# The Undersea Generator Nobody Has Built (MHD) Source: https://www.youtube.com/watch?v=8Y8b2t4zNf8 Recap page: https://rapidrecap.app/video/8Y8b2t4zNf8 Generated: 2026-02-06T15:12:40.451+00:00 --- ## Quick Overview The experiment to generate electricity from saltwater using a Magnetohydrodynamic (MHD) generator failed to produce significant voltage, yielding only a maximum of 450.9 millivolts, which was considered negligible power output for an open ocean application, leading the creator to conclude that the initial concept, despite theoretical promise, does not function practically as a power generator in this configuration. **Key Points:** - The experimental MHD generator, designed to harness energy from flowing saltwater, produced a maximum voltage reading of 450.9 millivolts (0.4509 Volts). - The creator noted that the theoretical maximum voltage for the design, running in water at 2m/s, was 0.8 Volts, suggesting the actual output was significantly lower than expected. - The experiment revealed several issues with the initial design, including directional bias, electrode spacing being too wide, magnetic field leakage, and poor electrical isolation. - Using stainless steel electrodes resulted in significant oxidation (resistance increasing up to 191.4 Ohms) when tested in saltwater, contributing to poor performance. - A redesigned, solid resin body version of the generator was printed, featuring narrower water channels and external magnets clamped to the body to focus the magnetic field, but this version also failed to generate usable power when tested in flowing water (producing only 24.5 mV). - The creator initiated a $500 public challenge for anyone to build a fully functional MHD saltwater generator based on the physics principles discussed. - The video concluded that the fundamental MHD principle works (generating voltage proportional to B*L*v), but the practical engineering challenges—especially magnetic field containment and electrical isolation—prevented the prototype from achieving practical energy generation. ![Screenshot at 08:00: The core principle of the induced EMF equation \(V = BLv\) is displayed, defining Voltage \(V\) as proportional to Magnetic Field strength \(B\), Electrode spacing \(L\), and Water velocity \(v\), setting up the variables the experiment aims to optimize.](https://ss.rapidrecap.app/screens/8Y8b2t4zNf8/00-08-00.jpg) **Context:** The video explores the concept of Magnetohydrodynamic (MHD) power generation, which involves running an electrically conductive fluid (like saltwater) through a strong magnetic field to induce a voltage across electrodes, a principle governed by the equation V = BLv. The creator builds and tests a prototype MHD generator designed to function underwater, contrasting the theoretical potential of this clean energy source with the practical difficulties encountered during construction and testing, particularly concerning magnetic field containment and corrosion. ## Detailed Analysis The video investigates the feasibility of building a Magnetohydrodynamic (MHD) generator to produce electricity from flowing saltwater, a concept that has intrigued engineers for decades. The creator initially demonstrates a small-scale MHD thruster concept (0:08) and then builds a larger, segmented prototype generator (0:44, 4:22) using 3D printed parts and powerful N52 Neodymium magnets (4:44). The first test submerging the device in artificially created saltwater flow (0:06, 6:04) yielded a disappointing maximum voltage of 450.9 mV (1:14), far below the theoretical maximum of 0.8 Volts for that flow rate. The creator identified several design flaws: directional bias, excessive electrode spacing, magnetic field leakage outside the channel, and poor electrical isolation (7:46). Further testing revealed that the stainless steel electrodes corroded rapidly, increasing resistance (7:35). The creator then redesigned the generator using a solid resin 3D print to improve electrical isolation and containment, clamping the powerful magnets externally to focus the field (8:36, 9:56). However, this second version performed even worse, producing only 24.5 mV during a test run (11:28). The creator concludes that while the physics (V=BLv) is sound, the engineering challenges—particularly containing the magnetic field effectively and maintaining electrical isolation in corrosive saltwater—make practical open-ocean MHD power generation extremely difficult with current accessible technology, prompting a $500 public challenge for anyone to succeed where the experiment failed (12:56). ### MHD Generator Concept - Explaining the principle V = BLv (8:00) - Initial thruster demonstration in water (0:06) - Theoretical maximum voltage calculated at 0.8 Volts at 2m/s flow rate (7:01) ### Prototype 1 Build & Test - Creator builds a segmented generator using 3D printed parts and 18 N52 Neodymium magnets (4:22, 4:44) - Test yields 450.9 mV with flowing salt water (1:14) - Identified issues: directional bias, magnetic leakage, poor electrical isolation (7:46) ### Material Corrosion - Testing stainless steel electrodes shows rapid oxidation in saltwater, leading to resistance spikes up to 191.4 Ohms (7:35) ### Prototype 2 Redesign - Creator prints a solid resin body with improved magnetic focusing via external clamps (9:56, 10:42) - This design also fails to generate significant power, showing only 24.5 mV (11:28) ### Conclusion & Challenge - The second design performed worse, confirming the difficulty of practical MHD power generation due to engineering hurdles (11:47) - Creator issues a $500 Public Challenge for anyone to build a functional MHD saltwater generator (12:56) ![Screenshot at 0:00: Initial demonstration of the first MHD generator prototype being submerged into a tank of water for testing.](https://ss.rapidrecap.app/screens/8Y8b2t4zNf8/00-00-00.jpg) ![Screenshot at 0:08: Computer simulation \(CREDIT: Orbital Marine Power\) showing the design of a real-world tidal turbine, providing context for large-scale MHD concepts.](https://ss.rapidrecap.app/screens/8Y8b2t4zNf8/00-00-08.jpg) ![Screenshot at 0:37: Demonstration showing blue dye being moved by the Lorentz force when electricity is applied to the electrodes in saltwater.](https://ss.rapidrecap.app/screens/8Y8b2t4zNf8/00-00-37.jpg) ![Screenshot at 1:14: Keysight multimeter displaying a voltage reading of 450.9 mV during the initial saltwater test of the first generator design.](https://ss.rapidrecap.app/screens/8Y8b2t4zNf8/00-01-14.jpg) ![Screenshot at 8:00: Blueprint style graphic illustrating the induced EMF equation V = BLv, defining the electrical output based on magnetic field, electrode length, and fluid velocity.](https://ss.rapidrecap.app/screens/8Y8b2t4zNf8/00-08-00.jpg)