Is Ocean Wind Power the Key to Efficient Renewable Energy?

New research from Carnegie suggests that generating power in the open ocean is much more effective than land based windfarms. The North Atlantic in particular could be ideal for this type of power generation. The work, undertaken by Carnegie’s Anna Possner and Ken Caldeira, was initially published in Proceedings of the National Academy of Sciences.

Previously it was known that ocean wind speeds were higher over the ocean than over land, and there was the potential to generate a much greater amount of energy there, up to five times more by some estimates. The work by the Carnegie researchers focussed on whether this greater wind speed could be practically tapped to provide the energy.

The energy from wind is originally generated high up in the atmosphere, and is then transported downwards, where the turbines can capture it. Some papers estimate there is a theoretical maximum rate of power that can be captured by land based turbines, which is determined by the rate of energy transfer from the winds in the upper atmosphere.

The Carnegie research investigated whether more energy was transmitted downward over the ocean, than what can be transferred over land. The researchers used sophisticated modelling tools to compare the output of large Kansas wind farms with the potential output from theoretical open ocean windfarms and found that some ocean areas had the potential to generate three times the output of the land based windfarms. 

The research also found that the drag introduced by the wind turbines would not slow the airflow as much as the ones on land do. This is because the North Atlantic ocean introduces large amounts of heat into the atmosphere, especially in winter. This heating causes low pressure systems, which are more efficient at transferring the energy from the upper atmosphere down to a height that it can be captured by turbines. This means that open ocean based windfarms can tap into the energy created at higher levels much more easily than land based windfarms.

There is one drawback, the researchers also found that this effect is seasonal. In the winter, the effect is magnified and the energy potential is enormous. In the summer the effect is less profound, although there is still a huge potential for energy generation from these ocean based windfarms.

The new research is expected to provide a strong incentive to companies that wish to develop technology for open ocean windfarms.

PSD