Tag Archives: exercise

Human Power: That Other Renewable

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Bike-powered peanut sheller and blender

Of all the renewable energy sources available today, one of them is constantly overlooked by modern society. It’s a shame, because this renewable energy is easy to harness, uses little space, and is complementary to wind and solar energy. I am speaking about that other, forgotten renewable: human power.

Using machines like a hand-crank, treadle, or pedal, human labor can be harnessed as mechanical or electrical work. The most common human-powered machine is the bicycle: mechanical work from a pedal is used to turn a wheel, which propels the rider forward. Bicycles, however, are not the only possible human-powered machines. With some clever engineering, human power has been harnessed to crank washing machines, plow fields, and saw wood. A bicycle can even generate electricity if equipped with a generator, voltage regulator, and battery. It can then power light bulbs, flashlights, laptops, and vacuum cleaners.

Hand-cranked and solar flashlight and radio


Hand-cranked red pepper processor

Unlike other renewable energy sources, human power requires active labor. Modern society, with its distaste for exercise in general, rejected human-powered machines for this very reason. That’s a shame, because human-power provides a nice complement to solar technology. Pedal-power can provide a handy back-up to photovoltaic panels on cloudy days. What’s more, pedal power can create short bursts of electricity, in contrast to the steady-stream of low power provided by solar panels.

An illustration involving an LCD monitor can provide perspective. A typical monitor requires around 100W of power to operate. After cloud cover and the earth’s tilt are considered, a photovoltaic panel might produce a power of around 25W/m^2 on average (1). So to power the monitor, we would need 4m^2 of solar panels. It only takes a single stationary bicycle, however, to generate 100W. Space is only needed for the bicycle itself and a few electronics, so the whole system can be contained in around one square meter. A fit cyclist, moreover, can produce even higher rates of sustained power — up to 200W in athletes. As a result, a well-trained cyclist can produce twice the energy of a photovoltaic panel in one-fourth of the space.

Pedal-power is not unreasonably expensive. A stationary unicycle can be built for under $250, and accompanying electronics can be purchased for around $400 (2). The combined total is $650, roughly the cost of similar solar panel installations.

The real cost savings, however, are for appliances that require only mechanical power. When there is no need to purchase expensive electronics, pedal power is clearly cheaper, since these machines can be built using only donated bicycles, spare hardware, and elbow grease. One NGO based in Guatemala, Maya Pedal, has taken discarded bikes and retrofitted them to make useful tools for local farmers. Old bicycles have been used to blend soap, pump water, grind flour, shell peanuts, and thresh grain. Not only has this removed the drudgery of agricultural work, it has also increased the income of local families. These projects promote development without burning extra gasoline or coal, all while recycling old garbage.

The Western world could learn a lesson. We chronically suffer from energy shortages, and we have no lack of people needing exercise. In the United States, more than one in four Americans are obese, and six in ten overweight. Cheap energy has allowed us to live sedentary lifestyles, which shorten our lifespans and waste trillions of dollars on unnecessary healthcare. If couch potatoes were forced to pedal for their television time, the rates of Western diseases — heart attacks, strokes, diabetes, and cancers — would rapidly plummet.

This is much better than going to the gym. Not only does gym membership cost thousands of dollars, but workout machines like treadmills actually waste additional energy to power. The average treadmill consumes 1500W of power — enough power to run 20 laptops. When people drive to the gym, moreover, they further add to greenhouse gas emissions. With human-power, they could instead burn their extra fat for productive purposes. Those calories might as well be used to wash clothes, blend smoothies, and generate electricity. Why not combat global warming while getting in shape?

Pedal-powered washing machine

Whether human power can truly make a difference depends on the efficiency of the exercise machine and the power demanded by your household. The average person can produce around 35-60W of power using a hand-crank, and 100W-120W using pedal power. Cell phones, flashlights, and watches can all be powered by hand-crank, while computers and televisions can be powered by pedals.

This sounds promising — that is, until you consider our monstrous demand for power. A medium-sized, window air conditioner uses around 1000W of power. To supply the energy for just that one AC unit, it would take a team of ten cyclists pedaling at full speed for the entire day. Once you add in laptops, televisions, clothes driers, washing machines, heaters, and light bulbs, human power becomes woefully inadequate. It would take a legion of cyclists to support the typical American home.

Storing generated electricity is a problem as well. Most pedal generators use lead-acid batteries, which store energy for later use. Devices can then be plugged into the battery rather than directly to the exercise machine. This helps avoid the awkward situation of having to simultaneously pedal while using your laptop. But as Low Tech Magazine points out, lead-acid batteries require massive amounts of energy to manufacture. Sulfuric acid can also cause severe burns, and lead can cause birth defects and brain disorders. Even pedal-powered electricity, then, isn’t perfectly green.

