Several European countries have policies to encourage the development of renewable energy sources. This is identified in, for example, the European green paper Energy strategy for a sustainable, competitive and secure energy supply (March 2006).
In the transition towards a European sustainable energy system for the future and to reduce the dependency of imported primary energy sources such as oil and gas, the development of offshore wind power is an essential element. EWEA assumes that almost 120,000 MW offshore wind power will be realised in the next two decades, amounting to 10% of the installed generating capacity. Apart from offshore wind energy, other offshore renewable energy sources such as wave energy, tidal energy and some experimental technologies of offshore energy have been considered.
Recent blackouts within Europe have shown that there is a need for increased European co-ordination regarding the transmission of electricity including aspects related to interconnections. In the EU technology platform Smart Grids, attention is paid to the networks of the future to ensure that they can accommodate and facilitate large amounts of renewable energy, both distributed and concentrated.
Following the European Smart Grids line of thinking, Airtricity has proposed a European offshore super grid (HVDC based on Voltage Source Converter technology), combining the grid integration of offshore wind farms with an interconnection grid between countries at sea. One could extend the role of this grid and connect all “ocean power” to it. The supergrid could then be part of the European backbone to connect and transmit bulk renewable power from remote generation sites, even as far as North Africa (Desertec).
The goal of this webinar is to discuss "Ocean Grids", grids at sea, at a conceptual level. The idea behind Ocean Grids is to provide an offshore backbone for the mainland transmission networks on one hand, and connection points for offshore wind power stations on the other hand. This will include offshore wind energy and other potential energy sources at sea.
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Question & Answer transcript
By Hans De Keulenaer / Published on Thu, 2009-02-19 16:03Herre Rost van Tonningen: Why do we discuss only wind power whereas wave power is 1000 x more dense.
ANSWER: wave power plants can also be connected to the ocean grid
Nickolai Parker: Are you aware of any proposals to combine offshore wind turbines with underwater tidal energy turbines?
ANSWER: Yes. If an ocean grid infrastructure is built to carry transmission to land, then it makes sense to place wind farms above water with ocean current wave energy turbines velow. The proposals that I am familiar with to develop an ocean transmission grid with offshore wind turbines along the Eastern Coast of the Unites States do not mention underwater tidal current energy. ANSWER: I’m not familiar with the USA plans for ocean grids but I can imagine that wind power technology is further developed than underwater tidal power technology (Nickolai Parker, New York)
Matthew Allen: How much of a a problem do you feel transmission losses will be?
ANSWER losses when using DC transmission are very small, roughly you can use 1ohm/100km as a rule of thumb for the loss calculation. Losses in the converters are much higher, 1.5-2% of the power.
Eoin Licken: What is the expected timing of these developments?
ANSWER: the first that that will be realised are “sea-sockets” (e.g. E.on and TenneT) for the connection of the wind parks, Next a basic design of the ocean grid has to be developed (can take a few years) with agreement of the different stakeholders, legislation has to be put in place and than start with the engineering and construction. Probably we have to unify forces forces(manufactures, TSO’s and regulators) it takes 20+ years to complete
Chi Su: what is the role of oil/gas platforms in the ocean grid?
ANSWER: these can be connected, either to be powered (e.g. reduction of emissions, space saving) or deliver the generated power from a “marginal gas-field”
Ivan Benes: How you see the prospect of realisation connection with the solar in the Mediterranean within GREEN PAPER TOWARDS A SECURE, SUSTAINABLE AND COMPETITIVE EUROPEANENERGY NETWORK issued in Brussels, 13.11.2008COM(2008) 782 final
ANSWER: fits perfectly in the concept of a Pan-European transmission network in combination with an ocean grid (probably this will be realised first)
James Birkin: What are the minimum technical matters to be agreed on a political level for a grid to work as a whole? A
NSWER: technology (HVDC VSC), capacity of the backbone cable, connecting-“hubs”, agreement how to connect (regulation, connecting code etc.)
Sonja Marwood: Could you expand on why shipping lanes and fishing areas would restrict where you can put this grid? I imagine the lines would be buried.
ANSWER: you can e.g. think of the possibility of anchor damage as a broken submarine cable is very difficult to repair
Yan Liu: How about the development of dc grid protection devices?
ANSWER: the technology is available for AC and with respect to the DC cables they can be protected/controlled with the power electronics (firing) of the converters
sebastian: So who will pay for this?
ANSWER: probably EU + National governments and TSO’s financial crisis is perhaps an opportunity?
Gouri Kumar: In Germany, TSOs are responsible for connecting wind farms to the land. Is it something that can be replicated in other countries?
ANSWER: Good idea, in a lot of European countries there is an obligation to connect (generators on land). This is unfortunately not true for the sea (yet)
Antonio Molina: In the maps shown in the presentation, there were some rubs of the ocean grid which ran parallel and close to the shore, for example north coast of Spain. why use an ocean grid in these cases and not land grid?
ANSWER: improves reliability and reduces the number of sea-land crossings
Dalia Valigy: especially in a High tourist zone..
Dalia Valigy: What u suggest as best technology to use in the carribean sea, and how can one define the best location for instalation??
ANSWER: depends on the actual situation (what are the plans to connect, how about the water depths etc. needs investigation.
James Birkin: and the political issues of enviromental opposition reduce/
ANSWER: probably more important than the technical challenges/issues
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