• 0 Posts
  • 44 Comments
Joined 6 months ago
cake
Cake day: March 3rd, 2024

help-circle







  • That’s a fair point, a device could theoretically harvest energy that would have otherwise been wasted, and that would be green energy. I imagine a wind system could work, though it might result in cars experiencing additional drag from slower wind speeds.

    However, the piezoelectric generators mentioned in the article quite clearly do not use waste energy. They compress under the weight of the cars, turning a small amount of gravitational potential energy into electricity. That energy must be made up with extra fuel.

    Finally, even if all of the vehicles on the road were powered by clean electricity, it would still be a useless system. Piezoelectrics are nowhere near 100% efficient, so you’re just taking electricity from the vehicles at a loss.


  • Last year the California Energy Commission posted the results of a study aimed at assessing efficiency of deploying piezoelectric systems to generate clean electricity from roadways.

    “Based on the laboratory evaluations and road tests, the application of the piezoelectric energy harvesting system in one lane of a one-mile-long roadway has the potential to generate 72,800 kilowatt-hours of energy per year,” the team reported.

    How is that clean energy, in any sense of the word? Any system that gains some energy from a passing car must necessarily decrease the (kinetic) energy of the car by an equal or greater amount. And the vast majority of cars get their kinetic energy by burning fossil fuels. Sounds like a more expensive, less direct, and less efficient version of a gasoline generator.