The Energy Blog

Largest Tidal Stream System Installed

Marine Current Turbines, has successfully completed the first installation phase of the 1.2MW SeaGen Tidal System, previous post, the world’s largest grid-connected tidal stream system, into the fast-flowing waters of Strangford Narrows off the coast of Northern Ireland.

A crane barge safely positioned the 1000 ton structure onto the seabed in the early hours of Wednesday morning, 2 April, and released its four moorings on 3 April. SeaGen’s location is roughly 1km south of the ferry route between Strangford and Portaferry, approximately 400m from the shoreline.

When fully operational later in the summer, its 16m diameter, twin rotors, one shown above, will operate for up to 18-20 hours per day to produce enough clean, green electricity, equivalent to that used by a 1000 homes, four times greater than any other tidal stream project so far built.

“SeaGen is a hugely exciting project, as well as an historic achievement for both Marine Current Turbines and for renewables in the UK and Ireland. Tidal energy has the great advantage of being predictable and no other system can harness the power of the tidal currents in the way this one can. We take great pride and see enormous potential in the technology and hope it will eventually make a significant contribution to the future energy needs of the British Isles, Ireland and beyond.”

-- Martin Wright, Managing Director of Marine Current Turbines

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Plans Announced for a Wave Power Plant in Hawaii

Oceanlinx, an Australian wave energy company, announced plans for a $20 million project to install three floating wave energy converters (WECs), i.e. wave-powered turbine platforms, to supply up to 2.7MW of electricity to the island of Maui, Hawaii. The company has signed a Memorandum of Understanding with Renewable Hawaii, Inc. (RHI), for potential passive investment in a project . RHI is owned by the Hawaiian Electric Company, Inc.

The project could be operational by the end of 2009.

Oceanlinx’s unit combines the established science of the Oscillating Water Column (OWC) with its own patented turbine technology, and has successfully completed a full scale trial at its pilot unit at Port Kembla, Australia.

Each WEC is about 65 by 100 feet and 15-25 feet high and will not likely affect views from land.

Seadog Wave Pump Exceeds Epectations

Independent Natural Resources Inc's. ( INRI^TM) SEADOG^TM wave pump is a form of wave power that has been around for a while that I hadn't heard of. It seems to me to have several advantages over other forms of wave power, being simpler than most, consuming no external power and having no electrical cables connecting it to the shore.

The SEADOG^TM pump captures ocean-wave energy to pump large volumes of seawater, consuming no fuel or electricity. The pump uses buoyancy to convert wave energy to mechanical energy. The main components of the  pump include a buoyancy chamber (the lower cage in the picture, buoyancy block (yellow object), piston assembly (center of upper chamber), piston shaft, piston cylinder, and intake and exhaust valves.  When positioned in the water the buoyancy block (filled with air) floats within the buoyancy chamber, moving up and down in relation to the ocean waves and swells. The buoyancy block is connected to the piston shaft which in-turn moves the piston assembly through the piston cylinder.

As the buoyancy block moves down in the trough of a wave it draws the piston downward through the piston cylinder.  The downward movement draws water into the piston cylinder through the intake valve filling the piston cylinder chamber. As the next wave lifts the buoyancy block the water within the piston cylinder is under pressure and is expelled through the exhaust valve (into the air in the picture). Each cycle of the buoyancy block rising and falling, drawing in and expelling water, is called a stroke. Each stroke of the piston causes the water to be pumped from the piston cylinder in a regular manner.

FYI: Washington Wave Power Project Gets FERC Approval

The first approved wave-power program in the United States has been given a green light for a pilot project in Makah Bay, a remote section of the Pacific Ocean just off of the northwestern tip of the Olympic Peninsula.

Finavera's (TSX: FVR.V ) (previous post) Makah Bay pilot plant will begin with four 250-kilowatt buoys anchored in an array 1.9 miles offshore. Electricity will be transmitted onshore using nearly four miles of underwater cable that eventually connects to a station on land that feeds into the Clallam County Public Utility District's power transmission grid.  . . . more

According to the Seattle Post Intelligence, the Electric Power Research Institute estimates that waves off the Washington, Oregon and California coasts could produce from 250 to 500 terawatt-hours per year. A terawatt-hour is a million megawatt-hours, or a billion kilowatt-hours. The nation uses about 4,000 terawatt-hours of electricity every year.  . . . more

In separate news item PG&E and Finavera Renewables announced the nation’s first commercial wave energy power purchase agreement for two megawatt (MW) of commercial wave energy. Located off the Northern California coast, the Humboldt County Offshore Wave Energy Power Plant will be developed by Finavera Renewables. The project is expected to begin delivering renewable, clean electricity in 2012.

AquaBuOY 2.0 Deployed Off Oregon Coast

Finavera Renewables Inc. (TSX-V: FVR.V) announced that it has successfully completed a major milestone in its wave energy development program with the deployment and commissioning of the AquaBuOY 2.0 wave energy converter off the coast of Newport, Oregon. This marks the first installation of a wave energy converter of this scale off the west coast of North America and moves the Company closer to achieving its goal of commercial electricity generation from ocean waves by 2010.

