To get a high-renewable electric grid, build more solar and wind than needed

Realistically, only two renewable energy

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resources are large enough to meet these very high-penetration objectives on the supply side in the U.S.—solar (by far) and wind.

Both, however, are variable resources, driven by weather as well as daily and seasonal cycles. Therefore, they must be "firmed—that is, capable of delivery power on demand—in order to replace fossil resources which can be dispatched as needed. Based on our research, we contend that this firm power transformation is not only possible, it is also affordable—if we stop having old ideas.

One entrenched, and very prevalent, idea—likely a result of historically high renewable energy prices—is that all the power generated by renewable resources must be sold as it is generated. The idea of discarding available wind or solar output is anathema, imposed on power producers when production from these sources exceeds what the grid can accept.

This old idea ignores a fundamental proposition: oversizing and proactively curtailing wind and solar. However counterintuitive, a study our colleagues and we conducted shows that these steps are the key to the least expensive path to an electric grid powered largely by solar and wind.

https://phys.org/news/2019-05-high-renewable-electric-grid-solar-thanneeded.html