These high-penetration levels have put enormous pressure on the electric grid and created considerable doubts about the ability to interconnect more variable resources with the grid safely.
Of course, more distributed generators contributing variable renewable energy to the grid means an increasing challenge to regulate the consistency of supply and demand.
The subsea power grid encompass pumps and compressors and large variable speed drives to transport the oil and gas from the wellhead to a processing facility.
That they are not including the cost of connecting wind power to the grid, the necessary costs of dealing with variable supply, of needed back up and so on.
While this is the most widely discussed issue associated with variable resources like wind and solar energy, there are many other problems they can create for grid operators.