It seems like there is new information published about the awe-inspiring power of wind almost every day. Hold on to your hats for this: a new study has found that there is so much wind energy power over the open oceans that theoretically it could generate “civilisation scale power”. But would it ever be possible?
Anna Possner and Ken Caldeira, researchers from the Carnegie Institute of Science, found that there is a marked difference between the power generated by farms offshore compared to those on land. Previous studies have shown that on land farms are limited to generating electricity at around 1.5 watts per sm. Modelling the generation rates over open oceans, in particular the North Atlantic, and the pair discovered that rates here could average more than 6 watts per sm – even taking seasonal fluctuations into account.
“Furthermore, the simulations suggest that, in certain areas of the ocean, atmospheric circulation patterns over the ocean allow wind farms to tap into the kinetic energy reservoir of the entire overlying troposphere, as opposed to the limited kinetic energy available at the ocean surface, thereby sustaining rates of wind power generation three times higher than those observed on land. According to the authors, if commercial-scale open-ocean wind turbines could be produced, open-ocean wind farms that are spread across approximately 3 million sq km could meet the current annual global energy demand of 18 terawatts.”
Ok, so the farm would need to be bigger than Greenland and could change the planet’s climate – which the research highlights. But where this does lead us is into incredibly interesting terrain that highlights the potential of floating wind farms over very deep waters. Especially when you consider that the smallest floating farm discussed in the study – covering 70,000 sq kms – could provide all of America’s electricity for 10 months every year.
In the wonderful manner of all scientists everywhere who underplay amazing discoveries, Caldeira said: “I would look at this as kind of a greenlight for that industry from a geophysical point of view.”
According to Possner, the issue for land-based farms is that the turbines interfere with each other. “The wind farms themselves generate substantial drag. That drag places an upper limit of about two watts per sm for a land-based wind farm.” Caldeira added: “If each turbine removes something like half the energy flowing through it, by the time you get to the second row, you’ve only got a quarter of the energy, and so on.”
That’s not an issue for floating wind farms. Possner and Caldeira’s simulations suggest that, in certain areas of the ocean, atmospheric circulation patterns over the ocean allow wind farms to tap into the kinetic energy reservoir of the entire overlying troposphere, as opposed to the limited kinetic energy available at the ocean surface, thereby sustaining rates of wind power generation three times higher than those observed on land.
There is one fairly significant issue that floating farms in areas where the ocean bed lies well over a mile below sea-level must overcome. The challenge of the cost. The huge engineering demands that having a farm many miles from shore present makes it difficult to be competitive with other forms of energy. As Caldeira says: “This is an industry in its birth stage. It really does look like the open-ocean environment can sustain a lot more power generation than on land. But making these technologies cheap enough to compete will be challenging.”
But there is appetite to try. With Hywind – the world’s first floating farm – starting production this week, with expectations it can power 20,000 homes, Statoil has announced its intention to explore further. Irene Rummelhoff, executive VP of Statoil’s New Energy Solutions says: “Hywind can be used for water depths up to 800 meters, thus opening up areas that so far have been inaccessible for offshore wind. The learnings from Hywind Scotland will pave the way for new global market opportunities for floating offshore wind energy. Through their government’s support to develop the Hywind Scotland project, the UK and Scotland are now at the forefront of the development of this exciting new technology.”
There is no doubt that this is a thrilling time to work in this field. We are itching to see what comes next.