Although wave and tidal is still at an early stage of development, the last couple of years have seen significant technological advances and the increasing internationalization of the business. While the UK still remains the global hub for this emerging industry, Portugal, Spain, Canada and the US are all making advances. By Alasdair Cameron.Marine energy, in the form of wave and tidal power, is entering an exciting phase in its development, with more and more technologies entering the ring, and more established systems moving out of the prototype phase and into pre-commercial testing. The first multi-megawatt wave farms are being constructed, while a number of tidal devices are being planned around the world, with the first likely to be installed in August 2007 at Strangford Lough in Northern Ireland.
Large utilities have recognized the potential of the sector and several have recently announced tie-ups with the manufacturers of wave or tidal systems. One of the most interesting developments, however, is the increasing number of countries looking to get in on the act. While the UK still has by far the largest concentration of wave and tidal companies, and some important infrastructure, other nations are working hard to catch-up. Portugal, Canada and several US states have declared their intention to exploit marine energy, while many others are considering the best way to proceed.
The original 300 kW Seaflow device was one of the world’s first tidal power generators. Tidal energy is appealing as it can provide reliable base load electricity mct
To reflect the international nature of the emerging marine industry, the main projects and devices will be discussed by technology (wave or tidal), while the policy regimes and government support in the main countries will be looked at individually, along with some of the smaller prototype technologies. The list is by no means exhaustive, but it gives an idea of the level of activity in some of the key regions.Policy and government support
The United Kingdom is home to the largest concentration of marine power companies in the world and is at the cutting edge of wave and tidal energy development. Thanks to its long coastline and strong winds, the UK has tremendous potential to harvest energy from the ocean, with recent studies putting the amount of electricity which could be realistically obtained from such sources as high as 20% of the country’s total requirement (of which 4% could be safely obtained from tidal energy). Shorter-term estimates suggest that Scotland alone could deploy 1300 MW of marine renewables by 2020.
The British government has recognized the chance for the UK to become the world leader in the emerging marine energy field, and, as such, support for marine renewable technology is fairly high. This support takes several guises. First, the UK government has part-funded various key infrastructure projects such as the European Marine Energy Centre (EMEC) on Orkney (off the north coast of Scotland) and the New and Renewable Energy Centre (NaREC) in the northeast of England. These centres have proved invaluable in providing a test bed for prototype machines, including both wave and tidal devices.
Sections of the Pelamis machine ready at the quayside OPD
In May 2005, the UK government introduced the Wave and Tidal Energy Demonstration Scheme to help marine energy companies bridge the gap between prototype development and commercial deployment. This package provides £50 million (€70 million) in funds to support the emergence of small-scale arrays in the UK. While the demonstration programme was broadly welcomed by the industry, at the time of writing no project has yet been successful in getting funding. According to a spokesperson for the British Wind Energy Association, which actively supports marine technologies, this is likely to change in the next year, as more devices reach maturity. For its part, the British government is considering ways to streamline the application procedure to make it easier for funds to be released, although any changes are unlikely to take effect until late 2007 or 2008.
Early in 2007, wave and tidal energy received another boost when the Scottish Executive (the devolved government for Scotland) awarded an additional £13 million (€19.24 million) in funds to a total of nine companies looking to deploy prototypes and small arrays at EMEC. Among those companies that received support were Ocean Power Delivery (OPD), Scottish Power, ScotRenewables, Open Hydro, Aquamarine Power, Wavegen, Tidal Generation Ltd, CRE Energy Ltd and CleanTechCom. Many of these companies will be discussed in greater detail below.
One of the key initiatives being proposed to promote wave power in the UK is the WaveHub – an undersea ‘socket’ on the seabed off the southwest coast of England. This will allow the installation of four separate devices, of up to 10 MW each, giving an opportunity to test out several competing designs in real ocean conditions.
In early 2006, the project moved a step closer with the announcement of the first three companies chosen to participate in the project. These are Ocean Prospect Ltd, Ocean Power Technology (see above) and Fred Olsen Ltd. Of these, Fred Olsen is the only one not currently developing in the UK, and has developed a multiple-point absorber system for extracting energy from waves which allows many devices to be grouped together on a floating frame for maximum stability.
