Offshore wind lulls

Offshore winds are generally stronger and more consistent than onshore winds. However, there are lulls (defined in a recent New York State Reliability Corporation report as wind power output that falls to just 5 to 20% of potential output). The report looked at 21 years of wind data.

Lulls lasting 24 hours or more occur about 30 times per year, with lulls of 48 hours or more happening about seven times annually and lulls of 72 hours or more happening about three times per year.

Wind lulls of up to 86 hours (about three and a half days) with an average of only five percent of potential output were observed at all seven study sites.



In other headline news, the sun does not shine at night, so solar energy is clearly impractical.


Not new news, but I had not come across the 86 hour number before.

If they are going to build massive amounts of offshore wind – NY is planning on 9GW in '35 and 18GW by '50 – then these lulls mean very wide swings in generation. Losing 8GW is a bit like having eight nuclear power plants go off line simultaneously.

I’m not sure what they are planning for backup. Hydro and nuclear are already committed for regular power needs, and renewables are not dispatchable.

That leaves massive amounts of storage, either battery or hydrogen based. The cost for enough batteries to cover several days demand (hundreds of thousands of MWh) would be hundreds of billions of dollars. Hydrogen is still experimental and certainly not on commercial scale. Maybe in the future? They say hope is not a plan.

The New York Climate Action Council put out a scoping plan last December. In it they admit that the state will need energy storage sufficient for “days, weeks, and even longer” to maintain reliability (p253).




50% of New York’s electric power comes from gas. While that is better than coal, certainly, it’s still burning a hydrocarbon to produce electricity. Those plants, which can be started or shut down quickly, could become “the backup”, and the use of the large scale wind be primary, thus reducing carbon emissions, which is the goal.

This is not free. Nobody said it was free.

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Is there some reason they can’t follow the steps outlined in the scoping plan? I mean, isn’t that purpose of coming up with the plan?

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The report mentions that meeting the ambitious goals “presents significant challenges that cannot currently be met by the deployment of these existing technologies.”

“Current studies identify that, even after full deployment of available clean energy technologies, there is a remaining need for 15 GW to 45 GW of zero-emission, dispatchable electricity generation capacity in 2040 to meet demand and maintain reliability, although that gap may change over time depending on forecasted demand.”

And speaking of forecasted demand, they note that “studies show a forecasted need of 111 GW to 124 GW in total generation capacity in 2040 as compared with the current electric system capacity of 37 GW in 2022. This equates to a three-fold increase in generating capacity between now and 2040.”


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However, that’s not their plan. From the report:
“With a supply mix increasingly composed of intermittent generation resources, the grid will face unprecedented challenges to remain resilient to weather events regardless of the location of supply resources. The current system is heavily dependent on existing fossil fueled resources to maintain reliability. To ensure reliability and that generation is available when needed, fossil fuel plants have dual fuel capability utilizing oil as a backup fuel during periods of high gas and electric demand. To replace these units, dispatchable and zero-emission resources will be needed to balance the system and must be significant in capacity, be able to come online quickly, and be flexible enough to meet rapid, steep ramping needs.”

This thread is more about feasibility and reliability than cost. It most definitely is not free. I think a more relevant question remains “Is it too expensive?” Politics and timelines change when the economics change.

From the ‘Headwinds continue’ thread on the METaR board:

“It’s one thing to announce a project, it’s another thing to pay for it,” said power sector analyst Paul Patterson at Glenrock Associates. “The question is how much appetite do states have to raise rates to meet developers demands. The politics can change when people have to pay.”


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The largest offshore wind farm in the US is the Block Island wind farm, but there are several more in various stages of development.

Generation data:

Production from Block Island was 111,195 MWh in 2022. At an installed capacity of 30 MW, this calculates to a 42% capacity factor. This is better than the average on-shore wind farm in the US, but still below 50%. As can be seen in the link directly above, monthly output can be highly variable. The summer months seem to be the lowest output, and the winter months tend to be the highest.

  • Pete

I found a New York poll done by Siena College back in February. They found that 54% would be willing to pay $20 or less per month (per household) to “adhere to the many components of New York’s climate plan”.