I was reading an advertisement claiming that batter powered devices are more enviromentally friendly that petrolium powered things.
Well... Yes and no.
You have to look also at how the electricity is produced and how the electronic devices are made.
Electricity can come from many sources. Dams, coal, gas, oil, nuclear, tides, wind, solar, etc.
Dams destroy habitate upstream, and fish runs, and the natura seasonal flow down stream, and tend to leak lubricant.
Coal and oil based electricity are just as poluting than cars, but even more concentrated as they never move.
Nuclear leaves highly toxic waste that is hard to store for eons.
Tides can be enviromentally friendly when using the in development bouy systems, but other wise have similiar problems as dams. Though the both still leak lubricant.
Wide is very positive except the best places for them are also hunting areas for hawks, which tend to fly into the blades and get killed.
Solar is good except in the manufacturing.
The manufacturing of electronic devices involves a lot of very dangerous chemicals. Arsnic, cynide, pcbs, and various heavy metals. This poses a risk in manufacturing, in the manufacturing waste, and in the eventual disposal of the electronic devices. Some of the chemicals are leathal, man are cancer causing, and all will leach in to the ground water.
Finally their is the means of power storage. All batteries are based on chemical reaction, and use very caustic and poisonous chemicals. Sulfuric acid, mercury, lithium, alkelie, etc.
Don't get me wrong, I think electricity is great and is in many way better than raw fossil fuels, but I think it's misleading to claim that electritiy is totally safe and non-damaging to the enviroment.