The AquaBuOY is a floating buoy structure that converts the kinetic energy of the vertical motion of oncoming waves into clean electricity.

The AquaBuOY 2.0 is situated approximately two and a half miles off the coast of Newport, Oregon. Over the next several weeks, Finavera Renewables will test and analyze the performance of the half-size prototype's components and monitor its hydraulic power output. During this phase, all onboard diagnostic equipment will be powered by an onboard Pelton turbine as well as solar panels and small wind turbines installed on the device. Data is being streamed live via wireless and satellite technology for analysis. This test data will be used for the design of a larger version, for commercial deployment, with a capacity of 250 kW, scheduled for construction in 2008. The current project does not generate power, rather the company wants to study the pressure output of the device.

Artifical Muscle Produces Ocean Power

SRI International has announced the deployment of a prototype buoy-mounted, ocean wave-powered generator off the coast of Florida in the Tampa Bay. The electroactive polymer artificial muscle (EPAM™) technology is used to produce electricity as they bob up and down attached to buoys. The deployment is part of a program sponsored by HYPER DRIVE Corporation, Ltd., a Japanese company focused on development and deployment of wave-powered generators around the world.

The wave-powered generators can be deployed on existing ocean buoys that use batteries as their energy source. The new generator utilizes patented electroactive polymer artificial muscle (EPAM™) technology, and offers a renewable method to continually power ocean buoys. The bouys will be equipped with instrumentation that allows remote monitoring of the generator’s output energy as well as wave height and buoy motion.  SRI is working with Artificial Muscle, Inc., an SRI spin-off company and the exclusive licensee of EPAM, in the development of the EPAM components for the wave-powered generators.

The generator, initially deployed on a navigation buoy for ports and harbors, is capable of generating 20 joules of energy per stroke, which corresponds to an average output power of more than 5 watts under typical ocean wave conditions. The current development program aims at developing generators that can produce 25 watts of average output power. This is sufficient to supply all the power required by navigational buoys. Future efforts will address the design, development, and deployment of wave-powered generators capable of generating power in the kilowatts range for large-scale clean energy production.

1.2 MW Tidal Energy Turbine Ready for Installation

According to a June 6, 2007 press release by Marine Current Turbines Ltd (MCT), the installation of its 1.2 MW SeaGen commercial tidal energy system will commence during the week of August 20th in Northern Ireland’s Strangford Lough. SeaGen will be the world’s largest tidal current device and will generate clean and sustainable electricity for approximately 1000 homes. Being a full size prototype, no scale up will be required for future commercial installations.

SeaGen consists of twin axial flow rotors, each of 16m diameter driving a generator via a gearbox much like a hydro-electric turbine or a wind turbine. The twin power units of each system are mounted on wing-like extensions either side of a tubular steel monopile 3m in diameter which is set into a hole drilled into the seabed. SeaGen will generate electricity from the flow in both directions.

On June 21 MCT annnounced that it had secured £7.5 million ($15 million) in funding from investment and savings bank Triodos Bank, along with new money from hedge fund AM2 (Bermuda) Ltd and some existing shareholders, will support the SeaGen tidal energy project and facilitate the company’s corporate ambitions and future project developments in UK and international waters.

Ocean Power Plugged in USA Today

USA Today had an article in yesterdays edition giving a big plug for ocean power, with descriptions of the major technologies.

Developers are using an array of contraptions — from spinning turbines to bobbing buoys and undulating, snakelike cylinders — to convert ocean or river movements into electricity.

The world's first commercial wave farm is scheduled to launch this summer off Portugal's coast. The first pilot tidal generator in the USA revved up in New York City's East River last December. And the USA's first utility-scale wave project, off Oregon beaches, won preliminary federal approval this year. All told, the Federal Energy Regulatory Commission has cleared 21 preliminary permits, and about 35 are pending for wave and tidal projects ...

Marine energy has some distinct advantages over its chief rival, wind power. ... more in USA Today

PG&E to Test Wave Power Technologies

PG&E To Study Wave Power In Humboldt & Mendocino
PG&E Press release, February 28, 2007

Pacific Gas and Electric Company took the first step towards developing generation projects that could convert the abundant wave energy off the coast of Mendocino and Humboldt Counties of California into electricity. Named "WaveConnect," the proposed developments would extend PG&E's environmental leadership by providing its customers with a new source of clean, renewable power. ...

The WaveConnect projects will begin with resource, environmental, and ocean use studies and if developed would use wave energy conversion (WEC) devices to transform the energy of ocean waves into clean, renewable electricity. This would be the first application in North America for a project that would allow multiple WEC device manufacturers to demonstrate their devices on a common site, which could help accelerate the development of wave energy technology. ...

PG&E, as the lead developer, will be responsible for the permitting of the sites and will encourage the participation of multiple WEC device manufacturers in the projects. ... Phased development of the sites would proceed if technical results support feasibility, environmental studies show that any significant impacts can be fully mitigated, and stakeholder considerations can be satisfactorily addressed.