This limitation can be largely overcome by simply transmitting work mechanically rather than electrically. One clever hobbyist retrofitted his bicycle to spin washing machines using only pulleys and belts. The Human Powered Home, a compendium of do-it-yourself pedal-powered machines, provides plans for mechanically connect your bicycle to a grain mill, sewing machine, and tool sharpener. With a little ingenuity, the mechanical applications of pedal power are endless.

Pedal-powered jig saw

Despite its flaws, human-powered electricity can still contribute to sustainable living. Every renewable technology has its limitations, and a human-powered generator is no exception. They may not be perfectly green, but neither are solar panels. When used properly, the benefits of renewable, off-grid electricity can outweigh the harm caused by pedal-power electronics.

Generating your own electricity can allow you to live off the land, which dramatically reduces your carbon emissions. One difficulty with living on rural, undeveloped land is the lack of grid electricity. Pedal power, along with photovoltaic panels, can provide electricity without an expensive connection to the utility company. One Laptop Per Child, for instance, has taken advantage of human power to design off-grid laptops. Students in remote villages often lack access to electricity, but one minute on a hand-crank can provide enough energy for ten minutes of laptop use.

Yet the most profound impact of human power is not the generated electricity itself, but rather the conservation ethic it instills. Producing electricity is hard work. When we hook up an appliance to a power outlet, we are blind as to how much energy we are truly wasting. But if we had to pedal forty-five minutes for each hour of television we watched, we would be more conscious about our electricity usage. We would never have to be reminded to turn off our lights or to sleep our computers, and few would dream of using an air conditioner. Ultimately, it’s conservation — in addition to our feet — that will provide us with the power to lower our carbon footprint.

Do-it-yourself bicycle-power plans are the most affordable and have the lowest environmental impact. There are also some commercially-available attachments. They are expensive, however, and may actually waste more energy than they produce. I encourage you to build your own instead.

  1. Sustainability: Energy: Without the Hot Air generously estimates that a solar panel in Britain produces around 22W/m^2 on average. Low-Tech Magazine estimates a power capacity of 100-150W for average cyclists and up to 300W for athletes.
  2. The Pedal Powered Prime Mover is one unicycle designed especially for pedal power. It costs around $100-$250. The exact electronics will vary depending on your needs.
  3. Photo credits: Alan Levine, CC BY. Engineering for Change, CC BY. AIDG, CC BY-NC-SA. AIDG, CC BY-NC-SA. Donkeycart, CC BY-NC. Bruce Turner, CC BY.

Bicycle Commuting Safely

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Enjoy the ride. Get out and bike!

Safety is a major concern for bicycle commuters. Cyclists often find themselves sharing the road with cars, sometimes on narrow streets without marked bike lanes. This dangerous arrangement has scared away many potential converts from switching over to bicycle commuting full-time. It’s a real tragedy, since cycling offers a cheap and effective solution for reducing our dependence on fossil fuels. But a lack of safe, dedicated bike paths is only half of the problem; the other half is ignorance.

By law, bicycles are vehicles: they are entitled to use the road, just as cars are (1). In fact, bicycles are forbidden to ride on the sidewalk. While they must usually ride on the right edge of the road, cyclists are allowed to occupy an entire lane when necessary for safety. They can even switch to the left lane to turn or to pass slower vehicles. Most motorists, however, are misinformed about the law. They think that bicycles are toys that belong on the sidewalk, so most cyclists are regarded as pests and troublemakers. When this ignorance is combined with two tons of high speed metal, cyclists need to watch out!

As a bicycle commuter, you need to bicycle defensively. Do whatever it takes to avoid getting hit. Don’t insist on your legal rights when you bicycle; it’s better to be wronged than to get hit by a car. Don’t expect motorists to follow the rules, or even the police to help you out. I discovered this first-hand when my high school friend got hit by a car. I witnessed a reckless driver smash into my friend’s bicycle, knocking him off and fracturing his arm and wrist. The law was on my friend’s side, but the police did nothing to help him. If you want to avoid a similar fate, you need to avoid getting hit in the first place (2).

Bicycle as if no cars can see you, because some of them won’t. Helmets are nice, but don’t let them give you an illusion of safety. You don’t want to get hit in the first place, so stay away from cars whenever possible.

The best tactic is to choose the safest route possible. Google Maps also provides bike paths, which is extremely helpful. Under the “More” tab, you can overlay a map with bike routes. A thin, sold green line indicates a bike lane shared with cars, while a thick, solid green line represents paths exclusive to bicycles.

