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Marine energy: fighting the headwind

Image credit: MeyGen

Tidal and wave energy technology could flow across the globe from Northern Scotland. All it needs is a bit of encouragement.

In the London-centric UK, the conventional wisdom is that all good things, including technology, start south and migrate northwards. Perhaps this is embedded in our psyche right back from when the Romans, desperate to impose their version of civilisation on the known world, reached the northern extreme of their empire and found barbaric Scots and Picts, built a wall and gracefully retired.

In more recent times the likes of Watt, Fleming, Bell, Braid and Maxwell have obviously redressed this, but it could be that such intellectual sophistication went back to prehistoric times. In fact the Neolithic settlements at Skara Brae on Orkney predate Stonehenge by a good 500 years and ongoing archaeological work at neighbouring sites, notably around the Ness of Brodgar, is leading some to suggest that Stone Age civilisation and technology came from the north and moved south rather than vice versa.

Now Orkney is poised to play a leading role, not just for Scotland or the UK, but the whole world, in a new wave of marine energy technology. The Orkney Islands are in a sweet spot where waves are large and frequent, and tidal flows are strong. Harnessing this abundance of natural energy has been worked on for many years but is still in its early stages, the more accessible avenues of wind and solar having dominated the renewables arena.

As fossil and nuclear fuel devotees are always eager to point out, the sun doesn’t always shine and the wind doesn’t always blow. On the other hand, what the tides will be doing at any instant in time can be reliably calculated for millennia in advance, while wave energy is estimated to have three times as much potential as tidal in certain western-facing coastal regions.

The technology for harnessing these natural phenomena is only being developed and, more importantly, being put into practice, at a handful of sites around the world. One of these is Orkney, which has been used as a testbed for marine energy technology for the past two decades. That technology now works. In fact it contributes to the archipelago’s generation of 115 per cent of its electricity requirements from renewable resources, exporting the excess over barely adequate grid cables across the Pentland Firth to the Scottish mainland.

The Islands have a progressive attitude to renewable energy, made possible in part by having a population of only 20,000, but also from the tight focus such a small community can bring – there is no point in constructing a wind turbine to power a village unless everyone can see the benefits and is behind the project. This attitude has resulted in Orkney having a disproportionately high number of small-scale wind turbines (780 rated under 50kW).

Ian Johnstone, a board member of the Orkney Renewable Energy Forum (OREF), comments: “We can call ourselves a ‘living laboratory’. If people want to try something, this is the place to try that piece of work, because we are basically trialling what will be rolled out around the rest of the country.  We are an island, the UK is an island.  Over time, as renewables penetrate the system, some of the issues that we’ve had on a small scale will be the same as the UK will face as they get rid of [fossil fuel] power stations and go down a renewable route.”  

I think there are some big issues that we’re dealing with at UK energy policy level that are acting as head winds at the moment, and they’re quite hard to actually have a logical, reasoned argument against.

Andrew Scott, Scotrenewables

Being located off a remote tip of the UK does have drawbacks. The energy infrastructure is not as robust as in more populous areas and the two 33kV grid links to the mainland are run at capacity. That the islands run at a renewable energy surplus without an ability to feed this surplus into the grid has not held them back. It has just meant finding new ways of using the excess energy. One way is to increase demand, for example using electric cars, of which there are now around 200, the most per capita in the UK. Another is to use the excess energy to create a more portable fuel – hydrogen.

Neil Kermode, managing director of the European Marine Energy Centre (EMEC) at Stromness, takes up the story, saying “this is where our hydrogen Surf ‘n’ Turf project has come in.” The problem was that the tidal energy test site off the northern island of Eday has 35MW of cable capacity taking energy from the generators to the shores of Eday. However, this is then funnelled into 4MW grid connection to take it off the island. With little prospect of getting a grid upgrade, EMEC joined forces with the Scottish Government to run a pilot project putting the marine energy to land-based use.

