Following the Rumsfeldian theme....
What are the events that will happen, but are not general known/thought about? There are many occasions when specialists or intersted parties have knowledge that hasn't reached the counciousness of the general public as a whole. For example, I was quite surpised during the Petrol Strike by the fact that people *didn't* know that 80% of the price of petrol is tax.
An interesting event that will occur is the replacement of petrol with battery powered. The current state of the art is that such cars have a reasonable range and good performance, but a very high price. Within 10 years, we will have cars in the sub-£20,000 category, capable of a driving 500 miles between charges. Such vehicles would be cheaper to own than the equivelant fossil fuel vehicles. While the possibility of electric vehicles is known, the rapidity wth which they are going to become a cheap practical transport system isn't
Hydrogen - the main competitor - is not capable of improving the energy density (the amount of fuel that can be stored) much further. Refueling times are fixed at the half hour level by the physics of cryogenic material. Fuel cells are complex and just as liable to degrade over time as batteries.
What will be the results of this change. A common place about electric vehicles is that if there is a mass takeup of the technology the electricity grid will collapse. There is a power shortage in the near future by most measures, after all. But consider - such vehicles might well be charged at night, when there is a vast surplus of generating capacity. An interesting possibility is that filling stations would store power in huge, fixed, battery banks. Cars would "fill up" from them rapidly, and they would steadliy charge overnight. This would be preferable to huge, short duration loads on the grid, by directly charging a car in 10 minutes (say). This infrastructure has been suggested by all the studies into mass use of electric vehicles.
Such a battery bank would be a vast store of electricty. This would enable electricty generators to "smooth" the generation curve. A perfect world for the generating companies would be a completely flat level of demand, 24 hours a day. This would mean that the number of power plants could be massively reduced - a huge amount of capacity is only there to meet peak demand. Good bye power shortage? Wind power would also become much more usable if there is somewhere to store the power generated at the wrong time.
What of revenue? Green vehicles are currently barely taxed. It would not take a great deal of takeup to start hitting the government hard in the wallet. Introducing taxes on green vehciles will be very difficult. For the foresable future, taxes at the level levied on fossil fuel vehicles would render alternative fuel transport uneconomic - they will cost more. It is quite possible that this will begin to be felt before the end of the next parlimentry term - definitely by the end of the one after next.
Planning is currently based on the idea that cars are undesirable. If they are silent and non-C02 emitting this will change. Houses next to major roads may become a lot less undesirable, for example...
So, power station construction may become less of an issue - not something that many are predicting at the moment. Taxation will be a major problem and urban planning will be massively effected. All within a decade or two. That and the collapse of the economies of the major oil producers. Scotland with oil no-one buys? Saudi Arabia minus 90% of it's income?