Why can't all the world's energy problems be solved by hooking excersise bikes up to the national grid?

Question

That's always been my answer when people say "Well what would YOU do about emissions from power stations and non-renewable fuel and efficient energy and the ever-approaching energy crisis?"

But two cyclists pedalling is enough to power three microphones, two electric guitars, a PA system etc. Apparently, bicycles are 90% efficient.

Well think of the millions of people across britain pedalling on excersise bikes/step machines in the gym or at home, and think of all that energy going to waste!

Answer 1

The average person who is in shape (I am not in shape) can produce about 200 watts of power. If that person spent one hour a day working out on a generator bike, he could could generate 6 kWh of electricity per month. (200 watts times 30 hours a month = 6000 watt-hours = 6 kilowatt hours). Now look at your electric bill and tell me how many kWh you used last month. The average household uses over 800 kWh per month.

Answer 2

It's not a STEADY AND RELIABLE source of energy. Have you ever ridden a bicycle and noticed that you DO NOT peddle at a constant rate? The rate at which a person peddles changes from time to time (bursts of energy and fatigue are the biggest factors) and if that peddling generated electricity, the current would fluctuate with the changes in the peddling rate. Mechanical means of producing energy (such as steam plants, nuclear plants and hydroelectic plants) can produce a steady, reliable current that does not fluctuate as much due to the constant source which drives the generator. In addition, it would take more people than are available to handle the demand that we currently put on power grids, especially in the summer and winter months when we rely on electricity to cool and heat our homes, places of recreation, schools, and businesses.

Answer 3

good solution and then there is also

sugar cane energy already being utilized in Brazil and other countries

I have been to several countries where a bike trail/walk trail/mini motorcycle is implemented in to the highway system and regulated
and by the way these people are NOT fat or overweight need I say more

solar energy

and then there is the undiscovered and yet to be sought of by all the geniuses

Answer 4

thats a pretty sweet idea I think... human power can definately contribute... but even if everyone put an hour a day into theirs it would still only make up about 10% of the daily energy needs... just an estimate.... a powerful horse on a self propelled treadmill at each house might work a little better.

Answer 5

If you had plenty of bikes, this may be at least partly possible. But the fact that there would be nobody to ride the bikes and no way to hook them up to the national grid would quickly dismiss the idea.

Answer 6

The energy output is too minimal to do anything but turn on maybe 3 or 4 lights.

Answer 7

i'm not sure, maybe you could sell the idea to some gyms and see how much money they save using energy from their excercise bikes to run the electricity.

Answer 8

They can, but unfortuneately Politicians are'nt bought and sold by Schwinn and Huffy....they're bought and sold by Emron, Texaco and the major petroleum producers.

Answer 9

because the government doesn't make a profit off it.

Answer 10

Power is the rate at which we use energy. It is measured in watts. Energy is measured in joules. One joule per second equals one watt. A joule is the application of one Newton of force (about 1/4 pound) over a distance of one yard. Lifting a hamburger to your mouth takes about a joule of energy.

A burning a barrel of oil releases about 6.1 billion joules of energy. Humanity burns about 28 billion barrels of crude oil each year. This is our species principal source of energy. That's a total of 170.8 billion billion joules of energy. Since there are about 31 million seconds per year, that means on average we use energy at a rate of 5.5 trillion watts!

Now, there are about 7 billion people in the world, so that averages about 790 watts per person.

Since energy use correlates with income, Americans consume about 1/4 of all the energy used. There are about 290 million Americans. So, their average rate of energy use is 4,740 watts per person!

Now a healthy person in the prime of their life - a Lance Armstrong sort of person - can generate about 150 watts on a bicycle for about 6 hours - max. Which is 1/4 of the day. So, the daily average would be 38 watts per person. This is about 3% of the global average and less than 1% of the US average rate of power use.

Of course only healthy folks between the ages of 13 and 53 could realy contribute in this way, and that limits the average to even less. about 1% of the global average and les than 1/4% of the US average - could be gathered in this way.

Now, it takes energy to make things. To dig ore out of the ground. Refine it to metal. To shape and treat the metal. To transport the things made to individuals. And so forth.

To make and distribute, wire up and control 7 billion or even 1 billion bicycle type generators would take energy. How much? Well, to refine a ton of steel and fabricate it into a bicycle takes about 80 billion joules of energy. And a steel bicycle frame with all the parts weighs about 10 lbs - 1/200th of a ton. 400 million joules of energy just for the metal. To weld it, transport it, and all that triples this figure. So, each bicycle frame costs in terms of energy 1,200,000,000 joules. And when people are sitting on it, they're generating 150 joules every second they pedal like Lance Armstrong. Most healthy people would do well to do half of that. Let's say 120 joules when someone' s on it. So, you need to pedal 10,000,000 seconds - like mad - or three thousand hours just to make enough energy for the generator itself!