PG&E intends to utilize the most effective technologies for the wave energy projects. If fully developed, the projects could each provide up to 40 megawatts of clean renewable electric supply.

Scottish Wave Farm Receives Funding

A Scottish company, AWS Ocean Energy Ltd., that had slipped under my radar, has secured £2.128 million (US$4.16 million) in funding from the Scottish Executive. The funds will be used to develop and commercialize AWS’ Archimedes Wave Swing, claimed to be one of the few proven technologies worldwide for generating clean, renewable electricity from the ocean’s waves.

The Archimedes Wave Swing, shown left (artist apparently took some liberty by showing it above the water surface), is submerged at least six meters below the sea surface which, as well as removing visual impact and hazards to shipping, avoids high storm impacts. Compared to most other wave energy devices, the Wave Swing also takes up a proportionately smaller area of the sea, in relation to power generated. Following a successful pilot project in Portugal, the £2.128 million will be used to develop a pre-commercial model of the device at the European Marine Energy Centre (EMEC) in Eday, Orkney.

Large Tidal Power Project Prposed in New Zealand

A 200 MW tidal power plant is being proposed in New Zealand. The US$400 million Crest Kaipara Energy Project, to be completed in 2011, if started as planned next year, would be located in the Kaipara harbor in New Zealand and generate 4% of New Zealand's power.

Crest Energy is developing the project that will place  200, 1 MW, 22m-high marine turbines, rotating at 5 rpm, in one of the largest harbors in the world. The turbines will located in the deepest part of the channel, submerged an average of 30 meters, 15 meters at low tide. The channel is rarely used for commercial purposes due to shifting sand bars and treacherous tides, and there are no large communities close to the shores of the harbor which makes it a good location for the project.

Two 30km-long cables 125mm in diameter would carry electricity from the turbines to a substation at the entrance to the Hoteo River near Glorit, south-west of Wellsford, where it would be fed into the national grid.   

Annual revenue from 200 operational turbines would be about $110 million at present wholesale electricity prices.

Update: Makah Bay AquaBuOY Wave Energy Pilot Project

AquaEnergy Group Ltd, an Ocean Energy division of Finavera Renewables Limited (Finavera Renewables), a private Irish renewable energy company, announced a further significant step in developing the United States' first commercial wave energy power plant.

AquaEnergy submitted an application for a license to construct the Makah Bay Offshore Wave Energy Pilot Project. This application marks a significant milestone for wave energy development in the United States.

AquaEnergy is developing the Makah Bay Offshore Wave project to demonstrate the economic and environmental benefits of wave energy conversion power plants in utilizing ocean resources to generate clean, renewable energy. The research and demonstration of the AquaBuOY pilot plant would contribute to advances in the worldwide ocean energy industry. AquaBuOYs are modular devices with a nameplate power rating of 250 kW, grouped together three miles offshore.

S.D.E. Wave Power for $0.02 per kWh

S.D.E. Energy Ltd. is a Tel Aviv, Israel manufacturer and marketer of Sea Wave Power Plants - utilizing sea wave energy to produce electricity economically, and in an environmentally-friendly manner claiming that their system an generate electricity for 2 cents.

SDE describes their system as follows: a method of using sea wave motion to generate hydraulic pressure, which is then transformed into electricity. The system takes advantage of the wave's speed, height, depth, rise and fall, and the flow beneath the approaching wave, thus producing energy more efficiently and cheaper than both other sea-wave and conventional technologies which require vast amounts of land space. The system has a potential to produce a net of 38kWh per meter of beachfront occupied (worldwide average). Manufacturing cost for a 1MW system is from US$ 650K and production cost is the lowest in the market. The erection cost of a 1MW S.D.E. station is from $650,000 while a comparable station costs $1,500,000 from coal, $900,000 from natural gas, $1,500,000 from solar sources, and $3,000,000 from wind. Using S.D.E. technology, production of electricity is 2 cents, compared to 3 cents from coal, 3.5 cents from natural gas, 12 cents from solar energy (when is that without subsidies?), and 3.6 cents from wind.

The company website states: "If we receive a letter of order from your government to purchase electricity for 20 years, we will raise all the necessary funds to build the power plant. Our power plants produce electricity at a cost of 2 cents per kW and cost from $650000/MW to build."

Tidal Power for San Francisco

According to a San Francisco Chronicle article turbines submerged in waters below the Golden Gate Bridge could generate enough alternative energy to provide power to nearly 40,000 San Francisco homes. City officials hope that these turbines will capture tidal energy and generate as much as 38 megawatts of power.

The tides at the Golden Gate offer one of the best locations on the western coast of North America to generate that power, according to a study conducted by the Electric Power Research Institute.

Further studies need to be done, however, to answer questions about where the turbines would actually be located, how big they would be, and the potential environmental impacts they would have on the bay and marine life.

Permitting Requirements for Renewable Energy Project

From Energy Central: New Jersey-based Ocean Power Technologies filed a pre-application permit in July with the Federal Energy Regulatory Commission for a commercial wave project off the coast of Reedsport, Oregon. The project would initially generate about 2 megawatts of electricity from buoys in a wave park about 2.5 miles off the coast. ... After that, the company plans to seek approval for a full-scale 50-megawatt power plant. ...

