The human body contains enormous quantities of energy. In fact, the average adult has as much energy stored in fat as a one-ton battery. That energy fuels our everyday activities, but what if those actions could in turn run the electronic devices we rely on? Today, innovators around the world are banking on our potential to do just that.
Movement produces kinetic energy, which can be converted into power. In the past, devices that turned human kinetic energy into electricity, such as hand-cranked radios, computers and flashlights, involved a person's full participation. But a growing field is tapping into our energy without our even noticing it.
Consider, for example, a health club. With every step you take on a treadmill and with every bicep curl, you turn surplus calories into motion that could drive a generator and produce electricity. The energy from one person's workout may not be much, but 100 people could contribute significantly to a facility's power needs.
That's the idea behind the Green Microgym in Portland, Oregon, where machines like stationary bikes harvest energy during workouts. Pedaling turns a generator, producing electricity that helps to power the building. For now, body energy supplies only a small fraction of the gym's needs, but the amount should increase as more machines are adapted. "By being extremely energy-efficient and combining human power, solar and someday wind, I believe we'll be able to be net-zero for electricity sometime this year," says the gym's owner, Adam Boesel. His bikes, by the way, aren't the first to put pedal power to work. In some parts of the world, cyclists have been powering safety lights for years with devices called bicycle dynamos, which use a generator to create alternating current with every turn of the wheels.
Dance clubs are also getting in on the action. In the Netherlands, Rotterdam's new Club WATT has a floor that harnesses the energy created by the dancers' steps. Designed by a Dutch company called the Sustainable Dance Club, the floor is based on the piezoelectric effect, in which certain materials produce an electric current when compressed or bent. (The most common example is a cigarette lighter, in which a hammer causes a spark to be emitted when it strikes a piezoelectric crystal.) As clubgoers dance, the floor is compressed by less than half an inch. It makes contact with the piezoelectric material under it and generates anywhere from two to 20 watts of electricity, depending on the impact of the patrons' feet. For now, it's just enough to power LED lights in the floor, but in the future, more output is expected from newer technology. In London, Surya, another new eco-nightclub, uses the same principle for its dance floor, which the owners hope will one day generate 60 percent of the club's electricity.
Beyond body-powered gyms and dance clubs, ideas are also in the works to provide electricity for more ordinary, useful things. Researchers are creating ways to power small mobile devices like cellphones, MP3 players and laptops when there is no access to conventional energy sources.
Max Donelan of the Locomotion Laboratory at Simon Fraser University in British Columbia, in collaboration with American and Canadian researchers, is developing an electromagnetic generator fitted to a standard knee brace. The prototype, which Donelan unveiled last February, turns a one-minute walk into enough current for a half-hour cellphone conversation.
The knee generator uses sophisticated electronics to ensure that it grabs only excess energy. A computer measures the angle of the knee during every step to determine when to engage and disengage the generator. In the course of an ordinary stride, we use muscle energy both to accelerate the leg forward in an arc and then to brake its downward motion. The generator kicks in only during the swing phase of a footstep when the muscles are already braking, so it doesn't take power away from your step and slow you down. The electricity then flows through a wire to charge or power a battery or device.
At more than three pounds, the generator, called the Bionic Energy Harvester, is cumbersome. But thanks to lighter gears and a framework made of lightweight materials such as carbon fiber, the latest model, which is expected in the next year or so, should weigh closer to one pound. A microcomputer will replace a standalone computer that is wired to the unit in the current prototype.
Such a device has many possible uses. The Canadian military is partially funding Donelan's research because soldiers carry as many as 30 pounds of batteries for communications and navigation equipment—a load that could be significantly lightened by an alternative energy source. Public-safety workers such as firefighters and police could also use the technology to power handheld equipment during emergencies. In the future, artificial limbs that require batteries may instead be designed with Donelan's technology. And next-generation devices could run gadgets like cellphones, global positioning systems, iPods and digital cameras. This could be particularly useful for hikers and mountain climbers, who spend much of their time away from power sources.
Other generators in development use the same electromagnetic principle as the Bionic Energy Harvester. For instance, Larry Rome of the University of Pennsylvania has created the Lightning Pack, a backpack that captures energy from the natural up-and-down movement of your hips. As you walk, a bag bounces on a spring, which connects through gears to an electrical generator. Wires carry the electricity to your batteries or gadgets. The output is impressive: 20 watts, enough for nearly all portable devices, Rome says. But the bag is impractical for most people because it needs to weigh 80 pounds to generate 20 watts. (The heavier the load, the more mass that oscillates up and down, and the greater the kinetic energy potential.) The U.S. Marine Corps, however, is interested and has commissioned a pack for soldiers.
A far cry from an 80-pound backpack, energy harvesters the size of a thread are being developed by Zhong Lin Wang and two colleagues at the Georgia Institute of Technology. These mini-generators can be woven into T-shirts or other clothing and will collect energy from the body's smallest movements, piping electricity to mobile devices.
Wang's generators use piezoelectricity on a small scale. For the prototype, he grew zinc-oxide crystals on yarnlike Kevlar fibers. The crystals jut out on nanowires like thousands of small bristles and, when rubbed against each other, they bend and create electricity. In the prototype, two centimeter-long fibers produced 16 picowatts, or 16 trillionths of a watt. It's a minuscule amount of electricity, but the output grows as more fibers are added. The researchers predict that clothing with these fibers could generate up to 80 milliwatts of electricity per 11 square feet of fabric, which is almost enough to power a cellphone or other mobile electronic device.
