Originally Posted by
PLyTheMan
What stood out to me from this is his comment on the efficiency of energy in > electric plant > electricity out. What fossil fuel and nuclear advocates love to rail against electric (cars/trains/anything) is how much energy goes into creating electricity, and, I agree. However, they neglect to take into account generating electricity through renewable resources. I know that windmills have their limitations, but it looks like solar-thermal panels (which are far more efficient than photvalic cells) would allow us to generate a hell of a lot of power from the sun out in the deserts. Mind you I'm no expert in solar-thermal power generation but from what I've seen it would be the way to go.
Once we have an efficient way to generate electricity we can use that to power light (and heavy?) rails making them more efficient. While cars would be running off the same electricity, we should stil aim to cut back on driving as having one person per car is still going to waste a lot of our power.
I'm not expert either but I've read some about this.
Solar power could yield several times our entire current energy use. More than oil, gas, coal, wind, geo-thermal, trash, human, and everything else combined. But the price is higher than oil, gas, coal, wind, geo-thermal, trash, and many other things (human is probably much more expensive). If you buy PV cells today you'll probably lose money (although maybe not in California).
The trouble with using gasoline (or diesel) in our cars is that we waste more than 80% of the energy in the oil. It's lost to heat. I would think that at a central station you could get a lot better efficiency just by using that heat to run a secondary generator (or maybe that's the primary one).
The Tesla Roadster claims an 86% plug to tire efficiency. So, if you burn gas in a central station with 80% efficiency, then transmit it at 70% efficiency and run the car at 80% efficiency you're still at 45% efficiency. That's compared to less than 20%. (I have no idea what power transmission efficiency is like or how efficiently you can burn gas centrally).
More interestingly we waste a bit of our power generated at night. Because the grid needs to support peak power it has excess at night when centralized power needs to still run. I've heard of doing things like pumping water up into a dam and running that as a generator during the day. But the night time is a good time to charge ones car.
Also there is plenty of room for residential PV and even residential wind.
I heard there's a company which thinks they could generate enough power for the whole country (if you could distribute it) on solar-thermal power in like 100 sq mi in Arizona. It was all a bit theoretical though.
I think the missing item is the inexpensive high density battery. That's probably just a matter of time though. The battery in the Tesla Roadster can run the car for 244 miles. It's about 1,000lbs and is made from commodity li-ion batteries. I don't think that density is quite good enough to fully replace the auto but it's good enough for a lot of folk's second car: The one that dad drives to work.
Now the Chevy Volt supposedly has a 375lb battery that powers the car for 40 miles. However, this was the electric car that was delayed because they couldn't floor it and run the surround sound system at the same time. I'm not sure why Chevy fails so badly in comparison to Tesla. The Roadster is a smaller car but I don't see how that explains such a huge drop in range from a much fancier battery.