Ecocentricity Blog: Tower of Power

By: John A. Lanier
Mar 6, 2019 9:30 AM ET
Summary: 

As the automated crane arms lower the blocks to the ground, they release their gravitational potential energy in the form of kinetic energy, which is captured by the system and converted into electricity on the grid. In other words, it’s a massive battery.

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I’m going to let you in on a secret. It will reveal some of the deepest aspects of who I am as a person, and what I am about to share with you would normally be reserved for only family and close friends. I hope that you receive this information as it is intended – a sign of my vulnerability, openness, and trust in you. Behold, I give you…my podcast subscription list:

  • CBS Sports Eye on College Basketball
  • CBS Sports Fantasy Football Today
  • Soccer Down Here
  • ExtraTime by MLS
  • Up First by NPR
  • Dan Carlin’s Hardcore History
  • FiveThirtyEight Politics
  • Serial
  • Invisibilia
  • Duolingo Spanish Podcast
  • The Skeptics Guide to the Universe

Though that first paragraph is dripping with sarcasm, I actually do think you can learn a lot about a podcast listener from their subscription list. Seeing that, you know that I watch college basketball and soccer, I play fantasy football, I try to stay informed about politics and the news of the day, I am a history nerd, I like stories, and I’m trying to learn Spanish.

I also geek out over science in general (that’s the last podcast on the list). Jim Hartzfeld gets full credit for introducing me to The Skeptics Guide to the Universe. It’s a fascinating weekly podcast that explores a whole host of topics in the scientific realm, and while I find myself disagreeing with some of their views from time to time, I respect the heck out of their combination of intellect and communication skills.

I learned about something pretty exciting in one of their recent episodes. They talked about Energy Vault, a start-up company working on grid-scale energy storage utilizing gravitational potential energy. That was a lot of words, so watch this, and then I’ll break it down.

[Twiddles his thumbs while you watch the one-minute video he just linked…]

All done? Great. So that’s a theoretical 35-story tower of concrete blocks, each weighing about 35 metric tons. As the automated crane arms lower the blocks to the ground, they release their gravitational potential energy in the form of kinetic energy, which is captured by the system and converted into electricity on the grid. In other words, it’s a massive battery.

You recharge the battery by using electricity from the grid when there is an excess of it. The cranes pull blocks back up and stack them on the tower, ready to be lowered again when needed. When might there be an abundance of grid electricity? Assuming you’ve got renewables on the grid, then perhaps when the sun is shining or the wind is blowing. Charge the battery when the renewables are generating electricity, then discharge the batteries when they aren’t. That’s the theory at least.

Energy Vault hopes to deploy their first commercial installation later this year, so we are still waiting for a full proof-of-concept. Still, I’m salivating over the potential here. They are projecting up to 35 MWh capacity, up to 5 MW power output, 90% energy efficiency, ultra-low operating costs as a result of automation, more than 30 years of life span for a system, zero battery degradation, and less than half the total cost of competitor storage solutions on a per-kWh basis. If it works, the scalability could be tremendous too. I’ve got my fingers crossed on this one.

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Valerie Bennett
Ray C. Anderson Foundation
+1 (770) 317-5858