Here's an article on a new battery technology. It's as cheap as lead-acid, but completely non-toxic, made from common materials, and lasts at least 10 times longer. The chief application is giving power companies a way to store power produced at non-peak times, and then release that power during peak times.
Which means it's great for solar power. I have a vision of tanker trucks driving from the solar power plants of Arizona to New York City, where the ion-charged water is dumped into the power grid. Although I can't do the math to figure out if moving tons of weight would be more energy efficient than pumping it through high-voltage wires.
But then, why not just pump the ion-charged water? A cross-country pipeline that delivers power stored in water. I've read before that 100 square miles of Arizona desert would power the entire nation. All we need is a way to store and deliver the power. And, of course, the political will to give up the oil addiction. A carbon tax would be a good way to do that.