Jussi Åkerberg, CTO of AW-Energy, talks on why wave energy will transform the renewables energy mix, from technical capability to building collaboration
There’s something significant when you take in to account the potential of the global ocean’s resources when considering the combinations that are possible between large water surfaces and marine resource diversity.
And, there are a wide variety of energy extraction options to consider. Offshore wind is a successful example of using the marine environment. Reports estimate that total capacity is close to reaching – and could exceed – 24.6 GW this year. With the offshore wind energy sector continually expanding since 2000 with larger size wind farms, turbines and distances from the shore line, it comes as no surprise that just three years ago, almost €18bn was invested in transmission assets and new offshore wind projects – and the investment is continuing.
However, on the cusp of transforming the energy sector even further is wave energy, and it would complete the third element of the renewables energy mix. Wave energy could potentially equal and even exceed the offshore wind sector by using the vast energy resource provided by the constant ocean surge, and the different forms of wave energy that can be targeted to help to capture and provide reliable power to on-shore grids.
Supplying demand
The Office of Energy Efficiency & Renewable Energy highlights that the global potential of wave power is around 29500 TWh/yr, from which currently only a small fraction is extracted near ocean coastlines, islands or semi-enclosed basins.
The successful development of wave technology in the European wave market could generate 188 GW (10%) of Europe’s electricity needs by 2050. For this to happen wave energy deployment would begin in 2022 – just two years from now. Research and development (R&D) on current projects has provided the necessary insight on how to cut the costs for future wave technologies, but a promising option is bringing together wave energy devices with existing offshore wind farms by sharing the same infrastructure. This would help accelerate and develop wave industry in areas where more reliable and predictable energy supply is needed.
Market opportunities… and storing energy!
A major advantage is being discussed in California, which has an objective to go to 100 percent renewable energy. The big challenge in California is that it’s windy and sunny in the summertime; the hot days in the desert creates the wind. But in the winter, there is a big drop off in this power production; for the 80 percent renewable scenario, the gap in December is about five terawatt hours, so it’s a huge gap in the energy resource. Some of the debate has been to store energy with lithium batteries in the summer and deliver it to the grid in the winter. If you look at the amount of rare materials you would need for that storage, the numbers are mind-boggling. It would require huge quantities of lithium to store that amount of energy!
So if you take five terawatts in December, that’s the same amount of wave energy coming into 100 miles of coastline. So you can fill that gap between the summer and winter with wave energy. Of course, you still need storage. Storage provides flexibility for daily supply and when its needed but it isn’t a seasonal buffer. So wave energy has a big role to really deliver renewable energy in all seasons in California.
If you look at the entire United States, then it’s a different story. I’d say we need different wave energy technologies to come to bear as well. So we’re in the coastal area; other technologies under development are in the deeper sea further offshore. So I’d say wave energy technology can make a very big contribution to the energy system in providing stability, in providing predictability, in providing energy when it’s cloudy, when it’s night time, when wind stops blowing, those sorts of things. I wouldn’t imagine wave energy technology supplying the entire grid.
Is it predictable?
We see that wave energy is also highly predictable compared to wind and solar. There’s been a lot of work in offshore marine engineering to predict wave energy based on weather simulations, so it’s possible to predict wave energy about a week ahead in the major oceans, and about two weeks in the tropical oceans. So it is very predictable. It’s possible to sell next week’s renewable energy as opposed to solar, where you just don’t know when the clouds are coming.
Value deflation or inflation?
I’d say the third point worth mentioning is value deflation in existing renewables. So as more solar comes onto the grid, when it’s sunny, solar competes with itself. Each new solar panel you put in it will compete with the others. And you see the same in wind as well. Value deflation really starts kicking in.
But, I would also emphasize that wave energy should not be considered a competing industry with other renewables but an indispensable and necessary addition to the renewable energy mix. Wave energy brings with it the base-load like characteristics that are required in order to deploy renewable energies globally, at scale.
It isn’t a single type of energy technology fits all approach
Wave energy is a technology that complements other renewable energy sources. We need different tools for different places, and this is one technology and one tool that can be applied to create increased grid stability, and then other types of renewables will be deployed as well.
For example, in Chile, the amount of wave energy coming into the coastline is far greater than the electricity demand in the country. On the other hand, in South Africa, we can make a very large contribution as the wave energy there is more than the demand. It depends on the country. In Australia, it’s definitely more than the demand. So it’s case by case and depends on the country, the wave resource and the electricity consumption.
How does wave energy work?
Waves are generated by the winds, but when the wind stops, the waves still come into the beach. The entire ocean is generating wave energy; you can think of the ocean as a giant battery, and we plug into it with WaveRoller®. With our technology, we convert the wave surge effect (ie. the backward and forward movement of a wave) in to energy through the hydraulic circuitry of the WaveRoller® system which uses hydraulic pistons. We use hydraulic accumulators to smoothen the peak and trough nature of the waves, which then enables WaveRoller® to feed the grid with smooth power by running generators with hydraulic motors.
We have a shore connection cable that goes out to WaveRoller® from the land. And on the shoreline, we have a substation. Because we’re quite close to the shoreline many of the critical electrical components are on the land. That’s one of the advantages of our technology: we’re close to the shore, because we’re in the 10 to 15 meter water depth – and up to a kilometre from the shoreline. We can keep a lot of the electrical components onshore in a substation, which means the maintenance guys can just go up to the substation, do their maintenance without having to go offshore.
Challenges and opportunities
I think the biggest challenge is being a newcomer to the renewables market. You see the costs of wave energy are presently higher compared to wind and solar; but reflecting back 30+ years it is the same scenario faced by wind and solar when they were early technologies. People tend to forget that! The costs were much higher than wave energy costs are today, but both technologies had a lot of incentives and support. In wind energy, there was a lot of support from, for example, Germany that supported development of the technology. We are already starting with a lower levelized cost of energy than wind energy in its early days. The challenge is to overcome this hurdle and move to larger commercial projects to really get the costs down… and the costs will come down. There is definitely a very strong case for wave energy in the future.
As value deflation of existing wind and solar renewables starts to kick in, it may be more difficult to reach renewable energy targets, and the return on investment is reduced. So that’s another benefit of wave energy: it can be produced to the grid at a different time compared to the current forms of renewable energy.
The key for any government and its country is that the future will be less influenced by the variability of a single resource. For example, if the wind is not blowing the waves can generate electricity. If the generators share the same infrastructure, it will be possible to cut the initial installation cost, especially in the case of wave systems. And, it could be possible to accelerate the WEC’s transition from the R&D stage to a full operational wave farm. This approach allows one site to generate energy from two types of technology wind and wave.
Sustainable ecosystems must be a priority
Since a renewable ocean or sea-based farm is designed to be a sustainable project, it is important to understand its impact on the local marine ecosystem. We are all too aware of the increasing necessity to rapidly deploy large quantities of marine renewable energy to reduce the carbon emissions from fossil fuel burning which are leading to ocean acidification, global warming and climatic changes. Done well and sensitively, its deployment could be beneficial to marine wildlife compared to the alternative scenario of greater levels of climate change.
While Europe is still the world leading market for wave energy technologies, other countries and regions outside of Europe are progressing fast. The challenge for any government and its industry is to have that broad view and investment plan on all energy sources and a long-term ‘horizon’ with an energy charter that supports a full and balanced renewables mix – not just a partial one
