Tidal stream power should take priority over lagoons

Britain’s efforts to exploit its abundant marine energy resources should focus on the commercialisation of tidal stream technology, the Energy Technologies Institute (ETI) has urged.

Tidal stream has the potential to “compete with other low carbon energy sources over the coming decades” while other marine technologies are “less developed”, the research organisation has said.

Alternative marine power options, including tidal lagoons, therefore “carry with them higher costs” and will require “large levels of investment” to demonstrate and deploy at scale. ETI believes there needs to be a “radical rethink” of the way wave energy is being developed if it is to become cost competitive.

The comments come after former energy minister Charles Hendry last week released his final report into the potential role for tidal lagoon power in the UK. The feasibility study concluded that tidal lagoon power could be cheaper than “all low-carbon alternatives” over the full lifetimes of projects. It said a large scale project in Cardiff could be built with a CfD strike prices averaging around £70/MWh (2012 prices) over the course of a 90-year contract. 

ETI identified the success of the MeyGen tidal stream project being developed by Atlantis Resources as “pivotal” to the future of marine power in the UK, and globally. The tidal array is located in the Pentland Firth – the stretch of water between mainland Scotland and Orkney – and up to 269 turbines with a total capacity of 398MW are planned for the site. 

Setting out its views on the UK’s marine power priorities, ETI insisted that tidal stream power is “reliable and predictable” and has a “low visual impact”.

However, it acknowledged that it is not a “blanket supply option” as the challenge of distributing the energy generated means it is only suitable for certain sites: “Many of the most powerful tidal sites are at remote locations the source is often a long way from the end consumer.” The technology will “work best serving inhabited coastal locations”.

A “crucial factor” in the future of tidal stream power will be the agreement of a Contract for Difference. “It is hard to see swift progress being made without one”, ETI said.

ETI offshore renewables strategy manager, Stuart Bradley urged the government to clarify its support for marine technology options. “Policy makers need to review the evidence base and decide the exact contribution of marine energy to a future low carbon energy industry”. He said this is essential “so the industry can move ahead, improve cost performance and contribute positively.”

He added: “The UK has some of the world’s best tidal and wave resources and we do lead the world in tidal and wave device development. But it remains an industry in relative infancy.”