The permitting and licensing procedure typically takes more than five years, but the state is working with federal regulators to get it done within three years, said Greg McMurray, marine affairs coordinator with the Oregon Department of Land Conservation and Development.

Energy Usage Forecast

The June issue of Popular Science features an article on energy technologies that they say will cut our oil consumption in half and reduce our dependence on fossil fuels to produce electricity almost entirely by 2025.

They forecast that ultralight parts and plug-in hybrids could reduce fossil fuel consumption by 19% and that use of biofuels could reduce fossil fuel consumption by 30%.

Electricity needs could be reduced by the following technologies and conservation.

Home Electricity Conservation - 36%
Wind - 20%
Biopower - 17% (biomass gasification and methane generation)
Distributed Generation - 10%
Solar Power - 10% (PV and thermal solar power)
Geothermal Power - 5%
Ocean Power - 2% (wave power and tidal power)

While I don't think that I would have come up with the same numbers, the numbers give some idea of what mix of technologies could be used to reduce our dependence on fossil fuels.  My two concerns are that, while that degree of conservation proposed is possible, electricity costs would have to be extremely high before sufficient motivation for this degree of conservation would be possible.  After reducing consumption as much as forecast by conservation the percentage of electricity produced by wind, solar, and ocean power is higher than could easily be integrated into a grid, without massive energy storage or a much stronger grid, because of the intermittency of these generation methods.  Economical energy storage on a large scale is unlikely by 2025.  Geographical separation of these methods in an area as large as the U.S. reduces the effects of intermittency, but a much stronger grid is required to transport the energy from one area to another which would mean a very costly investment in the electrical infrastructure.  The area between the great plains and the east coast is not especially suitable for these methods and the grid would have to be reinforced significantly in this area. Superconducting power transmission would be especially useful, but development of economical systems is progressing rather slowly, although some usage could be expected by 2025.

I would hope that plug-in vehicles would be in wider use by this time, but that is very dependent on the acceptance of the technology by manufacturers. Their forecast for use of biofuels, although possible someday, is very unlikely by 2025.

The articles (without statistics) can be viewed at http://www.popsci.com/popsci/energy/

GE Provides Capital, Takes Stake in Ocean Power Delivery (OPD)

GE's Technology Lending unit announced today that it is providing capital to Ocean Power Delivery, Ltd. (OPD), developer of the world's first commercial facility that will generate electricity from offshore ocean waves.  The transaction, extends a loan facility of $2.6 million (GBP 1.5 million) to UK-based OPD. Additionally, GE will take an equity position as part of OPD's $22.5 million (GBP 13 million) equity raise as OPD prepares to deliver on its first commercial contract for a wave power farm.

OPD has developed the Pelamis Wave Energy Converter, which generates 750 kilowatts of electricity from offshore wave motion. The company's first order is from a Portuguese consortium, earlier post, that will install the system to generate enough electricity to meet the demands of more than 15,000 Portuguese homes.  OPD expects to install and commission the first stage of the project during the summer of 2006.

GE Ecomagination has the broadest portfolio of any company in the energy market according to Fortune magazine, previous post. In the cleantech arena it has wind, solar, CO2 sequestration and hybrid electric locomotives.  They have several hydrogen related projects and are very actively involved with IGCC, gas turbines and nuclear power. The only major area that they are not involved in is biofuels.

After solar power, ocean power is my favorite renewable energy technology, because it is less obstrusive than wind.  Once proven ocean power should surpass wind power as the principle offshore power source.  In addition to being non-obtrusive it is not quite as intermittent as wind, because the waves keep on going at all times, albeit at a fairly low intensity level at times. Admittently wind has a huge head start, can be use on land and it will be many years if ever that ocean power catches up.

Thanks to Clean Edge for the tip.

Technorati tags: ocean power, wave energy, energy, technology

OPD Ships First Pelamis Wave Generator

Ocean Power Delivery Ltd (OPD) shipped the first of three 750kW Pelamis machines from Scotland to Portugal for installation in the world's first commercial wave farm to be operated by a Portuguese consortium led by Enersis SA.  The machines will be delivered to the Port of Peniche where they will undergo final assembly prior to commissioning and installation later this year at a site 5km off the coast of northern Portugal, near to Póvoa de Varzim. The 2.25MW system will be the first stage of a 24MW plant.

OPD has secured a Letter of Intent for a further 28 machines to complete the plant once the first phase has been successfully installed and commissioned.  The first full scale pre-production prototype has been built and is undergoing tests at the European Marine Energy Center in Orkney.

Video Clip on Ocean Power Technologies PowerBuoy

Ocean Power Technologies (OPT) has a nice video clip of it's PowerBuoy™ which can be found here (windows media player).  Wave power has the advantage that it can produce power continuously and has the potential to compete with fossil fuel power, without having the visual distractions of wind power.  OPT's PowerBuoy™ is designed to be deployed in approximately 100 feet (30 meters) of water. Inside, a piston-like structure moves as the PowerBuoy™ bobs with the rise and fall of the waves.  This movement drives a generator on the ocean floor, producing electricity, which is sent to the shore by an underwater cable.  A previous post on Wave Power has further information about OPT.

