Turning tide for ocean power: Is marine energy coming of age?

Ocean energy still has a long voyage before reaching the relative level of investment and maturity of other renewables, but recent activities in the sector are hinting at promising developments and breakthroughs in the coming years.

Below is a quick overview of what we’re seeing in terms of trends, innovators, and partnerships, but for a closer look at this space, please do get in touch with us at research@cleantech.com.

There are at least four different technologies to harness the energy of the sea – ocean thermal energy, salinity gradient energy, tidal energy, and wave energy.

Thermal and Salinity gradient

Ocean thermal conversion exploits the difference in temperature between deep and surface waters, while salinity gradient generation converts the difference in salt concentration between fresh and saltwater, typically found in fjords and deltas. Although a few start-ups such as Bluerise and REDstack are active in this space, these technologies remain largely in the concept stage and we’ll therefore focus on the latter two below.

Wave and Tidal energy

While wave energy converters capture energy from the motion of waves through either floating or submerged devices, tidal turbines generate electricity from the tides caused by the gravitational force of the moon and can be mounted to the seabed like submarine wind turbines (tidal stream), or integrated within a barrier impounding a lagoon (tidal range).

Advantages of tidal energy – apart from being clean and renewable – are its potential efficiency and predictability. As water is much denser than air, turbines can be smaller and generate energy from far slower velocities than wind turbines. Even more importantly, tides are not as erratic as winds but happen twice a day, which has the potential to offset the intermittent nature of solar and wind and makes annual production calculations much easier. Benefits of wave energy converters, on the other hand, include a very low impact on aquatic life, and the high power density resulting from multiple planes of movement (waves not only roll past the device, but push it up and down and side-to-side).

Both technologies could also be deployed at smaller scales for offgrid applications and energy security on small islands that typically suffer from energy scarcity and/or high electricity prices. Carnegie Clean Energy, for example, has been awarded $2.5M by the Australian Renewable Energy Agency late last year for a wave-powered microgrid project to be implemented on Garden Island in Western Australia in the coming months.

     (Photo credits: clockwise from the top left, Wello, Carnegie Clean Energy, Atlantis Resources, Sabella,)

Who is surfing the wave?

Similar to offshore wind farms, the deployment of these technologies faces challenges from difficulties in grid connections, as well as the harsh (salty & stormy) and remote (underwater) environment in which they are to be implemented. This explains in part why no single dominant design has yet to emerge for wave energy converters, and also why progress has been stymied by a few bankruptcies of early movers, such as Pelamis Wave Power and Aquamarine Power, gone out of business in 2014 and 2015, respectively.

However, we’ve also seen a plethora of new start-ups appear in our i3 platform in recent years. Relatedly, investment activity in the scene seems to have picked up the pace again with a number of equity and project financing rounds for innovators such as the InnoEnergy Spin-off CorPower Ocean, AW-Energy and Carnegie Clean Energy. Large utilities are taking up the race as well, with players such as ENEL Green Power partnering with the Italian start-up, 40SouthEnergy, and Finnish utility Fortum aiming to deploy the first multi-megawatt wave farm in 2020 off the coast of Scotland in a partnership with the Finnish start-up, Wello.

More research, pilot projects and experimentation like these will still be necessary before wave technologies become viable and competitive enough for wider industrial rollout.

Who is reaching for the moon?

The tidal energy industry has already seen initial large-scale capabilities deployed last year, and has more than one multi-megawatt project under construction. With a total lease capacity of 398MW, the MeyGen project installed in Pentland Firth (Scotland) by Atlantis Resources is the largest tidal energy farm in operation to date. But more are yet to come. Just last month, Tidal Bridge BV, a joint venture of DEC and Strukton International has been awarded the Palmerah Tidal Bridge Project in Indonesia, which will have an installed capacity of up to 115MV and has a contract value of an estimated $550 million. Other known names include Engie, Alstom, EDF, and Repsol, who have all been involved early on and have partnered with start-ups, such as Sabella or Tocardo, to speed up the development of tidal turbines. The Swedish company, Minesto, received attention two months ago when it closed a limited public share offering with $8 million in proceeds for an innovative tidal kite design, pointing out that the last word has not been said on the shape of tidal technologies to come.

While Europe is clearly spearheading innovation for ocean power, other countries such as Israel and Canada are advancing fast. With the potential for off grid applications, more developments for island states and remote coastal areas can be expected. Capitalizing on existing offshore infrastructures, naval capabilities, and under-used harbors might open up additional new pathways for deployments. For years, the spotlight has focussed on green energy, with blue energy gaining momentum in fits and starts. While tidal energy now seems on the crest of maturity with various deployments being carried out worldwide, wave energy has yet to breach the surface.