Then there are the wires... and batteries.. and controls.. to consider.

A far better solution would be to tap into alternative sources of energy. For example, solar panels, or nuclear power plants, or hydro-electric dams.

On a sunny day sunlight delivers nearly 1,000 watts per square meter of surface area. That's the same as 7 people bicycling like mad! And the cost of a square meter of surface area - about a square yard - is far less than 7 bicycles! So, we're ahead there!

But, solar panels are not 100% efficient at tapping into sunlight. They range in efficiencies from as low as 8% to as high as 40% - depending on the details of construction and operation. If we take an average of 20% - that means a square meter, or square yard, generates 200 watts - or about a quarter horsepower - when the sun shines. This is about 200 million watts per square kilometer. In English units that's about 520 million watts per square mile. Since humanity uses energy at a rate of 5.5 trillion watts that means we only need 10,000 square miles of solar panels to power all of industry, right? Nope! Because the sun doesn't shine all the time. In most places it shines between 1,200 hours and 2,200 hours per year. And there are 8,766 hours in a year. So, we need five times the power when the sun shines to make enough energy to use at the rate we use it when its not shining. That means we need about 50,000 square miles of solar panels. That's cool, because the US has a land area of about 9.6 million square miles - and guess what? - about 2 million square miles is sunny desert land.

But since the sun isn't shining all the time this means we've got to create some way to store it and use it for times when the sun's not shining. There are lots of ways to do this. One is to pump water uphill when the sun is shining and let it run downhill when its not through a hydroelectric plant to create the energy we need. Another is to create batteries. lots and lots of powerful batteries that get charged up when the sun is shining and discharged when its dark. Another is to create a chemical that stores energy and then react that chemical like a fuel to get the energy. Hydrogen is the best candidate for this. It can be made along with oxygen from water and electricity, and then turned back into electricity and water by combining it with oxygen in a fuel cell. The space shuttle uses hydrogen to make water and electricity in this way.

We can also use biomass to make synthetic fuels from sunlight and water. Plants grow in the sun and absorb carbon from the air to make hydrocarbons. Those hydrocarbons can be converted to synthetic fuels.

But that requires lots more land to achieve this in a significant way, and it also requires that a living thing be tended to and grown, which takes time and attention - and resources. It takes energy to make fertilizers, pump irrigation water around, fuel farm vehicles to plant and harvest and transport the crops, it takes energy to dry the crops and process them into fuels. About 600 million joules per acre of crop. And croplands are about 10% of the surface of Earth. 90% of Earth's surface doesn't have enough water, enough sun, the right soil conditions and so forth - for growing any sort of crop - even switchgrass. And the yeilds are disappointingly low. And the production is seasonal in most part of the world. And, the resources and time and talent needed to make fuel are not available to grow food - and there are people starving in the world TODAY.

Anyway, people argue over this, but there are lands that could be converted to fuel production, that cannot be used for anything else. And this could be used to produce about 20% of our global energy needs. Not too shabby - but other's say - and this is where the argument comes in - that the same money and talent and resources could be used in better ways. Making solar panels, or nuclear power plants or food from crops adapted to grow in these regions. Its a tough decision.

But bottom line - we won't get more than 1/4% of our power needs from bicycles! Even if we organized everyone on the planet to do it religiously every day!

Of course if people turned on a TV set and watched it - especially if it were a big screen TV - while they were doing their pedalling - they would actually consume MORE energy than they made!

But if they were bicycling rather than driving a car - THAT would make a big difference! In the US Europe and Japan. In other nations, not so much, since people don't use cars so much.

But in the US, if we could bicycle just reduce our average mileage by 2,190 miles per year - that's 6 miles per day - the same distance most people drive to work - and this could be achieved by car pooling too - at a consumption of 20 miles per gallon - we could save 109 gallons per person per year. At 120 million joules per gallon that's over 13 billion joules - or nearly 2 barrels of oil energy per person per year. That's 423 watts per person AVERAGED throughout the day! This is over 10x the energy produced directly by a stationary generator!! And is nearly 8% of the total energy use of an average American.

Now, since the price of gas is determined on the margin - that is a small change in demand versus supply - that 8% could have a significant impact on the price of gas! Especially if everyone decided to implement one day a week when they would not burn gas - they'd take a bike, ride with a friend and so forth. That way, people could have some impact on the price of gas.