1. Mick West

    Mick West Administrator Staff Member

    Philanthropist Manoj Bhargava plans to distribute 10,000 stationary electricity generating bikes in rural India. The bikes power an electric generator which charges a battery, which can then be used to power a few lights and charge some mobile devices in homes that often do not have any electricity.

    Unfortunately this story has been shared many times with the suggestion that it can power your home, typically with the suggestions that just one hour on the bike can power your home for 24 hours. Example:

    The reality however is that the bike is designed for very small houses in rural India, and the actual usage is limited to a few very low powered lightbulbs, possibly occasional use of a small fan, and charging portable devices like phones.

    An hour on the bike will generate around 0.11 kWh (more or less, depending on how fast you cycle, but probably not much more).

    The average american house uses 30 kWh per day. So an hour on the bike provides only 0.37% of the energy needed for 24 hours, or approximately enough for five minutes.

    People in the US who want to go "off-grid" prune down their homes to the bare necessities, using smaller homes and smaller energy efficient appliances. However they still use around 3-5 kWh per day, and so the hour on the bike would provide less than an hour of power.

    Now of course people in the US are famous for being big consumers of electricity. Could the bike power a typical home in a more energy frugal country?
    Source: http://shrinkthatfootprint.com/average-household-electricity-consumption

    No. While European countries have usages as little as 1/3 that of the US, that's still 10 kWh, which is still 100x what the bike generates in an hour.

    Even in India, the target market, the average home used 900kWh/year, or about 2.5 kWh/day

    So while Bhargava's bike might be a useful solution to the problem of powering a few lightbulbs in rural India, it cannot power a home with just an hour of pedaling. It can't even do it with 24 hours of pedaling.

    Bhargava kind of glosses over this point himself. In his documentary he shows the bike powering a wall of 24 lights, a small fan, an iPad, and an iPhone.
    On the board next to the display is written:
    • 10,500 Lumens
    • 1050 Watts equivalent lighting/power
    This is somewhat misleading, suggesting the bike is outputting 1kWh (1000 watts for an hour). However what they seem to be doing here is using very efficient 4 watt LED bulbs, and then calculating the power efficiency as if they were using old fashioned 40 watt incandescent bulbs, which gives them a power output ten times as high as it actually is.

    In fact the bulbs are clearly labeled 4W. 24 bulbs at 4W each is just 96 watts. They are also 12 volt bulbs, which uses DC voltage. To power your home, the power would have to be converted to AC, which loses around 10% of the energy.
    The wall of lights is also using ALL the output from the bike. It's not running off the battery. To keep the lights lit you'd have to pedal constantly for 24 hours. So if we are talking about pedaling for just an hour a day, well that's about enough to power one 4 watt bulb for 24 hours, and maybe charge your phone.
    Last edited: Feb 24, 2016
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  2. vooke

    vooke Active Member

    Looks like the philanthropist is being deliberately misled by the suppliers/manufacturers of the bikes.
  3. Mick West

    Mick West Administrator Staff Member

    I thought the bikes are the invention of his own research company, and he seems to have some technically savvy people.
  4. Shogan

    Shogan New Member

    I think it's more the public are being mislead by whoever wrote the headline for the article, but I'm not surprised as I see similar examples every day in all of the MSM that I read online.

    Often these claims then turn up on social media & more often than not I then feel obliged to set the record straight on the more outrageous claims & it was following up on an Anti-Vax claim that I came across this website as I always try to provide back up material when disclaiming something.

    One thing I have learnt over time is to always check the source of what I am reading & a quick Google search normally puts things into perspective, although judging by some people's comments on social media you would swear they have only read the headline.

    "Just because something is on the internet doesn't mean it's true!!" has become an often used statement of mine.
  5. vooke

    vooke Active Member

    In that case,this could just be a populist move, and like the free energy gang, the distribution of the bikes would never take off, with dozens of flimsy excuses for delay.

    I know the point of the article is to examine the specific claims made by the philanthropist, but I can't help questioning his sincerity. I think this would be measured by the amount of his wealth he pours into the bikes
  6. Elfenlied

    Elfenlied Member

    I would have expected more from National Geographic. If the bike alone wasn't sufficient to label him a fraud or an idiot, then his ridiculous idea about using graphene cables to transport geothermal heat surely would be.

