How much energy does it take to move a human from point A to point B? Ever wondered what the most energy efficient way to do this is? In a head to head contest on energy efficiency how would the Telsa Model 3 compare to a electric commuter bike?
Bike engineer Zach Krapfl looks at the environmental footprint of many methods of modern transportation and finds some surprising answers to these questions, along with big opportunities for change. A most promising one: People who have changed their main mode of transportation to electric bikes are living healthier, happier, more eco-friendly lives.
Zach is a mechanical and civil engineer based in Paonia, Colorado. He is dedicated to global energy conservation, reduction in fossil fuel consumption, increased energy efficiency and chooses to combine bicycles, light electric vehicles, and appropriate renewable energy technologies as a catalyst for earth lovin’ and a little personal happiness too.
How much do you love your car?
Americans drive 3 trillion miles every year, have 253 million cars on the road and 55% of car trips are under 10 miles, well within the range of a number of alternative transport options (check out our post on how to ride to work without sweating).
The average American spends over 300 hours in the car each year with 38 of those hours stuck in traffic. Congestion alone costs $1 Billion in gasoline not to mention the pollution this creates.
For those of us who crawl along in traffic on our daily commute to work these statics are probably a little depressing but they can also act as a catalyst for change.
Do you like your car so much that you want to spend the equivalent of 2 weeks 24/7 sitting in your car each year? Can you think of a better way that you would rather use that time?
According to Zach alternatives do exist. If you go to places like Copenhagen, Amsterdam, you find this unbelievable cycling infrastructure with lanes protected from the cars and where 35-40% of people ride bikes everywhere – rain, hail, or shine.
The United States has Cities with similar infrastructure as Copenhagen and Amsterdam but do not have anywhere near this level of ridership.
If you ask people if it is possible to commute by bike most will say no way. If you live in Seattle or San Francisco they will say the hills are too prohibitive, I will show up to work completely sweaty, we don’t have a shower there, or I’m not fit enough. In fact we have a post about how to ride to work without sweating using an electric bike, electric scooter, or electric skateboard.
So Zach started working on the electric commuter bike around 10 years ago to enable people to get out of their cars and make them feel comfortable to travel longer distances or to flatten those hills by developing the electric pedal bike and power assisted bikes.
The electric bycicle can assist the rider by using an electric motor and on board battery to drive the bike along at speeds around 20-30 mph. You can ride the bike on 100% electric energy or 100% human power by pedaling or any combination in between.
Electric bikes come in a wide variety of designs like this collection of Prodeco bikes. Click the image to compare models.
We need to start thinking of the bicycle as a mode of transportation not just recreation.
How much energy does it take to move a human from point A to point B?
Zach has always been interested in how to use the least amount of energy to go from point A to B.
When he was in college, Zach would go on road trips with his friends and in his efforts to get maximum millage per gallon he would avoid stopping for toilet breaks until his friends were busting and then he would switch off the engine as they climbed a hill and coast to the top for max efficiency before stopping. After his friends went to the bathroom they would have to push the car to get it started rolling down the other side of the hill and jump into the moving car.
He would tape up all the seams on the car and pull the side mirrors in to improve aerodynamics and get 48 miles per gallon instead of 35 mpg.
His obsession extends beyond fuel consumption. When he brews his own beer at home where he has solar panels in the roof he only brews when the sun is shining so that when he drinks his beer he knows every drop is brewed with the sun.
So what is the most efficient mode of transport and how much energy does it take to move a human from point A to point B?
In his TEDx talk below Zach provides a range of examples that are all normalised to be expressed in miles per gallon.
The following are some common forms of transportation and their energy efficiency from worst to best.
Utility vehicle 20mpg
Old Honda Civic (small car) 40mpg
Toyota Prius C 50 mpg
Pedestrian walking 55 mpg
Vintage motorcycle 65 mpg
Modern jet airliner (if full) 90mpg
Cycling 270 mpg
The pedestrian and cyclist numbers are based on our metabolism being around 25% efficient and are a little low because the food you eat requires energy to be delivered to you and hence your efficiency varies based on the food you eat. For example if you eat oranges from Florida or Kiwi fruit from New Zealand then you are using more energy.
How can we be more fuel efficient?
Zach then goes on to demonstrate how the food you consume affects your energy efficiency.
Zach’s friend Scott delivers organic food via electric eco bike. This locally grown food therefore has a lower energy footprint than food that might be transported from far away. What happens when you eat this food? – the pedestrian’s efficiency goes from 55 mpg to 70 mpg, biking from 270 mpg to 340 mpg.
Local food = Higher mpg
What happens when you add an electric motor to create an electric pedal bike?
Assuming your metabolism is 25% efficient, the electric motor will be around 80% efficient, your transportation efficiency on your new electric commuter bike jumps to 480mpg (if you have kids on the back) or 570mpg if you are riding on your own.
If you then consume local low energy food this jumps to 600 mpg and 710 mpg respectively.
What if you feed your electric motor local food and instead of using grid energy with 1x250W solar panel? Then your efficiency jumps again to 1340 mpg.
Hybrid e bike + local food + local energy = the most efficient way to move a human from A to B
Electric Commuter Bike vs Electric Cars
Electric cars are on the rise with the recent launch of the Tesla Model 3 receiving over 300,000 pre orders. So how does an electric car like the Tesla compare with an electric commuter bike?
If you use grid based energy and consider the losses of energy across the transmission system then electric car only gets around 114 mpg and you are still stuck in traffic for 38 hours a year.
So electric bikes are more than 10 times more efficient that electric cars if you use local food and local energy sources and most electric bikes will pay for themselves sin 6-9 months just based on savings of fuel, tolls, parking, and maintenance. This payback might even be better if is based on our top 5 best value electric bikes.
Many people have also found that simply by avoiding traffic that an electric bycicle can get you places in a third of the time it would take you to drive.
Riding an electric commuter bike has many benefits including reduced energy consumption, greater happiness levels, braggability having the latest gadget, saving money, lower stress, more free time, and health benefits.
If you look at just health benefits alone and Americans took 1% of the 55% of trips that are less than 10 miles on their new cool electric bike then you would take 17 billion car miles off US roads and 2.2 million Americans would lose between 25 and 50lbs.
When was the last time you heard a health professional tell you that you need to sit still, in a stressful environment, do no exercise, and put on weight. So why do we sit in a car for 300 hours every year getting stressed eating donuts and drinking coffee?
If you speak to any health care professional they always tell you to get some exercise and lose weight which an electric commuter bike will help you achieve.
Electric bikes are an alternative to break your dependence on the car and all the baggage that comes with them.
Remember when you were 5 years old and just having fun riding your bike – now imagine feeling that way every day.
Don’t know where to start? Check out our top 5 best value electric bikes post to get some ideas.