After attending All-Energy 2012 last week, Fran was so inspired by the abundance of both Scottish and global marine energy potential that she decided to reignite her passion for physical geography (and all things hydro) by exploring the power, policy context, and passion behind one of the world’s fastest-growing low-carbon energy sectors.
According to the Energy Technologies Institute (ETI) there will be up to 180MW of global wave and tidal energy projects available by late 2016, with the UK potentially hosting between 70-80 per cent of installations. This inspirational conclusion from the reNews Global Marine Renewables 2012 report provides the much needed support the marine energy industry needs to demonstrate to the world its instrumental role in securing our future low-carbon energy system.
Global marine energy potential
Across the pond Canada is taking a real lead in developing its marine energy sector just like Scotland. Giving a presentation at All-Energy 2012, Chris Campbell from Canada’s Ocean Renewable Energy Group (OREG) stated that now is the time for marine energy development to prove its worth and commercial viability. Mr Campbell was elated that the industry is no longer viewed as an add-on but seen as a leading low-carbon energy solution, which can deliver greenhouse gas reductions in addition to contributing to our energy security. This was recognised only last week by the UK’s draft Energy Bill, which set a target of achieving marine energy cost-competitiveness of 14p per KW per hour, by 2020.
For marine energy to really achieve its potential it must prove it is commercially viable and this means “developing marine solutions that meet utilities’ needs” (Chris Campbell, OREG). This was a clear message that emanated from All-Energy; the world’s available ‘water-to-wire’ resource cannot simply be harnessed but must become a major competitive industrial player. And, that’s just what the European Marine Energy Centre (EMEC), based in Scotland, aims to do; to test marine technologies to determine those that can connected to our electricity grids and those that are simply a great technological development, but idealistic in regards to cost-competitiveness. Some of the technologies on display at All-Energy were already deployed as test devices in various marine energy parks across the globe, whilst others had only recently been brought to the industry’s attention.
Tidal energy, unlike its close relative wave, has the potential to really be a major contributor to our global energy mix. Scottish tidal power is estimated at up to 7.5GW (25% of the EU’s total capacity). Water is around 830 times denser than air (measurements vary amongst sources) enabling a much greater energy output than wind. The commercial advantage of tidal technology is that it provides a predictable source of energy that can contribute to the overall energy mix to secure a constant source of power generation. In addition, unlike most renewable technologies that frequently face resistance due to their visibility (vast solar panel farms and giant offshore and onshore wind farms) tidal devices are submerged at subsea level, so there is no visual or audible pollution.
Displayed at All-Energy were multiple tidal turbines of differing design, each with its own unique approach to maximising tidal stream energy potential. It is this difference between the technologies, varying from very small singular turbines similar to established wind technology to huge turbines reminiscent of aeroplane propellers, that makes the marine energy industry such an exciting sector to explore.
All-Energy 2012 tidal technologies
Of the companies displaying their technologies at All-Energy, those using a more ‘traditional’ turbine developed from technology used by the wind industry included ANDRITZ HYDRO Hammerfest, Marine Current Turbines, Nautricity, TidalStream and Tocardo BV.
ANDRITZ HYDRO Hammerfest develop and supply ‘turn-key’ tidal array devices consisting of up to several turbines in an array. ANDRITZ HYDRO’s unique Hammerfest Strom HS1000 tripod design is weighted onto the seabed by gravity and additional ballast, reducing its seabed footprint. It is installed at 40-100 meters depth in tidal streams with a velocity in excess of 2.5m/s. The three-blade device maximises power generation through the regulating pitch of the blades and it is highly robust and energy efficient. The turbine has successfully been deployed at EMEC where it is being tested. The device has also been selected as the preferred technology for a pre-commercial array just south of Port Askaig in the Sound of Islay, a project partnered with ScottishPower Renewables, which has powered the Scottish Island of Eday by directly delivering electricity to the grid.
In comparison to seabed-mounted turbines Nautricity’s CoRMaT device, a contra-rotating turbine, is suitable for deployment in water depths of 8 to 500m. As the device floats (rather than being mounted on the seabed) the turbine can be connected to a tensioned mooring at a point in the water column where the flow velocity is greatest and surface wave action minimized: this maximises energy output as well as efficiency. The CoRMaT uses two closely spaced rotors moving in opposite directions, where the front rotor uses three blades and the rear motor four. The turbine has no gearbox, with the flooded generator cooled passively by the water, which helps eliminate energy losses. The device is very flexible and easy to install.