Earlier this month OPT announced that they had been selected to install a 5 MW system off the north coast of Cornwall, UK.  This is their sixth installation, other project sites include Spain, France Hawaii and New Jersey.

Technorati tags: wave power, ocean power, energy, technology

More Proof of Global Warming

Dr Michael Coughlin, head of the National Climate Centre was reported as saying that the world is now hotter than any time since prehistoric times.  He is supported by research using gas trapped in Antarctic ice going back 650,000 years that found that current levels of carbon dioxide in the air are 27% higher than at any tiny time during that period.  This goes along with NASA's report that says that 2005 is the hottest year on record.

Effects that have been attributed to the warming include that the Artic sea ice dropped to its lowest level ever, the record hurricane season and an unprecedented drought that reduced the flow of the Amazon river to its lowest ever rate.  Canada and Australia had their hottest ever weather this year, while India, Pakistan, Bangladesh and Algeria suffered heatwaves reaching 50C.

If this isn't strong enough proof that global warming is real, what do you need Mr President?  It certainly should be enough to convince you to take all possible measures to reduce global warming, which should include as its main point the reduction of burning of fossil fuels. The time required for any mitigating measures to have any impact is so great, that all stops have to be pulled out now.  Items that have been repeatedly indicated as being necessary include:

Simple Concept for Wave Energy

Trident Energy is developing a simple wave energy system, the Direct Energy Conversion Method (DEMC) that uses the up and down motion of a buoy to cause a magnetic translator to move up and down along a coil to generating electricity.  The small British company based in Southend-on-Sea has tested a 1/5th scale model in a large wave tank and results indicate that a full scale model should be able to produce 100 kW.  The generators would be attached to a stationary platform in the ocean and buoys located below the platform would move with wave action.  A linear generator, which consists of an electrical coil, attached to the buoy, and a translator, consisting of a stack of magnets which would move up and down past the coil in a housing attached to the platform, generating an alternating electrical current.  No mechanical devices that are frequently used in wave generators to translate the wave motion to the rotary motion needed drive a conventional generator are required, thus greatly simplifying the units.

The feasibility of DECM's and the anticipated advantages and problems were the subject of a study by the University of Durham, which is refererenced below.  They concluded that

• a permanent magnet translator was desirable
• that the motor chamber did not necessarily have to be sealed
• the units must be installed in clusters (not single units), of at least four, in order to obtain a smooth electrical output
• the efficiency of the system is likely to be higher than hydraulic systems
• the system could be maintenance free
• the basis for a control system was outlined

The DECM's would be self protected against stormy conditions.  This is achieved by having a sensor that could detect storm conditions which would change the mode of the equipment from generators to motors.  The (now) linear motors would lift the floats out of the sea into protective chambers, where they would be held until the storm or adverse wave condition had passed. 

Following extended research, Trident Energy has been able to obtain energy conversion rates among the highest for any known marine energy device.  Trident is planning to build four full size generators as their next step.  They hope to test these generators at the European Marine Energy Centre in Orkney by the end of 2007.

The founder of Trident Energy Ltd, Hugh-Peter Kelly, is also the inventor of the Tubular Linear Motor / Generator that is being adapted for the wave generator. This is an internationally established product and was invented by him in the early 1980’s for use in the automation industry. (There are over 32,000 motors of this type in use world wide and a further 15,000 actuators.)

This sounds like a great idea, fairly obvious once it is explained.  A long way to go before commercialization.  I wish them luck.  I hope they do not limit themselves to 100kW generators.

Site revised 10/16/05 based on information obtained from website.

Resources:

Trident Energy, Southend-on-Sea, UK
"Comparative Study of Linear Generators and Hydraulic Systems for Wave Energy Conversion", University of Durham, 2001
"Swell magnet strokes support for wave power", News-Nature.com,  10/11/05

Technorati tags: ocean power, energy, alternative energy, renewable, renewable energy

Wave Energy Update

AquaEnergy Group, Energetech and The Manchester Bobber have come to my attention as three additional developers of wave power systems.

AquaEnergy Group is developing a wave energy converter called the AquaBuOY.  Clusters of these small, modular buoys would be moored several miles offshore where the wave resource is the greatest.  Energy transfer takes place by converting the vertical component of wave kinetic energy into pressurized seawater by means of two-stroke hose pumps. Pressurized seawater is directed into a conversion system consisting of a turbine driving an electrical generator. The power is transmitted to shore by means of an undersea transmission line. The AquaBuOY consists of four elements:

1. Buoy - A 30 ft long buoy, 15 feet of which is submerged, is used to support the system and keep it stable.
2. Acceleration tube - The acceleration tube is a vertical, hollow cylinder rigidly mounted under the body of the buoy. The tube is open at both ends to allow unimpeded entry and exit of seawater in either direction.
3. Piston - Positioned at the midpoint of the acceleration tube is the piston, a broad, neutrally buoyant disk.  When the buoy is at rest, the piston is held at the midpoint by the balanced tension of two hose pumps that are attached to opposite sides of the piston and extend to the top and bottom of the acceleration tube, respectively. 
4. Hose-Pump - The hose-pump is a steel reinforced rubber hose whose internal volume is reduced when the hose is stretched, thereby acting as a pump. The pressurized sea water is subsequently expelled into a high-pressure accumulator, and in turn fed to a Pelton turbine which drives a generator. Generated electricity is brought to shore via a standard submarine cable.

