It is the bible of modern power system operations, and it will become more and more important as more renewable energy comes online. Understanding the concepts presented in this book is the difference between "why haven't we hit 100% renewables yet?!" and "we need market incentives for inertial ancillary services".
So unstable isn't actually a better name for renewable, because they are different dimensions. Battery research is underway to increase the availability of energy derived from renewable sources.
I'm not sure batteries are the answer on a grid scale. From the grid/market perspective, they're incredibly expensive energy time machines. They also come with their own environmental issues. Batteries make sense if you need to make small islanded systems, or need black start capabilities. If you just want to teleport energy/inertia around I think the answer is old school flywheels, pumped hydro, and synchronous condensers.
The real lowest hanging fruit is industrial demand-side response. I'm actively working on this from the grid side, implementing partial control room scada control of heavy industry for real-time grid balancing. Costs a few engineers some grey hairs, which is a lot cheaper than building grid scale batteries to provide the same end result.
It is the bible of modern power system operations, and it will become more and more important as more renewable energy comes online. Understanding the concepts presented in this book is the difference between "why haven't we hit 100% renewables yet?!" and "we need market incentives for inertial ancillary services".