Kermode says: “We’ve put a half-megawatt electrolyser on the island of Eday and it’s running today. We’re soaking up energy that’s brought in from the sea and turning it into a use fuel in the form of hydrogen gas.  The point is that I can increase the amount of hydrogen gas I can produce, I can get more electrolysers there quicker than I can get more cables to the island.  So this gives me a more flexible way of absorbing power.”

This hydrogen is stored and used in a fuel cell, producing electricity to power ferries when they are tied up at night, saving them having to run their diesel engines to provide the auxiliary power. It’s a small step, but the vision would be that the ferries themselves would be powered by hydrogen – and such is the nature of the Orkneys that the ferry fleet use as much energy as all the buildings on the islands.

Kermode concedes there is an early snag: “You can’t put hydrogen on ferries because there are no regulations that actually permit it.” The vision would be to develop ways and training methods of handling hydrogen on ships and gradually increase its use until it could be used to power them.

This all falls neatly into what EMEC, OREF and the Scottish Government would like to see happen: not just developing marine energy technology but building an industry that could be exported around the world.

Renewable fuels

Can hydrogen ever compete with fossil fuels?

In Orkney’s Surf’n’Turf project, surplus electricity is used to produce hydrogen, which then feeds a fuel cell.

That hydrogen is sometimes referred to as a ‘solar fuel’ probably indicates where tidal and wave energy are in terms of maturity. Solar fuels are simply fuels, like hydrogen, syngas and methanol, which have been created in a process that uses solar energy. The actual source of energy is irrelevant: the fuels could just as easily be produced in plants running on excess wind wave or tidal energy.

Researchers from the University of Amsterdam have recently produced a study predicting such fuels could become competitive with fossil counterparts within two decades.

One of the study team, Remko Detz, comments: “We consider solid oxide electrolysis [a process for extracting hydrogen from water] an early winner. But to achieve its potential, current systems with a typical size of 150kW must be scaled up to the megawatt level.’

In general, Detz adds: “whether they will truly become competitive depends on many factors, such as installed capacity, taxes, subsidies, other policies, and the price of CO2. Our results show, however, that the costs to produce renewable fuels can drop significantly over the coming decades.”

Detz adds that it is of prime importance to invest in research in these technologies as well as in approaches to stimulate learning-by-doing: “Efforts to improve the scalability, efficiency, integration, and affordability of the necessary components are all important aspects for successful large-​scale deployment.”

Developers of marine technology can use the established wave and tidal sites set up by EMEC to do long term testing on latest designs. There are seven berths for tidal and five for wave projects, although a developer called Aquamarine Power laid a further channel as its model involved pumping water back to the shore where it is used for generation. However the basic model is that each berth will have a cable that will feed the onshore substation, which is connected to the grid.  

“From day one, the idea was that this was a means to allow people to demonstrate their machines,” says Kermode. “It’s part trial, but when it does work you can do something useful with the electricity. Further to that we set ourselves up to be a testing laboratory to independently test or evaluate the performance of each of the machines.  So we can say each machine has got the following performance characteristics and that performance is attested to by EMEC as a testing laboratory. Our certificates from UKAS [United Kingdom Accreditation Service] make us the world’s only laboratory able to do tests on machines that will prove the claims that these developers are making.”

One such developer is Scotrenewables Tidal Power. Its second-generation device, the SR2000, has been occupying one of the EMEC berths since 2016. It’s a 2MW floating tidal device that comfortably endured the 8m waves of last winter’s storms. CEO Andrew Scott believes the device has been transformational in marine energy technology. He says: “My view around what tidal had done before, was it took the assumption of what the right solution was too far, and it built underwater turbines.”

It is not surprising. Wind turbine technology became mature, effective and therefore attractive for investors, so the thought process was just that wind turbine equivalents should be built on the sea floor. However, under the water is a completely different environment from up in the air and using wind turbines in the sea didn’t cater for the potential problems around initial cost, installation and maintenance.

