Renewables' Achilles heel

After much protest by the climate zealotry fraternity that the Spain /Portugal blackouts at the end of April were caused by unusual atmospheric conditions and were not an ongoing issue with a high proportion of renewables in the electricity grid, everyone has gone shtum. While many knowledgeable analysts at the time pinpointed the cause as the instability caused by fluctuations in the output of renewables in the grid, the zealots rejected that this was a serious concern for renewables. The media has quickly moved on, and once more, the warnings of the experts have been ignored. 

Yet, given the experts' concerns, when intermittent renewables become a significant energy source of the grid, fluctuations in the energy generated will cause a cascade that is very difficult to limit. Sophisticated automated grid management systems operate to ensure that fluctuations in frequency, which would damage the grid, are detected and the offending generators are switched out of the system. 

The cascade occurs when the consequence of switching one generator out of the system, in turn, causes a fluctuation that is transmitted across the next component and so on. It is just this type of process that resulted in all of Spain and all of Portugal having a blackout. Given that Spain's grid is connected to France, why didn't the cascade continue to France? The difference is that France has sufficient non-intermittent nuclear generators that ensure that the fluctuation of losing Spain is relatively small, and gives adequate time to France's grid management system to switch Spain out of its network.

So the Achilles heel of renewables is the fluctuations that occur with changes in solar output due to clouds, or just the natural changes in wind strength. The fluctuations can be handled when renewables are a relatively small proportion of the total power, but become unstable when the grid is majority renewables. 

This is the canary in the renewables coalmine! Countries that have bet the farm on 100% renewables must return to the drawing board.

Australian journalist Chris Uhlmann has followed renewables technology and government policies for some time. He has developed healthy scepticism about current Australian policies. Here is a short video of his interview with John Anderson. It is well worth a view.