Can renewable energy provide for our needs?
Can we decarbonise the global electricity sector by 2050?
A few points:
1. Our consumption of electricity is increasing rapidly.
2. Increasing energy prices would have a serious impact on those who can least afford electricity but for whom it provides many valuable functions.
3. Renewables are typically smaller in unit size and have availability charachtersistics that are different from large traditional power stations.
4. Increasing a proportion in a growing energy pie is a formidable challenge.
5. We are starting from a very low base.
6. Many people support an energy system more fully integrated through electricity as the carrier i.e electric cars or onsite H2 generation from electricity (less common).

If you have ever read the IEA energy projections then you will know what a roadmap straight to hell looks like. Globally emissions to 2030 are predicted increase by an eneromous amount (roughly a doubling?) rather than the dramatic cuts that we need.
How ambitious are the IEA projections for renewable energy? Surely they must be wholly conservative values.
http://climatechangeaction.blogspot.com/2006/11/renewable-energy-can-provide-for-our.html