We read at RenewEconomy that the Reliability Panel is reviewing the way they rate the reliability of the grid. The Panel operates under the auspices of the Australian Energy Market Commission (AEMC, not to be confused with the Australian Energy Market Operator, AEMO). The reliability of the grid has been a matter of great concern since the closure of Hazelwood power station in 2017 brought us to the point where there is next to no spare capacity in the conventional power system that has always been dominated by coal.

Leaving out a lot of technical detail for the moment, they have woken up to the rising risk of wind droughts. The post goes on…

These risks include [events] such as “dark doldrums”, or “dunkelflaute”, where there are unusually widespread and prolonged reductions of both sunlight and wind, or it could include transmission outages, ageing coal plant failures, or other “acts of God,” or should we say acts of climate change.

Even the very forecasting of “dark doldrums” is complicated by changing weather patterns, which are becoming more extreme and mean that using historic data is not adequate for accurate forecasts.

“The nature of renewable droughts, which require long periods of weather that is similar over time (no wind, no sun), means that the Panel will need chronologically consistent weather and cannot simply over-sample from the more extreme parts of the historic weather distribution,” it notes.

“As such, the panel is considering the need to develop a number of chronologically consistent, weather biased solar, wind and demand adjustments to be applied to existing model inputs.

“That effectively means that the modelling will adjust the period-by-period shape of the demand profiles and solar and wind inputs to reflect a lower solar and wind contribution and rerun the simulations.”

The panel notes that different countries have different measurements and different standards – some defined as loss of load expectation (LOLE), loss of load probability (LOLP), or loss of load hours (LOLH).

LOLE is defined as the expected proportion of time for which the available generation capacity is insufficient to meet demand at least once per day. LOLE is commonly used in Europe, where Ireland targets a LOLE of eight hours per year; France targets three hours per year, and the Netherlands targets four hours per year.

I think that the Reliability Standard needs to be revised to assess how often there will be a break in the continuity of supply of wind and solar power to the grid. In other words, the number of windless or effectively windless nights per annum or per decade when RE, that is wind, solar power and stored RE will break down and the grid will go black unless it is kept up by conventional power (some mix of coal, gas, hydro and nuclear power) that has been kept in reserve to  back up or “firm” the intermittent input from sun and wind.)

The LOLEs at present are applied to grids where there is still a great deal of reliable power in the system so they are only concerned with limited blackouts which sacrifice some consumers for the sake of the grid as a whole.

Wherever there is a seriously diminished supply of reliable power due to the success of net zero policies, then windless nights are a real danger. Britain and Germany have passed that point and we have reached the point where the closure of another coal plant or two will produce a crisis whenever there is a windless or near windless  night.

That is the threat that I tried to convey in the first briefing note that I wrote for the Energy Realists, using the term “choke point” to signal the sudden death nature of choking or drowning where people are completely deprived of oxygen. The comparable situation is deprivation of windpower when it really matters, that is, when the supply of dispatchable or reliable power has been reduced to a critical level that Britain, Germany, Australia and probably some states in the US and elsewhere have reached lately.

There is also the fact that RE can DISPLACE coal power but not REPLACE it.

The RE enthusiasts focus on the high points of RE penetration in South Australia on sunny and windy Sunday afternoons (100%) or the penetration across the NEM on sunny and windy afternoons where it is now routinely near 50% and often approaching 60%. They foster the illusion that our progress towards 100% RE will be sustainable, and on a good afternoon we are over half-way.

To nurture that illusion the AEMO added the Renewable Penetration tag to the Data Dashboard.

In fact we are not being dragged towards net zero by the ever-higher penetration of RE because we are moving towards that destination like a convoy that moves at the speed of the slowest vessel. The “slowest vessel”, the weak link in the chain, the lowest point of a flood levee or a fence is the windless or near windless night

Consequently wind droughts are about to take centre stage in the net zero drama.  The 64,000 dollar question is – how did they escape attention until they are about to crash the system? Spoiler alert, I think the irresponsible authorities in the met bureaux of the world used the wrong metric for “wind resources” namely the average wind velocity.

To be continued.