Germany already is getting >20% of their electricity from renewable energy. Germany is about as sunny as the State of Washington. They are planning on getting 50% very soon and 100% by 2050.
Wind scales up. Solar scales down. Wave power is available on many coasts. Tidal power is also very possible especially in bays. Biogas / methane can be made from sewage and farm waste. Small scale hydro can be done in all the existing dams. Geothermal can work in many places, and we can drill to get it, as well. We could have about 10X more power than we need from all these sources.
Dave Cloud's Dolphin goes 200 miles on lead acid batteries. The Illuminati Motor Works 7 goes 210+ miles on a ~33kWh lithium pack. The
SIM-LEI goes ~207 miles on a 24.5kWh pack; similar capacity pack to the Leaf. The Tesla S goes up to 300 miles on an 85kWh pack (if I recall correctly), and the DBM Energy Kolibri 99kWh lithium metal battery took a converted Audi A2 375 miles @ 55MPH and had ~18% of the charge left.
Both the early Aptera and the Edison2 VLCe show that <100Wh/mile is possible. The SIM-LEI uses ~134Wh/mile, and the Illuminati 7 is ~160Wh/mile and Dave Cloud's Dolphin is about 164-170Wh/mile.
For comparison, the Nissan Leaf is 340Wh/mile which translates to 99MPGe. The Dolphin and the 7 have the equivalent of 1 gallon of gasoline in their packs.