Ocean renewable energy growth management
Ocean renewable energy has remained a largely untapped renewable energy resource, despite decades of development efforts. Most of the current ocean renewable operating capacities have been represented by two tidal barrage facilities. Ocean renewable energy technologies had been deployed in open waters with the application of both tidal stream and wave energy technologies. New ocean renewable capacities that are coming online have mostly been launched in the waters of Scotland (REN, Renewables report, 2018).
Open-water technologies, such as tidal stream and wave energy converters, are generally in an earlier stage of development. Various ocean open-water renewable prototypes have been deployed but these are still in the development stages.
Tidal stream technologies are probably closer to technological maturity than the open-water technologies. These have shown a significant convergence around the use of horizontal-axis turbines, combined with a variety of mooring techniques. A good ocean tidal example is that the first ocean tidal turbine arrays with a cluster of multiple interconnected turbines have been deployed in 2017 (MRC, State of the Sector Report, 2018).
However, ocean wave energy technology developments have shown very little technological convergences. These were due in part to the diversity of the wave resources in different locations globally. In addition, the complexity of extracting energy from waves has added to the technological and operational challenges. Ocean wave energy converter demonstration projects have mostly been in the pre-commcrcial stage. The developments of various ocean thermal energy conversion and salinity gradient technologies have so far been in the developmental stages and are quite far away from commercial deployment. Only a few pilot projects have been launched. Experts have estimated that there are currently over 90 tidal energy technology developers around the world. About half of these are focusing on horizontal-axis turbine developments. At the same time, over 200 companies have been developing wave energy converters of various types. The point-absorber devices have generally become the most common development approach adopted by most companies and developers.
Scotland has continued to be the centre for ocean tidal energy developments. A good ocean tidal example is Scotland’s McyGcn tidal stream energy project which has just completed the initial leg of its first phase. All four 1.5 MW horizontal-axis turbines have started to deliver power to the grid in early 2017. The developers of MeyGcn have received full consent to expand the project up to 86 MW. It is expected that the installation of the expansions will continue into 2019/2020.
Another good example of an ocean pilot project in Scotland is that Nova Innovation from the UK has installed in the Shetland Bluemull Sound a third
100 kilowatt (kW) direct-drive turbine. This was the world’s first grid-connected tidal array. It had secured EU funding supports for its innovative ocean energy technology with an EU grant ofEUR19.3 million (USD23.1 million). Some of the EU funding should support expansion of the Bluemull Sound array to six turbines. It is generally expected that this should provide enough insight into various operational performances so as to reduce the costs of future ocean tidal energy generation. These should help to boost the confidence of potential investors in future ocean tidal energy projects. The ongoing Brexit developments have introduced uncertainties on future EU funding, in the case that the UK completes its exit from the EU.
In France, the ocean tidal turbine developer Guinard Energies had also undertaken a demonstration of its 3.5 kW P66 turbine. Its designs of the tidal turbine have aimed to simplify installation and maintenance in isolated areas. The design has also included innovative hybrid renewable energy applications together with solar PV and storage batteries.
There have also been various wave energy pilots and demonstration projects being undertaken in several emerging economies and developed countries. These included China, Spain, Sweden, etc. China has redeployed the 100 kW Sharp Eagle wave energy demonstration project with upgrades. This project should allow it to better serve the power requirements of remote islands. Spain has undertaken tests of a new ocean wave air turbine made by Kymaner from Portugal. Spain has undergone tests at the Mutriku wave power plant in the Bay of Biscay. These devices have been designed to harness wave-driven compressed air with an innovative technology known as an oscillating water column.
Some environmentalists have also raised various serious environmental concerns as some ocean renewable energy technology developments have been moving closer to commercialisation. These serious environmental concerns mostly covered the potential impacts on marine life and ecosystems by the new ocean renewable power turbines.
Ocean experts have, based on current experience and knowledge, advised that the deployment of single devices would appear to pose very small risks to the marine environment and ecosystems. In reality, there will need to be much more actual operating experience with larger commercial arrays so as to better assess and reveal any risk that they might poise to marine life. More research, data collection and sharing will be required to establish the risks more accurately, so that realistic accurate risk assessments on the marine lives in the sea can be undertaken. These should be important prerequisites for the assessment and approval of future ocean renewable projects.