Before we see garments that generate electricity—which could happen in about five years—Wang and his colleagues must overcome several challenges. The biggest problem is that these nanofibers can't get wet. A lining that zips out when laundering the garment could be the solution, and Wang is also exploring the possibility of waterproof nanofibers.
His next goal is to make the fibers more efficient. To this end, he is experimenting with different kinds of polymers and seeking better methods of combining the materials and collecting the electric charge. But even if the nanofibers don't become much more efficient, they might still be able to power gadgets entirely by body movement. Electronic devices continue to get smaller, requiring less power, and higher-capacity batteries will store the energy that is accumulated over a longer period of time—bringing us that much closer to an era when our movements are no longer wasted.
Soon, we might not even have to consciously move to create power. Wang is working on a polymer film that would surround his power-generating fibers and allow them to be implanted into our bodies. There they would harvest kinetic energy from the steady dilation and contraction of blood vessels, providing a source of electricity for pacemakers, insulin pumps and other medical devices—making for a truly powerful breakthrough.
I think the best that this device offers is the ability to assist in easier movement, and propulsion from the energy built up. Also powering electronics on your body is very nifty.
~ You fall somewhere in the Balanced Frequency of Nature. Someone Along the Infinite Spectrum of Life.
These are some great ideas, having are daily movements generate power is a great way to conserve energy. The green gym idea is completely brilliant, just think people who want to lose those pounds and calories, could exercise and be generating power for there own treadmill and they are also helping to conserve energy while losing those calories. The cellphone being charged while walking is a great idea too, say you run out of battery while your out, so you can't charge it because you don't have an outlet. But wait you have your knee generator thing, so you put your cellphone in and you take a walk and in minutes its fully charged how convenient.
Yes, it is always amazing that someone would drive five mile to the gym, pay a membership fee, stationary bike for ten miles, and then feel good about the exercise and the carbon they have saved the environment. Personally, I would just bike by the gym on the way to work and flip off the yuppie hippies inside.
Of course, anyone who is interested in entirely carbon and membership free exercise is welcome to come by my house and chop wood for a few hours. I won't even charge you to use my splitter.
The ideas r great... if they can make it small enuff to fit in the phone so it charges it self as i walk while in my pocket insted of luging anuther device around!!
also would be awsome to have the powered floor panels in high traffic areas like malls or even pave the streets with them sending the power to the grid to help cut our bills... but im mass thinking!!
All they need to do now is make it very light weight, indistructible, and attach it to two year olds. That would solve the energy crisis!
i love to walk and have my phone with me just in case but i always run out of battery since i walk for so long and forget to charge it. so being able to walk and have my phone not on my hip where i have the possibilty of losing it is the most wonderful idea every.now just to convince my sibling to wear it for a day and it wont die for a year.
Reality check here.
There is no energy savings.
The body requires energy just like any other engine and has to have fuel. Work the body harder and the more food is required.
More food means more food delivered to the grocery store in trucks. More food has to be grown and harvested by more tractors. More land has to be used to grow the food.
I ride a bicycle everywhere and put on about 1000 miles a month. I have a massive appetite and eat about 5000 calories a day. Our food bill is huge for just me and my wife. I save nothing riding a bike versus buying fuel for a car.
When humans exhale they exhale CO2. Work harder and you exhale more CO2. In fact you exhale 2-5 times the CO2 exercising than at rest.
Bottom line is there is no free lunch.
Well CliffCalvin, it may be true that there is no free lunch..but at least if your intentions are to harvest energy from wasted kinetics or from purposeful action such as exercise you can say energy is saved.
The idea of this energy saving i would say is analogous to:
Let say someone ate a slice of cake and still has 7 slices. Yes you purchased it...if you throw it away it matters not because you would have spent the same amount rather than storing it in a fridge. But it is a save if stored for later usage. (One of the things in the American culture...we eat more than we actually expend...hence why a good percentage of us are overweight)
Just imagine the usage especially when a person wants to lose weight, all that extra kinetic motion can be used to charge things while losing weight.
Though i think it would make walking feel a bit weird. After all that swing adds to our walking/running stride. Actually wouldn't be much problem imo...just takes time to get used to i suppose.
If there is resistance throughout the swing, it could be a nice exercising tool for strengthening leg muscles by walking.
Doh forgot to add this but, why the complaint in biking 1000 miles?
If you could harvest energy for every time you brake (because you need to, in order to avoid a collision, etc)
why not? The concept is same in my opinion. Just like those cars with brakes that regenerate energy.
On a side note, kudos for you in biking 1000miles per month. You're probably in good/great health condition, that can prevent health complications that can crop up from inactivity...which translates to money saved :P
Less time in hospital = more for possible productivity like work = more money in pockets :) opportunity cost :P
Apparently they have actively used stationary bikes in harvesting energy from humans. I've seen them implement the concept everywhere. Visit http://www.dogengine.com/used-stationary-bikes.php and look at the bottom of the page about "Stationary Bikes Used For Generating Energy" to see the different ways they have taken this concept.
This is great seeing so much movement in this area of Kinetic research as it is going to become more and more viable over th enext 5 years with rising energy prices and development of off grid applications.
I saw a few months ago ago a company called Pavegen Systems ( PAVEGEN(.)COM from the UK that produce energy harvesting floor tiles- like the sustainable dance club but with a very thin low, cost unit for exterior environments. I think they have been VC funded so expect some great new innovations from them soon. I will be monitoring this area very closely and good article!