Tipping point for tidal?

Atkins | 21 Mar 2014 | Comments

Some ideas are so simple, it can take ages for people to realise just how good they really are. Mark Shorrock, chief executive of Tidal Lagoon Power, offers his take on an old innovation.

The tidal lagoon project in Swansea Bay is based on a straightforward premise: why not try to capture the potential energy of one of the largest tidal ranges in the world?

By building a breakwater wall with built-in hydro turbines, enclosing 11.5km² of tidal area off the Port of Swansea in South Wales, the project could generate 240MW of tidal power, averaging 14 hours of generation every day.

As the Tidal Lagoon Swansea Bay project website points out, it could mean “clean, renewable, reliable and predictable power for over 120,000 homes (enough to power 70% of Swansea Bay’s annual domestic electricity use) for 120 years”. And it would do so while creating a new site for everything from international sailing events to ecological innovations such as mariculture farms.

It would ultimately play a big part in a more sustainable energy mix, create jobs, attract tourism and contribute power to the national grid in around half the time it would take to get a nuclear power plant up and running. It has the potential to do so at a comparable cost to wind or oil and gas.

And it’s an idea that’s already been tried and tested, albeit in a different form: the Rance Tidal Power Station on the estuary of the Rance River in Brittany, France opened in 1966. It was the first tidal power facility and has been in operation ever since.

Given all of the above, why has it taken so long for such a simple idea with such seemingly unlimited potential to be implemented in the UK?

What’s taking so long?

“The main reason it hasn’t happened yet is because, for decades, essential electricity generation in the UK focused on big centralised power stations and a centralised network,” says Mark Shorrock, chief executive of Tidal Lagoon Power, the company shepherding the project through to completion. The company heads up a consortium of engineering expertise that includes Atkins, Van Oord, TenCate, Costain and KGAL.

“Smaller projects such as these were overshadowed by larger ones like the Severn Barrage,” he adds.

Privatisation of energy in the UK in the 1990s only complicated matters. A national body like the Central Electricity Generating Board, which was responsible for electricity generation in England and Wales for almost 40 years, might have turned to tidal power, but private companies tended to focus on big profit centres.

“We ended up with highly regulated, sometimes foreign, sometimes UK ownership, sweating a highly regulated market and good assets, with no real compulsion to do something new,” says Shorrock. “And when there was a compulsion to do something new, under the UK Government’s Renewables Obligation set out in 2002, onshore and offshore wind took precedence. Tidal power was pushed further down the pecking order.”

Today, the situation has changed dramatically. Growing energy demands and the very real prospect of future brownouts mean that centralised power generation is giving way to the idea of a wider variety of energy generation sources.

“Oil and gas prices are up, there’s a globally constrained gas market and the UK is a net importer now: of course we’re going to start developing projects like these because this is home-grown power,” says Shorrock. “It’s popular (86% of people surveyed in Swansea are in favour of the project), it does no harm to the environment and it’s quick. And once something like this starts, it becomes obvious that it can and should happen.”

Long term vision

It helps that, unlike most other power generation alternatives, tidal lagoon power offers genuine longevity. The consortium of companies working behind the scenes is ensuring the designs live up to their promised 120-year lifespan.

For example, Shorrock points out that Atkins has been on the front-end of the engineering and design work on the project. This includes everything from seabed investigation to determine what designs would be suitable and what subsidence could be expected, to an assessment of what designs would work in areas that are subject to earthquakes (such as the Severn Estuary).

“The key was to plan for now and tomorrow,” says Shorrock. “For example, our flume tests threw 100, 200 and 500-year storms at the breakwater models so that we could be sure they would be completely stable even if hit by bigger storms than the ones we’ve seen in recent years.”

Time is of the essence

The fact that, in 2009, the UK committed to deliver 15% of its energy demand from renewable sources works to tidal power’s advantage: renewable sources contributed 11.3% of the electricity generated in the UK in 2012 and there is a need for new options to bridge the gap. There’s an urgency to the situation now that wasn’t there just a decade ago.

And unlike nuclear, which can take up to seven years just for the construction phase alone, a tidal lagoon power generation project can be up and running in half that time.

“It’s so simple,” says Shorrock. “You build a sand-core breakwater across a dam in the sea, with turbine housing inside, using the simplest form of concrete poured in situ or precast on the dockside and brought in. All of which means, from consent to delivery on a lagoon of this size, you’re looking at maybe three-and-a-quarter years. On bigger lagoons, it’s still only four years from start on site to delivery of electricity.”

Tidal Lagoon Power has drawn up plans for five such projects around the UK for delivery by 2023. Once all five are up and running, they will provide 18% of the UK’s domestic electricity.

“The work that we’re already starting on the four new power stations planned for after Swansea could translate into a planning application two years from now, with work starting onsite in three years and power generation and delivery in seven years,” says Shorrock.

Over the finish line

As ever with large infrastructure projects, there are always obstacles to be overcome. At the moment, the biggest challenge is getting the UK Government on board, specifically when it comes to funding.

The Swansea Bay project is slightly more expensive, in subsidy levels, than offshore wind, Shorrock points out. The second proposed lagoon, however, is much cheaper than offshore wind and the third lagoon is cost competitive with a gas site power station in terms of levelised cost of energy.

“This prompts the question: why don’t you abandon Swansea and just build the cost-comparative ones?” says Shorrock. “But Swansea represents three years of work and £10m worth of hard-won investment from individual investors. You’ve got to get that first one built and then the others will follow suit.”

The project has been given an “infrastructure project” denomination, which means it’s on a fast-track process for planning permission. You can never predict what might happen with such things, but Shorrock remains optimistic.

“The planning inspectorate has accepted us for examination, based on our 5,000 page submission, and we’re in the midst of a 28-day representation period. The key thing is to get enough people to drop a note to the planning inspectorate in support of the idea. Then we go into due process for eight months while the inspector writes up a report and it goes to the Secretary of State for Energy and Climate Change for a decision.”

In the meantime, Shorrock and the others in the consortium are working on detailed designs so they’re ready by financial close around September 2014.

“It’s a six-month process to drive out the detailed design on the project, so the budget is accurate. In parallel, we’ve got to get the politicians over the line,” he says. “I think we’re nearly there. Our close circle of partners – Costain, Atkins, Van Ord, General Electric, Alstom – see that this is real and can understand the numbers. The Department of Energy and Climate Change is starting to get it, but they’re tightly resourced and operating under a limited budget. But they can’t really ignore the potential.

“Tidal lagoon power is home grown, it’s 65% UK content and can produce power at two-thirds of the price of offshore wind. Wouldn’t you like to get behind that as an industry?”

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