Difference between revisions of "Hans Free Electric Bicycle"

From ScienceForSustainability
Jump to navigation Jump to search
(Created page with "Category: Human power <youtube>https://www.youtube.com/watch?v=Cgb9lfKW_d4</youtube> Manoj Bhargava, the inventor of this static pedal-powered generator, claims that "you...")
(No difference)

Revision as of 13:41, 2 August 2020

Manoj Bhargava, the inventor of this static pedal-powered generator, claims that "you pedal for one hour and you have electricity for 24 hours". However Bhargava but doesn't specify how much electricity you have for those 24 hours.[1]

What about the claims?

Hans free electric bike output.png

At 0:33 the video shows the generator producing 10 amps at 12 Volts = 120 Watts.

60 minutes on the generator will produce 120 Watt-hours, equivalent to an average of 5 Watts over the day.

This could provide some mobile phone charging and a few hours of electric lighting at night.

However an alternative would be a solar panel coupled with the same sort of battery that the "free electric bicycle" uses. A 120 Watt solar panel costs under 5,000 Rupees in India, about £50. Even if the bike could be produced for less it still requires extra food calories and time to generate electricity, commodities which are likely to be in short supply amongst people in their target market.

The video also suggests that the device could be an emergency back-up generator in developed nations, but at 120 Watts its output is not enough to run a fridge, even if one were pedalling non-stop, day and night,[2] let alone a whole house whose average electricity consumption in Europe is approximately 500 Watts, and more than double that in North America.

Online magazine articles such as this and this suggest: "What if you could power your house for an entire day just by exercising for an hour, would that motivate you to do it?" Maybe it would, but this device can't do that, and if electricity costs 15 pence/cents/etc per "unit" (kWh) the energy produced would be worth a bit under 2 pence/cents/etc. Would producing that value of energy motivate you to work out for an hour?

Footnotes and references

  1. One of the commentators on the video made their own estimate:

    Really hard exertion burns about 600 dietary calories per hour. That's about 0.7kWh. But really you only get about 25% efficiency from the human body so assuming a 100% maximally efficient generator bike and battery (both impossible) we get to at best 0.2kWh per hour from a person pedaling a bike really hard. So that's a maximum of 200 Watt Hours per day for 1 hour of work if the machine is PERFECTLY efficient.

    What can you do with 200 Watt Hours? Well it takes 150 Watt Hours to boil a quart of water. It takes 50 Watt hours to run a single 4 watt LED bulb for the night. Oops now you're out of power. You know how else rural people can boil a quart of water? By burning about a tenth of a log of firewood.

    These 3 billion people (half the world) who has no or little electricity? Do they have extra food? Are they eating more food than they need, are they overweight? No they aren't. So if they're going to burn an extra 600 calories per day, they're going to have to eat more food. So it's not free energy. Food costs money. And how about that hour of time? Do these 3 billion people have a lot of leisure time, can they afford to pedal for an hour a day? What are they giving up during that hour?

    "you will never run out of electricity" - Well until you can't afford to buy the extra food, or until you can't afford to spend the extra hour pedaling, or until you can't afford to replace the battery which will probably need to be replaced every 3 years (1000 deep charge/discharge cycles).

    "you will never generate pollution" - You're telling me that mining the materials for this machine, creating the machine, transporting the machine, and dealing with the tremendous environmental impacts of battery disposal all have no pollution? You're going to do that 3 billion times and generate no pollution? Fat chance. And then as I said all these 3 billion people are going to need to eat an extra 600 calories per day. Growing and transporting that extra food won't generate any pollution either huh?

    Most of the cost in this machine is going to be the battery. Why not give the same 3 billion people that same battery with a solar panel attached so they don't waste an hour a day and 600 calories of food keeping the battery charged? And then the video talks about people in the US stuck in a natural disaster - why not give those people a UPS unit which is just a big battery that they can charge by plugging it into their cheap grid power?

    I read somewhere that this machine is supposed to cost $100. I would believe you could buy this machine for $100 retail in the US or maybe that a factor would charge you $100 to produce it. But how about the costs to deliver the machine to all these ultra rural off the grid places and train the end users how to use it? The logistics on that ought to drive the cost up by quite a lot, this isn't a light weight or small item. So maybe it'd be $1000 or even $10,000 per ultra rural home once you account for these costs. Where does that money come from and why wouldn't you spend it on solar or other technologies instead?

    There's nothing at all revolutionary about this machine! It's harmful to people and the planet to consider this a viable option. It won't help with pollution or climate change or global poverty.

    And it won't even help Americans lose weight. Sure we've got lots of excess calories to burn in the developed world and we could use the exercise collectively. But this thing lets us generate 200 Watt Hours per Hour from our body fat. 200 Watt Hours costs about 2.5 cents. Do you think someone who wouldn't otherwise get on an exercise bike would hear "OH I can exercise for an hour and save 2.5 cents?!" I'm so doing that!

    2.5 cents per hour. That's what this machine is worth to its users in the US. And meanwhile 600 calories of food will cost anywhere from 12 cents (canola oil) to $9 (turkey cold cuts) or plenty more.

    A bit of perspective, a typical American household uses 30,000 Watt hours per day. This thing generates at most 200 Watt hours per day.

    There Ain't No Such Thing As A Free Lunch

  2. How Much Electricity Am I Using? Centre for Sustainable Energy