Following its recent installation, first power has been achieved from a 1.5-MW turbine in the MeyGen tidal power project in Scotland — an opening volley in game-changing development pitched to become the world’s largest tidal power array.
Installation of four 1.5 MW turbines (MeyGen Phase 1a) is taking place in the Inner Sound of the Pentland Firth, in the far north of Scotland and comes after successful placement of foundations in October.
Lead developer on MeyGen and global leader in the tidal power sector is Atlantis Resources, whose CEO, Tim Cornelius, stated: “This is the moment we have been working towards since we first identified the MeyGen site back in 2007, and I am immensely proud of and grateful for the remarkable team of people who have contributed to this milestone.”
He continued: “The success of this first phase is a foundation for the tidal industry to build upon to ensure we develop a new energy sector which can deliver clean, predictable and affordable power from the UK’s own abundant resources. When it comes to energy, we think consumers should be asking for the moon, and we know how to harness it.”
The 6-MW capacity of Phase 1a pales in comparison to the full scope for the MeyGen project though.
Speaking to Renewable Energy World, Cornelius said: “We’re underway with a very successful construction campaign offshore with installation of the first four 1.5-MW turbines within Phase 1a. Installation is due to be completed before the end of the year.”
He said that this part of the installation is only the precursor to rolling out the rest of the array to about 261 turbines in total.
“With capacity of 398 MW, it will be the largest tidal array in the world. We expect to announce first power towards the end of this year,” he said.
Of the significance of MeyGen Phase 1a for marine energy industry, Lindsay Roberts, senior policy manager at Scottish Renewables, told Renewable Energy World: “Scotland has been at the forefront of tidal energy innovation for many years, from design to testing, and now — with the MeyGen project — deployment.
Anatomy of Tidal Turbines
MeyGen Phase 1a is deploying one Atlantis-built and three Andritz Hydro Hammerfest (AHH) turbines.
Operating on principals akin to wind turbines, the tidal turbines include a pitching system for blades, and a yaw mechanism to turn the turbine approximately 180 degrees when the tide changes direction. The nacelles contain a generator and gearbox. The units weigh approximately 200 tons.
Both turbine types feature three-bladed horizontal axis designs with 18m diameter rotors. Fully submerged, the turbines have a minimum of eight meters of clearance to the sea surface at lowest astronomical tide.
Of the moderate turbine capacity, Atlantis stated: “This capacity was selected after extensive resource modelling and financial optimization in order to provide the lowest possible cost of energy for the project.”
Cornelius added, “We took the approach typically seen in hydro projects, where it’s not unusual to see multiple suppliers of turbines supplying into the same projects. We think it’s good for risk and for funding.”
According to Cornelis, the company will be issuing a tender for each phase.
“We have a tender in the market for Phase 1b, for example,” he said. “We would anticipate at least two or three more suppliers to come onto the project — selected on the basis of not just technical merit, but also on terms of finance they provide.”
Turbines are secured to the seabed using tripod gravity-base support structures, the design of which accommodates undulations of the seabed.
An Industry in the Making
Beyond question, tidal power stands to grow into a major source of clean, reliable power generation.
It is estimated that in the UK alone there is a technical resource of 29 TWh of energy per year available in tidal currents, of which 11 TWh is found in the tidal flows of the Pentland Firth.
Little wonder, therefore, that the UK has sought to foster development of the technology.
Roberts said: “[Scotland’s] waters have the lion’s share of the UK’s tidal stream resources, so it makes perfect sense that we utilize that advantage by installing devices like those developed by Atlantis.”
The UK is at the forefront of tidal power – in part, Cornelius said, because of how well the UK supports the industry’s development.
The MeyGen project has won support of various bodies, including the Scottish government via Scottish Enterprise’s Renewable Energy Investment Fund, the British government, and The Crown Estate.
Looking forward, Cornelius holds high ambitions for tidal power both within and beyond the UK.
“The MeyGen project is a commercial one,” he said. “Our view is it that once we’ve proven Phase 1a, this is where wind and solar power was 15 years ago. We’ll then see 10 years or more of a lot of expansion for tidal power because some of the best sites in the world are yet to be developed.”
Recent news from the UK government over plans for new renewable capacity and support feeds into Atlantis’ hopes.
“We’re delighted that tidal power has been included in the latest UK contracts for difference, and we can participate in those auctions next year,” Cornelius said.
If all goes to plan, the next few years will be busy ones for MeyGen, Atlantis and the industry at large.
“We would like to achieve financial close on Phase 1b early 2017, begin construction towards the end of the year, and then by the end of the year achieve financial investment decision on Phase 1c and commit that the year after,” Cornelius said.
It would be understandable to presume tidal power is prohibitively expensive — it is, after all, far from widely deployed. But Cornelius has a different take on the matter.
“We intend to demonstrate the competitive prices tidal can achieve as early as April next year in the UK Contracts for Difference auctions where we’ll compete against all other technologies,” he said. “The reality is that to be commercial, we need to be cost competitive. And we will be.”
MeyGen is not alone in its pursuit of tidal power. Though operating at far smaller scale, Edinburgh-based Nova Innovation recently grid-connected its second turbine at Bluemull Sound off the Scottish coast of Shetland.
Images credit: Atlantis