Patentlandscape’s Weblog

Technology Overview of Tidal/Wave Power Generation
September 1, 2008, 5:17 am
Filed under: alternative energy | Tags: , , , , ,

Patent Vantage Point discloses a unique list of renewable energy companies, which is based on the results of patent search provided by Business DNA. Ltd.

The list forms a Techno-Market Domain, which help us grasp the state of business development in the domain. However, to elucidate what is really going on in the field requires an overview of the technologies, rather than the companies which own them. So, in this article, I would like to introduce a Technology Overview Map of Tidal/Wave Power Generation System. This would help (technically-oriented) people not only find a key technology in the field and opportunities for investments, but also pridict the rise and fall of the companies.

Shown below is the technology orverview map of tidal/wave power generation. Since this field is still premature and the tehcnology has just emerged from the experimental phase, the map is rather simple. The technologies in this field can be divided into 3 groups, Structure, Power Transformation and Power Transmission. Majority of the companies listed in Patent Vantage Point and Patent Landscape own technologies related to “Power Transformation”, especially,those utilizing oscillating motion or axial force. The companies include: Peramis, Ocen Power Technologies, Waveplane International, Swedish Seabased Energy, Wave Star Energy, etc. Many of these technologies are currently in the demonstration stage, and some of them are in the large-scale test phase.
(See for example Wave Hub Project )

In the UK, a unique project, called wave hub project, is in progress. In this project, the wave power generation system from three companies will be tested before going into commercial production. It is expected that the Hub will have potential to generate electricity for over 10,000 homes and create about 700 jobs by 2020.

Technology Overview


Wave Power Generation in the World
July 14, 2008, 10:19 am
Filed under: alternative energy | Tags:

Wave Power Generation

Skyrocketing oil prices and increasing concerns about climate change are evident in the everyday local and global news. As a result, our attention naturally goes to alternative energy resouces, and pushes such energy resouces from the margins to the mainstream of the energy industry.

Companies having technology to generate electricity from wave & tide are attracting investors. In London’s Alternative Investment Market (AIM), IPO of such companies is expected within 1 to 2 years from now.

It is quite natural for anybody to wonder if such companies are really worth while to invest.

Patent Vantage Point has shown not only a group of such companies in the world, but also their ranking in R&D strength. The unique raking style of the site makes it very easy for laymen to imagine what’s going on in the technical domain, and what companies are trying to do business in the field.

But seeing is believing !

Here are pictures of wave & tide utilizing technologies available to invest.

Ocean Power Technologies

OPT’s Power Buoy(Registaered TM)

The OPT’s technology utilizes a smart buoy to capture and convert the wave energy into electricity. To generate 10 Megawatt of electricity, the OPT’s system occupy 0.125 square kilometers. This system is scalable to 100+ Megawatts.

Compared to wind power generating system (offshore and onshore), this wave capturing system has a high energy density, which is approximately 1000 times denser than wind power generation systems. Moreover, the OPT’s system can be implemented on most of coastlines. Even when installed near the coastline, the visual impact is small.

Upon receiving rise and fall of the waves, a piston-like structure (also called as a bluff body) within the smart buoy moves up and down (vortex induced vibration). This oscillation is coupled with an energy converter which converts the oscillatory motions into useful energy. The bluff body is electrically adjested so that it vibrates in resonace in response to the waves.

This technology was patented on May 29, 2007(filed on Jan. 13, 2005) in the US. The corresponding fopreign patent applications are pending in the countries including Japan, EP, and Canada.

A brief explanation of the technology is also available on this site.

Swedish Seabased Energy AB

The Swedish Seabased Energy’s technology utilizes a unique three-phase permanent magmet, linear generator, which enables to generate electricity cost-effectively and efficiently with the relatively slow speed of vertical motion of ocean waves. The very simple mechanics of the bouy and piston confer this system robustness and ease of maintainance.

The buoy on the surface of the sea/lake is connected to a linear power generator at the bottom of the sea, via a connection means (shown above), a rod-shaped rotor (shown above) and a spring means(not shown). The wave motion received by the buoy on the surface of the sea is transfered to the rotor (red and white rod in the picture), then the reciprocating motion is generated at the “stator” installed on the sea bed (see the gray T-shaped part at the bottom of the sea).

See also this.

This system was originally developed in cooperation with researchers at Uppsala University, Sweden, and a patent has been granted in the US and EP. Patent applicatins are pending in the countries including Canada, China, Germany, Japan, Norway, and Korea.

Marine Current Turbines Ltd.

MCT’s power generatin system is comprised of a vertical support column, a horizontal turbine support structure, and at least two turbine units. The turbine units are connected to the vertical support column via a horizontal wing-like support. The horizontal wing-like suppot is carried by a collar like sleeve longitudinally displaceable lengthways of the support column.

