By Paul Homewood
John Cullen left this comment yesterday, on the post about energy storage:
I fear that even Net Zero Watch (NZW) have underestimated the problem of wind droughts. Think, for example, of the year 1976 in the UK when there was a 16 week dry spell / heat wave due to a high pressure area dominating most of Europe during the summer months. Such high-pressure areas are typically associated with light winds (dunkelflauten).
https://en.wikipedia.org/wiki/1976_British_Isles_heatwave
https://en.wikipedia.org/wiki/1976_European_heatwaveAs an electrical engineer I would use, in an area of imperfect knowledge, a safety factor of at least 50%. However, in a safety critical case such as the electricity grid, my initial plan would be to use a safety factor of 100%. Thus if we have already had 16 week wind droughts in the relatively recent past then I would be looking for reliable storage capacity of roughly 2 x 16 weeks i.e. about 30 weeks’ storage based upon data from a single very bad year …
However, Lamb [Ref. 1] has shown that, exactly as NZW claim, dunkelflauten can occur in adjacent years thereby significantly exacerbating the size of the energy storage problem. Furthermore, reference 1 shows that the number of days of the UK’s prevailing Westerly winds are very variable in their annual frequency, varying from about 50 to 120 days per year.
Clearly analysis that relies on a single year’s data woefully underestimates the energy storage problem, as will any analysis that does not consider trends in long-term wind variability.
Reference
1. H. H. Lamb, “”Climate, History and the Modern World”, Routledge, 2nd ed., 1995, at pages 53 and 269.
.
John is spot on.
We obviously need plenty of hydrogen storage to see us through potentially weeks of light winds during winter.
But the other side of the coin is the need to have enough surplus wind power during the rest of the year, to produce the hydrogen needed to replenish that store. And as John points out, there are years when average wind speeds are much lower than others. Even in summer, when demand is low and there is usually a surplus or power, that surplus may not be big enough when we get a long heatwave.
The HH Lamb reference from John is actually very scary as far as our energy situation is concerned:
Lamb of course only plots westerly winds, but it is generally the case that these are on average stronger than winds from the south and east, ie from the continent.
Although his chart only runs up to 1979, when he was writing his book, we know that winds have returned to the levels seen in the 1920s to 50s. What Lamb records is closely related to the North Atlantic Oscillation (NAO). This measures the difference in pressure between Icelandic lows and Azores highs. When the difference is greater than normal, it is called a positive NAO. The Met Office describe this:
Winds from the west dominate, bringing with them warm air, while the position of the jet stream enables stronger and more frequent storms to travel across the Atlantic
These support mild, stormy and wet winter conditions in northern Europe and eastern US. Conversely, northern Canada, Greenland and southern Europe are prone to cold and dry winter conditions
https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation
The NOAO in winter has been largely in positive phase since 1980, but the 1960s and 70s were dominated by negative NAOs. This obviously coincides with Lamb’s charts:
https://meteo.plus/nao-index.php
Negative NAOs in winter tend to lead to cold weather as well, so we have a double whammy here- less wind and greater demand. Add in a summer like 1975 and 1976, and we will be in big trouble
via NOT A LOT OF PEOPLE KNOW THAT
January 26, 2024 at 10:54AM
Iowa Climate Science Education 