OT - energy generation
Yes, you're generally correct. However, you have to stop to think about what put the energy that you're drawing on in place. For a Hydro dam, the energy comes from gravity potential - water up high pushes a turbine as it falls. Evaporation, rain, and runoff recycle the water into the reservoir. That's a natural energy cycle that is otherwise not captured for another purpose.
With cars, the "stream" you're tapping is actually pulling energy away from another purpose - transportation. If I give with one hand and take away with another, I don't come out ahead (and, due to imperfect conversion, actually fall behind). Put a big enough box around the traffic thing, and you'll see that the only input is fossil fuel getting burned. Everything else is conversion from one form to another.
I prefer the regenerative braking concept, where energy that is currently thrown away as friction instead gets captured and reused from a flywheel or batteries. (Reverse the current in a generator and you get a motor.)
Wave action is another way to catch and use energy that otherwise crashes on the beach and dissipates. However, even that is not "free" energy - by significantly raising the "friction" of the tides and waves, we could throw the moon out of orbit ... in a few billion years or so.
- Mitch |