When deciding on a bicycle route, choose safety over distance. Safer routes may take longer, but they’re worth the peace of mind. It’s safer to ride in bicycle lanes, and even safer to route through exclusive paths. When neither option is available, I choose residential roads. Although major streets tend to be more direct, cars drive faster and may be less attentive. Finally, choose paths you’re already familiar with, so that if you get a flat tire, you’ll know how to navigate around.

Even though you’ll bicycle as if no cars can see you, you’ll still want to be highly visible–just in case. Make sure every car can see you clearly from afar. This means you should generally avoid bicycling at night, and if you must, bring strong headlights and taillights. They are required by law, anyway. Make sure they are highly visible and strong enough to avoid being obscured by car headlights. Reflective clothing and rear reflectors can also help. Finally, to help your own visibility, purchase a rear view mirror so you can better see cars coming from behind.

As a bicycle commuter, you’ll want to learn how to fix a flat tire by yourself. You will certainly get a flat eventually, and you’ll want to be able to fix it on the spot, especially if you ride at night. Always carry the necessary equipment to fix the bike yourself; bike stores often sell a small repair kit.

For some of you, bicycle commuting can be dangerous because of a lack of bike paths and reckless cars. It’s a real shame, but hopefully these tactics can help you overcome the many obstacles thrown against you.

For those who live in eco-conscious cities (3), bicycle commuting is actually an extremely safe way of transportation. In Irvine, biking is far safer than driving. Cities like Davis or Portland often have scenic bike paths where you can enjoy clean air, good exercise, and a relaxing ride while saving thousands of dollars each year. Not bad for conserving a little energy.

Can you bicycle commute instead of drive?

1 California Law dictates bicycles are allowed, and in fact must, ride on the road. Try telling that to the cars!

2 Bicyclesafe provides excellent tips to avoid getting hit by cars. It inspired much of this post.

3 Minneapolis, Portland, Boulder, Seattle, and Eugene are the top five bike-friendly cities in the US, according to Bicycling.com

How To Thrive Without A Car

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The Miaoli Train Station in Taiwan

With a little effort, you can live a happier life by not owning a car. Here’s how:

  1. Borrow a car. Rent a car, hire a taxi, find a carpool, take a shuttle — whatever form you choose, you can borrow a car instead of buying one. Borrowing a car is extremely handy when you only need to drive occasionally.

  2. Ride a bike. Bicycle commuting is extremely practical in biker-friendly cities, which include Portland, Minneapolis, San Francisco, Seattle, Boulder, and even New York City (1). The city of Irvine has an amazing network of bike paths. Look up your city on Google Maps to see what bike paths are available.

  3. Run. It’s obvious, yet often overlooked. You can run four miles in about half an hour 45 minutes. If you run to work, you can ditch your treadmill.

  4. Bus / Subway / Train / Metro. This heavily depends on where you live. Taiwan has great public transit, while California’s transit system is mediocre.

  5. Move closer to your work or take it online. Telecommuting also gives you the freedom to work anywhere in the world.

The most effective tactic is to simply commute less. Try to shorten your commute by moving closer to your work. Often, you can combine multiple errands into a single trip. Lastly, avoid unnecessary trips to the mall, department store, or restaurant. When you must shop, you can order online and have it delivered to your door, bypassing the need for a car (2). But often, there’s no need to shop at all. When you shop less, you’ll reduce the need for a car while saving money and time.

It’s helpful to make the transition slowly. Test-ride your bicycle for a few weeks while keeping your car parked in the garage. Weaning yourself off the car should be a gradual process; it takes time to get accustomed to bicycle commuting or riding the bus. And remember, even if you don’t want to live totally car-free, any reduction in driving will save money and gas.

Most importantly, don’t get discouraged easily. Commuting without a car will take longer, but don’t let it test your patience. Always remind yourself of why you sold your car in the first place. You’re protecting the environment by conserving oil and metal; you’re exercising more, freeing up garage space, and avoiding repair hassles. Think about the tens of thousands of dollars you’ll gain each year by selling your car, cancelling your auto insurance, and by not paying for rising gas prices. The trade off is definitely worth it.

Not only is living without a car possible, it’s actually enjoyable. I’ve lived for 18 months now without owning a car, and I’ve never looked back. With a little patience, you can join me, too. Together, we can show the world that life doesn’t have to depend on gasoline.

Can you thrive without a car?

1 Here’s the top 15 biker-friendly cities in the world, and here’s the top 50 US cities.  Some cities on the US list aren’t truly biker-friendly; they just have a lot of dedicated cyclists.

2 Online shopping still wastes gas and often contains a lot of packaging. Still, it might help you sell your car.