The Wave Mill converts ocean wave energy into power

Ocean and wave energy

• Ocean delivers waves energy 24/7.
• Ocean wave is the most concentrated form of renewable energy from the sun.
• Wave has the greater energy density than both solar and wind,
• The wave energy is more predictable and greater persistence (consistency).
• 15-20 x available energy per square meter than wind or solar.

World wave energy resource map.

Why there are not any commercially successful wave power plants?

Let make a long story short. There are not many designs concepts. Well known are

1.      Terminator devices, which extend perpendicular to the direction of wave travel and capture or reflect the power of the wave.

2.      The oscillating water column (OWC) is a form of terminator in which water enters through a subsurface opening into a chamber with air trapped above it.

3.      A point absorber is a floating structure with components that move relative to each other due to wave action

Most of the known designs have common disadvantage. They interact with wave crest and idle with wave trough.

There are a few reasons why we still do not have commercially successful ocean wave energy converter. I believe that the lack of ability to produce useful work constantly during the all wave period is one of the major reasons that make all previous wave energy projects unsuccessful.

There is only one solution to make wave farm generate electricity continuously – to make a line of devices, longer than average wave length, deployed perpendicular to approaching waves. But capital and operational expenditures obviously can make the cost of power unit astronomically high.

 I considered oscillating water column (OWC) as most promising concept for ocean wave energy conversion. OWC does not need any mechanical parts and it can be inexpensive in mass production.

What is main advantage of OWC against the other concepts, such as a float or buoy? OWC pumps air out and sucks it back, without additional mechanical parts. That means OWC converts wave motion into the high velocity air flow in very efficient way.

I realised that the line of the OWC’s can be configured as the regular reciprocating air pump where water inside of OWC plays role of piston. To do that I added inlet and outlet flaps to the each OWC and attached them to air ducts. One air duct always pushes air out and another one always sucks air in. If the line of OWC’s is longer than average wave length, the air turbine located between two air ducts will always receive continuous air flow.

The simple animation is here

The Wave Mill

The Wave Mill is array of rigidly connected OWC’s, which length is longer than average wave length in the mooring location. The generating capacity depends on the input from waves and active width (the total width of the front chambers, facing an approaching wave).

Trials

Initially we tested prototypes in the wave flume. We crossed channel with the V shape prototype. The Wave Mill absorbs and reflects 90% of wave energy.

We built the full-scale prototype and ran trials in the Moreton Bay, Brisbane, Australia. Prototype dimensions: length: 30 m, width: 1.5 m

Wave conditions: period (T): min 2 sec; max 3 sec; height (H): min 0.4 m; max 0.9 m

Input: min 240W; max 1600W

The recorded efficiency from wave to wire: 16%-32%

The Wave Mill advantages

From customer point of view, the Wave Mill is a large pontoon which generates power and operates quietly. Deck is totally open for customer applications.

That is how large WM unit can look like.

Wave Mill has a modular design and can be tuned for customer requirements.

Wave Mill applications:

-         Power generation for the close to shore communities

-         Floating facility

-         Floating foundation for offshore industries. Oil rig’s power demand is 5MWh. 150m x 150m WM unit has similar generating capacity.

-         Floating foundation for offshore wind projects. The cost of the offshore wind turbine is 30% of the total cost. Using the Wave Mill increases generating capacity and makes power output more stable and predictable.

-         Coastal protection and beach accretion. Wave Mill unit is a long pontoon. Two Wave Mill units moored as V shape generate a power. After some time, breakwater creates tombolo (salient) and breakwater can be moved to the next mooring position. the Wave Mill breakwater creates multiple tombolos along the coast line.

-         Floating marina

-         Aquaculture cage

We are looking for project partners.

Your feedback and comments are welcome. You can send them on [email protected]

You can find more information on our website