How Much Electricity Can An Electric Eel Produce?
A variant of that question was asked of me when I posted the following video to Zotz Electrical's Facebook page. With a quick calculation, I answered the question but then had second thoughts on my answer. The voltage that an electric eel produces is DC at up to about 500v (more in some cases) with low amperage output. I found the question intriguing and decided to do some research. Mechanical engineers and scientists have found that by mocking nature, many answers that they have been searching for have been out in nature all along. Could the electric eel be a good source of alternative energy? Maybe.
The electric eel is found in the middle and lower Amazon basins of South America. They have no scales. The mouth is square, and positioned right at the end of the snout. The anal fin extends the length of the body to the tip of the tail. This fish lacks dorsal, tail & pelvic fins and swims by undulation of the anal fin. Electric eels have a vascularized respiratory organ in their oral cavity. These fish are obligate air-breathers, rising to the surface every 10 minutes or so, the animal will gulp air before returning to the bottom. Nearly 80% of the oxygen used by the fish is taken in this way. It feeds on frogs, fish and crustaceans.
Electricity is used by the electric eel for several reasons. Low intensity charges by the eel ranging from 5v to 10v are emitted which are then bounced back by passing objects and detected by special electro-receptors on the skin. This allows the eel to navigate as well as locate prey. The electric pulses are also used for communication, with dominant males making the loudest and most frequent emissions. High intensity electrical discharges can also be used to stun or kill prey and even as a form of defence.
The electric eel has three abdominal pairs of organs that produce electricity: the Main organ, the Hunter's organ, and the Sachs organ. These organs comprise four-fifths of its body. These organs are made of electrocytes, lined up so that the current flows through them and produces an electrical charge. When the eel locates its prey, the brain sends a signal through the nervous system to the electric cells. This opens the ion channel, allowing positively-charged sodium to flow through, reversing the charges momentarily. By causing a sudden difference in voltage, it generates a current. The electric eel generates its characteristic electrical pulse in a manner similar to a battery, in which stacked plates produce an electrical charge. In the electric eel, some 5,000 to 6,000 stacked electroplaques are capable of producing a shock at up to 500 volts and 1 ampere of current (500 watts). The Sachs organ is associated with electrolocation. Inside the organ are many muscle-like cells, called electrocytes. The organs give the electric eel the ability to generate two types of electric organ discharges, low voltage and high voltage. Each cell can only produce 0.15V, though working together the Sachs organ transmits a signal of about 10V in amplitude at around 25 Hz. The signals by the Main organ and Hunter's organ can be emitted at rates of several hundred Hz.
There are no specific studies on why eels can shock other animals without shocking themselves but one possible explanation could be that the severity of an electric shock depends on the amount and duration of the current flowing through any given area of the body. For the purposes of comparison, an eel's body has roughly the same dimensions as an adult man's arm. To cause an arm to spasm, 200 milliamps of current must be flowing into it for 50 milliseconds. An eel generates much less energy than that because its current flows for only 2 milliseconds. Additionally, a large part of the current dissipates into the water through the skin. This probably reduces the current even more near internal structures like the central nervous system or heart.
It is possible to use an electric eel to produce electricity. But consistency is the problem. For the electricity to be useful, the eel would need to keep releasing it at a constant rate. For example, notice how the tree in the video varies the amount of bulbs that are lit. Scientists are studying the electric eel to see if an artificial "eel" could be used to produce electricity. They are learning great things about electrocytes and how to create electricity using them. Though now in principle, stacked layers of artificial cells in a cube slightly over 4 mm on a side are capable of producing continuous power output of about 300 microwatts to drive small implant devices. It can be only a matter of time before they are able to produce something with the power of the electric eel with the consistency that is required.
So, back to the original question, "How many (eels) do you think I need to heat my house?". In this person's house, they have electric baseboard heat and an air-source heat pump. I can't remember how many feet of baseboard they have, so I will only calculate for the heat pump, which will heat the house in the fall and spring along with air conditioning in the summer. The heat pump uses 30 amps at 240v, the electrical eel produces approximately 1 amp at 500v. To make this happen, you will need an inverter to change the DC to AC, a voltage regulator to keep the voltage constant and 24 electric eels. Remember, the electricity produced is not constant, so this is really not a viable choice for power generation. Plus, you also need aquariums, feed and space for all these "free" power generators!
For more information, check out the following links;
Wikipedia, Scientific American, Bright Hub
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