Overview

Imagine wading out in the nearest river to your location.  With you is a 4ft by 4ft square of plywood.  When you wade in far enough that the water is at least 4ft deep, crouch down with the 4x4 sheet of plywood perpendicular to the flow of the river.  Chances are that the flow energy will knock you off your feet.  The energy you experience is the lateral flow energy of the river.  Consider how many 4x4ft squares it would take to cover your river from bank to bank.  Consider the energy potential that could be gathered.  Consider also that similar energy could be collected another 100ft upstream, downstream, and in every river in the world.  Consider that this energy potential is available 24hrs a day - 365 days per year - and that this vast reservoir of clean energy is not being extracted.

Objective

Extract available lateral flow energy from rivers, streams, and tidal flows in the form of electrical energy.  In contrast to traditional hydro generation which utilizes large entrapments of water, the Lateral Energy Micro Hydro (LEMH) uses simple stream flow.  Rather than attempt to keep the hydro rotating at a synchronous speed as in traditional hydros, the LEMH utilizes voltage regulation and inverters to extract the maximum available energy for a given stream flow condition.  The environmental imapct of a LEMH would be comparable to a drift of trees commonly found in rivers and streams and the unit would not hinder river traffic.  Unlike other forms of Green Energy (solar, wind) whose source of energy is intermittent, the Linear Energy Micro Hydro takes advantage of never ending river flow.   The LEMH units can be used alone or in groupings in favorable locations.   Standardized sizes would help reduce costs.

The generating capacity of the Lateral Energy Micro Hydro is less than a reservoir-fed unit (and hence the "micro" comparative name), nonetheless the LEMH can be used in any river which is at least 8ft deep and 16ft wide.  The widespread utility of the LEMH more than makes up for it being "micro" as it is capable of extracting the vast amounts of free energy potential from the rivers of the world. 

Basic Design

As with most hydro generation, the Lateral Hydro employs a rotating shaft.  Attached to the shaft is a heavy Momentum Disk.  The Disk gathers the energy from the impeller vanes and its weight serves as a flywheel to ensure a steady rotational rate.  The Momentum Disk is 16ft in diameter.

Impeller

The impeller vanes are designed to capture the lateral flow energy of the river and direct it to the Momentum Disk.  The focal point of the vanes is as far out on the Disk as practical to achieve the greatest mechanical advantage. The Impeller vanes are mounted on the Momentum Disk at an angle.  This helps direct the flow energy to the Disk and also reduces the flow resistance to the rotation of the impeller.  The impellers are 4ft tall above the Momentum Disk.   A second 4ft array of impellers is on the underside of the Momentum Disk and is offset to the upper unit by 45 degrees to give a more even energy extraction.

Baffles & Stream Flow Guides

An important stationary unit is a Stream Flow Blocking Baffle (colored red).  This reduces the drag on an impeller which would otherwise be rotating upstream. The Blue Stream Flow Guides will channel a larger river cross section of flow and deliver the energy to the impeller vanes.  Bearings would of course guide and support the rotating shaft with a minimum of friction.  Debris grating would prevent large items from jamming the impeller.

Energy Extraction

Graphs

Stream Placement

Singles (no Stream Flow Guide), Single SFG, Multiples with SFG

Prototypes

My first protoypes were built to operate off of wind.   The very first was made from cut up beer cans.  Since that one worked fairly well, I next built one 4ft in diameter made from a plywood disk and aluminum flashing impeller vanes.  That one worked even better as I mounted it on bearings at the peak of our garage roof.  I was just about to do load testing when a thunderstorm brought some strong lateral winds  - and when they hit the garage roof, the winds were directed upward below the turbine.  I was using thrust bearings that were not designed for upthrust.  The whole unit was lifted and I found it the next day (destroyed) in our neighbor's pear trees.  For the water version, I would angle the vanes more to reduce stream flow resistance for the vanes rotating upriver.

Photo #1 was a closeup shortly after the unit was built and installed.  Photo #2 was a wide angle during the winter when I had locked the shaft from rotating and the unit collected a good deal of snow.

Where Next?

More rigorous design evaluation and testing