AquaEnergy is currently designing and permitting the Makah Bay (state of Washigton, USA) one megawatt demonstration power plant, with a goal of delivering power to the Clallum County Public Utility's grid by the end of 2006.

Energetech uses a parabolic wall to focus wave energy on to an oscillating water column (OWC) chamber.  The rising and falling motion of the waves causes an oscillatory water motion within the chamber, which in turn forces a high-speed airflow past a unique controllable turbine. The air flow past the turbine oscillates in the same manner as the water column requiring a turbine that can operate with this motion.  A control system senses the rising and falling of the waves and sends a signal to a 'Dennis-Auld' turbine which is designed to operate with an oscillatory flow. The turbine drives an induction generator to produce electrical power. 

Construction of the first 1 MW power plant, the Port Kembla (Australia) project, was begun in early 2004 and was initially installed in June 2005.  Initial tests indicated some minor improvements were required and the unit was brought back to shore for modifications.  During the time at the site, initial operation indicated that the chamber and design concept worked successfully and power was generated.  The modifications have been completed and a September report indicated the unit was back in operation.

Greenwave Rhode Island is a $3.5 million, 500 kw not-for-profit pilot Energetech project.  Operation is expected in 2006 and will continue for 3 years.  The states of Connecticut, Massachusetts and Rhode Island have contributed $1 million in planning and development funds to the project and it is being conducted in cooperation with the Universty of Rhode Island.

The Manchester Bobber, being developed by the University of Manchester, UK, generates electricity from the up and down motion of the ocean, no matter what the source; waves, tidal or current.  The advantages of this device are:

• All vulnerable componets are housed in protected environment located above sea level with easy access and readily available for maintenance, resulting in higher reliability.
• The 'Bobber' responds to waves from any direction with requiring any adjustment
• Each individual element of the 'Bobber' may be maintained independent of others in the group without interruption of the power generated in the group.

Phase one; design, development and testing of a 1/100th scale working model were completed in January 2005 and the phase two construction of a 1/10th scale model has been completed and testing was started in September 2005.  Phase three will involve a full scale prototype being constructed and tested in parallel with detailed costings and engineering design for the optimum full scale concept.

Resources:

AquaEnergy Group Ltd., Mercer Island, WA, USA
Energetech Australia Pty. Ltd., Randwick, Australia
"Manchester develops new wave energy device: The Manchester Bobber", U of Manchester press release, 9/5/05
Manchester Bobber: Technical Description, Manchester Bobber website

Technorati tags: ocean power, wave power, renewable energy, renewable

About Tidal Power

The tide moves a huge amount of water twice each day, and harnessing it could provide a great deal of energy.  Ocean currents are found along coastlines beneath the oceans surface at depths of 80 to 230 feet (25 to 70 meters) and with flow rates of 5 to 10 feet per second (two to three meters per second).  Horizontal or vertical axis turbines, much like underwater wind turbines, can be used to capture the energy from ocean currents or tidal flows.  They can be installed so as not to interfere with fishing or the passage of vessels.  The slow speed of the turbines does not interfere with aquatic life.

The potential for tidal power is large and a numerous potential sites have been identified.  However there are not nearly as many potential sites as there are for wave power.  The technology is so similar to that of wind turbines that it could be expected that a wind turbine manufacturer could jump into this market after it starts to develop.

The gravitational pull of the moon causes water to flow in from the ocean on the flood tides, and outward during ebb tides.  However, tides are totally predictable, so other power stations can be generating at times when the tidal station is out of action.  This energy source is independent of weather and climate change and follows the predictable relationship of the lunar orbit that is known many years in advance.  In order for this to work well, large changes in the height of tides are needed. 

Tidal dams are based on using a barrage, a damlike structure with openings allowing water to flow up and down an estuary as the tides move in and out.  They are located at a bay or estuary with a large tidal range.   As the tide flows in, water is allowed to flow up through openings in the barrage, into the estuary, then sluice gates on these opening are closed trapping the water above the barrage.  The sluice gates on the turbines are then opened, allowing the water to flow out through the turbine, generating electricity. 

About Wave Power

Unlike most kinds of renewable energy, wave power can produce power continuously.  Ocean waves represent a considerable renewable energy resource.  All of the energy is concentrated near the water surface with little wave action below 165 ft (50 meters) depth.  This makes wave power a highly concentrated energy source with much smaller hourly and day-to-day variations. The rising and falling of the waves off shore can be captured by several devices specifically designed for this purpose.