Scott continues: “What we should have realised is that we’re all familiar with what the solution was – turning rotor, gearbox, shaft, generator. And that’s the same as a marine propulsion system that you find on a boat. Boats are built to be at sea and you can quite easily access them for maintenance and there’s this benefit that you’re positioning the rotors in the best part of the resource. A tidal turbine should always look, to my mind, more akin to a boat than an underwater wind turbine.”

The innovation and the infrastructure up in the Orkneys should inspire and ensure optimism. As an opportunity to build a world-leading industry, all involved concur that it is within reach. As Kermode puts it: “We are making stuff work pretty well, but there’s a lot more we could do if we really decided we wanted to. If we want to make this our Apollo programme, we can absolutely do this. But if we don’t have the vision that says we really want to make this work then we’re likely to do the things we can afford as opposed to really doing the big picture, big vision stuff.”

And therein lies the rub. An industry ticks over waiting, or hoping, for the break that it needs if it is to step up to the next level. “You can argue that perhaps a lot of what the industry is at the moment is belligerence,” says Scott, “and the legacy of investments that have been made to date. Right now, if you had a brilliant idea about how to make tidal energy, I don’t see how you would raise investment, because there’s no market for it, regardless of how good the idea is.”

To sum up the problem, the financial advantages that the wind energy industry benefitted from for many years have been removed. In November 2015, the then Energy Secretary Amber Rudd said: “It takes the brilliance of business to commercialise [new energy technologies], but it often takes the patience of government support to get them off the ground. Energy research and development has been neglected in recent years in favour of the mass deployment of all renewable technologies. We do not think this is right. We cannot support every technology.” At which point the rug was pulled from under this developing sector.

In the same way that tidal lagoon energy (see p36) is unable to compete directly with current nuclear, solar and wind energy prices, marine energy inevitably could not match far more developed renewable sources. And while millions in investors’ money has previously gone into this sector, with government withdrawal of support in the form of a guaranteed market, that has largely dried up.

It is unlikely, believes Kermode, that price points will become competitive until we are at the gigawatt stage.

“We’ve got to get a thousand megawatts of this stuff installed before we’ve had enough practice to be really getting down to a price point which is getting somewhere near offshore wind, or the £100/MWh mark. How long? Well how hard do you want to try. If we really set our heart to it and want to get on with it, it could be five or ten years away. If, on the other hand, we’re just going to dither around on this and run the risk of somebody else snatching our coat off our back, then it could take a much longer time. So it really depends on determination but it’s more about repetition than time – its repetition that absolutely drives the cost down.”

Speaking at the All Energy conference in Glasgow in May this year, Energy Minister Claire Perry claimed: “We have reduced emissions faster than any other G7 nation and we want to continue to drive the UK as a world leader in clean growth.” However, it’s hard seeing how this will work for the marine energy business without there being the same sort of industrial commitment that similar technologies have been afforded in the past. The guaranteed market for the nuclear industry, for example, if restored to the marine energy sector, would re-energise investment in it.

 

Turning the tide for tidal

Atlantis Resources

The poster boy for tidal energy is Atlantis Resources, whose MeyGen site in the Pentland Firth is now a fully operational generation site using technology proven at EMEC, the Orkney-based European Marine Energy Centre. Atlantis CEO Tim Cornelius says: “We’ve made great strides in reducing our cost of generation so that we can slash our requirement for revenue support. However, I must acknowledge the difficulties of competing on a level playing field with established technologies like offshore wind, which has been operating at commercial scale in the UK for over a decade.”

He continues: “It would be a travesty if the UK were to lose out on another emerging industry where it has established a first-mover advantage and where the cost of energy is on a steep downward trajectory. We expect our ensuing discussions with BEIS to focus on how the future jobs and growth benefits of the sector can be secured for the UK.”

 

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