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?
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
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.