About the Author: Avimanyu Basu is an analyst and consultant with more than 7 years of experience in cross-vertical market research and management consulting. Domains of expertise include aerospace, sustainable energy and ICT, particularly across disruptive technologies.
The ocean is a source of infinite energy which can be harvested to address a significant portion of the global energy shortage challenge. Few nations such as the UK, Norway, Sweden, and Israel have progressed considerably in leveraging ocean energy. Ocean energy can be classified into wave and tidal energy. Depending on several external conditions, according to the World Energy Council 2016 report, the cost of deployment of a wave power and a tidal power pilot scale project ranges between $4 to $18 million per MW and $5.1 to $14.6 million per MW respectively. While these pilot scale projects progress to commercial scale, the CAPEX (capital expenditure) becomes $2.7 to $9.1 million per MW for wave and $3.3 to $5 million per MW for tidal.
However, the LCOE (levelized cost of energy) realized from wave and tidal power solutions is still on a higher side, at about $0.08 to $0.09 per kWh , as compared to wind power which is about $0.04 to $0.05 per kWh (Israeli Eco Wave Power has, however, claimed a LCOE of $0.05). Furthermore, wind turbines are getting bigger every year and with multi MW-scale offshore wind project deployments, the LCOE are expected to reduce further. However, many start-ups with promising ocean power technologies have emerged across the globe, particularly in the Scandinavian region, and and also from Israel who are directing their efforts to address this challenge pertaining to the LCOE. The Nordics already have a stable cleantech infrastructure in place, supported by suitable public policies and investments.
The global energy sector is progressively adopting a hybrid model. In other words, to meet energy efficiency across operations, energy companies have been employing multiple energy harnessing technologies along its value chain. The high energy requirement for oil and gas operations, particularly in the upstream or exploration segment has influenced few upstream stakeholders to leverage ocean power. The recent project by Italy-based Eni amidst the Adriatic Sea can be cited as an example. Eni has been working with US-based Ocean Power Technologies (OPT’s) PowerBuoy wave system PB3 to energize autonomous underwater vehicles (AUV) directed towards marine environmental monitoring. Though wave power is more or less persistent and predictable, in order to increase the reliability factor, OPT has included an energy storage module in its wave power harnessing device.
Reliability is one of the most important factors which dictates the future or advances of a technology disruption in the energy industry. It is always advisable to integrate an energy storage module with any renewable energy generating resource to ensure a continuous supply. Likewise, Vancouver-based Neptune Equipment have been considering flywheels for storage since conventional storage techniques such as capacitors or batteries due have limited cycle life necessitating frequent replacement.
What are the disruptive technologies?
Assessing some of the recent developments in the ocean power segment, few trends of the overall industry have been identified, which are as follows:
- Use of potential energy from wave heights: The Wavetube wave energy technology designed by the Sweden-based SME (small and medium sized enterprises) Wavetube is a power generation technology that leverages the conversion of the vertical energy of an ocean wave to the speed of freshwater movement inside the unit. When the device is placed offshore, the impact of the external waves makes the structure move. Consequently, the internal freshwater is moved to generate a torque on the turbine driveshaft, which feeds a permanent-magnet synchronous generator. The AC output from the generator is passed through a rectifier and converted to DC, stabilized, and then transmitted to a marine switchgear station.
- Prediction algorithms for ocean condition analysis: It has been estimated that with a bit more precise prediction of ocean conditions, the amount of energy extracted from waves can be twofold. Consistently, a team of researchers from the University of Exeter in the UK and Tel Aviv University in Israel devised a forecasting model to estimate the power of the next wave. To maximize the energy harvest and the longevity of the offshore power system, the researchers employed point absorbers consisting of floating devices. The floating devices move along the wave and generate energy, which is subsequently fed to the grid. The device uses an algorithm to control the response required for a wave of a certain height and volume.
- Low-speed rotation for nearshore waves: Few stakeholders modified basic turbine designs to complement stable energy generation from tidal waves. These turbines are usually installed nearshore at depths not more than 100 meters (at around 3 kilometers from the shore), where waves with velocities greater than 2.5 meters per second can be leveraged. As the turbines rotate at a low speed, it has no impact on the wildlife and does not affect the boat traffic. The Norway-based ANDRITZ HYDRO Hammerfest developed a similar turbine that can be represented as an underwater wind turbine featuring shorter blades for slower rotation. These turbines are gradually evolving as MW-scale systems, and thus, are appropriate for powering remote islands that have limited or no access to the grid.
- Increasing speed artificially for higher output: The Deep Green technology developed by the Swedish technology developer Minesto uses an underwater kite technology to harvest energy from low- to medium-velocity tidal currents. The technology uses a hydrodynamic process through which the velocity of the tidal current is boosted 10 times in magnitude before it hits the turbine. This enables Minesto to maintain low weight of the turbine, up to 10-20 times as compared to other tidal power innovations.