Finally, in spring 2007, the regional development agency for the south west of England managed to secure the necessary funding for the project to go ahead. Work is now under way to select contractors to construct the WaveHub.
Portugal While the UK may have the greatest number of emerging marine energy companies, Portugal will have the honour of hosting the world’s first multi-megawatt wave farm. The main reason for this has been the government’s supportive policies for marine power and renewable energy in general. Key legislation has included a feed-in tariff for marine energy, set at €0.23/kWh, and also sympathetic planning and grid-connection regulations.
Portuguese companies are less advanced in terms of the development of marine energy devices, and the wave farms being planned to date will all be built using technology developed overseas, notably the Pelamis device.
While marine energy development in Spain is limited because of a lack of sufficient support from the administration, its estimated potential stands at 21,000 MW, and several projects are under way to tap this resource. One of the most widespread is an oscillating water column being developed by Sea Energy which is being tested in at ‘al Guarda’ in Galicia. If successful it will likely be installed in a further 13 harbours around the country. Other projects involving the Pelamis device or OPT’s PowerBuoy are also being planned and will be discussed below. Despite this, more widespread growth is unlikely without the introduction of dedicated feed-in tariffs and a target to support marine renewables, something which the industry is lobbying heavily for.
Canada, like the US, is only just beginning to look seriously at marine renewables, yet early estimates suggest that it could have large resources, including 42 GW from tidal streams and 184 GW of wave energy. Several prototype devices have been installed, such as a 60 kW turbine at Race Rocks in Victoria. This system was designed by Vancouver-based Clean Current Power and was recently visited by Canadian Prime Minister Stephen Harper as part of a drive to highlight renewable energy technologies. A larger 2 MW version of this device is scheduled for installation in 2009. Several other small companies, such as Blue Energy and New Energy, are also springing up in British Columbia, keen to take advantage of an emerging global market. Other projects, including a proposed development by BC Hydro and UK company OPD, are still in the early stages (see below).
In terms of policy support, things are at an early stage, with provinces taking the lead. Among the west coast provinces, a marine energy policy is being developed which will include a process for developing systems of up to 10 MW and a US$25 million fund to promote innovation, while at a national level renewable energy projects are entitled to apply for funding from the $230 million Eco-Energy Technology Initiative.
Although the US has no national policy for encouraging the development of marine renewable energy, several states have taken the initiative in an attempt to maximize their involvement in the future industry. The west-coast state of Oregon is looking to take the lead and had invested in research and development through Oregon State University (OSU). So far, OSU has been involved in compiling resource data and in constructing a number of prototype devices. To date, however, no full-scale or pre-commercial device has yet been tested.
Elsewhere in the US, Ocean Power Technologies Has been conducting tests in Hawaii and New Jersey and recently won a contract to supply and build a 1 MW wave farm for the US naval base on Hawaii.
Republic of Ireland
Like the United Kingdom, Ireland has tremendous potential for wave and tidal exploitation, with the government estimating that up to 94% of the country’s energy demand (24 TWh) could be met from wave energy alone. Tidal energy could safely supply a further 6%. To stimulate the growth of marine renewables, the Irish government has funded several projects through the Marine Institute in Cork and through Sustainable Energy Ireland’s R&D programme. To date, however, the amounts of money invested have been low (only €1.2 million since 1994), so advancement has been slow. Nevertheless, Ireland is home to a number of emerging marine energy companies including, MTL, Clearwater (developer of the Wavebob device) and Open Hydro. The next stage will see the government invest a further €4.9 million for large-scale prototypes, followed by a further €10.5 million up until 2010 for pre-commercial arrays.
Despite this, in the short term at least, leading companies such as Open Hydro are likely to conduct their large-scale testing in the UK, where the marine infrastructure is more advanced.Ocean energy generators
Because it is still at such an early stage of development there is not yet a consensus over which types of generator can produce electricity from the ocean most efficiently and cheaply and be sufficiently robust to survive conditions at sea. Instead, there are a large number of competing models and designs for producing wave and tidal power.
