In this interview, Kim Lyle, Chairman of MAKO Tidal Turbines, talks to AZoCleanTech about tidal energy and the SeaUrchin Tidal Power System.
Could you briefly describe how tidal energy is generated?
Air and water are both fluid, so the physics of the conversion of kinetic energy from ocean currents/tides is superficially very similar to the conversion of kinetic energy in the wind. Not surprisingly products from the majority of tidal technology companies resemble conventional wind powered rotor turbines. Seawater, however, is up to 832 times denser than air with the effect that even modest tidal flows create enormous forces which result in tides generating significantly more power than wind.
The SeaUrchin is a 3rd generation design. It has been optimised for tidal energy extraction and does not use a conventional turbine like wind turbines or the majority of 1st generation tidal turbines in the market today. In conjunction with other patented design features, the SeaUrchin is not only the strongest tidal device it is also the most efficient at extracting energy and converting this to electricity.
How is the SeaUrchin unique in the tidal energy sector?
Currently the European Marine Energy Centre (EMEC) and the U.S. Department of Energy both list on their websites over 60 companies worldwide offering a range of ocean/tidal power generator technologies.
Over 70% of these companies listed have adapted a 1st generation marinised variation of conventional wind rotor blades for use underwater. The remainder have developed innovative, relatively low power devices. They are all logistically limited to only a few locations around the world, are expensive to build and appear to be years away from any realistic commercial applications.
The SeaUrchin from MAKO Tidal Turbines
Due to the huge forces generated by current/tidal flows, these conventional blade and boutique designs are massively and expensively engineered to withstand the harsh marine environment.
It is MAKO’s view that the vast, future markets for bulk, baseload and reliable marine energy will be best serviced by low cost, robust, tidal and ocean stream generators, scalable from micro sizes up to 1MW and which allow inherent economies of scale and ease of deployment.
The SeaUrchin, with its superior design, its cost efficiency and its ability to be deployed in the widest range of conditions, is well positioned to secure a significant market share.
The key features of the SeaUrchin’s Technology which set it apart from other tidal turbines in the marketplace:
- Powerful - is around half the size, generates up to 4 times the power and is up to 70% more efficient than competing first generation un-shrouded “blade”-style marine generators;
- Scalable - from micro 2kW units up to 1MW units suitable for utility scale installations in arrays;
- Ease of Manufacture – uses low cost materials and components which reduces the cost for manufacture and simplifies repairs;
- Reliable - can be configured with only one moving part and no gearbox in smaller turbines with optional simple robust drive mechanisms in larger SeaUrchins;
- Mass Producible - low cost materials and components make it suitable for high volume mass production;
- Low installation cost - large range of installation options including existing ocean towers, tidal fences, suspension from barges, seabed mooring and mooring from conventional shipping buoys;
- Efficient – very high efficiency at both low and high flow rates making the SeaUrchin suitable for the widest range of ocean and river locations worldwide;
- Bio-fouling Resistant - The SeaUrchin is resistant to marine growth due to the common marine-grade anti-fouling materials used in its construction:
- Self-aligning - design optimally aligns to continuous flows or changing tides;
- Zero emissions - no CO2 or noise pollution;
- Ease of Maintenance - a design which facilitates a ‘swap and go' maintenance approach.
- Remote monitoring and control – maintains optimised performance and is easier to monitor maintenance as required ;
- Minimal environmental impact - with no visual or noise pollution; and
- Cost Competitive - Potential to compete directly with coal and nuclear power generation.
Where is the SeaUrchin currently being implemented? Are you happy with the results so far?
The 2kW SeaUrchin has undergone extensive performance testing and it currently in the endurance testing phase. Following successful testing, a prototype 10kW will be fabricated for final testing before moving to production by our manufacturing licensees overseas.
The trials of the SeaUrchin which have taken place to date include:
- April 2011 - A pre-production 2kW micro SeaUrchin was successfully trialled in Newcastle Harbour Australia.
- Nov/Dec 2011 - Successful performance Trials of 2kW micro SeaUrchin undertaken in the Georges River Sydney, Australia.
- Mar/June 2012 - Performance Trials for product certification for use in India
- Late 2012 - Extended trials of single SeaUrchin turbine in real-world conditions followed by integration trials of multiple SeaUrchin arrays in advance of testing 1MW prototypes scheduled to take place in the Clarence Strait, Northern Territory, Australia
In all trials to date the SeaUrchin has exceeded anticipated performance specifications.
It is also anticipated that a 2kW installation will be commissioned in the Clarence Strait near Darwin in Australia’s Northern Territory in the 4th quarter of 2012 as a prelude to the roll-out of the 1MW SeaUrcin in this site in 2013. There is the potential for a 2kW installation with an independent third party during 2012 with the power generated to be used on-site to run lighting and therefore reduce the reliance on grid power as well as to generate valuable data for MAKO.
A SeaUrchin being readied for trials
Is the SeaUrchin scalable depending on the situation in which it needs to be implemented?