Tocardo BV use a single-blade, no gearbox, 100 kW T100 turbine and the larger 200kW T200 turbines are scalable concepts designed to operate in speeds ranging from 2 to 4 m/s, with a power output varying from 30 kW to 1MW. It is compact in size and therefore has versatile deployment possibilities. The device can be connected to regular power grids, but it is also an excellent solution for off-grid deployment in remote areas or for island economies.
TidalStream’s unique multi-turbine tidal Triton platform approach can ‘halve the cost of tidal energy’ in comparison to single and twin turbines, by maximising the costs benefits of using existing technology design. The platform system is designed for deep waters, typically 60m, often considered too deep and too rough for surface devices. The turbines are mounted on a variable-buoyancy platform which is connected to the seabed by a single, rigid swing-arm foundation. Because the platform is flexible, the turbines can swing with the tidal current to maximise energy capture and minimise off-axis loads, meaning it uses the full depth of the tidal stream. There are currently two platforms which can support either three or six turbines which can mount a variety of third party turbine devices. Currently the six-turbine output is between 6-10MW. The device’s float-out installation also means it is highly cost efficient. Its buoyancy tanks are flooded with seawater rather than filled with concrete like many devices, reducing its environmental footprint. The platform is easily maintained: the water is simply pumped out enabling the platform to float to the surface where access is gained through internal walkways.
Moving away from using ‘traditional’, well-established wind technology, OpenHydro’s seabed mounted Open-Centre turbine device is reminiscent of a giant aeroplane propeller! OpenHydro’s unique device was one of the biggest on display at All-Energy, able to produce up to 2MW of power, in addition to being heavily robust to withstand demanding tidal conditions. The device incorporates a slow-moving rotor and lubricant-free operation minimising risk to marine life. The company’s first 6m test unit produces enough energy to supply 150 average European homes and can save around 450 tonnes of CO2 greenhouse gas emissions each year. Not only is its size impressive, but so too are its environmental credentials.
Although less predictable than tidal power, to put the power of wave energy into perspective, Scotland has an estimated potential of up to 14GW (10% of the EU’s capacity) making it an important part of our energy mix. Although many wave energy converters were displayed at All-Energy including well-known Pelamis Wave Power, two technology developers who captured people’s imagination, and had come all the way from continental Europe to display their devices were Wello and Langlee Wave Power.
Wave technologies at All-Energy
Wello’s Penguin device is, according to the team, ‘truly organic and unique in design’. The device is shaped like a penguin (so it’s definitely unique), weighs in at 220 tonnes, and is 30 meters across with only 2 meters visible above water. It’s been designed to be simple, reliable and very durable. The exterior is made from renewable materials and has very low maintenance costs and durability over its lifetime, and is anchored to the seabed by wires. The device is currently being tested at EMEC. By capturing kinetic wave energy and turning it into electricity a single Penguin unit can produce between 0.5-1MW of power.
Langlee Wave Power’s E1 Wave Energy Converter is a surface floating steel structure with lightweight fibreglass water wings which ‘swing with the waves’. The device’s unique selling point (USP) is that its design is based upon tried and tested fish farming technology which allows for easy installation reducing the associated supply-chain costs. The device has also been able to lower its environmental impact by using just four mooring lines to tether it to the seabed. Each device generates up to 50kW and a key selling point for the device is that it can be towed to location pre-fabricated, making it an efficient and flexible wave energy system. The modular design of the device also enables for build and assembly near to the deployment site aiding local economic development. Langlee believe that within three years their device will be at the cost level of onshore wind power and that the energy required for the device’s construction and installation is offset by its clean energy production in less than two years.
As seen by the BBC’s satellite image of the UK’s (stormy) weather system at the beginning of this piece, in conjunction with the fantastic wave and tidal energy technologies spinning out from all over Europe as displayed at All-Energy, there is huge potential for the marine energy sector to enable and support both the UK and Europe’s future low-carbon energy roadmaps and targets. With such excitement, possibility and potential commercial viability, the answers to many of the difficult questions facing populations and politicians about future energy security could all be answered by simply looking to the waters that surround us.
- Newsnet Scotland, All-Energy 2012 and Scotland’s marine energy potential, 7 June 2012
- Low Carbon Economy, All-Energy 2012 and Scotland’s marine energy potential, 6 June 2012