- Low installation costs: Similar to Minesto, the Flumill Tidal system from the Norwegian SME Flumill features low weight (about an eighth of a standard Kaplan system) that enables it to be easily towed to the installation site with buoyant helical devices instead of engaging heavy lift vessels. The Flumill Tidal system does not require any kind of piling to minimize the installation cost. The system is affixed on the seabed at one end through four steady joints. The low initial cost along with the comparatively low cost of energy ($0.13 to 0.17/kWh) generated contributes to a faster return of investment.
- High scalability: The Euro Wave Energy system developed by the Norway-based Craft Services used findings from Akervoll patents. The technology follows the “Floating Absorber” principle, which makes it a versatile design and suitable for using across geographies. For example, the Cape Verde version of the technology involves more onshore operation than offshore and would be ideal for powering desalination plants or small facilities with low energy requirements. On the other hand, the vertical running rod design is appropriate for utility scale generation and can be installed in places where the waves move in the same direction for a longer time period. The basic design uses an absorber for capturing the mechanical energy from the waves and transferring them to the main module with the help of running rod or flexible drive line. The generator in the main module converts the mechanical energy to electrical energy and the electricity is transmitted onshore.
- High quality power: Several designs have been innovated for wave power harvesting. One of the most widely used design is the point absorber – in this, the buoy remains stationary in the ocean, whereas the float leverages the up and down motion of the waves to move its shaft, similar to a piston movement. This linear motion is converted to rotational motion to rotate the generator. As expected, the generated power often has harmonics which requires smoothening. Wello uses a battery management system which acts as a filter to remove these harmonics and charge the batteries which supplies the necessary load. This can be an industry-wide disruption since wave power harvesting systems often tend to generate low or high bursts of electrical energy due to the nature of the wave motions and few stakeholders find challenge in converting this to smooth and steady current. The Neptune developed by Vancouver-based Neptune Equipment can be cited as an example. As explained by Inventor of the Neptune, Charles Haynes, being a pulsed wave source, it is almost impossible to obtain a smooth waveform. Point absorbers are ideal for nearshore deployments i.e. where the system can be anchored to the ground at depths of 50 meters.
What are the industry-level impacts?
Though ocean power provides the advantage of perennialism as compared with other renewable resources such as wind and solar, the power companies or the utilities should assess the geographical parameters before zeroing in on a particular ocean power solution. With considerable enhancement in energy storage systems through disruptive innovations such as implementation of nanotechnologies, solar and wind power systems present significantly low cost of ownership. Though waves in the deep waters provide a higher magnitude of energy, the equipment placed offshore need to endure rough climatic conditions, thus reflecting higher maintenance costs. Furthermore, enhanced transmission equipment is required to transmit the generated electricity onshore, which in turn is associated with transmission losses. The nearshore solutions, on the other hand, depict minimal maintenance costs due to low speed water movement; however, they generate energy at a much lower pace. Utilities should analyze the energy requirement and consumer behavior to find an appropriate balance of voltage and maintenance cost. A considerably low voltage generation would also require the installation of a transformer offshore to step up the voltage to the usable level. Also, the arrays of tidal turbines installed offshore should be at considerable depths to maintain the aesthetic value of the coasts, particularly the ones that are major tourist attractions. An appropriate application segment can be the offshore oil rigs. The deep water upstream facilities can ideally utilize the wave power from the deep waters without investing in high-cost transmission lines.
The wave energy sector is already impacting other stakeholders across the energy value chain. Consistently, Germany based NKT has deployed a pilot scale project for testing a dynamic 1 kV and a 24 kV semi-dynamic power cable for a wave power project in Norway in collaboration with Swedish company Waves4Power. NKT is also testing the cable technology in collaboration with Chalmers University of Technology in the high voltage test center at RISE institute of Sweden. With this pilot-scale deployment, NKT claims to address the challenge with constant bending of cables due to the wave motion. three copper conductors with low mechanical friction were used in the cables and the armored sheath like conventional offshore cables were replaced with aramid yarn to increase the flexibility and mechanical strength.
Similarly, the wind power industry has also indirectly influenced the ocean power vertical. The H300 turbine is designed by Norwegian Ocean Power to harvest clean energy from tidal currents, can be cited as an example. The H300 design is influenced by the Darieus-turbine design, which is one of the well-known vertical axis wind turbine designs. The company envisions the commercial launch by 2020 and focuses developing an economically viable solution – according to Kent Thoresen, Technical director & founder of Norwegian Ocean Power “Our very long development time is due to the complexity in getting the technology economically interesting. It’s much harder than technical issues.”