Some of the main wave power companies around the world
In 2000, Scotland-based Wavegen installed the world’s first commercial wave power device on the Scottish island of Islay. This 500 kW device – the Limpet – uses generators built into the shore. As waves crash against the shoreline, compressed air is forced through turbines, generating electricity. Wavegen (acquired in May 2005 by Voith Siemens Hydro) has recently teamed up with a Faroese utility company to try and develop a larger wave farm built into the cliffs of the Faroe Islands. Recently, Wavegen was also awarded additional funding to test an advanced type of turbine at its existing Islay facility.
Perhaps the most widely known of the offshore wave power devices is Pelamis, a 750 kW, 100-metre long, snake-like machine developed by Edinburgh-based OPD in the UK. Following a period of testing at EMEC, plans are now under way to build several multi-megawatt wave farms using this device. The first of these is likely to be a 2.25 MW development in Portuguese waters with energy company Enersis. Under this deal, OPD will deliver three Pelamis machines, with options on another 30 if things go well. Manufacturing of the machines is under way and the first device was shipped to Portugal in March 2006.
Back in the UK, Scottish Power and AMEC are looking into building a small pre-commercial Pelamis array at EMEC, with work possibly being completed as early as 2008. Meanwhile Ocean Prospect Ltd, a division of Wind Prospect Ltd, has announced its intention to build a 7 MW wave farm in Cornwall using 10 Pelamis P-750 machines. This development is being planned as part of the WaveHub project, an initiative of the southwest regional development agency, an arm of local government (see below).
Looking further ahead, OPD has also expressed interest in building a 30 MW wave farm in South Africa and is looking into a development near Vancouver in conjunction with BC Hydro.
Not to be confused with OPD, Ocean Power Technologies (OPT) is based in New Jersey and listed on the London Alternative Investment Market (AIM). This company’s principal product is the PowerBuoy, a device which uses the rising and falling of water caused by waves to generate electricity. OPT has currently installed 40 kW devices at a US naval base in Hawaii and off the coast of New Jersey. In addition it has recently won contracts to develop 1 MW of additional power in Hawaii and is working on a product for Lockheed Martin that uses wave energy to power radio signals continuously.
PowerBuoy being prepared for deployment in New Jersey OPT
In mainland Europe, OPT recently entered into an agreement with Spanish utility Iberdrola to install 1.4 MW off the coast of Spain. In the UK, the company is planning a couple of different projects. The first of these will see it install a PowerBuoy device at EMEC, while in the longer term it intends to develop a 5 MW wave farm, consisting of 150 kW buoys arranged in a grid. This may later on also incorporate larger 250 kW machines). This larger development is planned as part of the proposed Wavehub project.
Another company planning to expand is Danish firm Wavedragon. Its main product uses a large barrier system to channel waves to a central receiver which compresses air and then generates electricity. Recently, Wavedragon announced a deal with KP Renewables to develop a 7 MW project off Milford Haven in Wales, with the possibility of increasing this to 77 MW in the future. In March 2006, this project moved a step closer to completion when the European Welsh Development Agency announced a £5 million support package for the project. If all goes well, the first 7 MW device could well be operational by 2008-2009.
In the Republic of Ireland, testing is under way on Wavebob, a device designed to be a lightweight and economical ‘point’ energy converter. The developers hope it will be cheaper than other floating buoy devices coming onto the market. The full-scale buoy will have an output of around 1 MW. Currently the Wavebob is undergoing 1:20 scale testing in Spiddal, County Galway.
Archimedes Wave Swing (AWS)
In 2007, AWS, developer of the Archimedes Wave Swing energy converter, was awarded £2.1 million (€3.1 million) to install a 500 kW prototype device, again at EMEC.
Like the PowerBuoy mentioned above, the Aquabuoy is a point energy converter, generating electricity from the rise and fall of the buoy. It was developed by Finavera, and plans are currently under way for it to be installed at three locations in the US states of California, Oregon and Washington.
