800 MW max nameplate capacity over 62 turbines, or about 6% of MA's summer generation (as of 2021.) Amazingly, the actual construction only takes a year, including the power lines which I assumed would be the time consuming piece. The next project is a similar 800 MW offshore wind project in CT, which will generate up to 14% of that state's electricity. Here's a list of planned projects in the US, which will total 19,158 MW on the East Coast alone before 2030 [1] assuming they all get built.
The only good news about all these delays is that there is a learning curve: equipment and installation prices are getting cheaper. I would assume that future incremental expansion of these facilities will be cheaper than the initial construction.
[1] https://en.wikipedia.org/wiki/List_of_offshore_wind_farms_in...