Whenever a headline grabs my eye for seeming too good to be true or is incredibly cool, it deserves some scrutiny! This week’s edition has a little bit of something that’s too good to be true, a little bit of something else incredibly cool, and just about everything a geoscientist can nerd out on. Great Pyramids? Check. River morphology? Check. GPR, satellites, CORES? Check, check, check! Let’s get to it!

Sarah Compton

Editor, Enspired

Behind Wind Turbines’ Carbon Footprints 

Engel.ac/Shutterstock.com

A new report claims wind turbines pay back their carbon emissions in about two years. If you’re thinking, “that sounds incredible,” you’re not alone, so I dug into the science behind the claim and found it questionable. Let’s take a look.

Context: The carbon footprint of a product is a quantitative estimate of the total greenhouse gas emitted over the whole life cycle—production, operation, and disposal—of a product or process.

• Carbon footprints are measured in grams of carbon dioxide equivalent per kiloWatt hour, or gCO2eq/kWh.

• That “equivalent” term comes into play because any greenhouse gases (including methane) emitted by a process, are quantified as amounts of equivalent carbon dioxide. So…really, there is some wiggle room within defining what “equivalent” means.

• Carbon footprints for wind turbines can range in the low single digits to nearly 100 gCO2eq/kWh. A natural gas power plant hovers in the low to mid hundreds gCO2eq/kWh.

The life cycle

1) Construction

• Turbines don’t just magically appear. There’s materials discovery and extraction—a key life cycle point in which geoscientists play a huge role.

• Once materials are discovered and extracted, they need to be processed and made into the motors, bases, turbines, and blades.

• Then, there’s site preparation, including clearance of the land, soil assessments—enter even more geoscientists—and concrete pouring.

• When it’s all said and done, this initial phase before operation accounts for approximately 90 percent of GHG emissions of onshore windfarms.

2) Operation

• For wind turbines, the operational portion of their carbon footprint is easiest to estimate, but even that literally depends on the weather.

• During operations in higher windspeeds, the carbon footprint of a turbine drops because it’s producing more energy.

3) Recycling and afterlife

• The end-of-life plan for a turbine also plays into its measured impact, but there seems to be a lot of optimism built into the study’s assessment.

• Recycling steel, copper, and aluminum is estimated to be as high as 90 percent according to the report. Seems a bit high to me ... 

• According to the report, estimates of REE recycling bumped up to 81 percent for neodymium, dysprosium, and boron because of the large amounts of these elements in the permanent magnets of some turbine generators.

• BUT, earlier in the report, the authors discuss how permanent magnet direct drive generators aren’t as common because they’re more expensive, so this assumption may not be accurate in many, if not most, cases.

• The assumption of a roughly 40 percent recycle rate for all the materials of the blades is also an optimistic projection. The authors even mention that rate isn’t happening yet, because costs are too high and there’s no market for these recycled materials.

The bottom line: The eye-catching headline that wind farms offset their emissions within two years is tenuous at best. Wind, like all forms of energy, is not one-size-fits all, and trying to fit a square peg into a round hole by shaving the edges off the peg and drilling the hole bigger is a solution, but maybe not the best one.

Sponsored

Offshore Brazil: Reduce Risk with Regional 3D Seismic

Explore new opportunities with a regional perspective using our Picanha 3D, Olho de Boi and Campos datasets in offshore Brazil! We offer over 170,000 KM2 of 3D seismic data, allowing you to evaluate pre-salt polygon blocks.

An Innovative Approach to Solving the Mysteries of the Pyramids

muratart/Shutterstock.com

Most everyone knows about the Egyptian Pyramids and the accompanying mystery around how they were built.

• The stones used to stack the pyramids are huge; the quarry where they come from is far away; and the river isn’t close enough to be helpful.

• How did this pre-industrial society get the giant stones from their quarries to the pyramid sites?

Geoscientists and other experts have long suspected the Nile River might have played a bigger role in materials transportation if it was closer to the construction site.

“Might have” doesn’t get you far in academia, however, and nailing down the exact location of the Nile, or one of its branches, at the time the pyramids were being built has proven tricky…until now!

Combining methods: Satellite data, geophysical surveys, and soil cores all came together to point to an old Nile branch, which has been given the name Ahramat Branch.

• One suspected site of the old branch indicated an abandoned riverbed approximately 400m wide and at least 25m deep.

• Some causeways, raised walkways connected to some pyramids, terminate at what’s interpreted to be the water’s edge of the Ahramat Branch.

Bigger picture: The work also created a roadmap for other studies so that more discoveries can be made. It’s highly probable there’s more to be found below today’s Egyptian soil and suburbs.

Data innovation: Seemingly disparate datasets sometimes grant us the gift of coming together nicely to paint a never-before-seen cohesive picture. In this instance, a suspicion was proven right, and an old branch of the Nile was given new life.

Read more here.

👍 If you enjoyed this edition of Enspired, consider supporting AAPG's brand of newsletters by forwarding to a friend or colleague and signing up for our other newsletters here.

Was this email forwarded to you? Sign up for Enspired here.