Other prototype devices
In addition to the companies mentioned here which are approaching commercialization, there is a host of other devices in the prototype phase. While there is little doubt that there are many ways to generate electricity from waves, it remains to be seen which of these devices will be able to produce it in the most reliable, and the most affordable, way. Some of the companies likely to move from the prototype phase to pre-commercial testing in the next few years include OWL, Ocean WavePower, Aquamarine Power, Scot Renewables and others.
Tidal current energy
As with wave energy, there are a variety of competing devices which generate electricity from tidal currents. Again, these can broadly be divided into those that operate in shallow shoreline water and those that work in deep, fast-moving tidal channels. Most of the devices approaching commercialization are in this second category and are being testing in the UK.
In Spring 2007, it was announced that E.ON UK and Lunar Energy were teaming up to develop an 8 MW tidal stream project off the west coast of the UK. The new project will use horizontal-axis systems developed by Rotech Tidal Turbines. These can be mounted on the sea bed and are invisible from the surface of the water.
The next step in the development of this technology will see a 1 MW project installed at the European Marine Energy Centre in Orkney. This is due to take place in 2008 and will provide ongoing testing and information for the larger project. An initial environmental impact assessment, conducted by Robert Gordon University, has already concluded that the turbines pose minimal threat to marine life, because of the slow movement of the blades.
According to E.ON, a number of sites are currently being reviewed for the final siting of the 8 MW tidal farm and, if all goes well, they expect the project to be completed by 2010.
Marine Current Turbines’ new SeaGen device, a two-rotor machine MCT
Just a few weeks later, rival utility Scottish Power declared that it was teaming up with Hammerfast of Norway to install a 1 MW tidal turbine in Scotland, with a view to eventually developing tidal farms of 100 MW or more.
Finally, one of the UK’s largest utilities, Scottish and Southern Energy, recently signalled its entrance into the tidal field, announcing that it will use the new facilities to trial its Neptune device, an underwater generator designed to convert energy from tidal streams into electricity for the grid. The prototype is due to be installed by the end of 2007, with the Scottish Executive providing £650,000 (€963,000) to help fund the test programme. The machine will consist of a central tower, which will be anchored to the seabed and have two arms, each supporting a three-bladed rotor.
Staying with underwater rotors, Open Hydro is a Florida and Dublin-based company which is conducting testing in the UK. Its next step will be to install a larger, 250 kW device at EMEC. For the longer term, Open Hydro has signed an agreement with Alderney Renewable Energy holdings to build undersea turbines to harness the island’s extensive tidal resources (Alderney is one of the UK’s Channel Islands, a group of small islands between Britain and France).
Marine Current Turbines
One of the most high-profile of the tidal companies is Marine Current Turbines (MCT). Its 300 kW single rotor SeaFlow device was first installed off Devon in 2003, and, following a period of testing, the company is looking to develop several larger megawatt-scale projects. The first of these will be a 1 MW project in Strangford Lough in Northern Ireland, which is being developed with funding from French utility EDF and the UK government. This will use MCT’s new SeaGen device, a two-rotor machine capable of generating more than three times as much power as the SeaFlow. The frames for the array have already been constructed, and the new tidal generator could be fully operational by the end of 2007.
MCT is also looking into developing a second, 10 MW tidal farm in the Bristol Channel called the Lynmouth SeaGen Arrays, consisting of 12 SeaGen devices. Although this project would be largely self-funded through the sale of electricity, it is still very much a research project, with a great deal of work planned to monitor the environmental impacts of the development.
While MCT remains the leader in the deep tidal market, there are a number of competitors including the Tidel machine developed by Newcastle-based SMD hydrovision. This is a twin turbine device which floats in the tidal current, turning to face the flow as the tide turns. The advantage of this system is that the device requires no support structure and is simply moored to the seabed making it easy to install and maintain. So far SMD has conducted scale-trials at the New and Renewable Research Centre in Newcastle (NaRec) and is also looking into building a 1 MW prototype in the next couple of years.
Another new entrant to this field is the Pulse Stream 100, being developed by BMT and IT Power. The Pulse Stream converter uses a pair of hydrofoils which oscillate across the tidal flow – enabling the extraction of tidal energy from shallow water (10-30 metres), an area not yet exploitable to conventional tidal generators. The Pulse Stream device is the first to target this resource and it will therefore increase the total exploitable tidal current power available in UK waters. The first goal for the group behind this new device is to build and install a 100 kW prototype. To help achieve this they have been awarded £878,000 (€1,229,000) in development aid from the UK Department of Trade and Industry.