The MCT’s patented technologies cover both the power generation system and the turbine. Patents have been granted in US and EP, and patent applications are pending in the countries including Great Britain, Australia, Canada, New Zealand, Korea etc.

MCT employs this technology in SeaGen Project, which is the final stage in the technology development prior to installing multiple units in arrays of turbines, as shown below.

See also this.

The twin rotor system in the picture is the prototype for 1MW power generation. The rotors can function with the flow in both directions.

Wave Star Energy

The Wave Star Energy’s machine is desigend to harness more wave energy than what can be harnessed by the other company’s machine. In the Wave Star Energy’s machine, by cutting waves at right angle to the direction of the waves, floates (see the orange part in the above pic. ) which are submerged in the sea water are lifted upward. Each of the floates is connected to, via support arm (the white part in pic.), a hydraulic cylinder with a piston, and when the floate is lifted upward, the piston will create pressure, which is conveyed to a power generator, thereby generating electricity. Due to an array of the floates, there are at all times at least two arms receiving wave motion and transmitting a power to a power conversion means, thereby continuously generating a power.

The floates can be kept in a locked positin above the sea level at the occurence of storm or prior to the occurence of icing.

This technology is covered in the patent applications filed in the countries including: US, EP, Austraria, New Zealand, and Japan.

Pelamis Wave Power Ltd. previously known as Ocean Power Delivery Ltd.

The Pelamis Wave Energy Converter shown in the above picuture is a semi-submerged structure composed of cylindrical sections, each of which is linked by hinged joints. The wave-induced motion at the hinged joints generates high-pressure fluid through hydraulic motors, which drives electrical generators to produce electricity.

“Current production machines are 140m long and 3.5m in diameter with 3 power conversion modules per machine. Each machine is rated at 750kW. The energy produced by Pelamis is dependent upon the conditions of the installation site. Depending on the wave resource, machines will on average produce 25-40% of the full rated output over the course of a year. Each machine can provide sufficient power to meet the annual electricity demand of approximately 500 homes.

This technology is covered in patent applications filed in the countries including: EP, US, Japan, China, GB, Canada, and Australia.See also Wave Hub Project.

AW Energy OY

The bottom-mounted moving wing, wave roller, which is totally submerged in the sea as shown in the above picture receives waves and swings back and forth. This motion is conveyed to the piston pump connected to the wing, thereby converting the wave energy to electricity. Wave roller is a module, which can be combined to another module. Therefore, depending on the requirement at each install site, an energy plant with varying sacle can be be constructed.

A moving picture demonstrating the concept of wave roller is

The expected nominal power outputs of individual Wave Roller is estimated to be 13kW.

This technology has been patented in EP, and patent applications are pending in US, Japan, Canada, Australia etc.

Independent Natural Resources, Inc.

Using buoyancy of Buoyancy Block (BB), which synchronizes with rise and fall of a wave motion, the device constituting a buoyance chamber and pinston pump draws water into the piston cylinder and expells water through exhaust valve. The energy of the expelled water is now being tested for hydroelectricity generation and desalination facilities. The simple structure of the device enables the scale-up and configuration of the device to fit in most of the shorelines.

This technology, although in its experimental phase, is patented in the US, and patent applications are pending in Mexico, Canada, China, EP, Australia etc.

ORECon Ltd.

OreCon’s technological breakthrough has made the conventional Oscillating Wave Column technology into a realistic solution for wave energy conversion application. ORECon’s Multi Resonant Chambers (shown in the pic.) have no moving parts below sea water, which makes this system easy to maintain and gives advantages over other technologies requiring underwater works for instalation and maintainance.

The Oscillating Wave Column shown above is arranged to float such that part of its structure protrudes from the surface of the water. This device has a plurality of flow paths into which (sea) water can be urged by wave action. The flow paths are provided with energy extraction means for extracting energy from air movements in the flow paths caused by wave action. This air movements is simply converted into mechanical energy for use by another system or the energy extractor and could be arranged to convert the energy in the air movement into hydraulic energy.

Patent Applications covering this technology are pending in US, EP, Japan, Great Britain, Canada etc.

See also Wave Hub Project.


Passing waves move an air-filled upper casing against a lower fixed cylinder, with up and down movement converted into electricity. As a wave crest approaches, the water pressure on the top of the cylinder increases and the upper part or ‘floater’ compresses the gas within the cylinder to balance the pressures. The reverse happens as the wave trough passes and the cylinder expands. The relative movement between the floater and the lower part or silo is converted to electricity by means of a hydraulic system and motor-generator set.

The future outputs of this system are expected to be up to 1MW.

This technology is patented in the US and EP.