The SeaUrchin is scalable from very small devices such as our 2kW and 10kW devices suitable for deployment in irrigation canals and small rivers all the way up to our 1MW turbines capable of supplying power to 1,000 homes.
Mini SeaUrchin Development
For the smaller 10kW SeaUrchin turbines, initial design work was undertaken under the direction of the Company’s Research Director utilising consulting engineers including e3k and RPC Technologies. Following initial design work, Kirloskar Integrated Technologies Limited (KITL), the renewable arm of the Indian Kirloskar Group, has undertaken design optimisation and preparation for mass production in collaboration with MAKO’s own engineers.
Macro SeaUrchin Development
For the 1MW SeaUrchin, the Company has assembled a consortium of consultants and component suppliers who will work together to undertake design, prototype fabrication and testing over the next 12-18 months. This consortium includes household names such as Prysmian Cables, ABB, Orbital2 as well as MAKO’s existing technology partners in Australia, e3k engineer, RPC Technologies and ATSA.
The 1MW Consortium will work under the direction of the Company’s engineers. This will ensure that the project can be managed efficiently in that duplication will be avoided and the Company will have access to the best available resources while controlling cost.
The 1MW SeaUrchin is planned to be deployed in the newly created Tropical Tidal Test Centre (T3C) planned for development in the Clarence Strait in the Northern Territory, Australia in conjunction with a leading University and Tenax Energy Pty Limited, a private developer. Following successful trialling and subject to meeting criteria set by the developer and the local power utility, the SeaUrchin will become a preferred technology for the adjacent Clarence Strait tidal power station with a total potential capacity of up to 450MW.
How many locations globally can tidal energy be utilised in?
Unlike many other turbine designs currently under development, the SeaUrchin is capable of being deployed in a wide range of locations due to its unique design features, including:
- Choice of positive, negative or neutral buoyancy;
- More compact dimensions than conventional blade designs;
- Automatically optimal alignment with current flow;
- Potential shipping in component form and assembly on site
- These features allow the megawatt class SeaUrchins to be deployed in the following ways:
- From shipping buoys or from barges near the surface
- From rigid structures fixed to the seabed such as towers;
- From existing floating structures such as oil rigs, drilling platforms of offshore wind barges
- In custom designed housing tethered to the sea floor with gravity anchors (see the SeaUrchin video)
The smaller micro SeaUrchins (up to 10kW) are more likely to be installed in rivers or engineered channels (such as hydro dam tail races or irrigation canals) and can be cost effectively deployed by tethering single or multiple arrays of turbines to the adjoining land using steel cables or can be housed on small floating barges. Worldwide, there are hundreds of thousands of kilometres of canals and engineered channels suitable to house SeaUrchin generators equating to a potential market for millions of mini SeaUrchins over time with low-volume initial sales expected early in the product lifecycle.
The fact that the SeaUrchin can be deployed in a multitude of configurations means that a cost-effective solution can be implemented to meet customer requirement and local conditions which is not the case with first generation (propeller) turbines or simple ducted designs which have so far only been capable of being deployed when affixed to the sea floor.
Potential tidal sites in India include the gulf of Kutch and the gulf of Khambat, both in Gujarat, which have a total potential installed capacity of 7900MW, according to studies by the World Energy Council. There is also potential in the Ganga delta in the Sunderbans region of West Bengal. The Chilla Canal in Northern India may also be a possible site for river tidal projects.
Apart from generating renewable energy, how else is the SeaUrchin eco-friendly?
The SeaUrchin is also eco-friendly because it:
- Can be sited underwater and be visually unobtrusive;
- Has minimal impact on the ocean bed; and is
- safe for most marine life to pass through the turbine unaffected.
The SeaUrchin has been designed to be assembled on-site using techniques which will minimise the energy used in construction and shipping the units to their eventual destination. Also, the SeaUrchin will use only a fraction of the total materials necessary for other 1st generation designs as it will be physically much smaller and lighter than these devices.
As well as the SeaUrchin itself, the deployment technology to be used will have less impact on the environment than other competing designs as it will not involve extensive gravity anchors and will not require pylons to be driven into the seafloor.
Is there any threat to marine ecosystems posed by the SeaUrchin?
The SeaUrchin is safe for smaller marine life to pass through the turbine unaffected. This is because of the large clearances within the 1MW SeaUrchin which has blades which are 9.5 metres in diameter. The blades rotate at 10-15 revolutions per minute which is slow enough to allow small marine life to swim through it.
In areas where large marine life exists such as migration routes for whales, seals and dolphins, a cage can be fitted to the front of the SeaUrchin if required and sonar transponders fitted to deter these large marine mammals.
As well as the SeaUrchin itself, the deployment technology to be used will have less impact on the environment than other competing designs as it will not involve extensive gravity anchors and will not require pylons to be driven into the seafloor. This will permit the SeaUrchin to be deployed in a wider range of locations, including environmentally sensitive regions with less risk to ecosystems.
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