While the UK has a head start in the initial development of marine renewable energy, it remains to be seen if it will be able to maintain its position as this technology moves towards commercialization. Other countries such as Portugal, France, Spain and South Africa are working hard to catch up in this area and have established feed-in tariffs for marine renewable energy, as well as a series of other support measures. In response, the Scottish Executive is looking at introducing additional financial support for marine renewables in Scotland, and, if successful, this could help keep the United Kingdom at the forefront of this new industry.
Alasdair Cameron is former Assistant Editor of Renewable Energy World
e-mail: [email protected]
The tidal currents of oceans and rivers have been tapped for centuries to produce mechanical power. Yet it is only 40 years since the first ‘sizeable’ plant designed to capture this ‘free’ energy and turn it into electrical power went into service, as Roger Charlier explains.
Comparatively small plants have been providing power in Russia, Canada and China ever since. Taking another example, a rather larger plant in Rance, France, has proved to be reliable, providing sustainable, highly useful power. Such plant can also provide various other regional and national advantages.
With oil prices having reached $60/barrel and beyond, the cost of an ocean-generated kilowatt has become attractive, and interest in ocean energies has been rekindled. There is even consideration being given to reviving the tide mill concept, which has been around for at least 150–200 years. There were once many such tide mills, which usually provided mechanical power to grind corn, but only one still exists in the UK. This is at Woodbridge, Suffolk, and it is now merely a tourist attraction.
Half a century ago, some such tide mills were still able to make a living, albeit an increasingly precarious one. Some isolated mills were still in operation in the British Isles, on the Iberic Peninsula and in Brittany, with several being situated in the Rance River estuary. In the 1960s, these French plants were dismantled to make room for a much larger electrical power plant.
The Rance river plant
Designed in 1959, Brittany’s Rance River station comprises a retaining basin, a barrage or dam and sluices, plus the 24 bulb type turbines (driving generators) which are fed by water from the dam. When first built, a large water head was required, but technological advances now allow the use of low-head turbines. Both ebb and flood currents can be used to generate electricity, an achievement then heralded as remarkable, though the extra cost of this innovation was possibly unjustifiable at the time.
The 9 metre – 14 metre tides on the Rance estuary can produce close to 550 MW capacity, or 550,000 kWh/day. The station, when put into operation, helped open up a then impoverished region. Being connected to France’s national electricity grid, this plant also provided electrical power to the rest of the country. An additional benefit for the local economy and populace is that the four-lane road built on top of the dam has shortened travel between the two banks of the Rance by several hours. The construction of this plant cost $100 million (roughly €81.5 million).
This pioneering French tidal power station is close to celebrating its half-century anniversary. It has performed well, having lifted an entire region out of a then enduring slumber and provided much-needed extra power to relatively remote areas, all with only minor environmental impact. Many lessons have been learned through this plant’s construction and operation. Stations built since 1966 have been experimental or pilot plants but, unfortunately, there have been no commercial projects of a comparable size. Major deterrents have been the capital-intensive nature of these developments and the resulting high cost of delivered electrical power. However, numerous recent cost-reducing approaches have lowered the price of power, which is further reduced when taking into consideration plant life cycle.
Tidal power stations, such as the Rance, can provide valuable power, yet other existing stations of a similar kind are very modest. If proponents of tidal stations have shied away from gigantic schemes – such as the Chausey Islands Project – it has not stopped engineers dreaming of large-scale developments, such as those proposed for the English Channel, and a major scheme recently put on track in Korea. There are also very new plans for a vast tidal power scheme planned for the Severn Estuary in the UK.
Increasingly, attention is being drawn to harnessing tidal currents that need no barrage. Funding has been obtained for this approach. The intense activity in tidal and tide energy sectors is being supported by government agencies and the EU.
Dr Roger Charlier is Professor at the Free University of Brussels and Florida Atlantic University
e-mail: [email protected]