The problem with trying to peer into the future is not being able to accurately forecast "quantum leaps" in technology, that are often simple breakthroughs into major increases in performance. These will definitely appear with electric technology.
Super-capacitors are going to be playing a big part in the electric drive systems of the future. The major part of transportation movement that currently hampers electric power is the need for rapid acceleration to get up to cruise speed.
In an aircraft, it's the sizeable power output required to get up to cruise level that sets the power level needed - and IC engines can produce that maximum power for as long as needed, or as long as you have fuel.
If super-capacitor development continues along the lines of current development trends, they will be able to provide the continued electric power surge needed to climb and reach cruise speed.
Once cruise level and cruise speed is reached, power requirements are considerably less than that needed initially, and this is where electric power has a major efficiency advantage over IC engines.
Your IC engine is generally burning, say, 10 gallons an hour regardless of whether it's producing full power or 2/3rds power. It might drop back to 8 gallons an hour with power carefully trimmed back - but there's still a lot wasted energy at that lower power setting.
An electric power source will only draw down the power needed to sustain flight and selected airspeed, and this would be much less than the average energy consumption of an IC engine on cruise setting.
Australia's CSIRO has been at the forefront of developing super-capacitors - but at present, only in the smaller sizes and in the small electronics field. The CSIRO experimented with super-capacitors in electric cars in the early 2000's - but only with the aim of improving lead-acid battery performance. The CSIRO did not proceed along the development path for super-capacitor use in transport equipment, they saw more current demand in the electronic and wireless fields.
As a result, the development of supercapacitors for transport use has stalled within the CSIRO. All it takes is someone such as Tesla to start pouring sizeable amounts of money, research, and effort into super-capacitor use in the transport field, and we will start to see some quantum leaps in electric power performance.
Last edited by onetrack; 24th Nov 2015 at 00:14.