Renew Extra Weekly

This interesting paper, by a team of North American and Chinese academics, says that ‘extended and unexpected periods of extremely low wind and solar resources (i.e., wind and solar droughts) pose a threat to reliability’ and it adds that ‘the challenge is further exacerbated if shortages of the two occur simultaneously or if they affect neighboring grids simultaneously’.  It propose three metrics to comprehensively assess renewable energy quality: resource availability, variability, and extremeness.  The paper, published in Nature, says that in China and many other countries, the resource availability ‘has traditionally been the decisive metric for renewable energy project development.’ But  renewable availability can and does also vary over time, so ‘variability’ is a second key metric. And extreme wind and solar ‘droughts’ can sometimes coincide locally. So it also proposes a third metric, ‘extremeness’.  Based on its mapping of China, it says that ‘at many sites...