Wave power is perhaps the least intrusive of all the renewable energy technologies.  Wave power is very environmentally friendly.  It does not create any waste, does not have any CO2 emissions or criteria pollutants, there is no noise pollution, no visual impact and it does not threaten marine life.   Although the technology is limited to coastal locations its potential impact is large because of the large concentration of population along the coasts and the suitability of most coastal locations to the implementation of wave power.  Proponents claim that the energy cost for producing electricity via wave power will be competitive with conventional power within a very short time.

However, wave power technology is still in its infancy with many competing technologies.  The reliability of the devices for capturing energy from the waves has not been demonstrated on a very large scale.  Some devices are quite complex and may require quite a bit of refinement before they can be considered mature technology.  Wind power currently has the lowest cost of producing electricity of any of the renewable energy technologies and is the most successful technology, but it suffers from its intrusiveness, noise and danger to wildlife. 

Where Does The Energy Revolution Stand?

The Energy Revolution has met some major milestones In the six months since I have been writing this blog, in that there there have been several key developments relating to energy technology and policy which I would like to review and comment on. 

Transportation Fuels

My focus immediately became on transportation fuels, as I soon found out it was our most immediate concern. The development of technology and “roadmaps” that could lead to independence from foreign oil imports for the US and other countries have made significant progress in the last six months.  Although funding to accelerate usage of biofuels is totally inadequate, further evidence of the availability of potential resources is a major step.

• The refusal of congress to institute new mileage standards for passenger vehicles and light weight trucks is a major disappointment. Causes of this complacency include: 1) Congress is unconvinced of the urgency of the problem 2) Lobbyists that are opposed to these standards are much too influential and 3) Congress would rather let market forces create a demand for biofuels and hybrid vehicles rather than getting involved.
• Release of the Hirsch report which presented three scenarios for mitigating a decline in oil production. This report clearly indicates that if aggressive action to mitigate peak oil is not taken at least 10 years before it occurs we will face grave economic impact.  A must reading for all concerned about peak oil and the mitigation thereof.
• Record quantities of ethanol are being produced in Brazil with 40% of new cars sold capable of burning 100% ethanol and all gasoline sold contains at least 25% ethanol. The country is nearly independent of oil imports and is becoming a major exporter of ethanol. Brazil is a model in the use of renewable fuels for the rest of the world.  Please take note!
• Release of the Oak Ridge report stating that up to 30% of our liquid fuels could be produced from cellulosic materials.
• Announcement by DOE that enzymes have been developed that permit using any cellulosic material as a feedstock to the production of ethanol. This development makes possible meeting goals for producing 30% of our liquid fuels from cellulosic materials. This occurance was anticipated in the previously item and makes biofuels a major, realistic alternative.
• Announcement by CleanFuels that it was in the process of commercializing production of biodiesel from algae using smokestack emissions as fuel. This is significant in that it complementary, not competitive with other biodiesel production routes. At the same time the process also reduces CO2 and NOX emissions from power plants.  Though not nearly as far along in development as ethanol, algae biodiesel would make it possible to be the major biofuel.
• Increasing sales and announcement of hybrid vehicles, which is our main means of conservation of gasoline.
• Announcement by scientists at the University of Wisconsin that they had developed a process for producing Alkane based biodiesel from any carbonaceous material.
• A new Renewable Fuels Standard in the new Energy Bill requiring a doubling in the use of biofuels to 7.5 billion gallons a year by 2012.  Biomass was redefined to include any organic material grown for the purpose of being converted to energy.  This is not nearly a large enough program to allow ethanol and biodiesel to replace our oil imports in a timely manor, but it is a step in the right direction.

The US Energy Bill of 2005

The US energy bill of 2005 has received a mixed bag of reviews depending on your interests.  The folowing are the portions of the energy bill that appear to be most relevant to the topics I discuss:

A two-year extension of a tax credit to companies that produce power from renewable sources — an allocation worth $2.7 billion. The bulk of those funds will promote the construction of new wind farms, a boon to utilities and wind turbine manufacturers, while the remainder will assist biomass, geothermal and hydroelectric companies.

Biofuels : A 7.5 billion gallon Renewable Fuels Standard (RFS) which would add billions of gallons of ethanol, biodiesel and other renewables to the nations fuel supply by 2012.  In addition to the RFS, the bill updates the small ethanol producer definition to 60 million gallons, extends the biodiesel tax credit through 2008, and establishes a 30% tax credit up to $30,000 for the cost of installing clean fuel refueling equipment, such as an E85 fuel pump.

Solar : Increases the permanent 10 percent business energy credit for solar to 30% for two years.   Eligible technologies include photovoltaics, solar water heaters, concentrating solar power, and solar hybrid lighting. The credit reverts back to the permanent 10 percent level after two years. The bill establishes a 30 percent residential energy credit for solar for two years.   For residential systems, the tax credit is capped at $2,000.

