On to the sea

Hydrogen platform
Hydrogen platform, © Tractebel

Building platforms or artificial islands to produce hydrogen near wind farms is not a new idea. In the meantime, however, a growing number of organizations have announced that they intend to turn this vision into action.

For instance, at the UN Climate Change Conference held in Madrid in late 2019, the Danish climate and energy minister, Dan Jørgensen, outlined plans for building an artificial island for electrolyzers in the North Sea. And in January, engineering firm Tractebel presented a new offshore platform design for producing hydrogen on the ocean.

Hydrogen is a hot topic across the energy sector, though it is still unclear what method should be used to produce the gas, especially the clean, green version of it. There is likewise a lack of electrolyzer capacity and not enough electric power generated by renewable sources of energy.

Large multi-megawatt electrolyzers could be manufactured as soon as the German hydrogen strategy (see p. 15) is in place to provide a stable and reliable framework for business. But where should all the clean electricity come from if fewer and fewer solar and wind farms are being added each year?

Offshore wind seems to be the solution, since the ocean offers enough space for putting up multiple large wind energy systems. This raises the question of how the electric power they produce is going to get to the coast.

The AC power currently generated by offshore wind turbines is first transmitted to special platforms equipped with large power converters to change AC to DC power, as the latter is easier to transmit over a distance of 100 kilometers to 200 kilometers (60 miles to 120 miles). Long 320-kilovolt submarine cables then transfer the DC power to the coast, where it is converted back to AC and fed into the public grid.

read more in H2-international May 2020

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