Generating power with bananas

This article is about the potential of bananas. I’ll just go ahead and say it, Bananas are awesome. Maybe you like the taste and maybe you think they are disgusting. This has very little impact on the awesomeness of bananas. Why? Well, first there is the obvious nutritional value. Maybe this is so obvious that I will not talk about this aspect.

Bananas Are Clones

This doesn’t have much to do with physics, but it’s still cool. Wild bananas are apparently terrible. They have seeds in them and aren’t as tasty as YOUR banana (which is also MY banana). Without seeds, bananas can’t reproduce. To fix this, humans just take a part of an existing banana plant and replant it. BOOM. You get more bananas. Okay, I am going to stop talking about banana clones before I say something that is just plain wrong (I might have already committed such a wrongness).

Bananas Are Radioactive

Radioactive isn’t such a bad word. Really, lots of stuff is radioactive. This means that there is some type of nuclear reaction going on in the banana. In this case it is due to the potassium. I did some investigation over the facts and figures about bananas which are listed:

  • Most of the potassium in a banana is 39K – 19 protons and 20 neutrons. This is stable.
  • A very small fraction of the potassium is 40K. This is radioactive.
  • There are three possible ways the 40K can decay.
    • It could have a beta decay and turn into 40Ca.
    • It could turn into 40Ar through electron capture.
    • It could emit a positron and also turn into 40Ar.
  • Although most of the potassium is not radioactive and most of the radioactive matter just creates electrons, sometimes it will make a positron.
  • For an average banana, it will (on average) produce 1 positron every 75 minutes.

Just to be clear, a positron is a type of antimatter. It is the antimatter version of the electron. So, rereading: bananas are clones, bananas are radioactive and bananas produce antimatter. Three cool things.

What Can You Do With an Antimatter-Producing Banana?

I thought a lot on this matter but the real question to consider is: how many bananas would I need to produce 2000 watts of electricity?

I started with some assumptions…

  • Like I said above, a banana on average produces 1 positron every 75 minutes.
  • This positron will annihilate in 10 cm of water (suppose I surround the banana with water).
  • 50% of the energy from this positron-electron annihilation will go into increasing the thermal energy of the water.
  • The efficiency of turbine-generator is also 50%. Guys, I’m just estimating.
  • I am assuming the energy from the beta decay and electron capture don’t matter (although they do but let’s keep them aside).

How Will This Actually Work?


The bananas make positrons that annihilate with electrons in the water. This heats up the water and makes steam. The steam is then fed into a normal steam turbine generator (like in a gas or nuclear power plant).

But how many bananas do we need? Let’s start with the average power of one banana. In 75 minutes, this average banana makes one positron. When the positron annihilates with an electron, we get energy from the mass-energy relationship E=mc2. Both the electron and positron have a mass of 9.11×10-31 kg. The speed of light is 3.00×108m/s. This gives:


Assuming 50% energy goes to the water and then 50% of this goes into actual electricity, we get a power (from one banana) of:


Clearly, we need more than one banana. We need n bananas to get to 2000 Watts. What is n?


Okay, that is a lot of bananas. How big would the banana generator actually be? Let us make some estimates. Say that an average banana is 150 grams (0.15 kg) with a density of about 1 g/cm3 (1000 kg/m3). The mass of all these bananas would be (0.15 kg) × (n) = 3.3×1019 kg. With the density, we can calculate the volume of all these bananas.


If we choose to make our banana generator spherical. How big will this sphere of bananas be?


With our calculated volume, this would be a giant ball with a radius of 2×105 meters. This generator can be seen from space as well.

We would require gigantic amount of energy to create this, if this idea works, we could revolutionise humanity.

I asked the bananas about what they feel, this is what they looked like after I asked them:clip_image002

If you guys have any ideas you want to share, please feel free to tweet us at @asdfScience or email us at

Courtesy: Rhett Allain | Dot Physics


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