    An absurd suggestion, heat transport by conduction is driven by temperature gradient: you need a temperature difference, and for a given heat flux, that difference will be proportional to the distance.
    Suppose you want to replace central heating pipes by so-called "graphine cables". The distance between radiator and boiler is 10 m, you allow a temperature drop of maximum 10° C over that distance, and the heat flux required is 3 kW.
    Based on a thermal conduction k of 5000 W/m.K for graphene (one study found 5300, others have questioned this result, their experiments gave values of only 1500 to 2500 W/m.K), what would be the required diameter for that cable?
    The amount of heat transferred per second is Q=k*A*T/L (A= cross-sectional area, T=temperature difference in °C or °K, L=length in meter k=thermal conduction).
    A=Q*L/(k*T) = 3000 * 10 / (5000 * 10) = 0.6 m², which gives you a required diameter of 0.87 meter!

    Say you want to use geothermal heat from a depth of 2 km, want to limit the temperature drop to 100 °C and your power plant has a thermal efficiency of 10% (fairly typical value for geothermal power plants); it would take 8000 m³ of graphene (a cable 2 km long, with a cross-section of 4 m²) for a heat flux large enough to generate 100 W of electricity. To put that in perspective: the power plant at Nesjavellir (Iceland) currently generates almost a million times more power (90 MW), using 10 holes with a combined cross-section of less than 0.5 m².
    Last edited by a moderator: May 6, 2016
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  7. Auldy

    Auldy Senior Member

    A bit more realistic usage of bike power.



    Of course, using the machine creates dirty clothes too, but at least there are no unrealistic power generation claims.
  8. Whitebeard

    Whitebeard Senior Member

    A lower tech version of that does the rounds of the music festivals in the UK, here it is at Glastonbury a couple of years back
  9. Dewis A

    Dewis A New Member

    I just watched the video a few days ago. I think that the news title that was misleading, click bait? :D.

    The bicycle always meant to bring light to the poor. Of course it can't generate 30KWh/hour but it's sufficient to power a few lights for one night. They pretty straight forward about it in their FAQ

  10. lsb61

    lsb61 New Member

    While the Kilowatt assessment is accurate it is interesting how intelligent people always jump to discredit an Idea rather than improve on it. The Idea is brilliant. In this country alone there are Millions of people potentially generating energy on Bikes, ellipticals, and who knows what else that is being wasted. With some tweeks to the idea more Wattage could easily be generated, and thus so to the effectiveness.
  11. Mick West

    Mick West Administrator Staff Member

    We were addressing the very specific claim that you can power your home for 24 hours with one hour of cycling. It was pointed out that you can power a few low powered lights for a while.

    The actual amount of energy you can get out is limited by how much is being put it. It's not physically possible to get significantly more out that the bike is currently doing.
  12. Trailblazer

    Trailblazer Moderator Staff Member

    With respect, people furiously pedalling bikes are never going to generate a great deal of electric power. Even a Tour de France cyclist will only average 300-400 watts power output over any sustained period. Actually probably less, as this analysis of a winning professional race ride shows:



    So even if you had a team of professional cyclists taking it in turns to pedal the bike non-stop, you would only be looking at about 0.4 kW x 24 hours = less than 10 kWh, or a third of the power consumption of a typical American home. (And that's assuming 100% electrical conversion efficiency.)

    And then you have to consider the cost of food needed to replace all those thousands of calories you burn while pedalling away.
    Last edited: Oct 18, 2016
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  13. NoParty

    NoParty Senior Member

    I see no harm in people being realistic.

    Are those easy "tweeks" something you could link to?
  14. Yasodha Porchezhian

    Yasodha Porchezhian New Member

    Obviously the free electric bikes are for rural households in India where the eleteicity to indidvidual homes is non existent or unreliable. All these homes want is some light during waking hours in the night and probably some charge for cellphones. I welcome any changes to the status quo that these bikes can bring. if it can not suffice, at least it is a definitive step in the right direction for a place where basic living facilities are uncomparable to the western world.
  15. Whitebeard

    Whitebeard Senior Member

    While I agree with your sentiments, the thrust of this thread is aimed at the claims that one hour peddling can power ANY house for a day. These claims are not coming from the projects originators, but from certain press outlets and other people and are misleading, that is what is being debunked here, not the original, and very worthy project.