For my points I want to talk Short and Long term.
Short Term Problem: Believe it or not it is storage. Reason? Li-Ion batteries for cars can cost more than the cost of the car itself.....
The sun is not up for 24 hours and the wind does not always blow. So because of this we need to produce "excess" and store it or rely on nasty fossil fuels to power during the dark and calm times.
Solution: EEstor........
As you can tell I am a BIG fan of ZENN and EEstor. The reason being that EEstor is new and designed from the onset to be used in large load applications. It is not super toxic like the battery tech today. It is LIGHT compared to even Li-Ion. And mass production means prices that can open up the road again to the lower middle class. And on top of that. For short term Auto use... It moves the pollution to the power plant. Where emmission controls are MUCH more advanced than the converter on the average car today.
http://en.wikipedia.org/wiki/EEstor
And some news
http://media.cleantech.com/3174/eest...itor-milestone
Long Term: We either fix the energy Crisis or go into Depression. Need it any clearer?
Solution?: Fusion, Yes FUSION! Before you go into your bahs and "What about solar" Keep in mind I said LONG term. As there are multiple projects on the way with chances strong that one of them will show sucess by 2030.
Fusion can be powered with a number of different fuels. Including He3 if you want to take a mining trip to the moon. Tho its better with PB11.
I am a fan of EMC2 fusion.
http://www.emc2fusion.org/ As I feel that with time it will be the reasonable solution. No giant plasma super plants. Just plants for counties and small countries suppling the energy needs without the danger and expence of current fission.