David asked contributors for end-of-year lists. Since I normally focus on conservative assumptions, I thought I'd use it as an excuse to look at future breakthroughs and cost improvements.
I was going to weasel by calling these "possibilities," but instead I decided to use the time-tested technique of public psychics: I'll call them predictions, crow over any that come true, and pretend the rest never happened.
1. Power storage that will make electric cars cheaper than gasoline cars.
Ultracapacitors, various lithium systems, lead carbon foam (PDF), and aluminum are among the candidates. The first storage device with a price per kWh capacity of $200 or less, mass-to-power ratio as good or better than LiOn, and ability to retain 75% or more of capacity after 1,000 cycles in real world driving temperatures and conditions wins.