ETI reports paint contrasting pictures for UK wave and tidal energy sectors

The first report, Insights into Tidal Stream Energy, reveals that tidal stream power has the potential to play a ‘significant role’ in the future energy system of the UK, and could one day be cost competitive with other low carbon energy sources. However, a second report, Wave Energy – Insights from the Energy Technologies Institute, offers a bleaker assessment for the wave energy industry, arguing that a cost competitive future is ‘less certain’ and that the industry needs a ‘fresh approach to how it extracts and converts energy from waves if costs are to come down and make it viable.’

The conclusions of the two Insight Reports are based on data gathered by the ETI’s own Marine Technology Programme, as well as an in-house energy system-level analysis. A key finding of the tidal report is that the UK currently ‘leads the rest of the world in the development of tidal devices.’ It also reveals that, in recent years, the sector has ‘transitioned … from small-scale prototype devices, through to full-scale demonstration,’ with several ‘early commercial arrays’ now in development.

However, in order to fully exploit the potential impact of the sector on UK GDP, which is estimated to be ‘in the range of £1.4 – 4.3 billion,’ the ETI argues that the focus of further cost reduction activities should be on ‘developing array-scale systems,’ as well as ‘co-ordinated investment into supply chain innovation, their processes and the training of people.’

“Tidal Stream device makers need to focus on cost reduction and taking a system approach to device and array development. The greatest effect will be from array and device design integration, although this is particularly difficult to achieve,” says report author Stuart Bradley, Strategy Manager – Offshore Renewables at the ETI.

On the flipside, the wave energy report highlights the fact that ‘more work needs to be done’ to make wave energy cost competitive over the medium term and that ‘even with aggressive cost reduction and innovation activities, current attenuator wave energy technologies are unlikely to make a significant contribution to the UK energy system in the coming years.’

“Wave Energy device developers need to collaborate and work with WES (Wave Energy Scotland) to gain the most from their initiatives. A clear focus on technology selection, with a step-change in levelised cost of energy is paramount,” says Bradley.

‘FALSE DILEMMA’
Nick Medic, Director of Offshore Wind at RenewableUK agrees with the assessment on tidal energy and points out that ‘there is a sense that tidal costs will be a function of scale of deployment, meaning that the more of this technology we deploy the more the costs are likely to come down.’ In his view, this is because we have already seen a number of devices generate consistently in ‘real-life’ test conditions, so ‘it is reasonable to assume that once we have a market for these devices, enabling industrial roll out, costs will come down.’

“The problem, however, and this is where we need Government vision, is that under the new Electricity Market Reform regime tidal energy will compete with other low carbon technologies, which are further down this cost reduction curve. So there has to be a strategy that will allow for that critical industrialisation to happen,” he adds.

On wave power, Medic is also keen to qualify the ETI’s view by pointing out that the sector needs ‘continued innovation.’ Even though the UK has already demonstrated ‘a number’ of engineering approaches to extracting energy from the waves, he believes that it is ‘perhaps the case’ that we need to ‘further refine these approaches, rather than tear everything up and start again.’

In relation to tidal, he believes that this approach could also mean that rather than insisting on an array or industrialisation strategy, wave ‘needs more primary R&D funding so that we could fully understand what the performance challenges are for the solutions on the table.’

“The differences stem from the different natures of the challenges on the table. When looking at utilising tidal flows, there are already precedents in hydro or wind engineering. Wave energy presents a different set of problems. But, the global wave resource is greater, so it is worth the effort,” he says.

“I would say that if we are serious about energy security and emissions’ reductions we should use the full range of tools in our decarbonisation toolbox. Remember that the Climate Change Act calls for 80% of energy from low carbon sources by 2050,” he adds.

Medic also cautions against falling into the ‘false dilemma’ of having to decide between wave and tidal. Rather than saying ‘wave is behind tidal, we should leave it on the shelf for now,’ he argues we should be saying ‘let’s make that extra effort to upgrade both wave and tidal energy so that they contribute to our energy supply.’

In his view, there is ‘no doubt’ that this can be achieved at an acceptable cost, and he points out that the UK has already developed a ‘world-leading industry with levels of investment which in the scale of things have been quite modest,’ particularly compared with expenditure on activities such as nuclear energy decommissioning.

“We have a world-leading base of technologies to build on in both sectors, developed at an extremely keen cost. It would be sensible to build on this advantage, as sooner or later we will need both wave and tidal energy,” he adds.

By Andrew Williams