The US has a huge amount of land with a very good supply of wind, and this has been developed with a large amount of WTs – wind turbines. Iowa has a lot of WTs, but Texas is the WT leader by far, with over 30 Gigawatts of installed WTs. Installing WTs is relatively easy because the area is sparsely populated, with thousands of square miles of federal or state land. The main disadvantage of installing WTs in those areas is the necessity of installing HV transmission lines to the population centers closer to the coasts. Installing offshore WTs would reduce the distances to population centers, but offshore WTs have their own disadvantages. The underwater cables are more expensive than onshore, so some of the advantage of shorter distances are lost. But the biggest disadvantage of offshore is the harsh marine environment means higher installation and maintenance costs. There has to be a special ship used for maintenance and servicing offshore WTs. It’s much easier to service onshore WTs. Plus the onshore WTs can be installed along with large solar farms and share the same power lines. It should also be mentioned that the onshore WTs are not as expensive as offshore, however it takes more onshore WTs to generate the same amount of power.
So someday when the “low hanging fruit” of US onshore WTs have all been picked, then there will be more incentive to install offshore WTs. Then there will be more offshore WTs in the Gulf of Mexico and East Coast of the US. But along the West Coast the WTs have to be floating in deep water, which is more expensive.
https://floodlightnews.org/is-us-offshore-wind-dead-in-the-water-or-just-poised-for-the-next-big-gust/?ref=im-a-reader-newsletter