How one schoolboy could cut 1.8m tons of CO2Jonny Cohen has been dreaming of making America’s school buses greener since he was 12. Now the high school inventor is on the verge of success.
Fast-forward four years and that observation has propelled him inside the covers of Forbes magazine, onto the stage with Kofi Annan and founders of Apple and Facebook, and into the offices of the U.S. Environment Protection Agency (EPA) to seek approval for an invention that could ultimately slash CO2 emissions by 1.8 million tons—equivalent to taking 320,000 American cars off the road for a year.
But to return to Highland Park; what Cohen noticed that day was devastatingly simple. School buses are aerodynamically hopeless. Their unyielding lines, sharp edges and chunky bodies invite maximum air resistance and drag. “Something that can be drawn very accurately with straight lines and 90 degree angles should not exist as a real life automobile,” he explained between speaking engagements and homework assignments. “If you can do that, then you are in trouble.”
Even aged 12, Cohen knew about these things. He had been studying aerodynamics in extra-curricular classes hosted by Northwestern University, spending time designing and building model cars to be as aerodynamic as possible.
“I was so excited by it and started sketching things and thinking: Wow! Things could be so much more efficient just by changing their shape,” he remembers. “Then I noticed the school buses.”
His idea was straightforward: to make school buses more aerodynamic. They would consequently use less fuel, spew out less CO2 and other pollutants, and cost schools less money to run. “We hear about school buses running a four-day week because of budget cuts,” Cohen says. “If we reduce their gasoline bill it could make a difference.”
On a national scale, upgrading school buses could make an enormous difference. There are about 480,000 school buses operating in America. The average model gets a paltry seven miles per gallon and schools spend around 6000 dollars a year on gasoline, according to the American School Bus Council. That produces about nine million tons of CO2 a year, almost equivalent to the annual emissions of two coal-fired power stations, calculates the EPA.
10-20 percent fuel savingsTogether with friends, family, school teachers, students and professors at Northwestern, Cohen devised and computer-tested numerous designs as well as setting up a wind tunnel in his garage and trying out his creations fitted to toy school buses. Finally he settled on the right one: the GreenShield.
The GreenShield is a curved 'airfoil'--a shape that generates lift or drag, most often used in wings or rotor blades. Made of fiberglass, the GreenShield is not quite as wide as the bus roof, and fits onto the leading edge of the bus roof. It has a curved raised front and then tapers down for about a meter to the sharp trailing edge. It acts to smooth the flow of air up and over the surface of the roof.
“This area is where the air flow usually separates and becomes turbulent rather than smooth and laminar. When air moves over a surface it should flow as if it was attached to that surface. The GreenShield is doing that,” Cohen explains.
The prototype, tested in wind tunnels and on a school bus donated by the owner of the Cook-Illinois Bus Company, has performed impressively. The results suggest that buses fitted with the GreenShield would use between 10 and 20 percent less gasoline, saving from 600 to 1200 dollars a year, and reducing carbon emissions accordingly.
If all the school buses in America achieved maximum fuel savings thanks to GreenShields, Jonny Cohen’s device would have saved a staggering 576 million dollars and 1.8 million tons of CO2—that’s the same amount of CO2 produced from the annual electricity usage of over 203,000 American homes.
These are heady numbers, and they have persuaded the Cook-Illinois Bus Company to put in a provisional order to fit GreenShields to its fleet of over 4000 school buses if the device is approved for mass production.
The last hurdleThe encouraging test results have also prompted interest from the Global Energy Initiative at Harvard and an advisor from MIT, not to mention MTV and Good Morning America. Most recently, Cohen presented GreenShields at the Americas Business Council's ABC Continuity Forum 2012, a celebration of social entrepreneurship, sharing the stage with Apple co-founder Steve Wozniak and Kofi Annan.
A manufacturer is lined up, and a provisional patent is in the pipeline. Weighing in at just eight pounds (3.6 kilograms), the GreenShield can be fitted very easily and quickly, says Cohen, and although it now costs about 500 dollars to make, if production can be scaled up to make use of injection moulding techniques the cost could be brought down to around 100 dollars and the GreenShield would pay for itself within a matter of months. It could also be made from recycled plastics rather than energy-intensive fiberglass.
All that remains is for the federal authorities and the Department of Transport in Illinois to approve the GreenShield. And that, Jonny Cohen has found, is the hard part.
“The biggest challenge is getting GreenShield approved. People don’t want to say yes as nothing good can come of it for them so there is no incentive to say yes. On the other hand, if they do say yes and someone gets hurt then they fear they are liable, and will get into trouble. If they would just treat it like they treat semi truck add-ons that would be great.”
And there’s the intriguing point about the GreenShields story. It is not an entirely novel concept. Many semi-trailer trucks use airfoils to bridge the gap between the truck cab and the cargo container in order to reduce drag. But until Jonny Cohen noticed something on the way to middle school, nobody thought to do something similar for school buses.
So could the GreenShield be attached to other vehicles? Certainly, says Cohen, although they would need to be reasonably large and have relatively long working lives to make the investment worthwhile.
In the meantime, however, this young inventor is concentrating on helping turn an enduring American icon from a gas-guzzling workhorse into a leaner, greener thoroughbred.
You can find out more about the GreenShields project here.