Prof. Dr. Axel Bochert
Prof. Dr. Axel Bochert holds the chair of marine technology and marine energy systems at the University of Applied Sciences Bremerhaven.
Students have been able to study maritime technologies in Bremerhaven for around ten years. Why has the course now been expanded to include marine energy systems?
Bochert: In view of ongoing climate change and the increasing scarcity of fossil fuels, it’s absolutely essential that we focus more intensively on expanding sustainable energy supplies. Above all, we have to dramatically reduce global CO₂ emissions. We will only succeed in this if we consider all the renewable energies available to us. Maritime energy resources will also play their part in the future.
At the moment, these still lag some 15 to 20 years behind offshore wind power technology. Hopefully, the students we are teaching today will contribute to building up this technology.
The North Sea and Baltic Sea are not generally suitable as locations for wave or tidal power stations. Why does Germany nonetheless view this as an important topic?
Bochert: It’s true that we in this country will not benefit directly from maritime energies. However, if we consider Germany in a European context, the potential takes on a whole new perspective. Along the Atlantic coast, there are various locations that lend themselves to the construction of wave or tidal power stations. Quite apart from this, the German economy can profit from an expansion of marine technology. German industry has decades of know-how in plant engineering and, with government support, Germany will strengthen its position as a leading provider of innovative energy technology.
What potential does energy from the ocean offer in terms of energy supplies in Europe and worldwide?
Bochert: The energy potential of the ocean far exceeds global energy requirements. However, we must differentiate between theoretical, technologically usable, and accessible potential. Accessibility relates not only to technological possibilities, but also to economic and ecological factors. This reduces the actual usable potential to under one percent compared to the theoretically available potential. Studies by the Intergovernmental Panel on Climate Change predict that up to 20 percent of the world’s energy requirements could be covered by wave and tidal power by 2050.
In my view, this forecast can also be applied to Europe as, compared to the situation worldwide, it offers relatively favorable conditions for the economic usage of wave and tidal power plants. Due to the technological lead Europe enjoys, we could even expect to see Europe at the forefront of this development.
What costs are involved in this potential?
Bochert: As soon as the various marine energy systems can be produced in technologically mature forms and in larger volumes, they will be able to compete with current energy prices. In addition, if the follow-up climate costs of various methods of power and heat generation are taken into account, the affordability of maritime energies would be unrivaled.
How environmentally friendly are the marine power plants currently under test?
Bochert: Various studies and ecological work conclude that wave and tidal power plants affect the ecological balance primarily in the construction phase. Installation work disturbs the plants and creatures on the sea bed. Marine mammals also avoid the areas to begin with. However, once the power plants are in operation, they return to their old stamping grounds. The flora and fauna recover quickly too, and use the new foundation structures as artificial coral reefs.
When will the first large-scale power plants be ready for the market?
Bochert: We are currently at a stage in which many projects are investigating very different technologies. Wave energy in particular is sheer heaven for inventors and developers. There are numerous methods, of which probably only a very few will ever be market-ready. Generators that utilize tidal currents are also being tested in a very wide range of designs. This, and research into other ocean-based energy sources, mean it is difficult to make any predictions.
As it stands, generating energy from the tides and waves is the most tangible option. However, the energy potential available due to the temperature difference between warm surface water and the cold water deep down is four times greater than the potential offered by waves and tidal currents. The same applies when it comes to using energy from the concentration gradients of salt at river mouths.
What are the biggest challenges in developing market-ready technologies?
Bochert: Marine power plants have to cope in an extremely hostile environment. Salt water accelerates corrosion. In the currents, sediment becomes like sandpaper, attacking the bearings and joints and, in extreme cases, damaging the surfaces. If rotor blades are optimized for currents or buoys for specific wave movements, incrustation can render all these calculations null and void. The varying ways of tackling these challenges is evident from the technologies used. Some developers use high grade optimized and regulated systems, while others rely on robust technology and put reliability above increased efficiency.
Just one more question to finish with: Could popular books with a scientific theme like “The Swarm” by Frank Schätzing help to promote “marine energy” as a research topic?
Bochert: I read the book a few years ago, or started to read it, I should say. The beginning was very interesting and exceptionally well researched. However, toward the end it all got too chaotic for me and it’s one of the very few books I’ve ended up putting to one side. I don’t think books like that will help us as far as research is concerned. The people who read these books are interested in the topic and have an awareness of climate problems. We need the right decisions to be made at the political level. To drive forward the economic use of marine energy, we will need long-term support in the form of research backing and subsidies.
(Interview with Prof. Axel Bochert, December 2013)