What’s Not To Like About Big Hydro? Plenty
While hydro energy is carbon-free (after the construction), there are numerous environmental drawbacks.
Here’s an extremely minor one. The world’s largest dam, China’s $30 billion, 22.6 gigaWatt Three Gorges, when completely full, will retain 9.43 cubic miles of water, weighing 42 billion tons. That mass of water, 500+ feet above sea level adds to the Earth’s “moment of inertia,” which is the inertia of a rigid body against spinning on its axis. This will decrease, albeit slightly, the rotation of the planet, adding a very short bit of time to each day. Think of a spinning figure skater, whose rotation increases when she brings her arms in towards her chest and slows when she extends them back out.
That, of course, is more of a curiosity than a concern. Real problems associated with dams is that they trap pollution and create earthquakes and landslides. Moreover, Three Gorges was built by relocating 1.3 million people, while destroying historical locations as well as the habitats of endangered animals.