The industry-level scalability issue is being addressed by one of the pioneers of the ocean power sector, Eco Wave Power. Wave power sector has also been gradually moving towards the MW-scale similar to the big wind turbines. The Mexican subsidiary of Israel-based Eco Wave Power has recently commenced 10 MW project in Manzanillo Port. The power plant will set up in the Cuyutlán/ Tepalcates Beach in Manzanillo, State of Colima and the harvested energy will be used by the Municipality of Manzanillo and State of Colima. Eco Wave Power’s technology has already been proven and it has commissioned its first grid connected 100KW wave energy array in 2017 in Gibraltar which recently completed 15000 grid-connection hours. The total planned capacity of 5 MW will suffice for up to 15% of Gibraltar’s electricity needs.
Effectual nearshore technologies can influence the marine sector as well. Vessels anchored at the port can directly utilize tidal power for stationary operations. However, there are challenges like a suitable validation of the cost-effectiveness and reliability of ocean power. The $60 million wave energy project close to Cornish coast involving power generation device Wave Hub by Seatricity is yet to produce electricity even after eight years since its installation. Finally, a number of countries in the Nordics have envisioned a roadmap of becoming completely carbon-neutral within a short-to-midterm period. Appropriate developments in the ocean power domain will enable the region to align with this ambition. It would be considerably straightforward for the governments to standardize favorable policies for the wave power stakeholders, as it is applicable only for utility-scale customers unlike other renewable power resources. Accordingly, ocean power at present is profitable only at locations where most of the facilities can be maintained offshore for feeding directly to the grid through the substation unit and for energizing desalination plants and microgrids in remote islands. Wave or tidal energy is ideal for remote islands which have limited or no access to power grids. A number of these islands run on diesel generators round the clock hence making the maintenance cost high. Consistently, a Scandinavian stakeholder, Wello from Finland, has acquired an order from the Indonesian infrastructure company Gapura Energi Utama (GEU) for the Penguin, which will generate clean electricity for Bali, Indonesia. The project has been claimed to be the biggest wave power park in the world.
Last but not least is the factor of declined oil prices. Renewable or sustainable energy projects took a backseat after the crude oil prices hit an all-time low in 2014. Though the prices are gradually going up, it has not recovered fully due to which the potential ocean power investors are still not convinced. It may be expected that the environmental regulations will play an important role in the adoption of ocean power across the globe, particularly in Europe. In order to gain pace in the emerging economies such as India and China, the ocean power harvesting device manufacturers should optimize the CAPEX. The regional governments can help this cause by introducing subsidies. Small islands, offshore oil rigs and ports can be transformed to zero-energy models with the appropriate use of ocean power. This will, however, be instrumental if the initial cost is optimized and reliability is maximized.
The “So What?” aspect
- Ocean power is gradually scaling up to MW-scale which is expected to bring down the LCOE
- Powering operations in offshore oil rigs and remote islands are two of the most promising applications
- Minimum or no moving part is desired on the submerged portion of the energy harvesting devices to keep the wildlife undisturbed at the point of deployment
- Deep waters offer better energy output while reflecting higher maintenance cost due to rough climatic conditions and high transmission costs. while nearshore projects offer lower maintenance and transmission cost along with lower output. An appropriate balance should be obtained considering the requirement.
- Primary Interview: Inna Braverman, Co-founder, Eco Wave Power, Israel
- Primary Interview: Kent Thoresen, Technical director & founder, Norwegian Ocean Power, Norway
- Ocean Energy Council: WAVE ENERGY, accessed 29 Apr 2018, accessible at http://www.oceanenergycouncil.com/ocean-energy/wave-energy/
- Tel Aviv University: Predicting wave power could double marine-based energy, accessed on 29 Apr 2018, accessible at https://english.tau.ac.il/news/predicting_wave_power
- Power Technology: Can the world’s biggest wave project turn the tide for the technology?, accessed on 29 Apr 2018, accessible at https://www.power-technology.com/features/can-worlds-biggest-wave-project-turn-tide-technology/
- Cornwall’s Wave Hub energy project yet to produce electricity, accessed on 29 Apr 2018, accessible at http://www.bbc.com/news/uk-england-cornwall-40294158
- Vancouver Courier: Neptune 5 testing the wave-power waters off Point Grey, accessed on 29 Apr 2018, accessible at http://www.vancourier.com/news/neptune-5-testing-the-wave-power-waters-off-point-grey-1.23260009
- Offshore Engineer: NKT develops wave power cables, accessed on 29 Apr 2018, accessible at http://www.oedigital.com/component/k2/item/16606-nkt-develops-wave-power-cables
- World Energy Council: World Energy Resources, Marine Energy 2016 accessed on 29 Apr 2018, accessible at https://www.worldenergy.org/wp-content/uploads/2017/03/WEResources_Marine_2016.pdf