Image source: ABB. 

What if you could charge your electric car every time you stop at a traffic light? What if buses and semi trucks could run on clean, renewable energy instead of diesel or natural gas?  

Fast charging has been a holy grail for the electric vehicle industry for a long time, but it's easier said than done. Tesla Motors (NASDAQ:TSLA) is building a network of fast-charging stations that will supply its vehicles with enough power to drive 170 miles in about 30 minutes. And other fast-charging technologies are starting to emerge. But one new concept in particular could be a game changer.

The new supercharger

Swiss power-technology manufacturer ABB (NYSE:ABB) has been testing a supercapacitor for charging buses that could eventually be a high-powered charging concept for all kinds of EVs. A supercharger is like a spring that can be slowly compressed (charged) and then later release its stored energy very rapidly  -- in this case, to charge an electric vehicle. Using the system company is developing in Geneva, a bus can get a 2.5 kWh charge (about 2.8% of a fully charged Model S) in 15 seconds at any one of 50 bus stops. At the depot, the bus is topped off for the next trip.  

The advantage of a supercharger is that it can draw energy from the grid -- whether it comes from traditional power plants or an intermittent source like wind or solar -- store that electricity for a period of time, and then discharge it very quickly when needed. If done efficiently, a supercharger can charge a battery very rapidly. And that's what ABB is doing with its prototype buses.

The supercharged bus has been tested in Geneva since 2013, and the city is so confident about the system that it's on course to launch a full supercapacitor powered bus line by spring 2018. This could create a template for cleaner public transit in the future. 

Supercapacitors charging an electric bus from above. Image source: ABB.

Is this Elon Musk's bus and semi plan?

We don't usually think of giant companies like ABB being on the cutting edge of electrically charged travel. But the company has quietly been working on this concept for years. And it could tell us something about what Tesla Motors has in mind in the future.

When Elon Musk released his "Master Plan, Part Deux" he talked about Tesla making buses and semi trucks, which seems improbable given the batteries and charging technology available for EVs today. Those large vehicles can't spend half the day charging, and they need to be on the road for more than 3 or 4 hours in a row, the time it's estimated a fully charged bus or semi could be driven before running out of juice.

Supercapacitors could be a valuable tool in the EV revolution

Until now, it's appeared that electric vehicles would remain smallish, and be useful only for relatively limited-range trips. But supercapacitors could be an solution to the problem of charging vehicles large and small very quickly, potentially with power from all renewable sources. And that would be a true revolution in energy.

ABB is leading the charge into fast-charging buses, but this could be just the beginning of how fast-charging technology develops in the transportation industry.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.