Arizona Republic: Al Gore recently challenged the American people to overcome the related dangers of global warming and U.S. dependence on foreign oil by reaching the goal of generating 100 percent of U.S. electricity from renewable energy in 10 years. But is Gore’s proposal even remotely feasible? Here is an estimate of its cost. The U.S. has roughly 1 million megawatts of electrical generating capacity, most from non-renewable resources. This generating capacity instead would need to come from …