Geothermal, Wind: The bill continues to include geothermal energy in the Section 45 Production Tax Credit (PTC) for the full 1.9 cent/kwhr credit amount, but expands the credit period from five to the full ten years. As a result, geothermal and wind will now receive equal tax treatment -- the full ten-year, 1.9 cent production tax amount. Other technologies, such as open loop biomass, receive the full ten-year credit but for half the credit amount, or 0.95 cents/kwhr. The biggest clean energy perk in the bill was a two-year extension of a tax credit critical to companies that produce power from renewable sources -- an allocation worth $2.7 billion. The bulk of those funds will promote the construction of new wind farms, a boon to utilities and wind turbine manufacturers, while the remainder will assist biomass, geothermal and hydroelectric companies.

Direct users of geothermal energy may use a simpler procedure for leasing, or establishing a fee schedule instead of royalties payments. State and local governments are allowed to use geothermal resources for public purposes at a nominal charge.

Hybrid, fuel efficient vehicles: Close to $875 million in tax credits could be given to those who buy hybrid gas-electric vehicles before 2010.  The bill favors companies that are just getting into the hybrid business. Each manufacturer can apply the tax credit to just 60,000 vehicles.  Toyota sells roughly 150,000 hybrids per year and Honda 50,000 which means that a only a portion of their vehicles will be eligible for credits. The bill fails to include any provision for new fuel efficiency standards.

A new category of tax credits known as clean renewable energy bonds, or CREBs, that have an estimated value of $400 million. These tax-exempt bonds can be issued by local governments or electricity cooperatives to help pay for wind, solar, biomass and other specified projects.  An additional $194 million will go toward the two-year extension of excise- and income-tax credits for manufacturers of biodiesel, a soybean derivative that is blended with regular diesel.

More on Wave Power

Wave power is coming of age!  Ocean Power Delivery (OPD) announced that it has received an order for the world's first commercial wave power installation.  In the first phase, worth $10 million (Euro 8 million), OPD will install three "Pelamis" P-750 machines with a total installed capacity of 2.25 MW.  The project is located 5 km off Portugal's northern coast, near to Povoa de Varzim.  A letter of intent was issued to order a further thirty Pelamis machines (20 MW) before the end of 2006 subject to satisfactory performance of the initial phase.

Each Pelamis machine measures 394 ft (120m) long by 11 ft (3.5m) wide (about the size of four train carriages) and weighs 750 tons fully ballasted. The Pelamis is a semi-submerged, articulated structure composed of cylindrical sections linked by hinged joints. The wave-induced motion of these joints is resisted by hydraulic rams, which pump high-pressure oil through hydraulic motors via smoothing accumulators. The hydraulic motors drive electrical generators to produce electricity. Power from all the joints is fed down a single umbilical cable to a junction on the sea bed. Several devices can be connected together and linked to shore through a single seabed cable.

OPD'S system was identified as the only system currently recommended for deployment in a recently announced report, (full report) 2/3/05, by Electric Power Research Institute (EPRI).  Three other wave power manufacturers are identified in the report as nearing the maturity of OPD.  The EPRI report concluded that wave power is lower in total cost than wind power, its initial cost being lower and operating and maintenance costs being higher.  Its very low profile makes it much less visual intrusive than wind power and it promises to be one of the most environmentally benign electrical generating devices.  They stated that when compared to wind power, solar PV, and tidal power it can be characterized as having the highest power density, the least intermittency, it is continuous but highly variable and is more predictable than solar or wind.  Harnessing just 24% of the available offshore wave energy resource of the U.S., at 50% efficiency, would generate as much electricity as all the conventional hydropower now installed, about 10% of our current electrical production. 

It looks like we will soon have another technology to put in our bag of tricks.

Technocrati tags: wave power, renewable energy

Diversity in Renewables Smooths Output

Renewable sources of power, wind, solar, wave and tidal power have been criticized because they do not produce power at a consistent or predictable rate. "By mixing between sites and mixing technologies you can markedly reduce the variability of electricity produced by renewables, Graham Sinden, of Oxford's Environmental Change Institute was quoted as saying in the May 12th edition of The Guardian.  Sinden went on to say, "And if you plan the right mix, renewable and intermittent technologies can even be made to match real-time electricity demand patterns. This reduces the need for backup, and makes renewables a serious alternative to conventional power sources."  He found that by combining a diversity of geographical locations and a diversity of technologies, renewables combined with domestic combined heat and power could ultimately make the the following contributions to Britain's total energy supply: wind 35%, wave and tidal 15%, combined heat and power 15%, and solar 5-10%. 

A more detailed report can be found at the University of Oxford's Environmental Change Institute's web site.  The Cambridge-MIT Institute has a related paper "Diversity and Security In UK Electricity Generation: The Influence of Low Carbon Objectives"

The conclusion that diversity reduces variability is rather intuitive.  These studies put some numbers on the required mix. I would assume that similar findings would apply to other regions of the world.  If eventually more than 50% of our electricity could be produced from renewables that would be an enormous contribution.  Add another 10% for hydro and 40% from a combination of bidiesel made from algae and syngas made from biomass and we have total independence from fossil fuels.