SCOTLAND'S aim to supply half its energy from renewable sources by 2020 is both admirable and ambitious. But is it achievable? This Herculean target will be satisfied only if Scotland now gives a more equal slice of renewable support to more reliable
energy sources, especially as new nuclear power stations have been ruled out in the short term.
Wind energy has received the lion's share of the renewables' pie. It has won huge political and financial support largely because it was the first renewable to be fully developed, but only last week it was announced a huge 11GW of wind development is stuck in the planning system, the equivalent of four Longannet-sized power stations.
In light of this, more commentators think government support needs to be redirected to renewables with greater capacity to deliver more predictable and reliable long-term, carbon-free electricity, which do not antagonise local feeling and encourage bitter planning opposition.
Only one renewable source ticks all of these boxes: tidal stream, and Scotland can lead the world. In fact, 25 per cent of Europe's tidal resources are found in Scotland, and one-fifth of UK electricity needs could be fulfilled by marine energy production in Scottish waters.
The Pentland Firth is the jewel in the tidal crown; every second, 2.5 million cubic metres of water (enough to fill 1,000 Olympic swimming pools) pass through at a rate of up to 12 knots. The flow has been described as the equivalent of an underwater hurricane. This could make the channel between Orkney and the mainland the world's most productive tidal project beside others off the Western Isles and in the Irish Channel.
Wave energy is harnessed near the water's surface and can be unreliable, like wind, but the stronger and predictable tidal currents deep below the surface are where tidal stream turbines can make a real difference. These turbines, secured up to 60 metres below the surface, on the seabed, harness the fiercest ebb and flow of the tides and come closest to a renewable baseload supplier. Importantly, at this depth, the systems offer no hazard to shipping or ecology.
The environmental impact of tidal stream is non-existent, as the technology is effectively invisible, eliminating costly and time-consuming planning inquiries that are holding back so many unpopular wind applications. But the initial phase is very expensive, involving extensive underwater survey work to establish a site's potential viability. This can cost up to £1.5 million.
The Glasgow-registered Lunar Energy is the leading British pioneer and has plans to install a huge 300 tidal stream turbine field. At a cost of £500 million, this will be the world's largest tidal stream energy plant at 300MW and provide enough energy to power 200,000 homes by 2015. But, sadly for the UK, this plant is being built by Lunar in South Korea, in conjunction with Korean Midland Power.
Where the Koreans recognised early on that Lunar's technology is worth supporting and developing, Britain still appears hesitant. All is not negative. however. Last year, Lunar Energy and E.ON announced a joint project to develop an 8MW commercial tidal power field off Pembrokeshire, but this is tiny in comparison with Korea. The future jobs potential for Scotland is huge with Lunar's unique Rotech Tidal Turbine designed and built in Aberdeen.
Of even more importance is the present inability of tidal stream companies to connect their technology into the National Grid. A new offshore grid network is vital and should go hand-in-glove with a general modernisation of the national network. Energy harnessed by underwater tidal fields has to have a grid connection.
With some of the world's fiercest tides on the planet, Scotland stands on the edge of an energy revolution. But words must now be replaced with action. Alex Salmond must now move to harness this free resource better and provide the framework to allow tidal stream, which ticks all the boxes, to flourish.
The full article contains 683 words and appears in The Scotsman newspaper.
