The UK may be the world leader in the nascent industry of wave and tidal energy, but competition around the world to develop the technology at scale is heating up.
Energy from wave and tidal streams has the potential to meet 20% of the country’s current electricity demand in the long run (30 to 50GW of installed capacity) according to UK government figures. If things going well this could mean 200 to 300 MW of capacity by the end of the decade - see planned sites in the map below.
A red dot = a test site (with several deployed prototypes), yellow dot = a marine energy site under 50MW, green dot = a site between 50-99MW, blue dot = 100MW-199MW and purple dot = over 200MW. Click on the dots for more information.
Energy from tidal range technologies, such as lagoon enclosures, could supply another 12% of our power, representing 25 to 30GW.
Yet Dr Stephanie Merry, marine advisor for the UK clean energy trade organisation Renewable Energy Association told Energydesk other countries are catching up fast - something the UK government also noticed several years ago.
The European Commission recently warned that competition from other countries around the world could claw back Europe's lead on technology development and deployment.
Global wave and tidal deployment could reach 337GW by 2050, according to the the International Energy Agency Ocean Energy Systems.
The US has significant tidal energy potential along its eastern seaboard; Canada is throwing millions of Canadian dollars into closing the research gap with the UK; Australia, is testing new wave power technologies; and China, which has invested nearly £100 million in ocean energy projects since 2010 and is working in joint venture partnerships to expand its testing rapidly.
Closer to home, France is investing €200m in developing tidal array technologies and The Republic of Ireland has Europe’s first wave energy farm going ahead in its waters, due to be operational by 2018.
State of the marine industry in the UK
The marine power industry in the UK - which encompasses energy generated by tidal stream, tidal range, and waves - is in its early stages. There are 11 prototype or test wave or tidal devices in the water generating around 8MW of energy according to up-to-date figures from Renewable UK. It's a tiny fraction of the 3.8GW of offshore wind capacity installed in the UK.
There are several competing designs (click on the illustration to the right to see an enlarged version). Some resemble underwater wind turbines turned by tidal flow, long snake-like tubes that harness the power of the waves, and spinning rotors in sea walls built in lagoons to take advantage of the ebb and flow of the tides.
Tidal energy technology is more advanced than wave power because of support for underwater ‘axial flow’ turbines.
Wave, though it has double the potential capacity energy of tidal, has yet to establish which technology to pursue and is more challenging because it needs to be built to survive not only powerful waves, but also so-called ‘100 year wave’ events.
But, for the sector as a whole, there are signs of a potential growth spurt with plans for around 40 more marine power sites in the next six years, according to data from The Crown Estate and news reports.
The surest bet is a tidal array in the strong tidal stream of Pentland Firth, which separates the Orkney Islands from the north of Scotland.
It is the world’s best site for tidal power and could provide half of of Scotland’s electricity - some 1.9GW - according to a Oxford University study. Energy company MeyGen have had approval to build 86MW of underwater turbines in the firth.
A second stage of the project is would take the array up to around 400 turbines with a capacity of 398MW, which would make it the largest tidal array in Europe.
There is also recently-announced deal for a 300MW tidal array off Alderney, in the English Channel. Work has been agreed on the 150 turbine array and grid interconnection to France.
And there are plans for a 240MW tidal lagoon off the Welsh coast (see above image). Developers Tidal Lagoon Power say the Swansea tidal lagoon, which is in the process of attempting to get planning permission, will be more wildlife friendly than barrage dams, which have failed to gain approval in the past.
The firm plans to scale up to at least five lagoons around the Severn estuary, which could generate around 10GW. Once there are three such projects the cost comes down from around £220/MW to £111/MW - below offshore wind according to a report from environmental consultants Poyry.
Because the project could last 100 years - and the subsidy is only for 35 - the rest of the power will be far cheaper.
Scotland dominates the marine energy landscape
Over three quarters of the UK’s wave and tidal sites currently in development will be in Scotland - see below map for test sites and planned projects.
It is already home to European Marine Energy Centre (EMEC) off Orkney, the leading marine energy testing facility, with with more devices deployed and connected to the grid than elsewhere in the world. In the pipeline are both Pentland Firth’s tidal array and the world’s largest approved wave energy array (40MW) off Lewis, in the Outer Hebrides.
This hotspot - areas around Orkney and North Scotland are the first to be licensed by The Crown Estate for commercial-scale development - aims to exploit Scotland’s massive marine energy potential.
Scotland has a quarter of Europe’s tidal stream potential - which could generate around 10GW - and 10% of its wave resource - which has a potential of around 15GW.
The other marine energy hub in the UK is located at Strangford Lough, Northern Ireland, where a 1.2MW SeaGen tidal converter has been in operation since 2008 and where two 3MW Minesto ‘Deep Green’ underwater kites arrays are also being constructed.
The Marine Management organisation has also recently started publishing plans earmarking sites for marine power development - starting with two plans covering the East Coast of England - which could boost the roll-out of marine power in the UK.
Hurdles to full-scale deployment
The fledgling industry is “facing tough times”, however, according to Lindsay Leask, senior policy manager at Scottish Renewables writing in The Scotsman.
Like offshore wind projects, some of the plans for wave and tidal technology may be challenged by wildlife protection - their impact on marine wildlife is not yet well understood - which may have an impact on whether or not they get consent.
For instance, the Swansea Bay tidal lagoon plan is seen as acceptable on wildlife grounds, but the next in a handful of planned lagoons around the Severn Estuary - at Bridgewater Bay - is likely to cause more controversy.
The main issue is financing. Government support for the industry and private investment flow that follows are both concerns for an sector with expensive technologies - until they are scaled up and costs fall.
For instance significant government support is needed to realise the potential of the Pentland Firth, says an analysis from Oxford University.
Recently the Scottish government recently announced a further £6m for developing new marine energy prototypes, on top of £15m already delivered. But government support also comes in the form of subsidies for renewables which are current being reformed.
“This policy shift holds the potential to halt or catalyse the development of the [marine energy] industry,” according to lobby group Renewable UK.
On a European level, private investment ocean energy projects has totalled $825m (£490m) over past seven years, with Siemens, E.ON and GlaxoSmithKline among those investing in the industry.
To commercially deploy the marine technology across Europe, however, will mean a further investment of €500m by 2020 (£410m), with public private partnerships and government support, as well as grid roll-outs, Remi Gruet policy and operations director for trade organisation Ocean Energy Europe told EurActiv.
No wonder, then, that Scottish renewables is calling for stronger co-operation with the EU, which it says could open up new finance streams and help smooth the way forwards for the new technologies. In January, the European Commission launched its new action plan to help accelerate the commercialisation of the sector.
If Scotland elects to become independent following the September referendum. Then the UK will lose the majority of its deployed and planned wave and tidal sites, and Scotland could possibly lose British government support for its renewables.
** If you have any feedback on the map please let us know via Twitter @EnergyDesk, in the comments, or via email.